A motor vehicle stop/start control system (10) for controlling at least a portion of a powertrain of a vehicle, the system (10) being configured to: receive speed information (WSS) indicative of vehicle speed; and receive brake information (BPS) indicative that a braking system has been activated to apply brake torque; wherein the control system (10) is further configured to cause an engine (121) of the motor vehicle (100) to be switched off when a first set of predetermined conditions are met, the first set of conditions including the conditions that the brake information (BPS) indicates that the braking system is active and the speed information (WSS) indicates that vehicle speed is a below a predetermined engine-off speed, the engine-off speed being determined by the control system at least in part by reference to information received by the control system.

Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, the inhibiting or preventing automatic engine stopping may be performed when a human driver releases a brake pedal, which causes the engine to automatically start, and the inhibiting may continue until vehicle speed exceeds a speed where the engine was automatically stopped.

A motor vehicle stop/start control system (10) for controlling at least a portion of a powertrain of a vehicle, the system (10) being configured to: receive speed information (WSS) indicative of vehicle speed; and receive brake information (BPS) indicative that a braking system has been activated to apply brake torque; wherein the control system (10) is further configured to cause an engine (121) of the motor vehicle (100) to be switched off when a first set of predetermined conditions are met, the first set of conditions including the conditions that the brake information (BPS) indicates that the braking system is active and the speed information (WSS) indicates that vehicle speed is a below a predetermined engine-off speed, the engine-off speed being determined by the control system at least in part by reference to information received by the control system.

Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, an engine may be automatically stopped in response to a brake booster vacuum threshold level that is adjusted responsive to vehicle speed so that opportunities to automatically stop an engine may be increased, thereby conserving fuel.

A starting assistance method and device for an internal combustion engine supplied with a fuel that may contain ethanol, and including a fluid connection pipe between an intake manifold and a braking assistance device. The method including determining the engine temperature, determining the outdoor air temperature, blocking the pipe between the intake manifold and the braking assistance device for a given duration during a phase of starting the engine when the temperature of the engine is lower than a first threshold value and the outdoor air temperature is lower than a second threshold value, and freeing the pipe between the intake manifold and the braking assistance device when the engine is rotating autonomously.

A stop-start system and method for a motor vehicle include a controller configured to shut down an engine of the motor vehicle automatically when the motor vehicle is moving and a predetermined engine shut down condition is achieved, to perform a rolling stop-start operation; and a mechanically driven auxiliary vacuum pump coupled to a transmission gear or output shaft and configured to provide vacuum pressure to a brake booster of the motor vehicle, wherein the controller is configured to operate the auxiliary vacuum pump during the rolling stop-start operation.

Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, the inhibiting or preventing automatic engine stopping may be performed when a human driver releases a brake pedal, which causes the engine to automatically start, and the inhibiting may continue until vehicle speed exceeds a speed where the engine was automatically stopped.

The invention relates to a restarting method for automatically starting an internal combustion engine (2) of a motor vehicle (3) by means of a brake pedal actuation, comprising the following steps: detecting a brake pressure (p) by means of a brake pressure sensor (14); emitting a corresponding brake pressure signal sequence to a control device (13); determining a brake pressure profile (p.sub.pr) from the brake pressure signal sequence; determining a reference pressure value (p.sub.R) from the brake pressure profile; detecting a brake release status, wherein, with the release of a brake pedal, a brake pressure decrease (p) is detected based on the determined reference pressure value (p.sub.R), with said decrease exceeding a pressure decrease limit value (p.sub.G); emitting a starting signal (S.sub.WS) to a starter (15) for starting the internal combustion engine (2), if the brake release status has been detected. The invention also relates to a restarting assembly for a motor vehicle (1) for carrying out a method of this type.

A method and system for determining the pressure in a brake booster used to actuate a brake system having at least one main brake cylinder. The brake booster connected in a fluid-conducting manner by a non-return valve to an intake manifold of an internal combustion engine. A reduced pressure loss in the brake booster resulting from actuation of the main brake cylinder is balanced with the reduced pressure gain in the brake booster as a result of a pressure difference between the brake booster pressure and the intake manifold pressure. The reduced pressure gain in the brake booster is determined based on time, the air mass flow between the brake booster, and the intake manifold.

A vehicle engine automatic control device has a brake pedal operation amount detecting unit that detects an amount of brake pedal operation by a driver, a negative pressure-based force multiplying unit that multiplies a force, with which a brake is operated, using an intake negative pressure of an engine, a negative pressure detecting unit that detects a negative pressure of the negative pressure-based force multiplying unit, and a coast stop control unit that stops the engine when the amount of brake pedal operation that is detected is equal to or greater than a first operation amount threshold during coast drive, and re-starts the engine when the negative pressure that is detected falls below a first negative pressure threshold after the engine stops.