Automotive brake fluid pressure control apparatus

• US 5,636,907 A
• Filed: 08/11/1995
• Issued: 06/10/1997
• Est. Priority Date: 08/11/1994
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Katou, Tomohiro, Takeda, Masayoshi, Sawada, Mamoru, Okazaki, Kouji
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US08/514,507
• Time in Patent Office: 669 Days
• Field of Search: 303/116.1, 303/10-12, 303/116.3, 303/116.2, 303/116.4, 303/113.2, 303/113.3, 303/119.1, 303/139, 303/114.1, 303/191, 188/355-359
• US Class Current: 303/10
• CPC Class Codes: B60T 2270/206 Monitoring, e.g. parameter monitoring, plausibility check
• 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 8/17636 Microprocessor-based systems
• CPC Class Codes: B60T 8/4872 pump-back systems
• CPC Class Codes: B60T 8/4881 having priming means

Abstract

Self-suction pumps are driven to take in brake fluid from a master-cylinder side before performing brake TRC control when at a low temperature and moreover when a vehicle is stopped. During driving of these self-suction pumps, pressure-increasing control valves and pressure-reducing control valves are both opened and brake fluid is accumulated in reservoirs. Because of this, an amount of pump discharge employed in brake TRC control when at a low temperature is assured, and responsiveness of brake TRC control is enhanced.

Claims

1. An automotive brake fluid control apparatus, comprising:

a reservoir to accumulate brake fluid expelled from a wheel cylinder via a pressure-control valve; and

a pump to boost pressure of brake fluid accumulated in said reservoir and supply said brake fluid to a wheel-cylinder side via said pressure-control valve, wherein said pump is a self-suction pump that takes in brake fluid from a master-cylinder side thereof;

pump operating means for causing said pump to start operation at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve, to take in brake fluid from said master-cylinder side; and

communicating path forming means for defining a path wherein a discharge side and an intake side of said pump are communicated so that brake fluid discharged from said pump circulates in said communicating path upon operation of said pump by said pump operating means.

2. An automotive brake fluid control apparatus according to claim 1, wherein said pressure-control valve comprises:

a pressure-increasing control valve to switch communication and interruption of said pump discharge side and said wheel cylinder; and

a pressure-reducing control valve to switch communication and interruption of said wheel cylinder and said reservoir, and

wherein said communicating path forming means defines said communicating path by driving both said pressure-increasing control valve and said pressure-reducing control valve to a communicated state.

3. An automotive brake fluid control apparatus according to claim 1, further comprising:

an interrupt valve disposed in a brake conduit between said pressure-control valve and said master cylinder to supply said brake fluid from said pump to a brake conduit connecting said interrupt valve and said pressure-control valve, and wherein;

said communicating path forming means drives said interrupt valve to interrupt communication of said pressure-control valve and said master cylinder when driving said pressure-control valve to cause said pump discharge side and intake side to be communicated.

4. An automotive brake fluid control apparatus according to claim 1, further comprising:

discharge state detecting means for detecting a state of insufficient amount of discharge from said pump; and

control initiating means for causing to initiate control by said pump operating means and said communicating path forming means at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to detection of a state of insufficient amount of discharge from said pump by said discharge state detecting means.

5. An automotive brake fluid control apparatus according to claim 4, wherein:

said discharge state detecting means comprises temperature estimating means to estimate a temperature of said brake fluid; and

an amount of discharge of said pump is detected as an insufficient state when temperature estimated by said temperature estimating means is a predetermined temperature or less.

6. An automotive brake fluid control apparatus according to claim 5, wherein:

said temperature estimating means has water temperature detecting means to detect a coolant-water temperature of an internal combustion engine; and

said brake-fluid temperature is estimated from said detected coolant-water temperature.

7. An automotive brake fluid control apparatus according to claim 1, further comprising:

vehicle state detecting means to detect a stopped or extremely low-speed state of a vehicle; and

control initiating means to cause to initiate control by said pump operating means and said communicating path forming means at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve when a stopped or extremely low-speed state of a vehicle has been detected by said vehicle state detecting means.

8. An automotive brake fluid control apparatus according to claim 1, further comprising:

control initiating means for activating said pump operating means and said communicating path forming means immediately after starting of an internal combustion engine of said vehicle.

9. An automotive brake fluid control apparatus according to claim 1, further comprising:

travel initiation detecting means for detecting initiation of travel of a vehicle; and

control terminating means for causing to terminate control by said pump operating means and said communicating path forming means when travel initiation of said vehicle has been detected by said travel initiation detecting means.

10. An automotive brake fluid control apparatus according to claim 9, wherein:

said travel initiation detecting means is provided with speed detecting means to detect travel speed of said vehicle; and

detection as said travel initiation of said vehicle is performed when a travel speed which said speed detecting means detects has reached a predetermined speed.

11. An automotive brake fluid control apparatus according to claim 1, further comprising:

brake operation detecting means for detecting brake operation by a driver; and

control terminating means for causing to terminate activation of both of said pump operating means and said communicating path forming means responsive to said brake operation detecting means detecting said brake operation.

12. An automotive brake fluid control apparatus according to claim 1, further comprising:

counting means for counting a time duration since said pump operating means and said communicating path forming means are activated; and

control terminating means for terminating activation of both of said pump operating means and said communicating path forming means responsive to said time duration having reached a predetermined time.

13. An automotive brake fluid control apparatus, comprising:

a reservoir to accumulate brake fluid expelled from a wheel cylinder via a pressure-control valve; and

a pump to boost pressure of brake fluid accumulated in said reservoir and supply said brake fluid to a wheel-cylinder side via said pressure-control valve, wherein said pump is a self-suction pump that takes in brake fluid from a master-cylinder side, and antiskid control and traction control are performed using said pump as a common pressure source, and further comprising;

a first switching valve, disposed in a conduit connecting said master-cylinder side and an intake side of said pump, to switch communication and interruption of said conduit;

communication driving means for driving said first switching valve to a state wherein said conduit is communicated at a predetermined timing before said traction control is executed;

pump operating means for causing said pump to start operating at said predetermined timing to take in brake fluid from said master-cylinder side; and

communicating path forming means for forming a communicating path wherein a discharge side and an intake side of said pump are communicated so that brake fluid discharged from said pump circulates in said communicating path upon operation of said pump by said pump operating means.

14. An automotive brake fluid control apparatus according to claim 13, wherein said pressure-control valve comprises:

a pressure-increasing control valve to switch communication and interruption of said pump discharge side and said wheel cylinder; and

a pressure-reducing control valve to switch communication and interruption of said wheel cylinder and said reservoir, and

wherein said communicating path forming means defines said communicating path by driving both said pressure-increasing control valve and said pressure-reducing control valve to a communicated state.

15. An automotive brake fluid control apparatus according to claim 13, further comprising:

an interrupt valve disposed in a brake conduit between said pressure-control valve and said master cylinder to supply said brake fluid from said pump to a brake conduit connecting said interrupt valve and said pressure-control valve, and wherein;

said communicating path forming means drives said interrupt valve to interrupt communication of said pressure-control valve and said master cylinder when driving said pressure-control valve to cause said pump discharge side and intake side to be communicated.

16. An automotive brake fluid control apparatus according to claim 13, further comprising:

discharge state detecting means for detecting a state of insufficient amount of discharge from said pump; and

control initiating means for causing to initiate control by said pump operating means and said communicating path forming means at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to detection of a state of insufficient amount of discharge from said pump by said discharge state detecting means.

17. An automotive brake fluid control apparatus according to claim 16, wherein:

said discharge state detecting means comprises temperature estimating means to estimate a temperature of said brake fluid; and

an amount of discharge of said pump is detected as an insufficient state when temperature estimated by said temperature estimating means is a predetermined temperature or less.

18. An automotive brake fluid control apparatus according to claim 17, wherein:

said temperature estimating means has water temperature detecting means to detect a coolant-water temperature of an internal combustion engine; and

said brake-fluid temperature is estimated from said detected coolant-water temperature.

19. An automotive brake fluid control apparatus according to claim 13, further comprising:

vehicle state detecting means for detecting a stopped or extremely low-speed state of a vehicle; and

control initiating means for causing to initiate control by said pump operating means and said communicating path forming means at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve when a stopped or extremely low-speed state of a vehicle has been detected by said vehicle state detecting means.

20. An automotive brake fluid control apparatus according to claim 13, further comprising:

control initiating means for activating said pump operating means and said communicating path forming means immediately after starting of an internal combustion engine of said vehicle.

21. An automotive brake fluid control apparatus according to claim 13, further comprising:

travel initiation detecting means for detecting initiation of travel of a vehicle; and

control terminating means for causing to terminate control by said pump operating means and said communicating path forming means when travel initiation of said vehicle has been detected by said travel initiation detecting means.

22. An automotive brake fluid control apparatus according to claim 21, wherein:

said travel initiation detecting means is provided with speed detecting means to detect travel speed of said vehicle; and

detection as said travel initiation of said vehicle is performed when a travel speed which said speed detecting means detects has reached a predetermined speed.

23. An automotive brake fluid control apparatus according to claim 13, further comprising:

brake operation detecting means for detecting brake operation by a driver; and

control terminating means for causing to terminate activation of both of said pump operating means and said communicating path forming means responsive to said brake operation detecting means detecting said brake operation.

24. An automotive brake fluid control apparatus according to claim 13, further comprising:

counting means for counting a time duration since said pump operating means and said communicating path forming means are activated; and

control terminating means for terminating activation of both of said pump operating means and said communicating path forming means responsive to said time duration having reached a predetermined time.

25. An automotive brake fluid control apparatus, comprising:

a reservoir to accumulate brake fluid expelled from a wheel cylinder via a hydraulic circuit including a pressure-control valve; and

a pump to boost pressure of said brake fluid accumulated in said reservoir and to supply said brake fluid to a wheel-cylinder side via said pressure-control valve, wherein said pump is a self-suction pump that takes in brake fluid from a master-cylinder side thereof;

a pump controller causing said pump to start operating at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve, to take in brake fluid from said master-cylinder side; and

a hydraulic circuit controller actuating said pressure-control valve so as to define a communicating path wherein a discharge side and an intake side of said pump are communicated so that brake fluid discharged from said pump circulates in said communicating path upon operation of said pump by said pump controller.

26. An automotive brake fluid control apparatus according to claim 25, wherein said pressure-control valve comprises:

a pressure-increasing control valve to switch communication and interruption of said pump discharge side and said wheel cylinder; and

a pressure-reducing control valve to switch communication and interruption of said wheel cylinder and said reservoir, and

wherein said hydraulic circuit controller defines said communicating path by driving both said pressure-increasing control valve and said pressure-reducing control valve to a communicated state.

27. An automotive brake fluid control apparatus according to claim 25, further comprising:

an interrupt valve disposed in a brake conduit between said pressure-control valve and said master cylinder to supply said brake fluid from said pump to a brake conduit connecting said interrupt valve and said pressure-control valve, and wherein;

said hydraulic circuit controller drives said interrupt valve to interrupt communication of said pressure-control valve and said master cylinder when activating said pressure-control valve to cause said pump discharge said and intake side to be communicated.

28. An automotive brake fluid control apparatus according to claim 25, further comprising:

a discharge detector detecting a state of insufficient amount of discharge from said pump; and

wherein said pump controller and said hydraulic circuit controller perform their respective operations at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to detection of a state of insufficient amount of discharge from said pump by said discharge detector.

29. An automotive brake fluid control apparatus according to claim 28, wherein said discharge detector comprises a temperature estimating unit estimating a temperature of said brake fluid;

and

an amount of discharge of said pump is detected as being insufficient responsive to a temperature estimated by said temperature estimating unit being not greater than a predetermined temperature.

30. An automotive brake fluid control apparatus according to claim 29, wherein said temperature estimating unit has water temperature detector to detect a coolant-water temperature of an internal combustion engine;

and

said brake-fluid temperature is estimated from said detected coolant-water temperature.

31. An automotive brake fluid control apparatus according to claim 25, further comprising:

a vehicle speed detector detecting whether a vehicle having the brake fluid control apparatus is traveling at no faster than an extremely low speed; and

wherein said pump controller and said hydraulic circuit controller perform their respective operations at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to one of a stopped state and an extremely low speed being detected by said vehicle speed detector.

32. An automotive brake fluid control apparatus according to claim 25, wherein said pump controller and said hydraulic circuit controller perform their respective operations immediately after starting of an internal combustion engine of a vehicle having said brake fluid control apparatus.

33. An automotive brake fluid control apparatus according to claim 25, further comprising:

travel initiation detector detecting initiation of travel of a vehicle having said brake fluid control apparatus; and

control terminating means for termination operation of said pump controller and said hydraulic circuit controller responsive to travel initiation of said vehicle has been detected by said travel initiation detector.

34. An automotive brake fluid control apparatus according to claim 33, wherein:

said travel initiation detector includes a vehicle speed detector; and

detection of initiation of travel of said vehicle is performed responsive to a travel speed detected by said vehicle speed detector having reached a predetermined speed.

35. An automotive brake fluid control apparatus according to claim 25, further comprising:

brake operation detectors that detect operation of a brake by a driver; and

wherein control operations of said pump controller and said hydraulic circuit controller are terminated responsive to said brake operation detector detecting brake operation.

36. An automotive brake fluid control apparatus according to claim 25, further comprising:

a counter counting a time duration since respective operations of said pump controller and said hydraulic circuit controller are initiated, wherein control operations of said pump controller and said hydraulic circuit controller are terminated responsive to said pump controller and said time duration having reached a predetermined time.

37. An automotive brake fluid control apparatus, comprising:

a reservoir to accumulate brake fluid expelled from a wheel cylinder via a hydraulic circuit including a pressure-control valve; and

a pump to boost pressure of brake fluid accumulated in said reservoir and to supply said brake fluid to a wheel-cylinder side via said pressure-control valve, wherein said pump is a self-suction pump that takes in brake fluid from a master-cylinder side thereof, and antiskid control and traction control are performed by employing said pump as a common pressure source, and further comprising;

a first switching valve, disposed in a conduit connecting said master-cylinder side and an intake side of said pump, to switch communication and interruption of said conduit;

a valve controller driving said first switching valve to a state wherein said conduit starts to be communicated at a predetermined timing before said traction control is executed;

pump controller causing said pump to start operating at said predetermined timing to take in brake fluid from said master-cylinder side; and

a hydraulic circuit controller activating said pressure-control valve so as to define a communicating path wherein a discharge side and an intake side of said pump are communicated so that brake fluid discharged from said pump circulates in said communicating path upon operation of said pump by said pump controller.

38. An automotive brake fluid control apparatus according to claim 37, wherein said pressure-control valve comprises:

a pressure-increasing control valve to switch communication and interruption of said pump discharge side and said wheel cylinder; and

a pressure-reducing control valve to switch communication and interruption of said wheel cylinder and said reservoir, and

wherein said hydraulic circuit controller defines said communicating path by driving both said pressure-increasing control valve and said pressure-reducing control valve to a communicated state.

39. An automotive brake fluid control apparatus according to claim 37, further comprising:

an interrupt valve disposed in a brake conduit between said pressure-control valve and said master cylinder to supply said brake fluid from said pump to a brake conduit connecting said interrupt valve and said pressure-control valve, and wherein;

said hydraulic circuit controller drives said interrupt valve to interrupt communication of said pressure-control valve and said master cylinder when activating said pressure-control valve to cause said pump discharge said and intake side to be communicated.

40. An automotive brake fluid control apparatus according to claim 37, further comprising:

a discharge detector detecting a state of insufficient amount of discharge from said pump; and

wherein said pump controller and said hydraulic circuit controller perform their respective operations at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to detection of a state of insufficient amount of discharge from said pump by said discharge detector.

41. An automotive brake fluid control apparatus according to claim 40, wherein said discharge detector comprises a temperature estimating unit estimating a temperature of said brake fluid;

and

an amount of discharge of said pump is detected as being insufficient state responsive to a temperature estimated by said temperature estimating unit being not greater than a predetermined temperature.

42. An automotive brake fluid control apparatus according to claim 41, wherein said temperature estimating unit has water temperature detector to detect a coolant-water temperature of an internal combustion engine;

and

said brake-fluid temperature is estimated from said detected coolant-water temperature.

43. An automotive brake fluid control apparatus according to claim 37, further comprising:

a vehicle speed detector detecting whether a vehicle having the brake fluid control apparatus is traveling at no faster than an extremely low speed; and

wherein said pump controller and said hydraulic circuit controller perform their respective operations at a predetermined timing before initiating regulation of brake fluid pressure applied to said wheel cylinder by said pressure-control valve responsive to one of a stopped state and an extremely low speed being detected by said vehicle speed detector.

44. An automotive brake fluid control apparatus according to claim 37, wherein said pump controller and said hydraulic circuit controller perform their respective operations immediately after starting of an internal combustion engine of a vehicle having said brake fluid control apparatus.

45. An automotive brake fluid control apparatus according to claim 37, further comprising:

travel initiation detector detecting initiation of travel of a vehicle having said brake fluid control apparatus; and

control terminating means for termination operation of said pump controller and said hydraulic circuit controller responsive to travel initiation of said vehicle has been detected by said travel initiation detector.

46. An automotive brake fluid control apparatus according to claim 45, wherein:

said travel initiation detector includes a vehicle speed detector; and

detection of initiation of travel of said vehicle is performed responsive to a travel speed detected by said vehicle speed detector having reached a predetermined speed.

47. An automotive brake fluid control apparatus according to claim 37, further comprising:

brake operation detectors that detect operation of a brake by a driver; and

wherein control operations of said pump controller and said hydraulic circuit controller are terminated responsive to said brake operation detector detecting brake operation.

48. An automotive brake fluid control apparatus according to claim 37, further comprising:

a counter counting a time duration since respective operations of said pump controller and said hydraulic circuit controller are initiated, wherein control operations of said pump controller and said hydraulic circuit controller are terminated responsive to said pump controller and said time duration having reached a predetermined time.