[0001] The present invention relates to decentralizing the gear box and semi-automating the gear shifting in commercial vehicles. The present invention particularly relates to a modular control system for automatic controlling of gear shifting in a gear box and a rear axle in the commercial vehicles.
BACKGROUND OF INVENTION
[0002] Commercial vehicles with a single drive axle are generally used for carrying medium to high range of loads. Various configurations of the commercial vehicles are illustrated in figures 1-3. Figure 1(a) shows a schematic view of the commercial vehicle, i.e. 4x2 commercial haulage truck, which has a steerable front axle (1) and a single live rear axle (2) (where 4x2 configuration represents the number of wheels in the commercial vehicle). Also, a 6 x 2 commercial haulage truck represented in figure 1(b), is composed of a steerable front axle (1) along with two rear axles (2, 3), i.e. one live rear axle (2) and one dead rear axle (3), whereas a 6 x 2 commercial haulage truck represented in figure 2(a), is composed of two steerable front axle (1) along with a single live rear axle (2). Similarly, a 8 x 2 commercial haulage truck represented in figure 2(b), is provided with two steerable front axles (1) along with two rear axles (2, 3), i.e. one live rear axle (2) and one dead rear axle (3), whereas a 10 x 2 commercial haulage truck represented in figure 3(a), is provided with two steerable front axles (1) along with three rear axles (2, 3), i.e. one live rear axle (2) and two dead rear axles (3). Further, a 4 x 2 commercial tractor-trailer truck represented in figure 3(b), is provided with a steerable front axle (1) and a single live rear axle (2). The vehicles are powered and driven by an engine (91), as shown in figure 4 illustrating an exemplary automotive diesel engine (91). The engine (91) is a power source for generating power by converting chemical energy into heat energy and heat energy into mechanical energy, where the power generated in the engine (91)

is transmitted to the rear drive axle through a vehicle transmission system. These vehicles are mostly used by fleet owners to transport goods like parcel/courier/cold chain products to the end customer and often return empty to the yard. In general, any vehicle with the load on its top requires a greater torque to move as the inertia is high, where the forward motion requires more torque in the case of transporting the heavy goods.
[0003] The engine (91) is coupled to gear boxes (also called as transmission unit) by means of clutch or clutch disc (5), as shown in figure 5(a), which illustrates a flywheel, clutch and cover assembly of the commercial vehicle. The clutch (5) enables to crank and start the engine (91) by disengaging the transmission, and also disengages the transmission while changing the gears to enable smooth power transmission. A flywheel (4) is an energy storing device connected to one end of a crankshaft of the vehicle for storing energy during the power stroke of the engine (91) and releasing the energy during the remaining strokes. The flywheel (4) helps to transmit the power from the engine (91) to the transmission system through the clutch disc (5). The face of the flywheel (4) is made of iron and is precision machined to a smooth surface. The clutch disc (5) is clamped and held against the flywheel (4) by the spring action of the pressure plate (8), where the pressure plate (8) bolts to the face of the flywheel (4).
[0004] In the figure 5 (a), the pressure plate (8) is a spring-loaded device that makes the clutch disc to engage or disengage with the flywheel (4). The clutch disc (5) is placed between the flywheel (4) and the pressure plate (8). During clutch operation, the pressure plate (8) moves back and forth inside the clutch cover assembly (6). The release levers are hinged inside the pressure plate (8) moving the pressure plate (8) face away from the clutch disc (5) and the flywheel (4).
[0005] In the figure 5(a), the clutch disc (5) consists of a splined hub and a round metal plate covered with friction material (lining). The splines in the center of the clutch disc (5) mesh with the splines on the input shaft of the transmission unit, which makes the input shaft and the clutch disc (5), turn together. However, the clutch

disc (5) is free to slide back and forth on the shaft. The clutch disc (5) is loaded with torsion springs, also termed damping springs, which absorb some of vibration and shock produced during clutch engagement. These torsion springs are small coil springs located between the clutch disc splined hub and the friction disc assembly.
[0006] When the clutch is engaged, the pressure plate (8) jams the stationary clutch disc (5) against the spinning flywheel (4). The torsion springs compress and soften as the clutch disc (5) first begins to turn with the flywheel (4). Clutch disc facing springs, also called cushioning springs, are flat metal springs located under the friction lining of the clutch disc (5), where these springs have a slight wave or curve, allowing the lining to flex inward slightly during initial engagement, which also allows for smooth engagement. Clutch disc friction material, also called disc lining or facing, is made of heat resistant asbestos, cotton fibers, and copper wires woven or molded together. Grooves are cut into the friction material to aid cooling and release of the clutch disc (5), and rivets are used to bond the friction material to both sides of the metal body of the clutch disc.
[0007] In the clutch operation, when the driver presses the clutch pedal (10), a clutch actuation or release mechanism pulls or pushes on a clutch release fork (11). The fork (11) moves a release bearing (15) into the center of the pressure plate (8) thru clutch diaphragm spring (7), causing the pressure plate (8) to pull away from the clutch disc (5) releasing the disc from the flywheel (4). The engine crankshaft can then turn without rotating the clutch disc (5) and the transmission input shaft. When the driver releases the clutch pedal (10), the spring pressure inside the pressure plate (8) pushes forward on the clutch disc (5), which locks the flywheel (4), the clutch disc (5), the pressure plate (8), and the transmission input shaft together. The engine (91) again rotates the transmission input shaft, the transmission gears, the drive train, and the wheels of the vehicle.
[0008] Further, the clutch actuation mechanism allows the driver to operate the clutch, where this clutch actuation mechanism is classified into a cable type clutch actuation mechanism and a hydraulic type clutch actuation mechanism. Generally, it

consists of the clutch pedal assembly, a mechanical linkage, a cable or hydraulic circuit, and the clutch fork (11). Figure 5(b) illustrates the cable type clutch actuation mechanism of the commercial vehicle, where this mechanism uses a steel cable (9) inside a flexible housing to transfer the clutch pedal (10) movement to the clutch fork (11). As shown in Figure 5(b), the cable (10) is usually fastened to the upper end of the clutch pedal (10), where the other end of the cable is connected to the clutch fork (11). The cable housing (9) is mounted in a stationary position, which allows the cable to slide inside the housing whenever the clutch pedal (10) is moved, where one end of the clutch cable housing (9) has a threaded sleeve for clutch adjustment.
[0009] Figure 6(a) illustrates the hydraulic type clutch actuation mechanism of the commercial vehicle, where this mechanism uses a simple hydraulic circuit to transfer the clutch pedal (10) movement to the clutch fork (11). It has three basic parts, i.e. a master cylinder (12), hydraulic lines (13), and a slave cylinder (14), where the movement of the clutch pedal (10) creates hydraulic pressure in the master cylinder (12), which actuates the slave cylinder (14) to move the clutch fork (11). As shown in figure 6(a), the master cylinder (12) acts as a controlling cylinder to develop the hydraulic pressure in the clutch system, whereas the slave cylinder (14) acts as an operating cylinder actuated by the pressure created by the master cylinder (12).
[0010] As shown in figure 6(a), the clutch fork (11) transfers motion from the release mechanism to the release bearing (15) and the pressure plate (8). The clutch fork (11) sticks through a square hole (16) in a clutch housing (92), as shown in figure 6(b), and mounts on a pivot. When the clutch fork (11) is moved by the release mechanism, it pries on the release bearing (15) to disengage the clutch (5) thru clutch diaphragm spring (7). As shown in figure 6(a), the release bearing (15) is a ball bearing and collar assembly, which snaps over the end of the clutch fork (11), where small spring clips hold the bearing (15) on the fork (11). The release bearing (15) reduces friction between the clutch diaphragm spring (7) and the release fork (11). The release bearing (15) is a sealed unit pack with a lubricant. It slides on a hub sleeve extending out from the front of the manual transmission, as shown in figure 7(a) and is moved by either hydraulic or manual (cable) pressure. Then, the clutch fork (11)

movement in either direction slides the release bearing (15) along the transmission hub sleeve.
[0011] Figure 6(b) illustrates a schematic view of the clutch housing (92) of the commercial vehicle. The clutch housing (92) enclosed with the clutch assembly is bolted to the rear side of the engine (91), where the transmission unit is bolted to the back side of the clutch housing (92). The lower front of the clutch housing (92) is formed of a metal cover that can be removed for flywheel ring gear inspection or for separating the engine (91) from the clutch assembly. A hole is provided in the side of the housing for the clutch fork (11). This clutch housing (92) can be made of aluminum, magnesium, or cast iron.
[0012] Figure 7(a) illustrates a schematic view of the manual transmission unit (gear box) (93) of the commercial vehicle, where this gear box (93) is a manual transmission unit. In general, the vehicles require high torque when climbing hills and when starting, even though they are performed at low speeds. On other hand, when running at high speeds on level roads, the high torque is not required because of momentum. Hence, there is a need for a system to change the vehicle's torque and its speed according to road and load conditions or as per the driver's requirements. This gear box (93) is a second element of the power train in the automobile, and is used to change the speed and torque of the vehicle according to variety of road and load conditions. The gear box (93) provides an effective medium to operate the engine (91) in a most economical zone across the terrain and vehicle operating condition. Many vehicles have multiple forward gear ratios based on its design and configuration. Figure 7 (b) illustrates a typical layout of the manual transmission unit (93) with gear changing mechanism, i.e. change speed operation (CSO) of gear shifting mechanism. It consists of a gear shift knob (17) that is connected to two cables through a shift lever mechanism (18), where a shift cable (19) is used to shift the gears and a select cable (20) is used for gear selection.
[0013] Figure 8(a) illustrates a schematic view of the rear drive/live axle (94) of the commercial vehicle. The axles (94) are classified into either a drive/live axle (2)
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used to transmit power or a dead axle (3) serving only as a support for load and having no power transmission to the wheels. The half shaft in the drive axle (94) assembly drives the wheels connected to it, where the rear drive axle (94) is connected to the transmission system through its differential unit (98) or assembly and a propeller shaft (95)as shown in figures 8(b), which illustrates a schematic view of the propeller shaft (95) of the commercial vehicle. In automobile, the gear box (93) is rigidly mounted to the engine (91). But due to undulation in the road, the rear axle (94) keeps moving with respect to the chassis, so that the relative motion between the chassis and the rear axle (94) is taken care with the help of this propeller shaft (95) having two universal joints on each end. The propeller shaft (95) transmits the torque in addition to controlling of the relative motion between the chassis and the rear axle (94).
[0014] The differential assembly in a rear-wheel drive vehicle has three functions, i.e. first essential function is to redirect the power flow from the propeller shaft (95) to the wheels. The power flow has to make a 90° turn between the drive shaft assembly and the rear wheels, which is accomplished in the differential assembly by the drive pinion and ring gears. The second function of the differential assembly is to multiply engine power by reducing speed at the output in the process. If there is no gear reduction (1:1 gear ratio), the vehicle accelerates very slowly. In some cases, the engine (91) can unable to move the vehicle. At the very least, mileage is harmed, since the engine (91) has not reaching its most efficient rpm range. For these reasons, the ring and drive pinion assembly is so designed to provide a reduced speed at its output. Finally, the third function of the differential assembly is to allow the vehicle to make smooth turns. If the differential assembly does not make allowances for the different speeds of the rear wheels during turns, at least one of the tires can lose traction with the ground as the vehicle turned corners.
[0015] Generally, manufacturers install a rear axle ratio that provides a compromise between performance and economy. If the axle ratio is more, then it increases acceleration and pulling power but decreases fuel economy, since the engine (91) has to run at a higher rpm to maintain an equal cruising speed. If the axle ratio is

less, then it reduces acceleration and pulling power but increases fuel mileage, since the engine (91) has to run at a lower rpm while it is used to supplement the gearing of other drive train components and is used in vehicles with a single drive axle. The operator can manually select the range or speed of this axle with a button on the shifting lever of the transmission unit or by a lever through linkage.
[0016] In order to generate more torque, gear boxes can multiply the torque based on the gear ratio adopted in the vehicle. In the vehicle, the gear ratios are changed in two places, i.e. one at the gearbox and other at the drive axle (which is a constant ratio). The driver can manually vary the gear ratio at the gear box (93) through the gear control provided in a driver cabin. In these goods carrying vehicles, the high torque is required only when the vehicle is in a loaded condition, whereas the high torque is no longer required when the vehicle is in an unloaded condition, i.e. when the vehicle is returning empty. In the empty condition, these vehicles require high speed to bring the engine (91) to its more economical zone, and thus provide higher mileage.
[0017] In present, these commercial vehicles are provided with a twin speed rear axle to increase the speed. The twin speed rear axle has two gear ratios namely deeper ratio and shallow ratio in comparison with the traditional axles having only one gear ratio. The gear in deeper axle ratio provides higher torque and low vehicle speed, which is capable of carrying the load, whereas the gear in shallow axle ratio provides lower torque and high vehicle speed, which is capable for the empty vehicle.
[0018] The twin speed rear axle is arranged with a crown wheel (26) with inner teeth, where four planetary gears are mounted on a differential casing and arranged to engage with the inner teeth of the crown wheel. Also, a sun gear shaft is mounted with differential casing for changing the axle ratio. A lever (24) is used to move the sun gear shaft in forward and reverse directions, such that the sun gear shaft makes the planetary gears to come into action. One end of the lever (24) is connected to the sun gear shaft and another end is connected with a vehicle gear shifter unit. The rotation of sun gear shaft can be locked or unlocked by a clutch plate (25).

[0019] At default condition, the rear axle is set at the deeper ratio, i.e. the sun gear shaft is locked by the clutch plate
[0020] Clutch plate(25) and the planetary gears moves around the shaft, where the gear reduction can achieve higher rear axle ratio. The rear axle can be shifted from the deeper to shallow ratio or vice versa by just not pressing the accelerator pedal (27) and manually pressing an actuation button of the twin speed rear axle in the driver cabin, which energizes a solenoid (39) in the shifter unit to actuate the lever (24). This results in the sun gear shaft sliding along the planetary gears in the rear axle to change the rear axle ratio from the deeper to shallow. By switching off the actuation button, the twin speed rear axle can be changed to the deeper ratio from the shallow ratio.
[0021] In the conventional approaches, the axle ratio shifting in the twin speed rear axle is predefined at the manufacturer end, which leads to a lot of failures in the axle ratio shifting in the real time vehicle running condition. It is mainly attributed to due to the shifting operation carried out without decoupling the engine (91) or the wheel and due to unawareness of the driver about the shifting operation procedure and the implication of the ratio.
[0022] On the other hand, for better fuel economy, the vehicle is always run at the shallow ratio in which the torque is not enough to move the vehicle when it is in fully loaded condition. In particular, while carrying heavy loads in the vehicle, the vehicle running in the shallow ratio can encounter gradient and traction effort on the drive axle, which is not enough to move the vehicle. During this condition, the driver manually changes from the shallow to deeper ratio, which creates torque interruption leading to an impact loading on the gears and thus results in failure and damages to parts of the gear box (93) and the drive axle in the vehicle. It also degrades the life time of the gear box (93) and the drive axle of the vehicle. Thus, conventionally there is no system to control the gear shifting in both the gear box (93) and the rear drive axle, which can overcome the above mentioned drawbacks and disadvantages.

[0023] Therefore, it is necessary to provide a simple modular gear shift control system which is capable of determining the vehicle parameters and automatically controlling the gear shifting in the drive axle without any control of the axle shift to the driver in order to reduce the probability of failures and damages.
OBJECTIVE OF THE INVENTION
[0024] A primary objective of the present invention is to provide a modular control system, which is capable of achieving automatic controlling of gear shifting in a gear box and shifting the twin speed rear axle between deeper and shallow gear ratios based on driver inputs.
[0025] Another objective of the present invention is to provide a modular control system, which is capable of achieving smooth and effortless gear shifting, and effortless clutch operation.
[0026] Another objective of the present invention is to provide a modular control system, which eliminates twin speed rear axle failures, gear shift linkage failures, gear failures, and clutch linkage failures.
[0027] A further objective of the present invention is to provide a modular control system, which facilitates modularity in vehicle powertrain to achieve different combinations of reduction ratios.
[0028] A further objective of the present invention is to provide a modular control system, which is simple, low cost and easily diagnosable with minimal maintenance during its lifetime.
[0029] A further objective of the present invention is to provide a modular control system, which reduces driver fatigue and provides high reliability and better fuel economy for the vehicle.

[0030] A further objective of the present invention is to provide a modular control system, which increases clutch and gear life, vehicle gradability (traction effort) and vehicle drivability.
[0031] A further objective of the present invention is to provide a modular control system, which minimizes the battery load while cranking the vehicle.
[0032] A further objective of the present invention is to provide a modular control system, which is cost beneficial and increases the productivity of the manufacturing unit by eliminating the need for clutch hydraulic system and its maintenance, number of parts of complex clutch sub assembly and number of variants of gear box.
SUMMARY OF THE INVENTION
[0033] According to the embodiment of the present invention to achieve the
objective of the invention, a control system is provided for automatic controlling of
gear shifting in a gear box and a rear axle in a commercial vehicle. The system
comprises an electronic paddle shifter having a gear shift knob for upward, downward
and reverse shifting one or more gears in the gear box. A pneumatic clutch actuator is
mounted on the gear box and associated with an electronic clutch pedal mounted on a
driver cabin to engage and disengage a clutch from a vehicle engine. A XY actuator is
assembled with a gear shifter section and a gate selector section for gear shifting and
gate selection on the gear box. A rear axle shifter unit is assembled with an axle
actuator in the rear axle, where the rear axle is a twin speed drive rear axle. A plurality
of sensors each is coupled with the clutch pedal, the clutch actuator, the gear shifter
section, the gate selector section, the rear axle and an accelerator pedal in the vehicle.
A gear shift control unit is electrically connected to each of the sensors to
simultaneously determine the position of the clutch pedal, the clutch actuator, the
accelerator pedal, the gear shifter section, the gate selector section and the rear axle.
The control unit is operatively connected to automatically shift and control the
operation of gears on the gear box and at the rear axle based on the determined
11

positions from each sensor and a gear shift pattern predefined with respect to vehicle configuration, road and load conditions. Thus, this control system is capable of achieving automatic and simultaneous controlling of gear shifting in both the gear box and the twin speed rear axle, which smoothens gear shifting and clutch operation as well as reduces impact loading of the transmission system.
[0034] Further, the predefined gear shift pattern is composed of gear shifting at the gear box or gear shifting at the rear axle or both. The XY actuator, the pneumatic clutch actuator and the rear axle actuator are monitored and controlled by the control unit. The gear shifter section of the XY actuator is coupled with a plurality of direction control valves connected to a main pressure line such that the gear shifter section moves the gear from neutral position into multiple gear positions. The gear positions are arranged in a shifting pattern from neutral position to even gear positions (reverse, second, fourth and sixth) or from neutral to odd gear positions (first, third and fifth). The gate selector section of the XY actuator is coupled with a plurality of direction control valves connected to the main pressure line such that the gate selector section moves the gear selection gate from one end to another.
[0035] The pneumatic clutch actuator is coupled with a plurality of direction control valves connected to the main pressure line for engaging and disengaging the clutch from the vehicle engine by moving the clutch actuator from one end to another. The rear axle actuator is coupled with at least one direction control valve to actuate the rear axle between deeper and shallow ratio positions. The gear shift knob is composed of an up-shift and down-shift switches with a gear light indicator, a neutral switch with a neutral light indicator, and a reverse gear shift switch with a reverse light indicator.
[0036] After switch-on, the control unit actuates the XY actuator and the rear axle shifter unit to control the gear box into the neutral position and the rear axle into the deeper ratio position. The control unit determines and allows the engine to crank only when each of the position sensors sense that the clutch pedal is fully pressed, the clutch is fully disengaged, the accelerator pedal is completely released, the neutral
1 r
position in the gear box and the rear axle in the deeper ratio position. The plurality of sensors determines that the clutch pedal is fully pressed, the clutch is fully disengaged and the gear shift knob is shifted, such that the control unit actuates the direction control valves in the pneumatic clutch actuator and the XY actuator to disengage the clutch and simultaneously shift the gear into the first gear position by moving the gear selection gate at 1/2 neutral point and maintaining the rear axle in the deeper ratio position.
[0037] While releasing the clutch pedal, the control unit simultaneously actuates the direction control valves in the pneumatic clutch actuator in order to engage the clutch with the engine to move the vehicle in the first gear position with the deeper ratio position. When the gear shift knob is further shifted, the control unit maintains the first or subsequent gear position in the gear box and energizes the direction control valve in the rear axle actuator to shift the rear axle from the deeper ratio position to the shallow ratio position and vice versa. When the gear shift knob is shifted subsequently, the control unit energizes the direction control valve in the gear shifter section to shift the gear into the second or subsequent gear positions in the gear box and simultaneously de-energizes the direction control valve in the rear axle actuator to shift the rear axle from the shallow ratio position to the deeper ratio position and vice versa.
[0038] When the clutch pedal and the neutral switch are pressed, the control unit actuates the direction control valves in the pneumatic clutch actuator and the XY actuator to disengage the clutch and simultaneously shift the gear into the neutral position in the gear box by moving the gear selection gate at 3/4 neutral point and maintaining the rear axle in the deeper ratio position. When the clutch pedal and the reverse switch are pressed, the control unit actuates the direction control valves in the pneumatic clutch actuator and the XY actuator to disengage the clutch and simultaneously shift the gear into the reverse gear position in the gear box by moving the gear selection gate at R neutral point and maintaining the rear axle in the deeper ratio position.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
[0039] The objects and advantages of the present invention will appear herein after as this specification progresses, reference being had to the accompanying drawings, in which:
[0040] FIG. 1(a) shows a schematic view of a 4 x 2 commercial haulage track with a steerable front axle and a single rear axle, in accordance with the prior art;
[0041] FIG. 1(b) shows a schematic view of a 6 x 2 commercial haulage truck with a steerable front axle and two rear axles, in accordance with the prior art;
[0042] FIG. 2(a) shows a schematic view of a 6 x 2 commercial haulage truck with two steerable front axles and a single rear axle, in accordance with the prior art;
[0043] FIG. 2(b) shows a schematic view of a 8 x 2 commercial haulage truck with two steerable front axles and two rear axles, in accordance with the prior art;
[0044] FIG. 3(a) shows a schematic view of a 10 x 2 commercial haulage truck with two steerable front axles and three rear axles, in accordance with the prior art;
[0045] FIG. 3(b) shows a schematic view of a 4 x 2 commercial tractor-trailer truck with a steerable front axle and a single rear axle, in accordance with the prior art;
[0046] FIG. 4 shows a schematic view of an exemplary automotive diesel engine, in accordance with the prior art;
[0047] FIG. 5(a) illustrates a flywheel, clutch and cover assembly of the commercial vehicle, in accordance with the prior art;
[0048] FIG. 5(b) illustrates a cable type clutch actuation mechanism of the commercial vehicle, in accordance with the prior art;

[0049] FIG. 6(a) illustrates a hydraulic type clutch actuation mechanism of the commercial vehicle, in accordance with the prior art;
[0050] FIG. 6(b) illustrates a schematic view of a clutch housing of the commercial vehicle, in accordance with the prior art;
[0051] FIG. 7(a) illustrates a schematic view of a manual transmission unit (gear box) of the commercial vehicle, in accordance with the prior art;
[0052] FIG. 7 (b) illustrates a typical layout of the manual transmission unit with gear changing mechanism, in accordance with the prior art;
[0053] FIG. 8(a) illustrates a schematic view of a rear drive/live axle of the commercial vehicle, in accordance with the prior art;
[0054] FIG. 8(b) illustrates a schematic view of a propeller shaft of the commercial vehicle, in accordance with the prior art;
[0055] FIG. 9 illustrates a schematic view of an automated manual transmission unit (gear box) of the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0056] FIG. 10(a) illustrates a schematic view of a twin speed rear axle of the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0057] FIG. 10(b) illustrates a detailed view of a twin speed rear differential unit, in accordance with an exemplary embodiment of the present invention.
[0058] FIG. 11(a) illustrates an operating procedure of the twin speed rear axle in the commercial vehicle, in accordance with an exemplary embodiment of the present invention.

[0059] FIG. 11(b) illustrates a general operating circuit of the twin speed rear axle in the commercial vehicle, in accordance with a present condition prior to the present invention.
[0060] FIG. 12(a) illustrates a detailed view of an electronic clutch pedal in the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0061] FIG. 12(b) illustrates a detailed view of an electronic paddle shifter in the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0062] FIG. 13(a) illustrates a detailed view of a pneumatic clutch actuator (PCA) in the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0063] FIG. 13(b) illustrates a detailed view of a XY actuator in the commercial vehicle, in accordance with an exemplary embodiment of the present invention.
[0064] FIG. 14 illustrates an overall block diagram of a gear shift control unit, in accordance with an exemplary embodiment of the present invention.
[0065] FIG. 15 illustrates an electrical and pneumatic control circuit of the XY actuator, the pneumatic clutch actuator and the rear axle actuator, in accordance with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0066] The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.

[0067] In the following, numerous specific details are set forth to provide a thorough description of various embodiments. Certain embodiments may be practiced without these specific details or with some variations in detail. In some instances, certain features are described in less detail so as not to obscure other aspects. The level of detail associated with each of the elements or features should not be construed to qualify the novelty or importance of one feature over the others.
[0068] The claimed subject matter has been provided here with reference to one or more features or embodiments. Those skilled in the art will recognize and appreciate that, despite of the detailed nature of the exemplary embodiments provided here; changes and modifications may be applied to said embodiments without limiting or departing from the generally intended scope. These and various other adaptations and combinations of the embodiments provided here are within the scope of the disclosed subject matter as defined by the claims and their full set of equivalents. Like numbers refer to like elements throughout.
[0069] The present invention of the modular control system is used for automatic controlling of gear shifting in a gear box and a rear drive axle in a commercial vehicle, where the rear drive axle used in this invention is a twin speed rear drive axle (TSRA). The present invention of the modular control system is operated by means of various components in the powertrain such as engine, clutch system with actuation of clutch through a pneumatic clutch actuator (PCA) and a zero-load electronic clutch pedal (acts as a switch), electronic accelerator pedal, electronic paddle shifter unit (acts as a gear shifter), gear box with a XY actuator (XY pneumatic shifter unit) and twin speed rear axle (TSRA). The present invention can be incorporated across the range of heavy commercial vehicle from 9T-49T (vehicle with single drive axle), i.e. can be implemented in any commercial vehicles, which is exemplarily represented in figures 1-3. This modular control system is electrically connected and operatively coupled to an automated gear box system (automated manual transmission unit) through a clutch mechanism and to the twin speed rear axle

that is connected to the automated gear box system through a propeller shaft (existing), which provides multiple ratios to select to achieve various objectives of the present invention.
[0070] The present invention mainly focuses on improving the efficiency of the truck through a stepped drive system and also reduces the driver fatigue by providing a zero-load clutch and a zero-load paddle shifter. In particular, with reference to the manual operation of clutch, accelerator and gear knob by the driver, the modular control system automatically determines and controls the shifting operation of gears on the gear box as well as at the rear axle with the help of a gear shift pattern predefined with respect to vehicle configuration, road and load conditions. Thus, it is capable of achieving automatic controlling of gear shifting in the gear box and shifting the twin speed rear axle between deeper and shallow gear ratios based on driver inputs. Hence, the driver can more focus on the driving to increase safety. Further, the gear shift control system provides multiple combinations of gears and shift patterns, which can be predefined based on vehicle load, road and vehicle configurations. This system can provide most optimal transmission configuration for the vehicle operation, and also enables alteration of gear shift patterns by resetting once again based on different load, road and vehicle configurations.
[0071] Referring to figure 9, a schematic view of the automated manual transmission unit (gear box) (96) of the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. It is designed as a manual transmission unit in which a gear shifting tower is replaced with an automated pneumatic XY actuator (83), as shown in figure 13(b). The automated manual transmission (96) is designed to match the load requirements of the vehicle to the power and speed range of the engine (91) by operating automatically depending on throttle position, vehicle speed, and the position of the control lever. The driver or operator control is limited to the selection of the gear range by moving a control lever. The automatic manual transmission (96) is coupled to the engine (91) through a clutch assembly. The clutch assembly is operated by a pneumatic clutch actuator (PCA) (82)

as shown in figure 13(a) with an automatic control system without any manual disengagement by the operator each time while stopping the vehicle.
[0072] In the present automotive power transmission system, the power developed in vehicle engine (91) is transmitted to the rear axle through the clutch mechanism, the gear box (96) and the propeller shaft (95). The engine power is first transmitted to the gear box (96) through the clutch mechanism which consists of a flywheel (4), a clutch or clutch disc (5) and a clutch cover assembly (6). Please note that same reference numerals for some of the existing components of the vehicle illustrated figures 1-8 described the background of the invention are also used and referred in the description only for the purpose of clarity and better understanding of the present invention. Internal splines of the clutch disc (5) are connected to external splines in an input shaft of the gear box (96). The torque multiplication and output takes place in the gear box (96), which is transmitted to the propeller shaft (95) through a gear box (96) output flange. Since other end of the propeller shaft (95) is connected to a differential unit (98) of the twin speed rear axle (TSRA) as shown in figures 10(a) and 10(b), the propeller shaft (95) transfers the power to the TSRA, which drives the wheels to move the vehicle.
[0073] Referring to figure 10(a), a schematic view of the twin speed rear axle (97) of the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. The twin speed rear axle (TSRA) (97) consists of a differential unit (98), half axles and a brake chamber, where the detailed view of the twin speed rear differential unit (98) is illustrated in figure 10(b). The differential unit (98) redoubles the number of gear ratios available for driving the vehicle under various load and road conditions. This differential unit (98) provides a gear ratio high enough to permit pulling a heavy load up steep grades and a low ratio to permit the vehicle to run at high speeds with a light load or no load. The conventional spiral bevel pinion and ring gear drives the two-speed unit, but a planetary gear train is placed between the differential drive ring gear and the differential case. The internal gear of the planetary gear train is bolted rigidly to the bevel drive gear. A ring, on

which the planetary gears are pivoted, is bolted to the differential case. A member consisting of the sun gear and a dog clutch slides on one of the axle shafts and is controlled through a button or lever accessible to the operator.
[0074] When the axle is shifted into high range (deeper ratio), the sun gear meshes with the internal teeth on the ring carrying the planetary gears and disengages the dog clutch from the left bearing adjusting ring, which is rigidly held in the differential carrier. In this position, the planetary gear train is locked together. There is no relative motion between the differential case and the gears in the planetary drive train. The differential ring gear directly drives the differential case, i.e. the twin speed rear axle (97) acts as like the single fixed gear rear drive axle. When the axle is shifted into low range (shallow ratio), the sun gear is slid out of mesh with the ring carrying the planetary gears. The dog clutch makes a rigid connection with the left bearing adjusting ring. Because the sun gear is integral with the dog clutch, it is also locked to the bearing adjusting rings and remains stationary. The internal gear rotates the planetary gears around the stationary sun gear, and the differential case is driven by the ring on which double-reduction final drive, where the planetary gears are pivoted. This action produces gear reduction or low speed of the axle.
[0075] Referring to figure 11(a), an operating procedure of the twin speed rear axle (97) in the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. The twin speed rear axle (97) (TSRA) is manually operated by the driver by releasing an accelerator pedal (27) and pulling an actuation switch (28) upward, where the TSRA actuation switch is mounted on a vehicle dash board for driver access and is provided with a rear axle shifter unit (34) that is assembled with an axle actuator (85) in the rear axle (97). At that time, a solenoid (39) in the shifter unit (34) is energized and pressurized air from a reservoir (32) is directed to the shifter unit (34) by a direction control valve (33) thru pneumatic connector (22) mounted on the TSRA (97). Then, the pressurized air pushes the shifter unit (34) in the TSRA (97) to change the axle ratio from deeper to shallow, which reduces torque and increases speed to the wheels. In order to shift the axle ratio from

shallow to deeper, the same procedure is followed by pushing the actuation switch (28) downward by the driver instead of pulling the actuation switch (28) upward.
[0076] Referring to figure 11(b), a general operating circuit of the twin speed rear axle (97) in the commercial vehicle is illustrated in accordance with a present condition prior to the present invention. This TSRA operating circuit depicts a schematic of electrical and pneumatic control system for shifting the axle ratio between deeper and shallow of the TSRA. It consists of a battery (29) which is a power source for all controls and indicators, where one power line from the battery passes and reaches a sensor (35) of the shifter unit (34) in the TSRA through a fuse (41), an indicator light (40) and an odometer (37) at line (36). Another power line from the battery (29) is connected in series to the fuse (41) and the TSRA actuation switch (28). The output of the TSRA actuation switch (28) is connected to the solenoid (39) of the pneumatic direction control valve (33). The compressed air from the reservoir (32) is connected to the pneumatic direction control valve (33), where output of the valve (33) is connected to the shifter unit (34) in the TSRA through a quick release valve (31) via a pipe line (30).
[0077] Referring to figure 12(a), a detailed view of an electronic clutch pedal (10) in the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. The electronic clutch pedal (10) is mounted on a driver cabin and assembled with one or more clutch pedal position sensors (59), preferably two position sensors (59) to provide good redundancy. The clutch pedal position sensor (59) is placed at the bottom side of the clutch pedal (10). The sensor (59) senses present position of the clutch pedal (10) and transmits the signal to a control unit (84) (micro controller) as shown in figure 14, where these sensors (59) can provide an analogue output of0.5Vto5.0VDC with respect to the clutch pedal (10) position to the control unit (84).
[0078] Referring to figure 12(b), a detailed view of an electronic paddle shifter (81) in the commercial vehicle is illustrated in accordance with an exemplary

embodiment of the present invention. The electronic paddle shifter (81) is used to shift the gears in the gear box (96). The electronic paddle shifter (81) has a gear shift knob for upward, downward and reverse shifting the gears in the gear box (96). The gear shift knob is composed of a forward or up-shift switch (43), a lower or down-shift switch (60), a neutral switch (42) and a reverse gear shift switch (44). The gear shift knob is used to shift the gear either high or low using the forward switch (43) and the lower switch (60) to move the vehicle in forward direction with different torque and speed variations.
[0079] Further, the neutral switch (42) is actuated and operated to keep the gear at neutral point in the gear box (96) to keep the vehicle in idle, whereas the reverse gear shift switch (44) is operated for reverse gear shifting to move the vehicle in reverse direction. The electronic paddle shifter (81) is also provided with a gear light indicator (47) connected to the forward and lower switches (43, 60), a neutral light indicator (45) connected to the neutral switch (42), and a reverse light indicator (46) connected to the reverse gear shift switch (44). The gear light indicator (47), the neutral light indicator (45) and the reverse light indicator (46) are activated and lightened to indicate the operation of respective switches in the gear shift knob. All the switches and light indicators are electrically connected to and controlled by the control unit (84) (micro-controller).
[0080] Referring to figure 13(a), a detailed view of a pneumatic clutch actuator (PCA) (82) in the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. The pneumatic clutch actuator (82) is mounted on the gear box (96) and associated with the electronic clutch pedal (10) for clutch operation in order to engage and disengage the clutch from the vehicle engine (91). The PCA consists of a set of electro pneumatic solenoid valves (48) for moving the PCA in forward and backward directions smoothly, which gets main compressed air line thru a pneumatic connector (49). Also, a displacement or position sensor (50) is placed adjacent to an actuating region of the PCA to sense the position of PCA. The PCA has a pusher rod that is connected to the clutch fork (11) in the clutch

mechanism, such that the clutch can be engaged into and disengaged from the engine (91) by operating the PCA in the forward and backward directions, respectively.
[0081] Referring to figure 13(b), a detailed view of a XY actuator (83) in the commercial vehicle is illustrated in accordance with an exemplary embodiment of the present invention. The internal parts of the XY actuator (83) are used to shift the gears in the main gear box (96) with the help of shifting lever (55) and centering spring (56). The XY actuator (83) is assembled with a separate gear shifter section (57) which consists a set of pneumatic valves (51) and a separate gate selector section (53) in a single casing (54) for gear shifting and gate selection on the gear box (96), respectively. The gear shifter section has a set of electro pneumatic solenoids for the gear shifting in the gear box (96), and a position sensor (52) placed in it to sense the position of the gear shifter section. Similarly, the gear selector also has a set of electro pneumatic solenoids for the gate selection in the gear box (96), and a position sensor (58) placed in it to sense the position of the gate selector section. The electro pneumatic solenoids and the sensors of the gear shifter and gate selector sections of the XY actuator (83) are energized and controlled by the micro controller (89) for gate selection and gear shifting.
[0082] Referring to figure 14, an overall block diagram of a gear shift control unit (84) is illustrated in accordance with an exemplary embodiment of the present invention. The gear shift control unit (84) is electrically connected to multiple position sensors that are coupled with the clutch pedal (10), the clutch actuator (82), the gear shifter section, the gate selector section, the rear axle (97) and the accelerator pedal in the vehicle to simultaneously sense and determine the actual position of the clutch pedal (10), the clutch actuator (82), the accelerator pedal, the gear shifter section, the gate selector section and the rear axle (97). The control unit (84) receives all the inputs from the sensors and to automatically control the shifting operation of the gears on the gear box (96) and at the rear axle (97) based on the determined positions from each sensor and the gear shift pattern predefined with respect to vehicle configuration, road

and load conditions, where the predefined gear shift pattern is composed of gear shifting at the gear box (96) or gear shifting at the rear axle (97) or both.
[0083] The gear shift control unit (84) consists of a power supply unit (88), a micro controller (89), an input isolator (87) and an output relays (86), where all the inputs and outputs are connected to the micro controller (89) through the input isolator (87) and the output relays (86), respectively. The set of digital and analogue input signals are inputted to the micro controller (89), which controls all the logics and the outputs to the respective vehicle components for the gear shifting operation. The input signals are connected to the micro controller (89) through the input isolator (87) that isolates the micro controller (89) to avoid unwanted power distortion or spikes from the input signals. The output signals are connected to the micro controller (89) through the output relays (86) with electrical ground signal (78) to boost the current output. The power supply unit is connected to the vehicle battery source for supplying power to all the input and output units, the micro controller (89), the input isolator (87) and the output relays (86).
[0084] In the gear shift control unit (84), the digital inputs connected to the micro controller (89) are as follows: an ignition key (58) gives signal during engine cranking and running; a brake switch (61) gives signal when the brake pedal is pressed; the neutral switch (42) in the electronic paddle shifter (81) (EPS) gives signal while the driver has pressed the switch when the driver intended to put the vehicle in neutral condition; the reverse switch (44) in the EPS gives signal while the driver has pressed the switch when the driver intended to operate the vehicle in reverse gear; the up-shift switch (43) in the EPS gives signal while the driver paddle the gear shift knob in forward direction to up-shift the gear; the down-shift switch (60) in the EPS gives signal while the driver paddle the gear shift knob in backward direction to down-shift the gear; and a TSRA position sensor or switch (23) in the TSRA shifter unit gives signal about the position of the axle ratio either in deeper or shallow ratio.
[0085] In the gear shift control unit (84), the analogue inputs connected to the micro controller (89) are as follows: the clutch pedal position sensor (59) gives

continuous signal about the position of clutch pedal (10) when it is pressed by the driver; the accelerator position sensor (27) gives continuous signal about the position of accelerator pedal when it is pressed by the driver; the PCA position sensor (50) gives continuous signal about the position of the pneumatic clutch actuator (82); the XY actuator (83) gear shifter position sensor (52) gives continuous signal about the position of the gear shifter actuator; the XY actuator (83) gate selection position sensor (58) gives continuous signal about the position of the gate selection actuator; an engine speed sensor (62) gives continuous signal about the rotation of engine (91) in rpm; a gear box output speed sensor (63) gives continuous signal about the rotation of gear box output shaft in rpm; and a rear axle wheel speed sensor (64) gives continuous signal about the rotation of wheel in rpm.
[0086] In the gear shift control unit (84), the digital outputs connected to the vehicle components from the micro controller (89) through the output relay unit are as follows: the neutral light (45) glows while the vehicle is in neutral condition; the reverse gear light (46) glows while the vehicle is operated in reverse gear condition; the forward gear light (47) glows while the vehicle is operated in forward gear conditions; the PCA solenoids (65-68) are used to operate the pneumatic clutch actuator (82) in the forward and backward directions using the direction control valves (DCV 7,8,9 and 10); the gear shifter solenoids (69-72) are used to operate the gear shifting actuator in the forward and backward directions using the direction control valves (DCV 1,2,3 and 4); the gate selector solenoids (73, 74) are used to operate the gate selecting actuator in the forward and backward directions using the direction control valves (DCV 5 and 6); the TSRA shifter solenoid (75) is used to operate the actuator in the TSRA shifter unit in the forward and backward directions using the direction control valve (DCV 11); a brake release solenoid (76) is used to release the pressurized air from the brake chamber; and an alarm buzzer (77) is used while alarming with buzzer.
[0087] Referring to figure 15, an electrical and pneumatic control circuit of the XY actuator (83), the pneumatic clutch actuator (82) and the rear axle actuator (85) is

illustrated in accordance with an exemplary embodiment of the present invention. The XY actuator (83), the pneumatic clutch actuator (82) and the rear axle actuator (85) in the TSRA shifter unit are continuously monitored and controlled by the micro controller (89) of the gear shift control unit (84). The XY actuator (83) is arranged with a single port for a main pressure line (79) containing the pressurized air, which is internally connected to all six-direction control valves (DCV 1-6).
[0088] The gear shifter section of the XY actuator (83) is connected and directly coupled with the four direction control valves (DCV 1, 2, 3 and 4). These six direction control valves (DCV 1-6) are operated by supplying of the pressurized air, which actuates the gear shifter section to move the gear from neutral position into multiple gear positions. In particular, the direction control valves (DCV 1, 2, 3 and 4) operates the gear shifter section either from the neutral position to the even gear positions, i.e. reverse or second or fourth or sixth gear positions or from the neutral position to the odd gear positions, i.e. first or third or fifth gear positions, where the XY shifter position sensor (52) senses the position of the gear shifter section of the XY actuator (83) and send this signal to the control unit (84). Similarly, the gate selector section of the XY actuator (83) is coupled with the two direction control valves (DCV 5 and 6) connected to the main pressure line such that the gate selector section moves the gear selection gate from one end to another (5/6 gate or 3/4 gate or 1/2 gate or reverse gear gate), where the XY gate selector position sensor (58) senses the position of the gate selector section of the XY actuator (83) and send this signal to the control unit (84).
[0089] The pneumatic clutch actuator (82) (PCA) is arranged with a single port for the main pressure line (79) containing the pressurized air, which is internally connected to all four-direction control valves (DCV 7, 8, 9 and 10). In particular, the pneumatic clutch actuator (82) is coupled with the four direction control valves (DCV 7, 8, 9 and 10) for operating the pneumatic clutch actuator (82) from one end to another for engaging and disengaging the clutch from the vehicle engine (91), i.e.

clutch from engage to disengage and vice versa, where the PCA position sensor (50) senses the position of the PCA and send this signal to the control unit (84).
[0090] Further, the TSRA shifter unit consists of a single acting actuator (also referred as rear axle actuator (85)) with a single solenoid DCV (DCV 11), i.e. the rear axle actuator (85) is coupled with the direction control valve (DCV 11), which actuates the TSRA between the deeper and shallow ratio positions. The TSRA position sensor or switch (23) provides an indication whether the axle is in deeper or shallow ratio, to the control unit (84).
Operating Principle:
[0091] The operating principle of the gear shift control unit (84) according to the present invention is described below. The vital function of the modular shift control unit is adapted to shift the gears automatically on the gear box (96) and at the twin speed rear axle (97) (TSRA) with the driver inputs and a predefined shift pattern based on vehicle configuration and application. When the input isolator (87) is switched-on, the control unit (84) sends the signal to actuate the XY actuator (83) and the rear axle shifter unit (34) on the TSRA to control the gear box (96) to come into the neutral position and the rear axle ratio into the deeper ratio position.
[0092] The control unit (84) determines and allows the engine (91) to crank only when each of the position sensors sense that the clutch pedal (10) is fully pressed, the clutch is fully disengaged, the accelerator pedal is completely released, the neutral position in the gear box (96) and the rear axle (97) in the deeper ratio position. In particular, while cranking the engine (91), the control unit (84) checks for the followings input signals:
1. Signal from the clutch pedal position sensor (59) to determine whether the clutch pedal (10) is fully pressed by the driver;
2. Signal from the PCA position sensor (50) to determine whether the clutch disc (5) is fully disengaged by the driver;

3. Signal from the accelerator pedal position sensor (27) to determine the complete release of the accelerator pedal (27) by the driver;
4. Signal from the XY actuator (83) gear shifter position sensor (52) to determine the neutral position in the gear box (96);
5. Signal from the XY actuator (83) gate selection position sensor (58) to determine the neutral position in the gear box (96); and
6. Signal from the TSRA position switch or sensor (23) to determine whether the rear axle (97) is in deeper ratio.
[0093] If all the above conditions are satisfied, then only the control unit (84) allows the engine (91) to crank, which avoids the damage on the transmission line during the starting of the vehicle and also reduces these additional loads on the starter motor.
[0094] Once the engine (91) is cranked, the driver has to press the clutch pedal (10) fully and paddle the gear shift knob on the forward direction. While pressing the clutch pedal (10), the control unit (84) senses the pedal position signal (59) and actuates the PCA to disengage the clutch by operating the direction control valves (DCV 8 and 9). The control unit (84) also senses and checks the signal from the PCA position sensor (50) to confirm the disengagement of the clutch disc (5), i.e. the clutch disc (5) is in intended position. If the clutch disc (5) is in the intended position, i.e. if the clutch pedal (10) is fully pressed, the clutch is fully disengaged and the gear shift knob is shifted, the control unit (84) provides the signal to actuate the XY actuator (83) to shift the gear to first gear position by operating the direction control valve (DCV 5) to move the gate selection actuator to 1/2 neutral point, and also senses the signal from the gate selection position sensor (58) to confirm the position of the gate selector section of the XY actuator (83). Then, the control unit (84) simultaneously operates the direction control valve (DCV 3) to move the gear shifter section of the XY actuator (83) in order to engage the first gear, and also checks the signal from the gear shifter position sensor (52) to confirm the engagement of first gear. In this above

scenario, the control unit (84) maintains the rear drive axle in the deeper ratio position itself.
[0095] When the driver releases the clutch pedal (10), the control unit (84) senses the clutch pedal position signal (59) and simultaneously operates the direction control valve (DCV 7) in the pneumatic clutch actuator (82), which enables the clutch (5) to start to engage with the engine (91). When the clutch pedal (10) is fully released, the direction control valves (DCV 7 and 10) in the pneumatic clutch actuator (82) are energized to fully engage the clutch with the engine (91), which is confirmed by the control unit (84) using the signal from the PCA position sensor (50). Now, the vehicle starts moving in the first gear ratio in the gear box (96) with the rear axle (97) in deeper ratio. During the vehicle runs in the forward gears, the forward gear light indicator (47) glows in the electronic paddle shifter (81).
[0096] While shifting the next gear in the upward direction, the same procedure is applicable for the driver but the gear change occurs at the rear axle (97) from the deeper to shallow ratio position instead of shifting the gear into second gear in the gear box (96). In particular, when the gear shift knob is further shifted upward, the control unit (84) maintains the first gear position in the gear box (96) and energizes only the direction control valve (DCV 11) in the rear axle actuator (85) to shift the rear axle (97) from the deeper ratio position to the shallow ratio position. The control unit (84) also checks the shallow ratio position of TSRA using the signal from the TSRA position sensor (23), i.e. there is no change in the position of the XY actuator (83). In this above scenario, the first gear ratio is maintained in the gear box (96) whereas only the deeper ratio is changed to the shallow ratio in the rear axle (97), which provides less torque to the wheels instead of more torque generation in the vehicle.
[0097] When the gear shift knob is further shifted in the upward direction to shift for the next gear, the same procedure is followed again and the shifting of gear takes place in both the gear box (96) and in the rear axle (97). The control unit (84) energizes the direction control valve (DCV 4) in the gear shifter section to shift the
on

gear from first to second gear positions in the gear box (96) and simultaneously de-energizes the direction control valve (DCV 11) in the rear axle actuator (85) to shift and change the rear axle (97) from the shallow ratio position to the deeper ratio position. In this above scenario, there is no change in the position of the gate selector section (58), i.e. the control unit (84) maintains the gate selector section in the same position itself.
[0098] Further, the gear shifting takes place in the control unit (84) depends on the predefined shifting pattern, as mention in any one of above three patterns, i.e. shifting the gear at the gear box (96) alone or shifting the gear at the rear axle alone or shifting the gear at both the gear box (96) and the rear axle. The gear shift pattern can be predefined based on vehicle configuration, application and loading patterns as well as road conditions. Similarly, the down shifting of gears by shifting the gear shift knob in the downward direction also operates and works in the above same procedures as like the up-shifting of gears, i.e. the gear shift knob is paddled backward for the down¬shift instead of paddling the gear shift knob forward.
[0099] In order to bring the vehicle to the neutral condition, the driver needs to fully press the clutch pedal (10) and press the neutral button (42) in the electronic paddle shifter (81) (EPS). In particular, when the clutch pedal (10) is fully pressed and the neutral switch is pressed, the control unit (84) actuates the direction control valves in the pneumatic clutch actuator (82) (PCA) to disengage the clutch from the engine (91), and simultaneously actuates the direction control valves in the gear shifter section of the XY actuator (83) to shift the gear into the neutral position in the gear box (96) by bringing the gate position of the gear selector section in the XY actuator (83) at 3/4 neutral point and maintaining the rear axle (97) in the deeper ratio position. After checking the position of the all the above sensors by the control unit (84), the neutral light indicator (45) glows in the electronic paddle shifter (81).
[00100] Further, in order to engage the reverse gear in the gear box (96), the vehicle has to be in idle condition, which can be ensured by the wheel speed sensor (64). When the clutch pedal (10) is fully pressed, the reverse gear switch (44) is

pressed on the EPS and the gear shift knob is paddled on backward direction, the control unit (84) provides the signal to actuate the direction control valves in the pneumatic clutch actuator (82) (PCA) to disengage the clutch from the engine (91), and simultaneously actuates the direction control valves in the XY actuator (83) to bring the gate position of the XY gate selector section to R neutral point (reverse point) and to bring the gear position of the XY gear shifter section into the reverse gear position in the gear box (96) as well as maintains the rear axle (97) in the deeper ratio position. After checking the position of the all the above sensors by the control unit (84), the reverse light indicator (46) glows in the electronic paddle shifter (81).
[00101] Thus, the present invention of the modular control system achieves automatic and simultaneous controlling of gear shifting in both the gear box (96) and the twin speed rear axle (97) based on driver inputs and preset gear shift pattern. Since the power train is disengaged from the engine (91) during the axle ratio shifts and as semi-automated shifting control system, the gear engagement can be taken place smoothly with effortless clutch operation, which reduces the torque fluctuation in the running vehicle. The usage of PCA and XY actuator (83)s smoothens out the gear shift and clutch engagement event in the vehicle, which reduces the impact loading of the transmission parts and thus increases its life.
[00102] Since there is a gear ratio made available in between one deeper ratio and two deeper ratios, the vehicle can run with one shallow gear where it cannot be run at two deeper gears. It also provides better traction effort and speed when we compare it with one deeper gear. Due to the availability of the shallow ratio, the vehicle can run at higher speeds than the deeper ratio during the return empty application of the vehicles which in turn provides the better fuel economy. Further, driver fatigue is substantially reduced as two of his main operations of clutch and gear shift which is made to zero loads and also eliminates the vibration felt by the driver in the gear knob in the conventional vehicle.
[00103] The present invention is a semi-automatic gear shifting control system to facilitate modularity in vehicle powertrain to achieve different combinations of

reduction ratios, which reduces driver fatigue and provides high reliability and better fuel economy for the vehicle. It also can eliminate twin speed rear axle (97) failures, gear shift linkage failures, gear failures, and clutch linkage failures Thus, it increases clutch and gear life, vehicle gradability (traction effort) and vehicle drivability. Therefore, the present invention is not limited to the embodiments herein before described which may be varied in both construction and detail within the scope of the appended claims. Many modification and other embodiments of the invention may come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and associated drawings. In addition, some changes (such as adding new control signals, new valves and deleing few valves) may be made to these specific embodiments, and such modifications are contemplated by the principle of the present invention. In addition, it is to be understood that the present invention is applicable for all the range of commercial vehicles with different configuration of front and rear axles. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.

1. A control system for automatic controlling of gear shifting in a gear box (96)
and a rear axle (97) in a commercial vehicle, comprising:
an electronic paddle shifter (81) having a gear shift knob for upward, downward and reverse shifting one or more gears in the gear box (96);
a pneumatic clutch actuator (82) mounted on the gear box (96) and associated with an electronic clutch pedal (10) mounted on a driver cabin to engage and disengage a clutch (5) from a vehicle engine (91);
a XY actuator (83) assembled with a gear shifter section and a gate selector section for gear shifting and gate selection on the gear box (96);
a rear axle shifter unit (34) assembled with an axle actuator (85) in the rear axle (97);
a plurality of sensors each coupled with the clutch pedal (10), the clutch actuator (82), the gear shifter section, the gate selector section, the rear axle (97) and an accelerator pedal (27) in the vehicle; and
a gear shift control unit (84) electrically connected to each of the sensors to simultaneously determine the position of the clutch pedal (10), the clutch actuator (82), the accelerator pedal (27), the gear shifter section, the gate selector section and the rear axle (97),
wherein the control unit (84) is operatively connected to automatically shift and control the operation of gears on the gear box (96) and at the rear axle (97) based on the determined positions from each sensor and a gear shift pattern predefined with respect to vehicle configuration, road and load conditions.
2. The control system as claimed in claim 1, wherein the predefined gear shift
pattern is composed of gear shifting at the gear box (96) or gear shifting at the rear
axle (97) or both.

3. The control system as claimed in claim 1, wherein the XY actuator (83), the pneumatic clutch actuator (82) and the rear axle actuator (85) are monitored and controlled by the control unit (84).
4. The control system as claimed in claim 1, wherein the gear shifter section of the XY actuator (83) is coupled with a plurality of direction control valves connected to a main pressure line such that the gear shifter section moves the gear from neutral position into multiple gear positions.
5. The control system as claimed in claim 4, wherein the gear positions are arranged in a shifting pattern from neutral position to even gear positions (reverse, second, fourth and sixth) or from neutral to odd gear positions (first, third and fifth).
6. The control system as claimed in claim 1, wherein the gate selector section of the XY actuator (83) is coupled with a plurality of direction control valves connected to the main pressure line such that the gate selector section moves the gear selection gate from one end to another.
7. The control system as claimed in claim 1, wherein the pneumatic clutch actuator (82) is coupled with a plurality of direction control valves connected to the main pressure line for engaging and disengaging the clutch (5) from the vehicle engine (91) by moving the clutch actuator (82) from one end to another.
8. The control system as claimed in claim 1, wherein the rear axle actuator (85) is coupled with at least one direction control valve to actuate the rear axle (97) between deeper and shallow ratio positions.
9. The control system as claimed in claim 1, wherein the gear shift knob is composed of an up-shift and down-shift switches with a gear light indicator, a neutral switch with a neutral light indicator, and a reverse gear shift switch with a reverse light indicator.

10. The control system as claimed in claim 1, wherein after switch-on, the control unit (84) actuates the XY actuator (83) and the rear axle shifter unit (34) to control the gear box (96) into the neutral position and the rear axle (97) into the deeper ratio position.
11. The control system as claimed in claims 1 and 10, wherein the control unit (84) determines and allows the engine (91) to crank only when each of the position sensors sense that the clutch pedal (10) is fully pressed, the clutch (5) is fully disengaged, the accelerator pedal (27) is completely released, the neutral position in the gear box (96) and the rear axle (97) in the deeper ratio position.
12. The control system as claimed in claim 11, wherein the plurality of sensors determines that the clutch pedal (10) is fully pressed, the clutch (5) is fully disengaged and the gear shift knob is shifted, such that the control unit (84) actuates the direction control valves in the pneumatic clutch actuator (82) and the XY actuator (83) to disengage the clutch (5) and simultaneously shift the gear into the first gear position by moving the gear selection gate at first and second gear neutral point and maintaining the rear axle (97) in the deeper ratio position.
13. The control system as claimed in claim 12, wherein while releasing the clutch pedal (10), the control unit (84) simultaneously actuates the direction control valves in the pneumatic clutch actuator (82) in order to engage the clutch (5) with the engine (91) to move the vehicle in the first gear with the deeper ratio position.
14. The control system as claimed in claim 13, wherein when the gear shift knob is further shifted upward, the control unit (84) maintains the first or subsequent gear position in the gear box (96) and energizes the direction control valve in the rear axle actuator (85) to shift the rear axle (97) from the deeper ratio position to the shallow ratio position and vice versa.

15. The control system as claimed in claim 14, wherein when the gear shift knob is shifted subsequently, the control unit (84) energizes the direction control valve in the gear shifter section to shift the gear into the second or subsequent gear positions in the gear box (96) and simultaneously de-energizes the direction control valve in the rear axle actuator (85) to shift the rear axle (97) from the shallow ratio position to the deeper ratio position and vice versa.
16. The control system as claimed in claim 11, wherein when the clutch pedal (10) and the neutral switch are pressed, the control unit (84) actuates the direction control valves in the pneumatic clutch actuator (82) and the XY actuator (83) to disengage the clutch (5) and simultaneously shift the gear into the neutral position in the gear box (96) by moving the gear selection gate at gear box neutral point and maintaining the rear axle (97) in the deeper ratio position.
17. The control system as claimed in claim 11, wherein when the clutch pedal (10) and the reverse switch are pressed, the control unit (84) actuates the direction control valves in the pneumatic clutch actuator (82) and the XY actuator (83) to disengage the clutch (5) and simultaneously shift the gear into the reverse gear position in the gear box (96) by moving the gear selection gate at reverse neutral point and maintaining the rear axle (97) in the deeper ratio position.
18. The control system as claimed in any of the preceding claims, wherein the rear axle (97) is a twin speed drive rear axle.