Back-up braking in vehicle braking systems

A vehicle braking system comprising:

• an electro-hydraulic braking arrangement which operates normally in a brake-by-wire mode, wherein hydraulic pressure is applied to braking devices at the vehicle wheels in proportion to the driver's braking demand as sensed electronically at a brake pedal, and which, if the brake-by-wire made should fail, operates in a push-through mode wherein hydraulic pressure is applied to at least one of the braking devices by way of a master cylinder coupled mechanically to the brake pedal;
• and
• an electric parking brake arrangement adapted to selectively actuate at least another one of the braking devices for parking braking purposes, the electric parking brake arrangement further being adapted to selectively actuate the at least another one of the braking devices at the same time that the electro-hydraulic braking arrangement is operating in the push-through mode to apply hydraulic pressure to the at least one of the braking devices.

A vehicle braking system comprising:

• an electro-hydraulic braking arrangement which operates normally in a brake-by-wire mode, wherein hydraulic pressure is applied to braking devices at the vehicle wheels in response to an electronic braking demand signal, and which, if the brake-by-wire mode should fail, operates in a push-through mode wherein hydraulic pressure is applied to at least one of the braking devices by way of a master cylinder coupled mechanically to a brake pedal;
• and
• an electric parking brake arrangement adapted to selectively actuate at least another one of the braking devices for parking braking purposes, the electric parking brake arrangement further being adapted to selectively actuate the at least another one of the braking devices in response to movement of the brake pedal in coordination with the actuation of the electro-hydraulic braking arrangement in the push-through mode.