A direct injection engine is coupled to a vacuum brake booster wherein vacuum created from engine pumping is used to supplement driver braking force. The brake booster is coupled through a check valve to the engine intake manifold. A method is disclosed for estimating pressure in the brake booster based on operating conditions. A method is also disclosed for estimating operating parameters based on measured brake booster pressure. Further, a method is disclosed for diagnosing degradation, or monitoring, a brake booster pressure sensor based on operating conditions. In addition, a method is disclosed for diagnosing degradation in other vehicle and engine sensors based on measured brake booster pressure.
An algorithm residing in, for example the ECM of a motor vehicle, which predicts brake booster vacuum for vehicles using vacuum for brake pedal assist. The predicted brake booster vacuum is compared to a calibrated brake booster vacuum threshold to determine if adequate brake booster vacuum is available to meet vehicle braking requirements, whereupon engine operation can be modified, as necessary, to improve intake manifold vacuum such that brake booster vacuum requirements for vehicle braking are better satisfied.
An algorithm residing in, for example the ECM of a motor vehicle, which predicts brake booster vacuum for vehicles using vacuum for brake pedal assist. The predicted brake booster vacuum is compared to a calibrated brake booster vacuum threshold to determine if adequate brake booster vacuum is available to meet vehicle braking requirements, whereupon engine operation can be modified, as necessary, to improve intake manifold vacuum such that brake booster vacuum requirements for vehicle braking are better satisfied.
A direct injection engine is coupled to a vacuum brake booster wherein vacuum created from engine pumping is used to supplement driver braking force. The brake booster is coupled through a check valve to the engine intake manifold. A method for estimating pressure in the brake booster uses various engine and vehicle operating conditions. A method for estimating operating parameters uses measured brake booster pressure. Further, a method for diagnosing degradation, or monitoring, a brake booster pressure sensor is based on engine or vehicle operating conditions. In addition, a method for diagnosing degradation in other vehicle and engine sensors uses measured brake booster pressure.
An air mass is supplied to the combustion chambers by an intake manifold (12) in an internal combustion engine (10). An underpressure store (18) of a servo system (20) can be subjected to an underpressure via this intake manifold (12). The air mass flow in the inlet region (30) of the intake manifold (12) is determined by a sensor (32) and is supplied to an electronic control unit (26) for the fill computation. The actuation of the servo system (20) is detected and the determined air mass flow is corrected with or directly after a detected actuation of the servo system (20).
A method and system for ensuring reliable operation of a brake booster system for a vehicle braking system in which a pressure value prevailing in the brake pressure reservoir of the brake booster system is sensed by a pressure sensor. An error occurring in the brake booster system is detected by evaluating the sensed pressure value prevailing in the brake pressure reservoir as a function of the actuation of the brake actuating mechanism. The brake booster system includes a diagnostic circuit that is connected to the pressure sensor and to the brake actuating mechanism.
