Brake control system for an electrically driven vehicle
AssigneeNissan Motor Co., Ltd.
InventorShinichiro Morishita
Life of this patent
Estimating the term…
Abstract
During regenerative coordinate braking control, a target brake force is defined by eliminating influences of brake system component tolerances to achieve a comfortable brake feel and secure regenerative energy. A brake control system includes a master cylinder, wheel cylinders, a VDC brake fluid pressure unit and a motor controller. In response to a brake pedal operation by a driver, a brake pedal stroke position is detected at which a pressure in a master cylinder actually begins to be generated. A target deceleration characteristic is adjusted from a theoretical characteristic so that the target deceleration equals a maximum value of an add-on brake force (i.e., the regenerative brake gap) at the detected brake pedal stroke position.
Claims13
A brake control system for an electrically driven vehicle, comprising:
- a master cylinder for generating a master cylinder pressure in response to an operation of a brake pedal by a driver;
- a wheel cylinder at a driving wheel for applying a brake force in accordance with a wheel cylinder pressure;
- a brake fluid actuator having a fluid pressure pump disposed between the master cylinder and the wheel cylinder and driven by a motor;
- a differential pressure valve for controlling a pressure difference between the wheel cylinder pressure and the master cylinder pressure during operation of the motor;
- an electric motor connected to the driving wheel for controlling a regenerative braking force;
- and
- a brake controller programmed to:
- obtain a brake target force for the brake force based on the brake pedal stroke position and a target deceleration characteristic;
- achieve the brake target force by summing a base brake pressure portion derived from the master cylinder pressure and an add-on brake portion derived from at least one of a regenerative brake portion due to the regenerative braking force or a pump-up pressure portion from the brake fluid actuator;
- and
- set the add-on portion to a maximum value at an adjusted brake pedal stroke position at a point at which the master cylinder first begins to actually generate the master cylinder pressure.
A brake control system for an electrically driven vehicle, comprising:
- means for obtaining a brake target force for a brake force to be applied to a wheel cylinder at a driving wheel based on a brake pedal stroke position of a brake pedal and a target deceleration characteristic using a brake controller;
- means for achieving the brake target force by summing a base brake pressure portion derived from a master cylinder pressure generated by a master cylinder in response to an operation of the brake pedal by a driver and an add-on brake portion derived from at least one of a regenerative brake portion due to a regenerative braking force controlled by an electric motor connected to the driving wheel or a pump-up pressure portion from a brake fluid actuator having a fluid pressure pump disposed between the master cylinder and the wheel cylinder and driven by a motor a differential pressure valve controlling a pressure difference between the wheel cylinder pressure and the master cylinder pressure during operation of the motor;
- and
- means for setting the add-on portion to a maximum value at an adjusted brake pedal stroke position at a point at which the master cylinder first begins to actually generate the master cylinder pressure.
A brake control system for an electrically driven vehicle, comprising:
- obtaining a brake target force for a brake force to be applied to a wheel cylinder at a driving wheel based on a brake pedal stroke position of a brake pedal and a target deceleration characteristic using a brake controller;
- achieving the brake target force by summing a base brake pressure portion derived from a master cylinder pressure generated by a master cylinder in response to an operation of the brake pedal by a driver and an add-on brake portion derived from at least one of a regenerative brake portion due to a regenerative braking force controlled by an electric motor connected to the driving wheel or a pump-up pressure portion from a brake fluid actuator having a fluid pressure pump disposed between the master cylinder and the wheel cylinder and driven by a motor, a differential pressure valve controlling a pressure difference between the wheel cylinder pressure and the master cylinder pressure during operation of the motor;
- and
- setting the add-on portion to a maximum value at an adjusted brake pedal stroke position at a point at which the master cylinder first begins to actually generate the master cylinder pressure.
Dependencies are inferred from the claim text.