Brake fluid pressure control system
First Claim
1. A brake fluid pressure control process for controlling a brake fluid pressure with a solenoid valve, the control process comprising:
- a valve condition discriminating step of checking an operating condition of the solenoid valve and producing a PWM permission signal when the operating condition of the solenoid valve is in a predetermined region allowing a pulse width modulation control, the operating condition of the solenoid valve being the temperature of a coil of the solenoid valve; and
a mode switching step of switching a brake pressure control mode to a PWM mode of the pulse width modulation control when the PWM permission signal is present, and to a non-PWM mode when the PWM permission signal is absent.
2 Assignments
0 Petitions
Accused Products
Abstract
In a brake pressure control system for ABS control, traction control or vehicle motion control, a control unit controls each of pressure control solenoid valves in a PWM (pulse width modulation) control mode to prevent pulsation in the wheel cylinder pressure during the presence of a predetermined temperature or pressure condition, and a non-PWM control mode in the absence of the predetermined condition. The control unit includes a process section such as a computer and a PWM switch section including subsections each for a unique one of the solenoid valves. The process section has a single PWM port connected through a PWM signal line to each subsection of the PWM switch section.
28 Citations
16 Claims
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1. A brake fluid pressure control process for controlling a brake fluid pressure with a solenoid valve, the control process comprising:
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a valve condition discriminating step of checking an operating condition of the solenoid valve and producing a PWM permission signal when the operating condition of the solenoid valve is in a predetermined region allowing a pulse width modulation control, the operating condition of the solenoid valve being the temperature of a coil of the solenoid valve; and
a mode switching step of switching a brake pressure control mode to a PWM mode of the pulse width modulation control when the PWM permission signal is present, and to a non-PWM mode when the PWM permission signal is absent. - View Dependent Claims (2)
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3. A brake fluid pressure control system comprising:
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a brake actuator comprising a solenoid valve for regulating a brake fluid pressure for a wheel of a vehicle;
a sensor for sensing a vehicle operating condition; and
a control unit for controlling the brake fluid pressure by producing a drive signal to drive signal to drive the solenoid valve of the actuator in accordance with the vehicle operating condition sensed by the sensor, and for producing, as the drive signal, a PWM control signal according to a pulse width modulation in the case of existence of a predetermined PWM control condition, and a normal control signal comprising an on signal and an off signal in the case of nonexistence of the predetermined PWM control condition;
wherein the control unit comprises a drive section for delivering the drive signal to the solenoid valve, and a switching section for causing the driver section to deliver the PWM signal when the PWM control condition is present, and to deliver the normal signal when the PWM condition is absent; and
wherein the actuator comprises a plurality of said solenoid valves, the control unit further comprises a control section comprising a plurality of normal signal ports for outputting signals for producing a plurality of aid normal control signals, and a PWM signal port for outputting a signal for producing the PWM signal with a single duty ratio, the number of the normal signal ports of the control section is equal to the number of the solenoid valves in the actuator, the switching section comprises switch signal ports for outputting switch signals, the number of the switch signal ports is equal to the number of the normal signal ports, the drive section comprises a plurality of output ports, the number of the output ports is equal to the number of the solenoid valves, and the drive section is arranged to change over the output signal from each output port between the normal control signal and the PWM control signal, in accordance with signal conditions of the normal signal ports, the PWM signal port and the switch signal ports.
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4. A brake fluid pressure control system comprising:
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a brake actuator comprising a solenoid valve for regulating a brake fluid pressure for a wheel of a vehicle;
a sensor for sensing a vehicle operating condition; and
a control unit for controlling the brake fluid pressure by producing a drive signal to drive signal to drive the solenoid valve of the actuator in accordance with the vehicle operating condition sensed by the sensor, and for producing, as the drive signal, a PWM control signal according to a pulse width modulation in the case of existence of a predetermined PWM control condition, and a normal control signal comprising an on signal and an off signal in the case of nonexistence of the predetermined PWM control condition; and
wherein the control unit is configured to produce a PWM condition signal representing the existence of the PWM control condition when the temperature of a coil of the solenoid valve in the actuator is in a predetermines temperature region. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A brake fluid pressure control system comprising:
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a brake actuator comprising a solenoid valve for regulating a brake fluid pressure for a wheel of a vehicle;
a sensor for sensing a vehicle operating condition; and
a control unit for controlling the brake fluid pressure by producing a drive signal to drive signal to drive the solenoid valve of the actuator in accordance with the vehicle operating condition sensed by the sensor, and for producing, as the drive signal, a PWM control signal according to a pulse width modulation in the case of existence of a predetermined PWM control condition, and a normal control signal comprising an on signal and an off signal in the case of nonexistence of the predetermined PWM control condition;
wherein the control unit is configured to produce a PWM condition signal representing the existence of the PWM control condition when the temperature of a coil of the solenoid valve in the actuator is in a predetermined temperature region; and
wherein the control unit is configured to produce a PWM condition signal representing the existence of the PWM control condition when a differential pressure between a master cylinder pressure and a wheel cylinder pressure is in a predetermined region. - View Dependent Claims (11, 12)
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13. A brake fluid pressure control apparatus comprising:
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a drive section comprising a first drive subsection for delivering a first solenoid drive signal to control a first brake fluid pressure control solenoid valve for varying a brake actuating force applied on a first wheel of a vehicle, and a second drive subsection for delivering a second solenoid drive signal to control a second pressure control solenoid valve for varying a brake actuating force applied on a second wheel of the vehicle;
a PWM section comprising a first PWM subsection including first, second and third input ports and an output port connected to the first drive subsection, and a second PWM subsection including first, second and third input ports and an output port connected to the second drive subsection; and
a process section for putting each of the PWM subsections in one of a PWM control mode and a non-PWM control mode by changing input conditions of the input ports of the PWM subsection, the process section comprising first and second normal signal ports connected, respectively, with the first input ports of the first and second PWM subsections through first and second normal signal lines, first and second switch signal ports connected, respectively, with the second input ports of the first and second PWM subsections through first and second switch signal lines, and a PWM signal port connected with the third input ports of the first and second PWM subsections through a PWM signal line. - View Dependent Claims (14, 15, 16)
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Specification