Torque compensation method and system

• US 9,487,207 B2
• Filed: 01/17/2014
• Issued: 11/08/2016
• Est. Priority Date: 05/06/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Nagashima, Dan, Mizuno, Takahide, Toyoshima, Hirokazu, O'Donnell, Lee, Tonokura, Naomichi, Muto, Akio, Ishikawa, Yutaka
• Primary Examiner(s): Rojas, H
• Application Number:
  US14/157,580
• Publication Number:
  US 20140195130A1
• Time in Patent Office: 1,026 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/119 including control of all-wheel-driveline means, e.g. transfer gears or clutches for dividing torque between front and rear axle B60W10/14 takes precedence
• CPC Class Codes: F02D 2200/021 Engine temperature
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 2400/12 Engine control specially adapted for a transmission comprising a torque converter or for continuously variable transmissions
• CPC Class Codes: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0215 in relation with elements of the transmission
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F16H 2059/467 of torque converter
• CPC Class Codes: F16H 45/00 Combinations of fluid gearings for conveying rotary motion with couplings or clutches gearing systems consisting of a plurality of hydrokinetic units operating alternatively F16H41/22 , F16H47/085
• CPC Class Codes: F16H 59/72 dependent on oil characteristics, e.g. temperature, viscosity
• CPC Class Codes: F16H 63/50 Signals to an engine or motor

Abstract

A system and method of compensating for torque converter slip in a motor vehicle include measuring rotational speeds of an engine crankshaft and mainshaft, as well as measuring operating temperatures of a fluid associated with the motor vehicle. Engine output torque is adjusted as required by controlling some combination of ignition timing, intake air flow, fuel injection, and accessory load. A system and method for deactivating a torque compensation system retrieves a number of times the torque compensation system has been activated over a set period. If the number exceeds a predetermined number of activations, the torque compensation system is deactivated.

Claims

1. A system for adjusting output torque of an engine for a motor vehicle including a torque compensation system, comprising:

an electronic control unit;

a first sensor for detecting a rotational speed of a first shaft in a drive train of the motor vehicle, the first shaft being an input shaft;

a second sensor for detecting a rotational speed of a second shaft in the drive train of the motor vehicle, the second shaft of the motor vehicle being an output shaft hydraulically coupled to the first shaft; and

a temperature sensor for determining a vehicle fluid temperature;

wherein the electronic control unit is configured to calculate an actual slip ratio based on a measured speed from the first sensor and a measured speed from the second sensor;

wherein the electronic control unit is further configured to activate the torque compensation system by;

determining an expected slip ratio based on a measured vehicle fluid temperature from the temperature sensor, wherein the expected slip ratio is determined based on a correlation between the vehicle fluid temperature and the expected slip ratio stored in a database in communication with the electronic control unit;

determining whether the actual slip ratio between the first shaft and the second shaft exceeds the expected slip ratio corresponding to the measured vehicle fluid temperature; and

adjusting the output torque based on a result of the determining whether the actual slip ratio exceeds the expected slip ratio corresponding to the measured vehicle fluid temperature;

wherein the electronic control unit is further configured to retrieve a number of times the torque compensation system has been activated in a current driving cycle; and

wherein the electronic control unit is configured to deactivate the torque compensation system if the number of times the torque compensation system has been activated in the current driving cycle exceeds a predetermined number of activations.

2. The system according to claim 1, wherein the electronic control unit is further configured to provide a signal to the engine to generate a normal torque output upon determining that the actual slip ratio does not exceed the expected slip ratio, the normal torque output being determined as a function of the measured vehicle fluid temperature;

and

wherein the electronic control unit is further configured to provide a signal to the engine to generate an increased torque output upon determining that the actual slip ratio exceeds the expected slip ratio;

the increased torque output being greater than the normal torque output and wherein the increased torque output is determined as a function of the measured vehicle fluid temperature.

3. The system according to claim 2, wherein the signal to the engine to generate the increased torque output includes adjusting ignition timing.

4. The system according to claim 2, wherein the signal to the engine to generate the increased torque output includes adjusting engine intake air supply.

5. The system according to claim 2, wherein the signal to the engine to generate the increased torque output includes adjusting fuel injection.

6. The system according to claim 5, wherein the fuel injection is adjusted by varying one or more of injection timing, injection pressure, and injection open time.

7. The system according to claim 2, wherein the signal to the engine to generate the increased torque output includes decreasing accessory load.

8. The system according to claim 7, wherein the accessory load is decreased by one or more of decreasing an alternator field, decoupling an alternator, decoupling a power steering pump, and reducing a power steering pump pressure.

9. The system according to claim 1, wherein the predetermined number of activations is set for one or more of:

a life of the motor vehicle, a single cycle of starting and shutting down the engine of the motor vehicle, and a given distance that the motor vehicle is driven.

10. The system according to claim 1, further comprising a signal filter associated with at least one of the first sensor and the second sensor.

11. A method for adjusting output torque of an engine for a motor vehicle including a torque compensation system in communication with an electronic control unit, comprising the steps of:

detecting a rotational speed of a first shaft in a drive train of the motor vehicle using a first sensor, the first shaft being an input shaft;

detecting a rotational speed of a second shaft in the drive train of the motor using a second sensor, the second shaft of the motor vehicle being an output shaft hydraulically coupled to the first shaft;

determining a vehicle fluid temperature using a temperature sensor; and

wherein the electronic control unit further performs the steps of;

activating the torque compensation system by;

calculating an actual slip ratio based on a measured speed from the first sensor and a measured speed from the second sensor;

determining an expected slip ratio based on a measured vehicle fluid temperature from the temperature sensor, wherein the expected slip ratio is determined based on a correlation between the vehicle fluid temperature and the expected slip ratio stored in a database in communication with the electronic control unit;

determining whether the actual slip ratio between the first shaft and the second shaft exceeds the expected slip ratio corresponding to the measured vehicle fluid temperature;

adjusting the output torque based on a result of the determining whether the actual slip ratio exceeds the expected slip ratio corresponding to the measured vehicle fluid temperature;

wherein the electronic control unit further performs the steps of;

retrieving a number of times the torque compensation system has been activated; and

deactivating the torque compensation system if the number of times the torque compensation system has been activated exceeds a predetermined number of activations.

12. The method according to claim 11, wherein the step of retrieving a number of times the torque compensation system has been activated further comprises retrieving a number of times the torque compensation system has been activated in a current driving cycle;

and

wherein the step of deactivating the torque compensation system further comprises deactivating the torque compensation system if the number of times the torque compensation system has been activated in the current driving cycle exceeds the predetermined number of activations.

13. The method according to claim 11, further comprising setting the predetermined number of activations using the electronic control system.

14. The method according to claim 13, wherein the step of setting the predetermined number of activations comprises setting the predetermined number for one or more of:

a life of the motor vehicle, a single cycle of starting and shutting down the engine of the motor vehicle, and a given distance that the motor vehicle is driven.

15. The method according to claim 11, wherein upon determining by the electronic control unit that the number of times the torque compensation system has been activated does not exceed the predetermined number of activations, the electronic control unit activating the torque compensation system.

16. The method according to claim 15, wherein the step of activating the torque compensation system further comprises varying operation of the engine of the motor vehicle using the electronic control unit to maintain a predetermined output torque of the engine of the motor vehicle.

17. The method according to claim 16, further comprising:

providing a signal to the engine from the electronic control unit to generate a normal torque output to the first shaft as an input torque upon determining that the actual slip ratio does not exceed the expected slip ratio, the normal torque output being determined as a function of the vehicle fluid temperature.

18. The method according to claim 17, further comprising:

providing a signal to the engine from the electronic control unit to generate an increased torque output to the first shaft as the input torque upon determining that the actual slip ratio is above the expected slip ratio, wherein the increased torque output is greater than the normal torque output and wherein the increased torque output is determined as a function of the vehicle fluid temperature.

19. The method according to claim 18, wherein the signal to the engine to generate the increased torque output includes at least one of adjusting ignition timing, adjusting engine intake air supply, and adjusting fuel injection.

20. The method according to claim 11, further comprising filtering a signal associated with at least one of the first sensor and the second sensor to increase a signal to noise ratio.