Vehicle brake hydraulic pressure controller

Patent metadata

Field	Value
Publication number	US-9434365-B2
Application number	US-201414300672-A
Country	US
Kind code	B2
Filing date	Jun 10, 2014
Priority date	Jun 12, 2013
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

There is provided a hydraulic pressure controller to be mounted on a vehicle which is configured so that a driving torque transmitted to wheels during a stop of the vehicle reduces. The hydraulic pressure controller includes a vehicle holding controller configured to carry out a vehicle holding control to hold a brake hydraulic pressure applied to the wheels during the stop of vehicle stop. In the case that an actual-pressure-equivalent hydraulic pressure corresponding to a brake hydraulic pressure actually applied to the wheels is not more than a predetermined hydraulic pressure at a start time of the vehicle holding control, the vehicle holding controller sets a pressurization target pressure using a specific driving torque applied at the start time of the vehicle holding control and carries out a pressurization control to raise the brake hydraulic pressure to the pressurization target pressure.

First claim

The invention claimed is:

1. A vehicle brake hydraulic pressure controller to be mounted on a vehicle which is configured so that a driving torque transmitted to wheels during a stop of the vehicle reduces, the vehicle brake hydraulic pressure controller comprising:
a vehicle holding controller configured to carry out a vehicle holding control to hold a brake hydraulic pressure applied to the wheels during the stop of vehicle,
wherein, in the case that an actual-pressure-equivalent hydraulic pressure corresponding to a brake hydraulic pressure actually applied to the wheels is not more than a predetermined hydraulic pressure at a start time of the vehicle holding control, the vehicle holding controller sets a pressurization target pressure using a specific driving torque applied at the start time of the vehicle holding control and carries out a pressurization control to raise the brake hydraulic pressure to the pressurization target pressure.

2. The vehicle brake hydraulic pressure controller of claim 1 , further comprising:
a road surface gradient estimator configured to estimate a road surface gradient,
wherein the vehicle holding controller corrects the pressurization target pressure on the basis of the road surface gradient estimated by the road surface gradient estimator.

3. The vehicle brake hydraulic pressure controller of claim 2 ,
wherein the road surface gradient estimator estimates the road surface gradient on the basis of a longitudinal acceleration, and
the vehicle holding controller corrects the pressurization target pressure under the condition that the longitudinal acceleration has been stabilized.

4. The vehicle brake hydraulic pressure controller of claim 3 ,
wherein the vehicle holding controller calculates a vehicle stop optimum holding pressure at which the vehicle stops in a state of zero driving torque on the basis of the road surface gradient estimated by the road surface gradient estimator while the pressurization control is carried out and sets the pressurization target pressure to the actual-pressure-equivalent hydraulic pressure in the case that the actual-pressure-equivalent hydraulic pressure is larger than the vehicle stop optimum holding pressure.

5. The vehicle brake hydraulic pressure controller of claim 1 , further comprising:
a setting storage configured to store a minimum pressurization target pressure,
wherein the vehicle holding controller sets the pressurization target pressure to the minimum pressurization target pressure in the case that the pressurization target pressure is smaller than the minimum pressurization target pressure.

6. The vehicle brake hydraulic pressure controller of claim 1 ,
wherein the vehicle holding controller raises the brake hydraulic pressure at a preset constant incremental gradient in the pressurization control.

7. The vehicle brake hydraulic pressure controller of claim 1 ,
wherein the vehicle holding controller sets a pressurization target pressure using the specific driving torque only at the start time of the vehicle holding control and carries out a pressurization control to raise the brake hydraulic pressure to the pressurization target pressure.

8. The vehicle brake hydraulic pressure controller of claim 7 ,
wherein after the start time of the vehicle holding control, the vehicle holding controller sets the pressurization target pressure without using the driving torque T.

9. The vehicle brake hydraulic pressure controller of claim 1 , wherein
the vehicle holding controller judges whether the actual-pressure-equivalent hydraulic pressure is not more than the predetermined hydraulic pressure, and
the vehicle holding controller carries out pressurization control by driving an electric motor forward in the case that the actual-pressure-equivalent hydraulic pressure is not more than the predetermined hydraulic pressure and maintains a rotation stop state of the electric motor in the case that the actual-pressure-equivalent hydraulic pressure is more than the predetermined hydraulic pressure.

10. The vehicle brake hydraulic pressure controller of claim 1 , wherein
the actual-pressure-equivalent hydraulic pressure is a target value of the brake hydraulic pressure of one subsequent control cycle and the brake hydraulic pressure applied to the wheels during the vehicle holding control is nearly equal to the actual-pressure-equivalent hydraulic pressure.

11. The vehicle brake hydraulic pressure controller of claim 10 , wherein at the start time of the vehicle holding control, the actual-pressure-equivalent hydraulic pressure is set to a same value as a start time value of the brake hydraulic pressure.

12. The vehicle brake hydraulic pressure controller of claim 11 , wherein in a case that the vehicle holding control is carried out thereafter, a same value is maintained without being changed.

13. The vehicle brake hydraulic pressure controller of claim 12 , wherein in the case that the pressurization control is carried out at the start time of the vehicle holding control, the actual-pressure-equivalent hydraulic pressure is set as a latest target value to which the brake hydraulic pressure is raised from a present brake hydraulic pressure to the pressurization target pressure at a constant upward gradient.

14. The vehicle brake hydraulic pressure controller of claim 13 , wherein, the actual-pressure-equivalent hydraulic pressure is set to a total value of the present brake hydraulic pressure and a hydraulic pressure incremental amount per unit time corresponding to an upward gradient.

15. The vehicle brake hydraulic pressure controller of claim 11 , wherein the vehicle holding controller is configured so as to correct the pressurization target pressure on a basis of road surface gradient.

16. The vehicle brake hydraulic pressure controller of claim 15 , wherein the vehicle holding controller calculates an optimum holding pressure on the basis of the road surface gradient calculated in a state in which the pressurization control is carried out.

17. The vehicle brake hydraulic pressure controller of claim 16 , wherein
the vehicle holding controller judges whether the control request hydraulic pressure is larger than a vehicle stop optimum holding pressure,
in a case that the control request hydraulic pressure is larger, the vehicle holding controller sets the pressurization target pressure to the actual-pressure-equivalent hydraulic pressure, and
in the case that the actual-pressure-equivalent hydraulic pressure is larger than the vehicle stop optimum holding pressure, the vehicle holding controller sets the pressurization target pressure to the actual-pressure-equivalent hydraulic pressure, whereby the pressurization control is ended promptly.

18. The vehicle brake hydraulic pressure controller of claim 16 , wherein
in a case that the pressurization target pressure is smaller than the minimum pressurization target pressure, the vehicle holding controller sets the pressurization target pressure to a minimum pressurization target pressure.

19. The vehicle brake hydraulic pressure controller of claim 11 , wherein the vehicle holding controller is configured so as to correct the pressurization target pressure under a condition that a longitudinal acceleration output from a longitudinal acceleration sensor has been stabilized.

20. The vehicle brake hydraulic pressure controller of claim 19 , wherein the judgment as to whether the longitudinal acceleration has been stabilized is made by judging whether a condition that a change amount o

Assignees

• Nissin Kogyo Kk
• Autoliv Nissin Brake Systems Japan Co Ltd

Inventors

• Kinoshita Takashi

Classifications

• B60T13/662

  characterised by specified functions of the control system components · CPC title

• B60T13/686

  in hydraulic systems or parts thereof · CPC title

• B60T13/745

  acting on a hydraulic system, e.g. a master cylinder · CPC title

• B60T13/146

  Part of the system directly actuated by booster pressure · CPC title

• B60T8/00

  Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force (by changing number of effective brake cylinders in power brake systems B60T17/10) · CPC title