Vehicular motion controlling system

• US 5,947,221 A
• Filed: 07/24/1997
• Issued: 09/07/1999
• Est. Priority Date: 07/24/1996
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Nagata, Toshirou, Sawada, Mamoru, Taniguchi, Masahiko
• Primary Examiner(s): Mai, Lanna
• Assistant Examiner(s): Fleming, Faye M.
• Application Number:
  US08/899,677
• Time in Patent Office: 775 Days
• Field of Search: 180/197, 180/370, 701/84, 701/86, 303/141, 303/142, 303/146
• US Class Current: 180/197
• CPC Class Codes: B60T 2270/303 Stability control with active acceleration
• CPC Class Codes: B60T 8/4872 pump-back systems
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 2720/28 Wheel speed

Abstract

In the present invention, when the wheel speeds of drive wheels are reduced by an engine brake, there are executed drive wheel control for adjusting the braking forces applied to the drive wheels by the engine brake, and driven wheel control for reducing the wheel speeds of driven wheels by an brake actuator. Drive wheel control raises lateral resistant force of the drive wheels by increasing an engine output torque, and driven wheel control brakes the driven wheels by the brake actuator such as a hydraulic brake. As a result, sufficient deceleration of a vehicle can be obtained while retaining the stability of the vehicle.

Claims

1. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driving wheel control device which operates concurrently with said drive wheel control device for reducing the wheel speeds of driven wheels by a brake actuator.

2. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein said drive wheel control device reduces the braking force due to said engine brake by increasing an engine output torque.

3. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein said drive wheel control device and said driven wheel control device adjust distribution of brake force provided to said drive wheel and said driven wheel in response to slip states of several wheels and/or a road surface state.

4. A vehicular motion controlling system according to claim 3, wherein said drive wheel control device and said driven wheel control device start their operations when a predetermined slip is caused in the drive wheels by said engine brake.

5. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein braking force corresponding to said engine brake is distributed between braking forces of said drive wheels and braking force of said driven wheels so that the vehicle can stably travel.

6. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein braking force corresponding to said engine brake is distributed between braking forces of said drive wheels and braking force of said driven wheels so that deceleration caused by said engine brake can be obtained.

7. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein said engine brake is operated when a driver releases an accelerator pedal.

8. A vehicular motion controlling system comprising:

a drive wheel control device for adjusting a braking force provided to drive wheels by an engine brake when the wheel speeds of said drive wheels are reduced by said engine brake; and

a driven wheel control device for reducing the wheel speeds of driven wheels by a brake actuator;

wherein said engine brake is operated when an automatic control device automatically adjusts braking force and/or drive force of the vehicle.

9. A vehicular motion controlling system utilized for a vehicle including at least rear side wheels serving as drive wheels, comprising:

engine brake detecting means for detecting that engine brake is applied to said drive wheels in response to a reduction in drive force provided from an engine to said drive wheel; and

braking force controlling means for applying braking force to front side wheels by a brake actuator in response to load movement in a vehicle caused by said engine brake when said engine brake is applied to said drive wheels.

10. A vehicular motion controlling system utilized for a vehicle having rear side wheels serving as drive wheels and front side wheels serving as driven wheels, comprising:

engine brake detecting means for detecting that engine brake is applied to said drive wheels in response to a reduction in drive force provided from an engine to said drive wheels; and

braking force controlling means for applying braking force to said driven wheels by a brake actuator so that said braking force applied to said driven wheels is equal to or more than braking force applied to said drive wheels due to said engine brake when said engine brake is applied to said drive wheels.

11. A vehicular motion controlling system utilized for a vehicle having rear side wheels serving as drive wheels and front side wheels serving as driven wheels, comprising:

engine brake detecting means for detecting that an engine brake is applied to said drive wheels in response to a reduction in drive force provided from an engine to said drive wheels; and

braking force controlling means for applying braking force to said driven wheels by a brake actuator so that said braking force applied to said driven wheels is equal to or more than braking force applied to said drive wheels when said engine brake is applied to said drive wheels.

12. A vehicular motion controlling system utilized for a vehicle including at least rear side wheels serving as drive wheels, comprising:

wheel braking force generating means mounted on each of the wheels of the vehicle for generating braking force according to a given brake fluid pressure in each wheel;

brake fluid pressure generating means for generating brake fluid pressure to be fed to said wheel braking force generating means;

driving force generating a means for generating driving force for driving at least rear side wheels;

detection means for detecting a state in which an engine brake is effective; and

control means for activating said brake fluid pressure generating means to apply brake fluid pressure to said wheel braking force generating means mounted on front side wheels so that braking force is generated in said front side wheels, when said state in which said engine brake is effective is detected by said detection means.

13. A vehicular motion controlling system according to claim 12, wherein said control means causes said brake fluid pressure generating means to generate brake fluid pressure according to a load movement generated in the vehicle due to said engine brake, and applies said brake fluid pressure to said wheel braking force generating means of said front side wheels, when said state in which said engine brake is effective is detected by said detection means.

14. A vehicular motion controlling system according to claim 13, wherein said control means determines said load movement based on a wheel speed difference between a wheel speed of said front side wheels and a wheel speed of said rear side wheels and controls brake fluid pressure to be applied to said wheel braking force generating means of said front side wheels in accordance with said wheel speed difference.

15. A vehicular motion controlling system according to claim 14, wherein said control means inhibits an increase in brake fluid pressure to be applied to said wheel braking force generating means of said front side wheels when said wheel speed of said front side wheels is lower by a predetermined value or more than said wheel speed of said rear side wheels.

16. A vehicular motion controlling system comprising:

an engine for generating a driving force to be transmitted to drive wheels of a vehicle;

driving force adjusting means for adjusting said driving force generated by said engine;

adjusting state detecting means for detecting an operating state of said drive force adjusting means;

condition determining means for determining whether or not condition for effecting an engine brake is satisfied, on the basis of said operating state detected by said adjusting state detecting means; and

driving force controlling means for driving said driving force adjusting means to increase said driving force when it is determined by said condition determining means that said condition for effecting said engine brake is satisfied.

17. A vehicular motion controlling system according to claim 16, wherein said driving force adjusting means is either a throttle valve or an accelerator pedal.

18. A vehicular motion controlling system according to claim 17, wherein said adjusting state detecting means detects said operating state of said driving force adjusting means based on at least one of a throttle valve opening degree, a changing rate of said throttle valve opening degree, an accelerator pedal opening degree and a changing rate of said accelerator pedal opening degree.

19. A vehicular motion controlling system according to claim 17, wherein said adjusting state detecting means detects said operating state of said driving force adjusting means indirectly based on at least one of an intake air pressure, a changing rate of said intake air pressure, an intake air flow, a changing rate of said intake air flow, and a state of an idle switch which detects that said throttle valve is returned to a fully-closed position.

20. A vehicular motion controlling system according to claims 16, wherein said driving force controlling means increases a throttle valve opening degree to increase an engine output torque.

21. A vehicular motion controlling system according to claim 20, wherein said driving force controlling means opens said throttle valve by a predetermined amount when said throttle valve is fully closed.

22. A vehicular motion controlling system according to claim 20, wherein, when said driving force controlling means increases said throttle valve opening degree, an initial value of said throttle valve opening degree is set according to said operating state of said driving force adjusting means.

23. A vehicular motion controlling system according to claim 20, wherein said driving force controlling means increases said throttle valve opening degree after an elapse of a predetermined time period from when said throttle valve opening degree reaches to an opening degree at which said engine output torque becomes zero.

24. A vehicular motion controlling system according to claim 16, wherein said driving force controlling means increases fuel amount fed to said engine to increase engine output torque.

25. A vehicular motion controlling system according to claim 16, wherein said driving force controlling means increases said driving force according to a state of a road surface state on which the vehicle travels.

26. A vehicular motion controlling system comprising:

braking force generating means for generating wheel braking force to each of front-left, front-right, rear-left and rear-right wheels of a vehicle in response to a given brake fluid pressure;

a brake fluid pressure generating source for generating brake fluid pressure to be supplied to said braking force generating means;

a driving force generating source for applying a driving force to drive wheels which are either said front-left and front-right wheels or said rear-left and rear-right wheels;

driving force increasing means for increasing said driving force to be applied to said drive wheels by said driving force generating means, in accordance with a turning state of the vehicle; and

control means for comparing a real turning state of the vehicle and a target turning state obtained from a steering operation by a driver, and applying said brake fluid pressure from said brake fluid pressure generating source to said braking force generating means corresponding to one of left and right driven wheels so that said real turning state approaches said target turning state.

27. A vehicular motion controlling system according to claim 26, wherein said control means executes at least one of under-steer control to apply said brake fluid pressure to said braking force generating means of an inner driven wheel of a turning circle when said vehicle is in an under-steer state, and over-steer control to apply said brake fluid pressure to said braking force generating means of an outer driven wheel of said turning circle when said vehicle is in an over-steer state.

28. A vehicular motion con trolling system according to claim 26, wherein said control means applies said brake fluid pressure from said brake fluid pressure generating source to said braking force generating means corresponding to one of said drive wheels and one of said driven wheels so that said real turning state is brought close to said target turning state by a braking force generated at one of said drive wheels, in addition to a braking force generated at one of said driven wheels.

29. A vehicular motion controlling system according to claim 28, wherein said control means applies said brake fluid pressure to said braking force generating means of an inner drive wheel of a turning circle when said vehicle is in an under-steer state, and applies said brake flu id pressure to said braking force generating means of an outer drive wheel of said turning circle when said vehicle is in an over-steer state.

30. A vehicular motion controlling system according to claim 26, wherein said control means determines said brake fluid pressure to be applied to said braking force generating means so that a braking force caused by said brake fluid pressure offsets said driving force increased by said driving force increasing means.

31. A vehicular motion controlling system according to claim 30, wherein said control means calculates a required yawing moment necessary for controlling said rear turning state of said vehicle to said target turning state, and determines a magnitude of increase in said driving force by said driving force increasing means and said brake liquid pressure to be applied to said braking force generating means on the basis of said requested yawing moment.

32. A vehicular motion controlling system comprising:

turning state detecting means for detecting a turning state of a vehicle; and

driving force increasing means for increasing driving force to be transmitted from a power system of a vehicle to drive wheels thereof with a predetermined value, when said turning state detected by said turning state detecting means exceeds a predetermined degree.

33. A vehicular motion controlling system according to claim 32, further comprising:

brake detecting means for detecting whether or not a braking force is applied to said drive wheels,

wherein said driving force increasing means increases said driving force to be transmitted from said power system to said drive wheels with said predetermined value, when said turning state detected by said turning state detecting means exceeds a predetermined degree and said brake detecting means detects that said braking force is applied to said drive wheels.

34. A vehicular motion controlling system according to claim 32, further comprising:

driving force determining means for determining whether or not said driving force transmitted from said power system to said drive wheels is no more than a predetermined value,

wherein said driving force increasing means increases said driving force with a predetermined value, when said turning state detected by said turning state detecting means exceeds said predetermined degree and it is determined by said driving force determining means that said driving force is no more than said predetermined value.

35. A vehicular motion controlling system according to claim 32, further comprising:

brake detecting means for detecting whether or not a braking force is applied to said drive wheels; and

driving force determining means for determining whether or not said driving force transmitted from said power system to said drive wheels is no more than a predetermined value,

wherein said driving force increasing means increases said driving force to be transmitted from said power system to said drive wheels with a first predetermined value when said turning state detected by said turning state detecting means exceeds said predetermined degree, it is detected by said brake detecting means that said braking force is not applied to said drive wheels, and it is determined by said driving force determining means that said driving force is no more than said predetermined value, and increases said driving force to be transmitted from said power system to said drive wheels with a second predetermined value larger than said first predetermined value, when said turning state detected by said turning state detecting means exceeds said predetermined degree, it is detected by said brake detecting means that said braking force is applied to said drive wheels.

36. A vehicular motion controlling system according to claim 33, wherein said brake detecting means detects whether or not said braking force is applied to said drive wheels, by detecting that a brake pedal of said vehicle is depressed.

37. A vehicular motion controlling system according to claim 33, wherein said driving force increasing means increases said driving force to be transmitted to said drive wheels, the more for the higher braking force, when said turning state detected by said turning state detecting means exceeds said predetermined degree and it is detected by said brake detecting means that said braking force is applied to said drive wheels.

38. A vehicular motion controlling system according to claim 32, wherein said driving force increasing means increases said driving force to be transmitted to said drive wheels, the more for steeper turning state of said vehicle which is detected by said turning state detecting means.

39. A vehicular motion controlling system according to claim 32, wherein said driving force increasing means increases said driving force to be transmitted to said drive wheels by increasing an output torque of an engine mounted on said vehicle.

40. A vehicular motion controlling system according to claim 32, wherein said turning state detecting means detects said turning state of said vehicle on the basis of at least one information of a lateral acceleration of said vehicle, right and left wheel speeds of said vehicle and a steering angle of said vehicle.

41. A vehicular motion control method for a vehicle having an engine, drive wheels coupled with the engine, driven wheels and a braking device, said method comprising the steps of:

detecting a reduction in a rotation speed of said drive wheels;

increasing an output torque of said engine in response to the detection of speed reduction thereby to reduce engine braking force applied to the drive wheels; and

increasing braking force applied from the braking device to the driven wheels in response to the detection of speed reduction.

42. A vehicular motion control method according to claim 41, further comprising the step of:

detecting an engine braking operation which reduces the engine output torque, wherein the speed reduction detecting step calculates a slip state of the drive wheels after the detection of engine braking operation, and

detects the speed reduction when the calculated slip state reaches a predetermined reference state.

43. A vehicular motion control method according to claim 42, wherein the slip state is calculated as a function of a difference between a rotation speed of said driven wheels and the rotation speed of said drive wheels.

44. A vehicular motion control method according to claim 41, wherein the torque increasing step increases opening of a throttle valve of said engine irrespective of accelerator position.

45. A vehicular motion control system comprising:

wheel cylinders provided for vehicle wheels, respectively;

a hydraulic unit for supplying hydraulic pressure to each wheel cylinder;

a drive shaft for applying a drive force to each wheel shaft;

a drive source coupled to said drive shaft and capable of generating a negative driving force thereby to apply a braking force to each wheels; and

control means for operating the hydraulic unit and the drive source concurrently thereby to control a total braking force, which is a sum of a braking force applied from the hydraulic unit and the braking force applied from the drive source, to a demanded braking force.