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.

An electric vacuum pump applied to a vacuum boosting brake system is provided. The pump has a water containing capacity that is greater than a backflow water capacity of an internal space defined in a pump housing which forms vacuum pressure. The pump includes a watertight chamber that is coupled to an exhaust port of a pump housing.

A check valve of a vacuum booster device is provided with a main body assembled in a vacuum pressure inlet port, a first passage, an accommodating portion and a second passage, a valve seat formed in the first passage, a valve body accommodated in the accommodating portion, and a spring which urges the valve body toward the valve seat. The spring is configured to include an end coil portion which engages with a spring seat, an expanding and contracting coil portion which expands and contracts and is separated from a flange portion of the valve body, and a linking coil portion which is separated from the flange portion and the spring seat and links the end coil portion and the expanding and contracting coil portion.

A brake booster is mounted on a forward bulkhead of a motor vehicle having two elements, a first element being securely connected to the brake booster whilst a second element is securely connected to the bulkhead. The two elements are restrained against vertical movement relative to one another by at least one connector which is deformed or fails upon a movement of the brake booster upward relative to the bulkhead. An actuator is movably mounted to the bulkhead below the brake booster and rearward of a gearbox housing such that rearward movement of the gearbox housing during a frontal collision presses against the actuator and moves the actuator upward to apply pressure to the brake booster, the pressure causing the brake booster to move upward relative to the bulkhead.

A method of controlling vacuum pressure for vehicle braking may include checking whether a vehicle is idle or enters a deceleration state, comparing an engine vacuum pressure and a booster vacuum pressure of the vehicle with a preset reference value, checking whether a valve control system of the vehicle is operable when the engine vacuum pressure and the booster vacuum pressure are lower less than the preset reference value, controlling the valve control system when the valve control system is operable; and controlling an air conditioner (A/C) or an alternator of the vehicle when the valve control system is inoperable.

A vacuum pump for automobiles used for brake application is provided wherein a method of reducing power consumption and running torque in a vacuum pump of a motor vehicle is explained. The present invention also provides a vacuum pump for automobiles comprising an actuator, a new vane locking assembly, a new vane and rotor assembly, a new non return valve assembly, the controlled oil supply means and a reed stopper assembly that reduces power loss and unnecessary frictional forces and to maintain a controlled oil supply to the vacuum pump.

A vacuum pump for automobiles used for brake application is provided wherein a method of reducing power consumption and running torque in a vacuum pump of a motor vehicle is explained. The present invention also provides a vacuum pump for automobiles comprising an actuator, a new vane locking assembly, a new vane and rotor assembly, a new non return valve assembly, the controlled oil supply means and a reed stopper assembly that reduces power loss and unnecessary frictional forces and to maintain a controlled oil supply to the vacuum pump.

An expansion chamber for a rotary vane vacuum pump is provided. The expansion chamber is in fluid communication with the discharge side of the rotary vane vacuum pump, such that the expansion chamber attenuates sound as a Helmholtz resonator. The expansion chamber includes an internal volume of between 80 cubic centimeters and 100 cubic centimeters, inclusive, and includes a curved sidewall that extends partially around, and generally conforms to, the exterior of the rotary vane vacuum pump. The expansion chamber also includes a downward extending port, open to the atmosphere, for attachment to a hose in applications in which the expansion chamber is below a water line.

An expansion chamber for a rotary vane vacuum pump is provided. The expansion chamber is in fluid communication with the discharge side of the rotary vane vacuum pump, such that the expansion chamber attenuates sound as a Helmholtz resonator. The expansion chamber includes an internal volume of between 80 cubic centimeters and 100 cubic centimeters, inclusive, and includes a curved sidewall that extends partially around, and generally conforms to, the exterior of the rotary vane vacuum pump. The expansion chamber also includes a downward extending port, open to the atmosphere, for attachment to a hose in applications in which the expansion chamber is below a water line.

This blow-by gas recirculation device for an internal combustion engine is provided with a vacuum pump which supplies negative pressure to a brake booster and usable for recirculation of blow-by gas to an intake passage. This device includes: a PCV device for recirculating blow-by gas in a crankcase to the intake passage; a ventilation shortage region determination unit which determines whether or not an operational region of the engine is a PCV ventilation flow rate shortage region; and a brake negative pressure determination unit which determines whether or not the negative pressure of the brake booster is secured. The vacuum pump ventilates blow-by gas in the crankcase only when the determination units determines that the operational region is the PCV ventilation flow rate shortage region and that the negative pressure is secured. This reduces a contact risk of blow-by gas with engine oil, and inhibits the degradation of the oil.