Hydraulic pressure control apparatus having device for estimating amount of fluid in reservoir to which the fluid is discharged to reduce cylinder pressure

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle, a reservoir for storing the fluid discharged from the brake cylinder, and a pump for pumping up the fluid from the reservoir and supplying the pumped-up fluid to said brake cylinder to increase a pressure of the fluid in the brake cylinder, said apparatus comprising:

• deceleration obtaining means for obtaining a deceleration value of a body of the vehicle;
• pumping time obtaining means for obtaining a pumping time during which the fluid is pumped up from said reservoir by said pump;
• and
• flow-out amount estimating means for estimating a cumulative amount of flow of the fluid from said reservoir, on the basis of said pumping time obtained by said pumping time obtaining means and a deceleration value of said body of the vehicle obtained by said deceleration obtaining means.

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle, a reservoir for storing the fluid discharged from the brake cylinder, and a pump operated by an electric motor for pumping up the fluid from the reservoir and supplying the pumped-up fluid to said brake cylinder to increase a pressure of the fluid in the brake cylinder, said apparatus comprising:

• motor speed obtaining means for obtaining an operating speed of said electric motor;
• pumping time obtaining means for obtaining a pumping time during which the fluid is pumped up from said reservoir by said pump;
• and
• flow-out amount estimating means for estimating a cumulative amount of flow of the fluid from said reservoir, on the basis of said pumping time obtained by said pumping time obtaining means and said operating speed of said electric motor.

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle and a reservoir for storing the fluid discharged from said brake cylinder when a pressure of the fluid in said brake cylinder is reduced, said apparatus comprising:

• pressure reducing time obtaining means for obtaining a pressure reducing time during which the pressure of the fluid in said brake cylinder is reduced;
• a pressure detecting device for detecting the pressure of the fluid in said brake cylinder;
• and
• flow-in amount estimating means for estimating a cumulative amount of flow of the fluid into said reservoir, on the basis of said pressure of the fluid in said brake cylinder detected by said pressure detecting device and said pressure reducing time obtained by said pressure reducing time obtaining means.

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle, a reservoir for storing the fluid discharged from the brake cylinder, and a pump operated by an electric motor for pumping up the fluid from the reservoir and supplying the pumped-up fluid to said brake cylinder to increase a pressure of the fluid in the brake cylinder, said apparatus comprising:

• a current obtaining device for obtaining an electric current flowing through said electric motor;
• pumping time obtaining means for obtaining a pumping time during which the fluid is pumped up from said reservoir by said pump;
• and
• flow-out amount estimating means for estimating a cumulative amount of flow of the fluid from said reservoir, on the basis of said pumping time obtained by said pumping time obtaining means and said electric current detected by said deceleration obtaining means.

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle, a reservoir for storing the fluid discharged from the brake cylinder, and a pump for pumping up the fluid from the reservoir and supplying the pumped-up fluid to said brake cylinder to increase a pressure of the fluid in the brake cylinder, said apparatus comprising:

• pumping time obtaining means for obtaining a pumping time during which the fluid is pumped up from said reservoir by said pump;
• pump state estimating means for estimating an operating state of said pump;
• and
• flow-out amount estimating means for estimating a cumulative amount of flow of the fluid from said reservoir, on the basis of said operating state of said pump estimated by said pump state estimating means and said pumping time obtained by said pumping time obtaining means.

A hydraulic pressure control apparatus for a brake including a brake cylinder activated by a pressurized fluid for braking a wheel of a vehicle, a reservoir for storing the fluid discharged from the brake cylinder, and a pump for pumping up the fluid from the reservoir and supplying the pumped-up fluid to said brake cylinder to increase a pressure of the fluid in the brake cylinder, said apparatus comprising:

• a pressure detecting device for detecting the pressure of the fluid in said brake cylinder;
• pumping time obtaining means for obtaining a pumping time during which the fluid is pumped up from said reservoir by said pump;
• and
• flow-out amount estimating means for estimating a cumulative amount of flow of the fluid from said reservoir, on the basis of said pumping time obtained by said pumping time obtaining means and said pressure of the fluid in said brake cylinder detected by said pressure detecting device.

A hydraulic braking system for a motor vehicle, comprising:

• a master cylinder having two pressurizing chambers;
• two fluid passages for connecting one of said two pressurizing chambers of said master cylinder to a front wheel brake cylinder and a rear wheel brake cylinder for braking a front and a rear wheel, respectively;
• a first shut-off valve selectively placed in a connecting state for connecting said front and rear wheel brake cylinders to said master cylinder and a disconnecting state for disconnecting said wheel brake cylinders from said master cylinder;
• a reservoir for storing a working fluid;
• a pump for pressurizing the fluid pumped up from said reservoir and delivering the pressurized fluid to said front and rear wheel brake cylinders;
• a valve device having a first state for permitting flows of the fluid from both of said front and rear wheel brake cylinders into said reservoir, a second state for permitting a flow of the fluid from said rear wheel brake cylinder into said reservoir while inhibiting a flow of the fluid from said front wheel brake cylinder, and a third state for inhibiting the flows of the fluid from both of said front and rear wheel brake cylinders while permitting a flow of said pressurized fluid from said pump into at least one of said front and rear wheel brake cylinders;
• anti-lock pressure control means for controlling an operation of said pump while said first shut-off valve is placed in said connecting state, and selectively placing said valve device in said first, second and third states, so as to control pressures of the fluid in said front and rear wheel brake cylinders such that a slip of each of said front and rear wheels on a road surface upon activation of said front and rear wheel brake cylinder is maintained at a substantially optimum value;
• and
• said anti-lock pressure control means comprising reservoir fluid amount estimating means for estimating an amount of the fluid stored in said reservoir, on the basis of a pressure reducing time during which said valve device is placed in said first state, and an operating time of said pump.