Claims:
We claim:
1. A control unit (110) for traction control of a vehicle (100), said vehicle (100) comprises at least a generator (106) coupled to a crankshaft (112) of an engine (108), and one speed sensor (104) for each wheel (102, 104) of said vehicle (100), and said control unit (110) in electronic communication with said speed sensors (104) and said generator (106), said control unit (110) adapted to
detect wheel slip based on signals received from said speed sensors (104), characterized in that, said control unit (110) is further adapted to
drive said generator (106) for reducing torque transferred to a drive wheel (124) by said engine (108) to regain traction.

2. The control unit (110) as claimed in claim 1, wherein said drive comprises control of electrical energy supplied by said generator (106) to at least one electrical load (120).

3. The control unit (110) as claimed in claim 2, wherein said electrical load (120) is selected from at least one of a battery (118) and an electrical accessory 122.

4. The control unit (110) as claimed in claim 1, wherein said generator (106) is driven until said wheel slip is eliminated.

5. The control unit (110) as claimed in claim 1, wherein said generator (106) is an Integrated Starter Generator (ISG).

6. A method for controlling traction of a vehicle (100), said vehicle (100) comprises a generator (106) coupled to a crankshaft (112) of an engine (108) and one speed sensor (104) for each wheel (102, 104) of said vehicle (100), and a control unit (110) in electronic communication with said speed sensors (104) and said generator (106), said method comprising the steps of:
detecting wheel slip by monitoring signals from said speed sensors (104), said method is characterized by
driving said generator (106) for reducing torque transferred to a rear wheel (124) by said engine (108) to regain traction.

7. The method as claimed in claim 6, wherein driving comprises controlling supply of electrical energy to at least one electrical load (120).

8. The method as claimed in claim 7, wherein said at least one electrical load (120) selected from a group comprising a battery (118) and an electrical accessory 122.

9. The method as claimed in claim 6, wherein driving of said generator (106) is performed until said wheel slip is eliminated.

10. The method as claimed in claim 6, wherein said driving of said generator (106) is performed in combination of existing control measures to control traction of said vehicle (100).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present invention relates to a control unit and method for controlling traction of a vehicle.

Background of the invention:
[0002] A Traction Control System (TCS) controls a vehicle and provides stability during scenarios of wheel slip. The TCS available in the market currently makes use of an Electronic Throttle Control (ETC) to control the wheel torque in case when the wheel slip is detected. An alternate strategy used in the vehicle comprising Mechanical Throttle Control, where the ignition angle is retarded to reduce the torque at the wheels. The MTC are not as efficient as the ETC in traction control as ignition angle retard at an operating point is limited by the rise in exhaust temperature, which potentially could damage exhaust components.

[0003] According to a patent literature US2002138182 discloses a regenerative deceleration for a hybrid drive system. A control system is provided for the drive system of automotive vehicles. The control determines a combination of torque to be applied from an integrated starter-generator and compression torque to be applied from an engine. The combination of the integrated starter-generator torque and engine compression torque results in a desired deceleration torque. The control preferentially applies torque from the integrated starter-generator over the compression torque, thus maximizing regeneration.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0005] Fig. 1 illustrates a control unit for traction control of a vehicle in a block diagram, according to an embodiment of the present invention, and
[0006] Fig. 2 illustrates a method for controlling traction of the vehicle, according to the present invention.

Detailed description of the embodiments:
[0007] Fig. 1 illustrates a control unit for traction control of a vehicle in a block diagram, according to an embodiment of the present invention. The vehicle 100 comprises a generator 106 coupled to a crankshaft 112 of an engine 108 and one speed sensor 104 for each wheel 102, 124 of the vehicle 100. The speed sensor 104 is adapted to measure the wheel speed. The control unit 110 is in electronic communication with each of the speed sensor 104 and the generator 106. The control unit 110 is adapted to detect wheel slip based on signals received from the speed sensors 104, characterized in that, the control unit 110 further adapted to drive the generator 106 for reducing torque transferred to a drive wheel 124 by the engine 108 to regain traction. The drive comprises control of supply of electrical energy to at least one electrical load 120. In an embodiment, the electrical energy is supplied to at least one electrical load 120 until the wheel slip is eliminated.

[0008] The engine 108 which is already driving the drive wheel 124 through the transmission 114 is further made to drive the generator 106. The load on the engine 108 increases, and thereby the torque produced by the engine 108 gets diverted to generate electrical energy, in addition to propelling the vehicle 100. The diverted torque reduces the torque at the drive wheel 124 and assists in regaining the traction of the drive wheel 124. The engine 108 is either a spark ignited or compression ignited.

[0009] The electrical load 120 is selected from at least one of a battery 118 and at least one electrical accessory 122. The electrical accessory 122 are selected from but not limited to an odometer, an infotainment system, a horn, a wiper, a headlight, a brake light, a radio, an air conditioning system, and the like. Further, the control unit 110 is adapted to supply the electrical energy directly to the electrical accessory 122 or through the battery 118.

[0010] In an embodiment, the control unit 110 is an Engine controller in communication with a generator controller 116. The generator controller 116 regulates the supply of electrical energy or current to the at least one electrical load 120 based on a command signal received by the Engine controller. In an alternate embodiment, the generator controller 116 and the Engine controller are provided as a single component, i.e. as the control unit 110.

[0011] In one embodiment, the generator 106 is not in operation while the vehicle 100 is travelling. The control unit 110 activates the generator 106 on detection of the wheel slip. Once activated, the control unit 110 controls the supply of electrical energy to at least one electrical load 120 until the wheel slip is eliminated. For example: the control unit 110 increases the number of electrical loads 120 on the generator 106 in order to draw more electrical energy from the engine 108, and thereby reduces the torque transferred to the drive wheel 124, by the engine 108, to regain traction.

[0012] In another embodiment, the generator 106 is already in operation while the vehicle 100 is travelling. The control unit 110 then directly controls the supply of electrical energy to the at least one electrical load 120. For example: if the generator 106 is charging the battery 118, then the control unit 110 adds more electrical loads 120, such as the electrical accessory 122 to the generator 106 to increase the total current or energy drawn, thereby reducing the torque of the engine 108. Once the wheel slip is eliminated, the control unit 110 resumes the normal operation.

[0013] The vehicle 100 shown in Fig. 1 is a two-wheeler, however the control unit 110 is applicable to be used for a three-wheeler such as an auto-rickshaw, a four-wheeler such as a car, and other vehicles 100 which are fit with the generator 106.

[0014] The generator 106 is an alternator or an Integrated Starter Generator (ISG). Also, the engine 108 is coupled to the drive wheel 124 by the transmission 114 selected from a group comprising a manual transmission, Automated Manual Transmission (AMT) and a Continuously Variable Transmission (CVT), and the like. The vehicle 100 is either an all-wheel drive or rear-wheel drive or a front-wheel drive or selective wheel drive.

[0015] In accordance to an embodiment of the present invention, the control unit 110 is adapted to drive the generator 106 to control traction of the vehicle 100 in combination with at least one existing control measure of the vehicle 100. The existing control measure comprises spark control for the combustion of fuel, braking the wheels 102, 124, throttle control in an Electronic Throttle Control (ETC) system, control of quantity of fuel injected and the like.

[0016] Fig. 2 illustrates a method for controlling traction of the vehicle, according to the present invention. The vehicle 100 comprises the generator 106 coupled to the crankshaft 112 of the engine 108 and one speed sensor 104 for each wheel 102, 124 of the vehicle 100. Further, the control unit 110 is in electronic communication with the speed sensors 104 and the generator 106. The method comprising the steps of, a step 202 comprising detecting wheel slip by monitoring signals received from the speed sensors 104. The method is characterized by a step 204 comprising driving the generator 106 for reducing the torque transferred to the drive wheel 124 by the engine 108 to regain traction. The driving comprises controlling supply of electrical energy to at least one electrical load 120. The supplying of electrical energy to at least one electrical load 120 is performed until the wheel slip is eliminated.

[0017] The at least one electrical load 120 is selected from a group comprising the battery 118 and the electrical accessory 122. The driving of the generator 106 is performed by the generator controller 116 in communication with the Engine controller. Alternatively, only one control unit 110 is used to drive the generator 106 and the engine 108.

[0018] The engine 108 drives the wheel 102 through the transmission 114 selected from the group comprising the manual transmission, the Automated Manual Transmission (AMT) and the Continuously Variable Transmission (CVT).

[0019] The method for controlling traction of the vehicle 100 is performed in combination with at least one existing control measure. The existing control measure comprises spark control for the combustion of fuel, braking the wheels 102, 124, throttle control in an Electronic Throttle Control (ETC) system, control of quantity of fuel injected and the like. The adverse impact of the existing measure is greatly reduced if used in combination with the present invention.

[0020] In accordance to an embodiment of the present invention, a traction control system using a generator 106 mounted on the crankshaft 112 of the engine 108 is provided. The present invention provides a cost effective traction control system for low cost Electronic Fuel Injection (EFI) segments of vehicles 100 without the use of ETC. When the wheel slip is detected, the control unit 110 reduces the torque at the drive wheel 124. Alternatively, the control unit 110 calculates the torque to be reduced on the wheel 102 and loads the engine 108 correspondingly. This essentially reduces the torque transferred to the drive wheel 124 thereby reducing wheel slip. The control unit 110 modulates the torque of the engine 108 using a Proportional and Integral controller logic.

[0021] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.