Propulsion control using lateral acceleration and propulsion control signals to select slip thresholds

• US 4,933,856 A
• Filed: 12/17/1986
• Issued: 06/12/1990
• Est. Priority Date: 12/21/1985
• Status: Expired due to Fees

• Current Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Inventors: Leiber, Heinz
• Primary Examiner(s): Chin, Gary
• Application Number:
  US06/942,693
• Time in Patent Office: 1,273 Days
• Field of Search: 364/426, 364/431.07, 180/197, 361/238, 303/95, 303/97, 303/100
• US Class Current: 701/70
• CPC Class Codes: B60K 23/08 for changing number of driven wheels , for switching from driving one axle to driving two or more axles B60K17/3515 takes precedence
• 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: B60T 2270/202 for all-wheel drive vehicles
• CPC Class Codes: B60T 2270/211 Setting or adjusting start-control threshold
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60T 8/1769 specially adapted for vehicles having more than one driven axle, e.g. four-wheel drive vehicles
• CPC Class Codes: B60W 2520/125 Lateral acceleration

Abstract

A propulsion control system for motor vehicles for preventing an undesirable spinning of the driven vehicle wheels when their slip exceeds a certain threshold value, having several slip thresholds that are connected or disconnected by a logic circuit as a function of vehicle speed, the lateral acceleration and control signals of the propulsion control. The logic circuit may also be used for changing the increase and adjusting speeds of the control elements of the propulsion control, and for connecting the drive of the wheels of an additional axle and disconnecting it again directly or under certain conditions, in a delayed way.

Claims

1. In a propulsion control system for a motor vehicle for preventing an undesireable spinning of the driven vehicle wheels, having a plurality of sensor means for providing signals indicative of the speed of the vehicle wheels, having slip means for determining the slip of the driven vehicle wheels from the signals of said sensor means, having a first slip comparator means for each driven vehicle wheel for comparing the driven wheel speed to an indicated threshold value and providing an output signal when the threshold is exceeded, having means for actuating a control element to reduce the output torque of an engine of the vehicle in response to an input signal indicative of at least one of the driven wheels of the vehicle tend to spin, having a vehicle speed comparator means for comparing vehicle speed to a second indicated threshold value and providing an output signal when the second threshold is exceeded, having a means for measuring the lateral acceleration of the vehicle, a first lateral acceleration comparator means for comparing said lateral acceleration to a third indicated threshold value and providing an output signal when the third threshold is exceeded, the improvement comprising:

at least a second lateral acceleration comparator means for comparing said lateral acceleration to a first indicated additional threshold value and providing an output signal when the first additional threshold is exceeded,

for each driven vehicle wheel, at least one additional slip comparator means for comparing said driven wheel speed to a second additional indicated threshold value and providing an output signal when the second additional threshold is exceeded, and

logic means for enabling at least said additional slip comparator means instead of the first slip comparator in response to a predetermined combination of said output signal of the vehicle speed comparator means, said output signal from said lateral acceleration comparator means and said input signal to the actuating means for the control element affecting the engine output torque.

2. A system according to claim 1, wherein said logic means enables the additional slip comparator means when one of said first and second lateral acceleration comparator provides an output signal.

3. A system according to claim 1, wherein said logic means enables the additional slip comparator means when one of said first and second lateral acceleration comparator means provides an output signal and said actuating means receives said input signal simultaneously.

4. A system according to claim 1, wherein said logic means enables the additional slip comparator means when one of said first and second lateral acceleration comparator means and the vehicle speed comparator means provide output signals simultaneously.

5. A system according to claim 1, wherein said logic means enables the additional slip comparator means when one of said first and second lateral acceleration comparator means and the vehicle speed comparator means provide output signals and said actuating means receives said input signal simultaneously.

6. A system according to claim 1, wherein said logic means includes all-wheel logic means for actuating a control element of a connectable all-wheel drive when said actuating means receives said input signal.

7. A system according to claim 6, wherein said all-wheel logic means includes delay means for delaying deactivating of the connectible all-wheel drive.

8. A system according to claim 7, wherein said all-wheel logic means includes means for disabling said delay means when one of said first and second lateral acceleration comparator means emits an output signal that is significantly higher with respect to high lateral acceleration and the vehicle speed comparator means emits an output signal that is significantly lower with respect to low vehicle speed.

9. A system according to claim 1, including:

means for actuating the wheel brake of individual driven vehicle wheels that tend to spin; and

said logic means selectively enables one of said first and said additional slip comparators per driven vehicle, if, in addition to the input signal to the actuating means for the control element affecting the engine torque, an input signal to the actuating means for the wheel brakes of the driven vehicle wheels is present.

10. A system according to claim 9, wherein said logic means enables the additional said slip comparator means when one of said first and second lateral acceleration comparator means provides an output signal and at least one of said actuating means receives said input signal simultaneously.

11. A system according to claim 9, wherein said logic means enables the additional slip comparator means when one of said first and second lateral acceleration comparator means and the vehicle speed comparator means provide output signals and at least one actuating means receives said input signal simultaneously.

12. A system according to claim 9, wherein said logic means includes all-wheel logic means for actuating a control element of a connectable all-wheel drive when at least one actuating means receives said input signal.

13. A system according to claim 9, wherein said logic means includes means for changing the rate of the brake pressure change in the wheel brakes as well as the rate of adjusting the power control element of the vehicle engine.