Claims:We claim:

1. An adaptive clutch fill up modulation control system (120), for calibrating the clutch fill up rate as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system, comprising of : an electronic control unit (ECU) (122), for receiving input signals from plurality of sources and processing the received input signals in accordance with the operator demand; atleast a sensor (121), said sensor is in communication with the said ECU (122); a hydraulic manifold valve (123), operatively coupled to the said ECU (122); a hydraulic system (125), wherein said hydraulic system (125) is in fluid communication with the said hydraulic manifold valve (123), for providing hydraulic fluid flow to the said hydraulic manifold valve (123); and a clutch system (124), fluidly coupled to the said hydraulic manifold valve (123), wherein said hydraulic manifold valve (123) controls the flow of fluid to the said clutch system (124).

2. An adaptive clutch fill up modulation control system (120), as claimed in claim 1, wherein said sensor (121) is a temperature sensor.

3. An adaptive clutch fill up modulation control system (120), as claimed in claim 1, wherein said hydraulic manifold valve (123) is a pressure proportional valve.

4. An adaptive clutch fill up modulation control system (120), as claimed in claim 1, wherein said clutch system (124) is a wet clutch system.

5. An adaptive clutch fill up modulation control system (120), as claimed in claim 1 & 4, wherein said clutch system (124) is a hydraulic forward /reverse clutch system.

6. An adaptive clutch fill up modulation control system (120), as claimed in claim 1, wherein said hydraulic fluid is transmission oil.

7. A method for adaptively modulating the clutch fill up as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system, comprising steps of:

a) detecting the temperature of the operating hydraulic fluid by means of a sensor (121);
b) transmitting the sensed fluid temperature to the electronic control unit (122), wherein said ECU (122) processes the fluid viscosity based on the sensed fluid temperature;
c) receiving the operator demand signal for clutch fill up modulation by the ECU (122);
d) calibrating the pressure profile based on the received operator demand and fluid viscosity;
e) modulating the clutch fill up modulation parameters as a function of fluid viscosity devised based on fluid temperature;
f) sending the modulated parameters as actuation signal to the hydraulic manifold valve (123);
g) energizing/de-energizing the hydraulic manifold valve (123) based on the received actuation signal, which directs the flow of hydraulic fluid from the hydraulic system (125); and
h) actuating the said clutch system, based on the operation of the said hydraulic manifold valve (123).

8. The method for adaptively modulating the clutch fill up rate, as claimed claim 7, wherein said sensor (121) is a temperature sensor.

9. The method for adaptively modulating the clutch fill up rate, as claimed claim 7, wherein said clutch fill up parameters includes but not limited to, clutch fill pulse time, clutch fill time, clutch fill pulse pressure and clutch fill pressure.

10. An adaptive clutch fill up modulation control system, as claimed in claim 1, wherein said ECU (122) controls the pre-fill of the said clutch system before enabling clutch engagement, wherein said pre-fill pressure (E) required for pre-filling the said clutch system (124) is modulated based on the hydraulic fluid temperature, this eliminates the static friction of the said hydraulic manifold valve (123).
, Description:FILED OF THE INVENTION

The present invention relates generally to transmission control system, in particular, the present invention is related to an adaptive clutch fill up modulation control system for wet clutch systems.

BACKGROUND OF THE INVENTION

In the field of transmission control systems for work vehicles, especially in agricultural tractors, number of transmission configurations and control schemes have been proposed and are widely in use. In most vehicles a transmission system translates the rotational speed of an engine shaft into a drive speed for the vehicle. A transmission system typically includes a series of intermeshing gears and selectively engage-able friction elements, known as clutches, which are selectively engaged to provide a series of gear ratios between an engine output shaft/transmission input shaft and a transmission output shaft. The transmission input shaft is coupled to the vehicle engine through a fluid coupling such as a torque converter, and the transmission output shaft is coupled to the vehicle drive wheels. The series of gear ratios established between the transmission input shaft and transmission output shaft transmits the engine torque at a desired speed to driven wheels of the vehicle. The gear ratios generally includes forward and reverse gears that range from low to high to provide different powers and speeds for the vehicle depending on the different operating condition. A desired gear ratio may be obtained by engaging one or more clutches within the transmission. shifting from one gear ratio to another involves releasing or disengaging the off-going clutches associated with the current gear ratio and applying or engaging the on-coming clutches associated with the desired gear ratio. Both the off-going clutches and the on-coming clutches cannot be engaged at the same time without causing serious wear and possible damage. On the other hand, if the off-going clutches are disengaged long before engagement of the on-coming clutches, the vehicle will be disengaged entirely for a period of time, and will decelerate. The optimum situation is to begin engaging of the oncoming clutches while the off-going clutches are being disengaged. Thus, as torque applied by the off-going clutches decreases, torque applied by the on-coming clutches increases. This overlap of torques eliminates the static friction and provides a smoother transition between gears.

It is difficult to properly overlap the torques due to inherent and changeable time delays during clutch engagement and disengagement. To improve the shifting of transmission, several transmission manufactures have utilized electronic control technology. Conventionally, the electronic control system includes a microprocessor-based transmission control module capable of receiving input signals indicative of various vehicle operating conditions such as engine speed, torque converter turbine speed, transmission output shift speed, etc. Based on the information contained in these signals, the controller generates control signals for actuating the pressure valves associated with each of the transmission clutches. A transmission system may utilize many types of clutches such as, for example, fluid/hydraulic clutches or mechanical clutches to engage a particular gear ratio.

In hydraulic clutches, a pressurized fluid may be introduced into a chamber to create an engagement force and a control valve governs the fluid flow into the clutch chamber. To engage the clutch, the control valve is opened to allow a restricted flow of fluid to enter and fill the clutch chamber. Once the chamber is filled with fluid, the valve is gradually modulated to a maximum open position to gradually increase the pressure of the fluid and the engagement force of the clutch. If the valve is open too quickly, or open prior to the clutch chamber filling, the clutch engagement may occur too quickly and cause the vehicle to jerk. The control system sends electric signals to the control valves that channels pressurized fluid to the clutches thus enabling the clutches to engage and disengage in predetermined combinations to accelerate, decelerate and drive the vehicle as desired by the operator. Hydraulic clutches must be filled with hydraulic fluid for an initial period, known as pre-fill time, before they begin engaging and transmitting torque. In most cases the control valves have a built in lag from the time they are energized to the time they open and permit fluid flow to the clutches.

One method of compensating such clutch fill delay is to actively control clutch engagement by measuring the pressure in the clutches or torque transmitted by the clutches as engagement occurs, and adaptively controlling the rate of clutch filling. Typically this would require a pressure sensor on each clutch as well as control valves capable of adaptively regulating the fluid flow to and from the clutches. This type of active control, however, adds complexity to the vehicle and increases the chance of breakdowns.

Further the clutch fill delay is not constant, and varies depending on environmental factors such as fluid viscosity, temperature, and wear that changes over time. To provide for precise shift timing, the clutch fill parameters for the on-coming clutch must be determined at the start of each shift. The accuracy of the fill parameters determines the quality of the resulting shift. These fluid fill parameters are used by the electronic transmission controller to effectively control fluid application to each element in order to provide an optimum shift quality or feel. Thus, an adaptive control method is desired to automatically adjust the fill parameters in order to produce an optimal shifting transmission. In particular, there is a need in the art for a better method of synchronizing the engagement and disengagement of clutches while changing gears in power shift transmissions. More particularly, there is a need for a control system for clutch fill up modulation for synchronizing clutch engagement and disengagement that will adapt to, and compensate for, changes in vehicle conditions such as hydraulic fluid temperature and viscosity etc. Variation in hydraulic fluid temperature varies the fluid viscosity and thereby pressure build up rate differs for each operation.

US Patent 5551930 relates to an adaptive control method for an automatic transmission. The method includes the steps of: (a) commanding a predetermined clutch to fill in accordance with a plurality of clutch fill parameters; (b) determining the actual time to completely fill the clutch; (c) comparing the actual fill time with a predetermined fill time; and (d) adjusting at least one of the plurality of clutch fill parameters in response to the comparison in order to modify the clutch fill period during subsequent shifts to the predetermined clutch.

US Patent 5853076 includes an apparatus for calibrating fluid clutch fill times including a valve, a clutch connected to the valve, a fluid supply connected to the valve, a pressure transducer connected between the fluid supply and the valve, and a processor adapted to control the valve, read the pressure transducer, and calculate the time required to fill the clutch. The invention further includes a method for adaptively controlling clutch engagement and disengagement in a clutch control system including signalling a first clutch valve to fill a clutch, measuring the time required to fill the clutch, signalling a second clutch valve to empty a second clutch, and saving the time value. The invention also includes a transmission system for a work vehicle that includes a transmission, two fluid clutches that engage the transmission in two gear ratios, respectively and a transmission controller that will calibrate the clutches and shift the transmission while the vehicle is in motion by engaging one clutch and disengaging another clutch while calculating the time required to fill the first clutch.

US patent 6640950 discloses a system for fluid clutch fill detection and method thereof. A command is received to engage a clutch having a chamber. A control valve is opened to allow pressurized fluid to flow from a fluid supply line into the clutch chamber. The pressure of the fluid within the fluid supply line is monitored as fluid flows through the control valve to enter the clutch chamber. A rate of change in the volume of fluid entering the chamber is determined based on the sensed pressure of the fluid within the fluid supply line. A fill point of the clutch chamber is detected when the rate of change in the volume of fluid entering the chamber is less than a volume differential threshold.

US 6039674 provides a method for determining fill volumes of a plurality of clutch elements in an automatic transmission wherein each clutch element is applied in a predefined order and the fill volume of each clutch element is obtained by determining when the rotational speed of the engine varies from the rotational speed of the transmission's turbine by a predefined amount.

US 6292732 relates to an improved on-coming clutch fill control method in which a model of the transmission hydraulic system is used for control purposes to accurately predict the achievement of on-coming clutch torque capacity based on a comparison of the modeled volume of supplied fluid to a reference volume representing the actual volume of the on-coming clutch, and in which the reference volume for each type of shift is adaptively adjusted based on input speed aberrations observed during shifting. If input speed flaring occurs due to an underestimated reference volume, the reference volume is adaptively increased based on the volume of fluid supplied to the on-coming clutch between the initial detection of flaring and a detection of maximum flaring. If the input speed does not flare, but an early pull-down or overlap is detected, the reference volume is adaptively decreased based on the volume of fluid supplied to the on-coming clutch between the initial detection of pull-down or overlap and the expected achievement of on-coming clutch torque capacity.

US patent application 20090159389 provides system and method for controlling a hydraulic transmission uses a solenoid valve having a pressure sensor linked to the valve body operable to sense a hydraulic fluid pressure within a cavity of the valve body and to transmit an electrical signal based on the sensed pressure. The transmitted signal is used to identify the end of fill time, and thus to end a clutch fill phase and commence a clutch modulation or lock-up phase.

All of the above cited prior-art documents provides a control system and method for clutch fill volumes and for calibrating the clutch fill rates. In the existing prior-art documents the clutch fill time and volumes are controlled based on the hydraulic fluid pressure, engine speed, or compared with the predetermined or reference fill volume and time. None of the existing prior-art documents considered vehicle operating conditions such as hydraulic fluid temperature and viscosity as a key factor in modulating the clutch fill up. Further none of the prior art documents addresses the system errors such as static friction and hysteresis error of the valve and clutch system. Hence there exists a need in the art to provide an adaptive control system for clutch fill up modulation as a function of transmission fluid viscosity based on the transmission fluid temperature. The system is adapted for wet clutch system which acts as an adjunct to the existing wet clutch transmission system in work vehicles. The adaptive control system for clutch fill up modulation according to the present invention adapts an unique pre-fill technique which overcomes the static friction of the valve and the modulated pressure profile of the clutch fill up system reduces the system hysteresis error. Further the present invention eliminates the dynamic vehicle behaviour such as vehicle jerk by effectively controlling the clutch fill volume with respect to change in fluid viscosity.

OBJECTIVES OF THE INVENTION

The main object of the present invention is to provide an adaptive clutch fill up modulation control system, for modulating the clutch volume fill up rates as a function of hydraulic fluid viscosity based on the hydraulic fluid temperature.

Another object of the present invention is to provide an adaptive clutch fill up modulation control system for wet clutch systems that acts as an adjunct to the existing wet clutch transmission system.

Another object of the present invention is to provide a method for adaptively controlling the clutch volume fill up by modulating the pressure profile and other clutch fill up parameters in accordance with the hydraulic fluid viscosity devised based on the hydraulic fluid temperature.

Still another objective of the present invention is to provide a control system which adaptively modulates the clutch fill up modulation in wet clutch system and adapts a unique pre-fill technique to overcome static friction of the valve and clutch system.

Yet another objective of the present invention is to provide a control system design which adaptively modulates the pressure profile of the clutch fill up modulation in wet clutch system and reduces the system hysteresis error.

Final objective of the present invention is to eliminate the dynamic vehicle behaviour such as vehicle jerk by effectively controlling the clutch fill volume with respect to change in fluid viscosity as a function of fluid temperature.

SUMMARY OF THE INVENTION

The present invention provides an adaptive clutch fill up modulation control system (120), for calibrating the clutch fill up rate as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system, comprises of : an electronic control unit (ECU) (122); atleast a sensor (121); a hydraulic manifold valve (123); a hydraulic system (125); and a clutch system (124). In the preferred embodiment, wherein said sensor (121) is a temperature sensor. The said electronic control unit (ECU) (122) is in communication with the said temperature sensor and receives the real time temperature of the hydraulic fluid. In an embodiment of the present invention, a method for adaptively modulating the clutch volume fill up as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system is also disclosed. The ECU (122) receives the operating hydraulic fluid temperature signals from the temperature sensor (121) and also receives signals in relation to the operator command. The ECU (122) processes the fluid viscosity from the sensed fluid temperature and also calibrates the clutch volume fill up rate and pressure profile based on the fluid viscosity. The calibrated pressure profile signals along with modulated clutch fill up parameters are transmitted as actuation signals to the said hydraulic manifold valve (123) for its operation, wherein said hydraulic manifold valve (123) is operatively coupled to the said clutch system (124). Based on the actuation signals received by the hydraulic manifold valve (123) the hydraulic fluid from the hydraulic system is directed to optimally fill up the clutch volume. In an embodiment of the present invention, the said ECU (122) also control the pre-fill of the said clutch system (124) before enabling clutch engagement, this pre-filling of the clutch system eliminates the static friction of the said manifold valve (123) in tandem with the clutch system (124). Further the present invention also address the system hysteresis error by adopting a modulated pressure profile and an uniquely designed intellectual control system.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of the adaptive clutch fill up modulation control system according to the present invention.

Figure 2 represents the adaptive clutch fill up modulation pressure profile with respect to hydraulic fluid temperature.

Figure 3 shows the look up table of various fill up modulation parameters as a function of hydraulic fluid temperature.

Figure 4 depicts the hysteresis curve of the proportional pressure control valve of the present invention.

Figure 5 represents the adaptive clutch fill up modulation control system of the present invention for wet clutch systems acting as an adjunct to the existing wet clutch transmission system.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention as embodied by an "Adaptive clutch fill up modulation control system and method thereof" succinctly fulfils the above-mentioned need(s) in the art. The present invention has objective(s) arising as a result of the above-mentioned need(s), said objective(s) being enumerated below. In as much as the objective(s) of the present invention are enumerated, it will be obvious to a person skilled in the art that, the enumerated objective(s) are not exhaustive of the present invention in its entirety, and are enclosed solely for the purpose of illustration. Further, the present invention encloses within its scope and purview, any structural alternative(s) and/or any functional equivalent(s) even though, such structural alternative(s) and/or any functional equivalent(s) are not mentioned explicitly herein or elsewhere, in the present disclosure. The present invention therefore encompasses also, any improvisation(s)/modification(s) applied to the structural alternative(s)/functional alternative(s) within its scope and purview. The present invention may be embodied in other specific form(s) without departing from the spirit or essential attributes thereof.

Throughout this specification, the use of the word "comprise" and variations such as "comprises" and "comprising" may imply the inclusion of an element or elements not specifically recited.

The present invention provides an adaptive clutch fill up modulation control system (120), for calibrating the clutch fill up rate as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system, comprising of : an electronic control unit (ECU) (122), for receiving input signals from plurality of sources and processing the received input signals in accordance with the operator demand; atleast a sensor (121), said sensor is in communication with the said ECU (122); a hydraulic manifold valve (123), operatively coupled to the said ECU (122); a hydraulic system (125), wherein said hydraulic system is in fluid communication with the said hydraulic manifold valve (123), for providing hydraulic fluid flow to the said hydraulic manifold valve; and a clutch system (124), fluidly coupled to the said hydraulic manifold valve (123), wherein said hydraulic manifold valve controls the flow of fluid to the said clutch system (124).

In the preferred embodiment, wherein said sensor (121) is a temperature sensor.

In the preferred embodiment, wherein said hydraulic manifold valve (123) is a pressure proportional valve, wherein said hydraulic manifold valve is a solenoid valve.

In the preferred embodiment, wherein said clutch system (124) is a hydraulic wet clutch system, that is engaged by filling fluid, wherein said wet clutch system is a forward /reverse clutch system.

In the preferred embodiment of the present invention, wherein said hydraulic fluid is transmission oil.

Fig. 1 illustrates the adaptive clutch fill up modulation control system (120) of the present invention, where the said hydraulic manifold valve (123) is in communication with the said hydraulic system (125) and said clutch system (124). The hydraulic system (125) supplies the hydraulic fluid flow to the said hydraulic manifold valve (123). The said manifold valve (123) is in communication with the said clutch system (124), controlling the fluid flow to the clutch system based on the operator demand and hydraulic fluid viscosity devised based on the sensed fluid temperature. The said electronic control unit (ECU) (122) is in communication with the temperature sensor (121) and receives the real time temperature of the hydraulic fluid. The ECU (122) calibrates the clutch fill up rate based the received operator demand and fluid viscosity devised from the received fluid temperature.

In an embodiment of the present invention, the hydraulic manifold valve (123) is energized i.e. opened to allow the flow of fluid into the said clutch system (124) and maintains the set pressure in the said clutch system calibrated by the said ECU (122), and de-energized i.e. closed to allow the flow of fluid out of the clutch system (124), thus releasing the pressure inside the clutch system, thereby creating a pressure drop inside the said clutch system (124). The said hydraulic manifold valve (123) is a reverse flow preventing check valve which prevents the back flow of fluid during pressure drop. The said ECU (122) controls the opening and closing of the said manifold valve (123) by communicating the opening and closing signals to the said manifold valve (123). The ECU (122) receives the operating hydraulic fluid temperature signals from the temperature sensor (121) and also receives signals in relation to the operator command. Finally it calibrates the clutch fill up rate and pressure profile based on the operator demand and hydraulic fluid viscosity calculated from the fluid temperature. The calibrated pressure profile signals are transmitted to the said hydraulic manifold valve (123) to energized/de-energize the same.

A method for adaptively modulating the clutch fill up as a function of hydraulic fluid viscosity based on hydraulic fluid temperature, for transmission system, comprising steps of:

a) detecting the temperature of the operating hydraulic fluid by means of a sensor (121);
b) transmitting the sensed fluid temperature to the electronic control unit (122), wherein said ECU (122) processes the fluid viscosity based on the sensed fluid temperature;
c) receiving the operator demand signal for clutch fill up modulation by the ECU (122);
d) calibrating the pressure profile based on the received operator demand and fluid viscosity;
e) modulating the clutch fill up modulation parameters as a function of fluid viscosity devised based on fluid temperature;
f) sending the modulated parameters as actuation signal to the hydraulic manifold valve (123);
g) energizing/de-energizing the hydraulic manifold valve (123) based on the received actuation signal, which directs the flow of hydraulic fluid from the hydraulic system (125); and
h) actuating the said clutch system (124), based on the operation of the said hydraulic manifold valve (123).

In an embodiment of the present invention, said electronic control unit (122) receives the input from user for clutch fill up modulation and transmission oil temperature, ECU modulates the clutch fill parameters to optimally fill up the clutch volume and to develop required clutch pressure for further clutch engagement phase, wherein said clutch fill-up parameters includes clutch fill pulse time, clutch fill time, clutch fill pulse pressure and clutch fill pressure .

In an exemplary embodiment of the present invention, when the operator demands an clutch engagement, the ECU (122) receives the operator demand/command and also receives the real time temperature of transmission oil by means of the said temperature sensor (121). The ECU (122) then processes the oil viscosity based on the sensed oil temperature and then calibrates the pressure profile based on the input information i.e operator demand and oil viscosity. The ECU (122) also modulates the other clutch fill up parameters such as clutch fill pulse time, clutch fill time, clutch fill pulse pressure and clutch fill pressure. The modulated pressure profile along with the modulated clutch fill parameters in accordance with the fluid/oil viscosity is transmitted as actuation signal to the said hydraulic manifold valve (123). The said hydraulic manifold valve (123) is energized by allowing a modulated amount of fluid/oil inflow from the hydraulic system (125) to the clutch system (124) to maintain the calibrated set pressure inside the clutch system, wherein said amount of fluid/oil required for optimum fill up of clutch volume to enable clutch engagement is modulated as a function of transmission oil viscosity calculated based on the transmission oil temperature.

In another exemplary embodiment of the present invention, when the operator demands an clutch dis-engagement, the ECU (122) receives the operator demand/command and also receives the real time temperature of transmission oil by means of the said temperature sensor (121). The ECU (122) then processes the oil viscosity based on the sensed temperature and then calibrates the pressure profile based on the input information i.e operator demand and oil viscosity. The ECU (122) also modulates the other clutch fill up parameters such as clutch fill pulse time, clutch fill time, clutch fill pulse pressure and clutch fill pressure. The modulated pressure profile along with the modulated clutch fill parameters in accordance with the fluid/oil viscosity is transmitted as actuation signal to the said hydraulic manifold valve (123). The said hydraulic manifold valve (123) is de-energized by releasing a modulated amount of fluid/oil from the clutch system (124) to the hydraulic system (125) this releases the pressure inside the clutch system, wherein said amount of fluid/oil to be released for optimum fill up of clutch volume to enable clutch dis-engagement is modulated as a function of transmission oil viscosity calculated based on the transmission oil temperature.

Fig.2 shows clutch fill up modulation pressure curve with respect to sensed hydraulic fluid temperature and also shows the modulated clutch fill parameters based on the hydraulic fluid temperature. In fig. 2, A is the clutch fill up time (A), B is the fill pulse time (B), C is fill pulse pressure (C), D is the fill target pressure (D), E is pre-fill pressure (E) and a zone H showing the reduction in valve hysteresis error.

In another embodiment, wherein said ECU (122) controls the pre-fill of the said clutch system to eliminate the static friction of the valve. From Fig. 2, clutch fill up modulation curve based on the transmission oil temperature, a pre-fill zone (I) can be inferred which overcomes the static friction of the said hydraulic manifold valve. The graph also provides a pre-fill pressure (E) modulated based on the transmission oil temperature required for pre-filling the said clutch system before enabling clutch engagement.

In an embodiment of the present invention, wherein said ECU (122) is designed to address the valve hysteresis error by adopting a intellectual control system strategy. In a typical fill pulse profile, in case of transition from pre-fill pressure (E) to fill pulse pressure (C), the clutch pressure follows a pressure on curve (126) as shown in figure 4 and while transition from fill pulse pressure (C) to fill target pressure (D), the clutch pressure follows Pressure off curve (127) which gives a pressure hysteresis error. To avoid the jump of pressure curve from pressure on curve (126) to Pressure off curve (127) and retain it in pressure on curve (126) profile throughout the clutch fill up modulation, a step profile with increasing and reducing momentary profile is adapted. In Fig. 2, the zone H is indicated with a step showing that transition from pressure on curve (126) to Pressure off curve (127) is avoided. When the fill pulse time (B) is completed, pressure demands follows pressure off curve (127) and at the end of Zone H, pressure demands again follows pressure on curve (126) this reduces the valve hysteresis error. The pressure on curve (126) and pressure off curve (127) along with ideal valve character (128) is shown in Fig.4. This control technique avoids the undesired vehicle dynamics during clutch fill and helps to launch the vehicle in a gentle or smoother manner.

Other clutch fill up parameters modulated based on real time hydraulic fluid/transmission oil temperature is also depicted in Figure. 3 as look up table. This phenomenon helps to optimally fill the clutch volume and also avoid the vehicle jerkiness or sluggish of vehicle movement under various ambient temperature conditions.

In an embodiment of the present invention, the adaptive clutch fill up modulation control system acting as an adjunct to the existing wet clutch transmission system is depicted (Fig.5). In Fig. 5, the existing wet clutch transmission system, comprising of: an engine (129); a transmission unit (130), in communication with the said engine, wherein said transmission unit (130) is provided with plurality of gears, in particular speed gears (131) and range gears (132); vehicle drive wheels (133), operatively coupled to the said transmission unit (130); and a wet clutch system (124), placed in-between the said engine (129) and the said transmission unit (130);, is additionally provided with the adaptive clutch fill up modulation control system comprising of: an ECU (122), for receiving input signals from plurality of sources and processing the received input signals in accordance with the operator demand; atleast a sensor (121), said sensor is in communication with the said ECU (122); a hydraulic manifold valve (123), operatively coupled to the said ECU (122), wherein said hydraulic manifold valve controls the flow of fluid to the said wet clutch system (124); a hydraulic system (125), wherein said hydraulic system is in fluid communication with the said hydraulic manifold valve (123), for providing hydraulic fluid flow to the said hydraulic manifold valve
(123).

It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the spirit and the scope of the invention may be made by a person skilled in the art.

LIST OF REFERENCE NUMERALS

122 - Electronic Control Unit (ECU)
121 - Sensor
123 -Hydraulic manifold valve
125 -Hydraulic system
124 -Clutch system
126 - Pressure on curve
127 - Pressure off curve
128 - Ideal valve character
129 - Engine
130 - Transmission Unit
131 - Speed gears
132 - Range Gears (High/Low)
133 - Vehicle drive wheels
A - clutch fill up time
B - fill pulse time
C - fill pulse pressure
D - fill target pressure
E - pre-fill pressure
H - Zone showing the reduction in valve hysteresis error
I - Clutch pre-fill zone