DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
AN AUTOMATIC THERMAL COOLING SYSTEM AND METHOD FOR CRAWLER BULLDOZER
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
[001] The present invention relates to the field of cooling system. The present invention in particular relates to an automatic thermal cooling system and method for crawler bulldozer.
DESCRIPTION OF THE RELATED ART:
[002] A Giant Crawler Bull Dozer, weighing ~100 tons is configured with a semi-U blade of 25.6 cu.m and single shank giant ripper. It is powered by a 30 litre electronic engine meeting EPA Tier-I emission norms, delivering 900 FHP @ 2000 rpm.
[003] This Bulldozer is a crawler (continuous tracked tractor) equipped with having vertical blade at front end for moving earth, tree, rocks, stumps etc. Primarily Bull dozer runs through power train system for its Dozing operation. Power train system consists of various subs systems viz, Engine, PTO, Torque converter, transmission, final drive with brake system. Also, the Dozer blade operation is carried out hydraulic pump and control valve, which actuate the hydraulic cylinders for lift, lower & tilt operations. During dozing operation the power train system is in the active & the hydraulic system is used to operate dozer blade in the passive mode. The Dozer blade lift and tilt are operated by Hydraulic cylinders which are actuated through pilot hydraulics. These operations result in considerable heating of hydraulic oil and transmission oil along with engine oil and engine coolant. Due to heavy sizing of the Dozer it is always a challenge to design and develop an energy efficient thermal cooling system which can automatically do the cooling of various systems as per the requirement of each subsystems. Sizing and engineering of Fan subsystem, cooling unit and engine Radiator posed considerable challenge as overall dozer dimension to be maintained within the specified limits without overshooting the limits which was adding to limitations in the spacing of the Fan subsystem, cooling unit and engine Radiator.
[004] Reference may be made to the following:
[005] Publication No. CN202672204 relates to a cooling system of a hybrid power bulldozer. The cooling system of the hybrid power bulldozer comprises a hollow-hollow intercooler, a comprehensive radiator, an engine water radiator, a hydraulic oil cooler and a cooling fan. A main pump motor, a rotary motor, a generator and a motor controller of the hybrid power bulldozer form a loop through an electric water pump, the comprehensive radiator and the hydraulic oil cooler, an engine of the hybrid power bulldozer and a water pump of the engine form a loop through the engine water radiator, the engine of the hybrid power bulldozer and the hollow-hollow intercooler form a loop, and the cooling fan cools high-temperature circulating water inside the engine water radiator, high-temperature water inside the comprehensive radiator and hot air inside the hollow-hollow intercooler. The cooling system of the hybrid power bulldozer has the advantages of effectively resolving problems of untight sealing and air leakage among the radiators, reducing space arrangement, and improving cooling effect of the cooling system.
[006] Publication No. CN202672204 is a hybrid type dozer cooling system and uses thermostats to detect the temperature and uses electric motor for FAN drive and the working principle is different from present automatic thermal cooling system.
[007] Present Automatic thermal cooling system consist of engine driven axial piston pump which drives the motor and FAN with variable speeds. The programmable controlled pump swash plate angle, delivers the required flow and pressure input to the FAN motor based on the feedback signal from temperature sensors fitted on sub systems.
[008] Publication No. US6216778 relates to a cooling system for an off-highway vehicle includes a heat exchanger (e.g., an engine coolant or hydraulic oil heat exchanger) and a fan mechanism for flowing air along a flow path through the heat exchanger. In the improvement, the fan mechanism is a centrifugal fan mechanism and is substantially the sole means for flowing air along the flow path. That is, there is substantially no ram-urged air. The mechanism includes a housing and a fan in the housing. The fan has forward curved blades, thereby to reduce system noise. A preferred fan has a depth-to-diameter ratio not in excess of about 0.4 and, most preferably, not in excess of about 0.25. An alternate embodiment includes what might be termed a split-discharge arrangement wherein air blown by the fan is discharged along two paths.
[009] Publication No. US6216778 discloses cooling FAN and a centrifugal fan mechanism for an off highway vehicle where as the principal present invention provides an automatic thermal cooling system and method for crawler bulldozer.
[010] Publication No. US7028646 relates to the cooling system of a skid-steer loader provides for heat exchangers, e.g. liquid, oil coolers, mounted in the upper portion of an engine compartment and in direct communication with a forced air flow. Circulating air is drawn into the engine compartment from the rear, is carried over the engine and is blown out through the heat exchangers to cool the liquid within the heat exchangers. The housing of a centrifugal fan is rigidly coupled to the engine block and the fan is also directly coupled to the engine flywheel. This allows for closer tolerances between the fan and its housing which results in higher efficiency because this dual coupling to the engine inhibits differential vibration between the fan and the housing. Interconnection between the heat exchangers and fan housing is via a flexible bellows and an air diffuser.
[011] Publication No. US7028646 uses an engine driven centrifugal fan to cool the radiator and oil cooler and the working principle and methodology is different from our Automatic thermal cooling system. The present invention consists of engine driven axial piston pump which drives the motor and a sucker FAN with variable speeds. The programmable controlled pump swash plate angle, delivers the required flow and pressure input to the FAN motor based on the feedback signal from temperature sensors fitted on sub systems. Whenever heat is generated in sub systems, the program senses and generates a demand from pump, to increase the Motor speed so as the cooling takes place efficiently. It ensures fan drive optimally i.e., the rate of change in fan speed is directly proportional to the magnitude of input signal to the pump. At zero signal to the pump, Fan runs at minimum set speed, which saves engine power drastically and also reduces noise generated, which in turn reduces overall equipment sound decibels.
[012] Publication No. US8875823 relates to a vehicle includes a chassis; a plurality of ground-engaging members; and an engine that cooperates with the plurality of ground-engaging members to move the chassis of the vehicle. The engine is positioned within an engine compartment. The vehicle further includes a cooling system including a baffle having a first side and a second side; a battery positioned on the first side of the baffle; and a heat exchanger positioned on the second side of the baffle. The baffle defines a first air pathway to cool the battery and a second air pathway to cool the heat exchanger.
[013] Publication No. US8875823 uses a Baffle blade to cool the heat exchanger. the working principle and methodology is different from our Automatic thermal cooling system. Present invention provides an automatic thermal cooling system and method for crawler bulldozer uses a large sucker FAN which fits within the specified limits without overshooting the limits of Equipment Envelope of a 950 Hp giant dozer.
[014] Publication No. US6571751 relates to a method and apparatus for controlling a fan on a work machine. The method includes the steps of sensing a temperature of air at an inlet manifold, sensing a temperature of an engine coolant fluid, sensing a temperature of a hydraulic fluid, and sensing a temperature of a transmission fluid. The method also includes the step of controlling the fan responsive to at least one of the sensed temperatures. Publication No. US6571751 uses an electronic controlled FAN drive cooling system and an algorithm is developed to control electronically present invention provides an automatic thermal cooling system. Present invention provides an automatic thermal cooling system and method for crawler bulldozer uses a large sucker FAN which fits within the specified limits without overshooting the limits of Equipment Envelope of a 950 Hp giant dozer.
[015] Publication No. CN107961921 relates to a cooling self-cleaning system for a bulldozer and a control method thereof. The self-cleaning system comprises a cleaning device, an adjusting device, and a controlling device. The cleaning device is arranged at one side of a radiator and comprises a plurality of nozzles which are distributed at intervals; the adjusting device is connected with the nozzles to be used for adjusting the location and the jet angle of each nozzle; and the controlling device is connected with both the cleaning device and the adjusting device, according to detected operating parameters of the radiator, and fluid from the nozzles is controlled to jet towards the surface of the radiator. A cooling self-cleaning method comprises the following steps that operating parameters of a plurality of locations of the radiator are obtained in real time, and the operating parameters are passed to the controlling device; received operating parameters are compared with the corresponding preset value by the controlling device, the blocking state and the blocking level of the radiator are judged, the cleaning location and the cleaning pressure of the cleaning device are determined, and treatment is in time, so that harm to the performance and life of the cooling system caused by a continuous operation is prevented.
[016] Publication No. CN107961921 is a self-cleaning system for the Radiator using Nozzels. The Radiator blocks are removed by cleaning air pressure to enhance the life of cooling system whereas the present invention Automatic thermal cooling system saves the engine power drastically by allowing the Fan at minimum speed during normal operation and increasing the fan speed only during requirement of cooling leading to reduction in the Fan Noise generated which plays a role in reducing overall equipment sound decibels.
[017] Publication No. DE69836474 relates to a cooling apparatus for a construction machine, which comprises at least one heat exchanger including a radiator for cooling water used to cool an engine of a hydraulic excavator, and a cooling fan for producing cooling air (P) to cool the heat exchanger by means of a rotary shaft being driven, substantially disk-shaped flow guide means having an outer diameter size (Do) smaller than an outer diameter size (D) of the cooling fan is provided on the blow off side of the cooling fan. Thus, noise can be reduced down to a lower level than that allowed currently, while ensuring a sufficient flow rate of cooling air, in consideration of the tendency toward more strict regulations on construction machines. Publication No. DE69836474 is a drive noise reduction by efficiently designing and sizing of Fan and Shroud, which also ensures sufficient flow rate of cooling air in a construction machine whereas present invention relates to an automatic thermal cooling system and method for crawler bulldozer.
[018] Thus, sizing and engineering of fan subsystem, cooling unit and engine Radiator posed considerable challenge as overall dozer dimension to be maintained within the specified limits without overshooting the limits which was adding to limitations in the spacing of the Fan subsystem, cooling unit and engine Radiator.
[019] Also, the existing cooling system in the giant dozer was of manual type wherein the fan was having only two speeds irrespective of the temperatures attained by various subsystems, which in turn was resulting in inefficient cooling and Engine was excessively heating and which was reducing life of engine and hydraulic components. Hence there needed a cooling system which can efficiently solve the cooling issues in the giant dozer.
[020] In order to overcome above listed prior art, the present invention aims to provide an automatic thermal cooling system and method for crawler bulldozer.
OBJECTS OF THE INVENTION:
[021] The principal object of the present invention is to provide an automatic thermal cooling system and method for crawler bulldozer.
[022] Another object of the present invention is to provide an automatic thermal cooling system and method for crawler bulldozer which can be fit within the specified limits without overshooting the limits.
[023] Another object of the present invention is to save the engine power efficiently by allowing the Fan at minimum speed during normal operation and increasing the fan speed only during requirement of cooling leading to reduction in the Fan Noise generated which plays a role in reducing overall equipment sound decibels.
SUMMARY:
[024] The present invention relates to an automatic thermal cooling system and method for crawler bulldozer. This is an automatic thermal cooling system invention consist of engine driven Axial piston pump which drives the motor and FAN with variable speeds. The programmable controlled pump swash plate angle, delivers the required flow and pressure input to the FAN motor based on the feedback signal from temperature sensors fitted on sub systems. Whenever heat is generated in sub systems, the program senses and generates a demand from pump, to increase the Motor speed so as the cooling takes place efficiently. It ensures fan drive optimally i.e., the rate of change in fan speed is directly proportional to the magnitude of input signal to the pump. At zero signal to the pump, Fan runs at minimum set speed, which saves engine power drastically and also reduces noise generated, which in turn reduces overall equipment sound decibels.
BREIF DESCRIPTION OF THE INVENTION
[025] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[026] Figure 1 shows automatic thermal cooing system for dozer.
[027] Figure 2 shows hydraulic circuit of the system.
[028] Figure 3 shows the flowchart according to the present invention.
[029] Figure 4 shows fan speed control system.
[030] Figure 5 shows method used for control of fan speed.
DETAILED DESCRIPTION OF THE INVENTION:
[031] The present invention provides an automatic thermal cooling system and method for crawler bulldozer. This is an automatic thermal cooling system invention consist of engine driven Axial piston pump which drives the motor and FAN with variable speeds. The programmable controlled pump swash plate angle, delivers the required flow and pressure input to the FAN motor based on the feedback signal from temperature sensors fitted on sub systems. Whenever heat is generated in sub systems, the program senses and generates a demand from pump, to increase the Motor speed so as the cooling takes place efficiently. It ensures fan drive optimally i.e., the rate of change in fan speed is directly proportional to the magnitude of input signal to the pump. At zero signal to the pump, Fan runs at minimum set speed, which saves engine power drastically and also reduces noise generated, which in turn reduces overall equipment sound decibels.
[032] Fig. 4 shows method to control of fan speed with a set point defined by up to 6 different temperature values and external fan power requests. Features such are fan standstill and reversing is incorporated with DC valve. The default feature set to standstill mode and fan reversing is used for automatic cleaning the cooler. The fan control calculates the set point power of the fan considering the temperatures, which are transmitted via sensors. Each temperature value is compared to a stored curve, defines the temperature to start cooling and the temperature at which the highest fan power is reached. Between these two thresholds, the set point increases in proportion to the temperature changes. An over-temperature can be defined, if this value is exceeded the user will be notified by the error lamp.
[033] Present invention provides an automatic thermal cooling system and method for crawler bulldozer uses a large sucker FAN which fits within the specified limits without overshooting the limits of Equipment Envelope of a 950 Hp giant dozer.
[034] Present invention also saves the engine power drastically by allowing the Fan at minimum speed during normal operation and increasing the fan speed only during requirement of cooling leading to reduction in the Fan Noise generated which plays a role in reducing overall equipment sound decibels.
[035] Figure 1 shows automatic thermal cooing system for dozer. The system comprises drive pump (tandem) (1), drive motor(2), DC-valve for fan reversal(3), check valve(4), hydraulic oil cooler(5), pump controller(6), fan(7) and hydraulic tank (8). It consist of engine driven Axial piston pump(1) which drives the motor(2) and FAN(7) with variable speeds. An intelligent program(6) developed guides and controls the pump swash plate to deliver the required flow and pressure, in order to generate motor speed based on the temperature requirement of various subsystems. DC-valve for fan reversal (3) is used for fan reversal for cleaning function of Radiator and Oil cooler and check valve (4) are for protection of Tandem pumps(1). Whenever there is heat is generated in a subsystem, the system senses and generates a demand to pump to increase the Motor speed so as the cooling in cooler(5) takes place efficiently. This ensures the Fan is driven optimally i.e., fan speed is increased whenever there is a demand only and during normal condition Fan is run at minimum speed saving the engine power drastically and also reducing the Noise generated which plays a role in reducing overall equipment sound decibels.
[036] The oil from the hydraulic tank is sucked up by the drive pump, which is a tandem type. The both pump deliveries are merged in junction block, protected by check valve. The flow from the junction block enters the DC-valve, which is used for fan reversal during maintenance time. DC-valve guides the oil from its A-port to drive motor B-port in normal operation condition and rotates the fan drive motor clock wise when viewed from the blade side. This direction of rotation of Fan sucks hot air from the engine chamber and blows outside (in front of radiator guard) cooling the Radiator, CAC and Hydraulic oil.
[037] Return oil leaving from the motor B-port enters the oil cooler through DC-valve T-line. After being cooled, it passes through hydraulic return line filters and returns to the hydraulic tank.
[038] The swash plate angle of the pump is controlled by pump controller which is operated by electrical signal received from the electronic controller. Electronic controller receives the signal based on signal detected by the three temperature sensors viz. engine water temperature, CAC and hydraulic oil temperature. Pump controller adjusts the swash plate angle position to control the fan to a suitable speed, by means of varying the pump flow and pressure, based on the temperature inputs received.
[039] When the fan reversal switch is ON, the solenoid valve will get energized and it controls the pilot signal for DC valve spool and changes the spool position. Oil will get diverted from DC-valve B-port to A-port of the fan drive motor. This results the change in direction of the fan (anti-clock wise when viewed from blade side).By reversing hydrostatic Fan, Mud, dust or leaves, blocking the cooler and Radiator shall be blown off. The Fan reversal switch, provided in the dashboard to be used for reversing the Fan so that the air is sucked from the front (blade side) and blown on to the Radiator and cooler to clean the Dust. The hydraulic circuit of the system as shown in figure 2 comprises Hydraulic tank (1), Return line filter (2), Manifold block (3), Check valve (4) and drive pump (5), Fan drive motor (6), Breather (7), Suction strainer (8), DC valve for fan reversal (9), and hydraulic oil cooler (10).
[040] The system consist of engine driven Axial piston pump(1) which drives the motor(2) and FAN(7) with variable speeds. An intelligent program(6) developed guides and controls the pump swash plate to deliver the required flow and pressure, in order to generate motor speed based on the temperature requirement of various subsystems. DC-valve for fan reversal (3) is used for fan reversal for cleaning function of Radiator and Oil cooler and check valve(4) are for protection of Tandem pumps(1). Whenever there is heat is generated in a subsystem, the system senses and generates a demand to pump to increase the Motor speed so as the cooling in cooler(5) takes place efficiently. This ensures the Fan is driven optimally i.e., fan speed is increased whenever there is a demand only and during normal condition Fan is run at minimum speed saving the engine power drastically and also reducing the Noise generated which plays a role in reducing overall equipment sound decibels.
[041] Figure 3 shows the flowchart according to the present invention.
[042] Step 1: controller tracks the subsystems viz. hydraulic system, transmission system and Engine coolant and engine oil temperature and draws a linear graph based on the inputs from these subsystems.
[043] Step 2: controller signals the drive pump to deliver the required flow and pressure, which drives the motor and speed with an optimum speed to cater the subsystems.
[044] Step 3: Any over load in the subsystem is sensed by the controller and accordingly signal the pump to increase the speed of motor and fan to efficiently cool the system.
[045] The system (fig 5) is an easily adjustable method used for control of fan speed with set point is defined by up to 6 different temperature values and external fan power requests. Features such are fan standstill and reversing can be incorporated with DC valve. The default feature set to standstill mode and fan reversing is used for automatic cleaning the cooler. The fan control calculates the set point power of the fan considering the temperatures, which are transmitted via sensors. Each temperature value is compared to a stored curve, defines the temperature to start cooling and the temperature at which the highest fan power fan power is reached. Between these two thresholds, the setpoint increases in proportion to the temperature changes. An over-temperature is defined and if this value is exceeded the user will be notified by the error lamp. Fig 4 shows the fan control system. The air flow observation at different points measured in a radial direction shown in Fig 5 are as shown below
[046] AIR FLOW OBSERVATION TABLE:
1350 1400 1450 1280
1200 190 190 1000
1340 170 170 1050
1350 980 1050 1050
Peripheral velocity of the fan (u) ? u=(p*d*N)/60
Pressure exerted by the air flow (?p) ? ?p =?(u/(0.89*f_b))?^2
Power consumed by fan drive system (P) ? P=(Q*?p)/?
[047] The FAN drive system in giant ripper brought down the power extraction from engine nearly 20-30% this in turn substantially reduces the fuel consumption and provides effective cooling in efficient manner.
[048] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.
,CLAIMS:WE CLAIM:
1. An automatic thermal cooling system and method for crawler bulldozer comprises-
a) engine driven Axial piston pump (1) which drives the motor (2) and FAN (7) with variable speeds.
b) an intelligent method (6) developed guides and controls the pump swash plate to deliver the required flow and pressure, in order to generate motor speed based on the temperature requirement of various subsystems.
c) DC-valve for fan reversal (3) is used for fan reversal for cleaning function of Radiator and Oil cooler and check valve (4) are for protection of Tandem pumps (1) and whenever there is heat is generated in a subsystem, the system senses and generates a demand to pump to increase the Motor speed so as the cooling in cooler (5) takes place efficiently which ensures the Fan is driven optimally.
2. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein whenever there is heat is generated in a subsystem, the system senses and generates a demand to pump to increase the Motor speed so as the cooling takes place efficiently which ensures the Fan is driven optimally.
3. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the control of fan speed with a set point defined by up to 6 different temperature values and external fan power requests and default feature set to standstill mode and fan reversing is used for automatic cleaning the cooler; the fan control calculates the set point power of the fan considering the temperatures, which are transmitted via sensors; each temperature value is compared to a stored curve, defines the temperature to start cooling and the temperature at which the highest fan power is reached and between these two thresholds, the set point increases in proportion to the temperature changes.
4. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the automatic thermal cooling system for crawler bulldozer uses a large sucker FAN which fits within the specified limits without overshooting the limits of Equipment Envelope of a 950 Hp giant dozer.
5. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the oil from the hydraulic tank is sucked up by the drive pump, which is a tandem type and both pump deliveries are merged in junction block, protected by check valve; the flow from the junction block enters the DC-valve, which is used for fan reversal during maintenance time. DC-valve guides the oil from its A-port to drive motor B-port in normal operation condition and rotates the fan drive motor clock wise when viewed from the blade side and this direction of rotation of Fan sucks hot air from the engine chamber and blows outside (in front of radiator guard) cooling the Radiator, CAC and Hydraulic oil.
6. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the return oil leaving from the motor B-port enters the oil cooler through DC-valve T-line. After being cooled, it passes through hydraulic return line filters and returns to the hydraulic tank.
7. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the when the fan reversal switch is ON, the solenoid valve will get energized and it controls the pilot signal for DC valve spool and changes the spool position; oil will get diverted from DC-valve B-port to A-port of the fan drive motor which changes the direction of the fan and by reversing hydrostatic Fan, Mud, dust or leaves, blocking the cooler and Radiator shall be blown off.
8. The automatic thermal cooling system and method for crawler bulldozer, as claimed in claim 1, wherein the fan speed is increased as per the demand only and during normal condition Fan is run at minimum speed saving the engine power drastically and also reducing the Noise generated which plays a role in reducing overall equipment sound decibels.