Abstract: Methods and systems are provided for adjusting operation of a plug-in hybrid electric vehicle responsive to a seasonal grade of the fuel available in the vehicle's fuel tank. If the seasonal grade of fuel in the fuel tank does not correspond to the seasonal grade of fuel mandated during the time of engine operation, a fuel injection amount is adjusted to compensate for differences between seasonal grades of a fuel.

Abstract: A vehicle and vehicle system are provided with a controller that is configured to generate output indicative of a vehicle mass estimation. The vehicle mass estimation is based on a longitudinal acceleration and a wheel torque when at least one of the longitudinal acceleration, a vehicle speed and a yaw rate indicate an occurrence of a qualified event. The controller is further configured to generate output indicative of a dynamic road gradient estimation based on the vehicle speed, the wheel torque and the vehicle mass estimation.

Abstract: A vehicle-hold control method is used to hold an engine-powered vehicle from rolling backward on a road gradient during an engine start. The engine shuts down when the vehicle is stopped following operation of the vehicle under engine power. The engine is re-started during an engine cranking interval as vehicle wheel brakes are applied. The brakes are released in response to detection of pre-calibrated engine speed characteristics.

Abstract: A vehicle and a vehicle system are provided with a controller that is configured to generate output indicative of a kinematic road gradient estimation using an extended Kalman filter. The extended Kalman filter includes a system input based on a longitudinal acceleration and an acceleration offset, and a system output based on a predicted vehicle speed. The acceleration offset is based on at least one of a lateral velocity, a lateral offset, and a vehicle pitch angle. The controller is further configured to generate output indicative of a kinematic quality factor corresponding to an availability of the kinematic road gradient estimation.

Abstract: A vehicle includes an engine configured for automatic shutdown and restart. The vehicle is provided with a controller that is configured to restart the engine when a difference between an actual brake pressure and a filtered brake pressure is greater than a threshold value. The filtered brake pressure is dependent upon a magnitude of the actual brake pressure and a rate of change of the actual brake pressure.

Abstract: A vehicle is provided with an engine that is configured for automatic shutdown and restart. The vehicle is also provided with a controller that is configured to shutdown the engine in response to brake effort exceeding a first threshold and to restart the engine in response to brake effort decreasing below a second threshold. The first threshold and the second threshold are based on an estimated vehicle mass and a road gradient.

Abstract: Methods are provided for controlling a vehicle speed during a downhill travel. Based on the estimated grade of the downhill travel and further based on an input received from the operator, different combinations of an engine braking torque and a regenerative braking torque are used to maintain the vehicle speed during the downhill travel. A battery rate of charging is also adjusted based on the duration or distance of the downhill travel, as indicated by the operator input.

Abstract: An engine with a fast vacuum recovery brake booster system is disclosed. In one example, an actuator is adjusted in response to a flow between the brake booster and an engine intake manifold. Operation of the engine and vehicle brakes may be improved especially when the engine is boosted.

Abstract: A system for detecting accelerator pedal failure in an accelerator pedal system including a vehicle control system, the pedal failure detecting system having an accelerator pedal; a pedal arm; a sensor configured to interpret a force applied to the accelerator pedal and further configured to transmit a signal as a sensor output to the vehicle control system, wherein the vehicle control system is configured to correlate the sensor output to an accelerator pedal position, and to indicate a failure condition when it is not feasible the to read the sensor output given the accelerator pedal position. A method for detecting accelerator pedal failure conditions in an accelerator pedal system.

Abstract: Methods and systems are provided for controlling the automatic shutdown of an idling vehicle engine. When the vehicle is parked in an enclosed space, the idling engine may be automatically shutdown, while when the vehicle is parked in an open space, the automatic shutdown may be delayed based on an ambient temperature. In this way, the vehicle cabin may be maintained at a temperature that provides enhanced driver comfort while allowing wasteful engine idling to be reduced.

Abstract: Methods and systems are provided for controlling the automatic shutdown of an idling vehicle engine. When the vehicle is parked in an enclosed space, the idling engine may be automatically shutdown, while when the vehicle is parked in an open space, the automatic shutdown may be delayed based on an ambient temperature. In this way, the vehicle cabin may be maintained at a temperature that provides enhanced driver comfort while allowing wasteful engine idling to be reduced.

Abstract: Methods are provided for controlling a vehicle speed during a downhill travel. Based on the estimated grade of the downhill travel and further based on an input received from the operator, different combinations of an engine braking torque and a regenerative braking torque are used to maintain the vehicle speed during the downhill travel. A battery rate of charging is also adjusted based on the duration or distance of the downhill travel, as indicated by the operator input.

Abstract: Methods and systems are provided for adjusting operation of a plug-in hybrid electric vehicle responsive to a seasonal grade of the fuel available in the vehicle's fuel tank. If the seasonal grade of fuel in the fuel tank does not correspond to the seasonal grade of fuel mandated during the time of engine operation, a fuel injection amount is adjusted to compensate for differences between seasonal grades of a fuel.

Abstract: An engine with a fast vacuum recovery brake booster system is disclosed. In one example, an actuator is adjusted in response to a flow between the brake booster and an engine intake manifold. Operation of the engine and vehicle brakes may be improved especially when the engine is boosted.

Abstract: Systems and methods are described for controlling engine operation of an engine that may be shut-down during engine idle stop conditions. The engine may include a high pressure direct injection fuel system. In one embodiment, a method stops the engine when a temperature of a fuel rail is below a threshold during a selected engine idle stop condition. On the other hand, when the temperature of the fuel rail is above the threshold, engine operation is maintained during the selected engine idle stop condition.

Abstract: Systems and methods are described for controlling engine operation of an engine that may be shut-down during engine idle stop conditions. The engine may include a high pressure direct injection fuel system. In one embodiment, a method comprises during at least a first fuel rail temperature below a threshold, automatically stopping engine operation during a selected engine idle stop condition; and during at least a second fuel rail temperature above the threshold, maintaining engine operation during the selected engine idle stop condition.

Abstract: Systems and methods are described for controlling engine operation of an engine that may be shut-down during engine idle stop conditions. The engine may include a high pressure direct injection fuel system. In one embodiment, a method comprises during at least a first fuel rail temperature below a threshold, automatically stopping engine operation during a selected engine idle stop condition; and during at least a second fuel rail temperature above the threshold, maintaining engine operation during the selected engine idle stop condition.

Abstract: A vehicle powertrain with mechanically independent sets of front and rear traction wheels has separate motive power units. An electronic control system including traction wheel slip control is electronically coupled to a first motive power unit and to a second motive power unit to separately establish maximum rear wheel traction and maximum front wheel traction. Independent requests are made for an increase or a decrease in wheel torque for one set of traction wheels and an increase or decrease in wheel torque for the other set of traction wheels thereby improving acceleration performance and enhancing vehicle stability.

Abstract: A method is presented for improved interaction between driver demand, cruise control system and traction control system in an internal combustion vehicle. Desired engine output torque is adjusted based on the above inputs and vehicle operating conditions. This method improves drive feel and customer satisfaction with vehicle performance.

Abstract: A method is presented for improved interaction between driver demand, cruise control system and traction control system in an internal combustion vehicle. Desired engine output torque is adjusted based on the above inputs and vehicle operating conditions. This method improves drive feel and customer satisfaction with vehicle performance.