Vehicle braking system capable of controlling pump for optimum rate of change of brake cylinder pressure
First Claim
1. A braking system for a motor vehicle, comprising:
- an operator-controlled brake operating member;
a master cylinder for generating a fluid pressure according to an amount of operation of said brake operating member;
a wheel brake cylinder for operating a wheel brake to brake a wheel of the motor vehicle according to a fluid pressure applied to said wheel brake cylinder;
a reservoir for storing a working fluid;
a pump for pressurizing the fluid sucked up from said reservoir, and delivering the pressurized fluid toward at least one of said master cylinder and said wheel brake cylinder;
a DC power source;
a pump actuator driven by said DC power source to operate said pump;
an electrically operated pressure control device having a plurality of operating states which are selectively established to electrically control the fluid pressure in the wheel brake cylinder and which include a pressure-increase state for substantial fluid communication of the wheel brake cylinder with at least one of the master cylinder and a deliver side of the pump, and a pressure-decrease state for substantial fluid communication of the wheel brake cylinder with the reservoir;
a pump actuator control device having a power supply portion for intermittently supplying electric power from said DC power source to said pump actuator such that a duty ratio of the pump actuator is controlled in response to a duty ratio signal, and a signal generating portion for generating said duty ratio signal; and
said signal generating portion of said pump actuator control device comprising monitoring means for detecting at least one of a physical value which influences an amount of delivery of said pressurized fluid from said pump, and a selected one of said operating states of said electrically operated pressure control device, and optimizing means responsive to said monitoring means, for optimizing a rate of change of the fluid pressure in said wheel brake cylinder during an operation of said electrically operated pressure control device.
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Accused Products
Abstract
A vehicle braking system including, a pump operated by a pump actuator driven by a DC power source, an electrically operated pressure control device having operating states which are selectively established to electrically control the fluid pressure in wheel brake cylinder and which includes a pressure-increase state for fluid communication of the wheel brake cylinder with at least one of a master cylinder and pump and a pressure-decrease state for fluid communication of the wheel brake cylinder with a reservoir, and a pump actuator control device having a power supply portion for intermittently supplying electric power from the DC power source to the pump actuator such that the duty ratio of the pump actuator is controlled in response to a duty ratio signal, and a signal generating portion for generating the duty ratio signal. The signal generating portion includes a device for optimizing a rate of change of the wheel brake cylinder pressure depending upon at least one of an output of the DC power source and a currently selected operating state of the pressure control device.
42 Citations
17 Claims
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1. A braking system for a motor vehicle, comprising:
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an operator-controlled brake operating member; a master cylinder for generating a fluid pressure according to an amount of operation of said brake operating member; a wheel brake cylinder for operating a wheel brake to brake a wheel of the motor vehicle according to a fluid pressure applied to said wheel brake cylinder; a reservoir for storing a working fluid; a pump for pressurizing the fluid sucked up from said reservoir, and delivering the pressurized fluid toward at least one of said master cylinder and said wheel brake cylinder; a DC power source; a pump actuator driven by said DC power source to operate said pump; an electrically operated pressure control device having a plurality of operating states which are selectively established to electrically control the fluid pressure in the wheel brake cylinder and which include a pressure-increase state for substantial fluid communication of the wheel brake cylinder with at least one of the master cylinder and a deliver side of the pump, and a pressure-decrease state for substantial fluid communication of the wheel brake cylinder with the reservoir; a pump actuator control device having a power supply portion for intermittently supplying electric power from said DC power source to said pump actuator such that a duty ratio of the pump actuator is controlled in response to a duty ratio signal, and a signal generating portion for generating said duty ratio signal; and said signal generating portion of said pump actuator control device comprising monitoring means for detecting at least one of a physical value which influences an amount of delivery of said pressurized fluid from said pump, and a selected one of said operating states of said electrically operated pressure control device, and optimizing means responsive to said monitoring means, for optimizing a rate of change of the fluid pressure in said wheel brake cylinder during an operation of said electrically operated pressure control device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A braking system for a motor vehicle, comprising:
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an operator-controlled brake operating member; a master cylinder for generating a fluid pressure according to an amount of operation of said brake operating member; a wheel brake cylinder for operating a wheel brake to brake a wheel of the motor vehicle according to a fluid pressure applied to said wheel brake cylinder; a reservoir for storing a working fluid; a pump for pressurizing the fluid sucked up from said reservoir, and delivering the pressurized fluid toward at least one of said master cylinder and said wheel brake cylinder; a DC power source; an electric motor driven by said DC power source to operate said pump; an electrically operated pressure control device having a plurality of operating states which are selectively established to electrically control the fluid pressure in the wheel brake cylinder and which include a pressure-increase state for substantial fluid communication of the wheel brake cylinder with at least one of the master cylinder and the pump, and a pressure-decrease state for substantial fluid communication of the wheel brake cylinder with the reservoir; a diagnostic device for diagnosing said electric motor by supplying electric power from said DC power source to said electric motor; and said diagnostic device intermittently supplying the electric power from said DC power source to said electric motor such that said motor is alternately turned on and off for a predetermined length of time consisting of alternate on-times and off-times each of which is larger than zero. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification