A control device for an engine, includes: an air intake controller controlling a quantity of intake air to be supplied to a catalyst provided in an exhaust passage by controlling an open degree of a throttle valve provided in an intake passage; a fuel controller controlling fuel supply to the engine, wherein the fuel controller stops the fuel supply and the air intake controller performs a first control supplying intake air to the catalyst by opening the throttle valve, for a predetermined period of time after an end of the first control, the fuel controller stops the fuel supply, and the air intake controller performs a second control decreasing the open degree of the throttle valve to an open degree smaller than that during the first control, and after the predetermined period of time passes, the fuel controller starts a third control supplying the fuel to the engine.

Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

An air amount control valve of a vehicle changes an intake air amount drawn into a cylinder. A fuel cutoff process stops fuel injection from a fuel injection valve when stopping combustion in the cylinder in a case in which a crankshaft is rotating. When execution of the fuel cutoff process is requested, a temperature-increase limiting process is executed to draw fresh air into a catalyst by increasing the intake air amount through control of the air amount control valve. In a case in which an anomaly occurs in driving of the air amount control valve when executing the temperature-increase limiting process, an amount of air drawn into the catalyst is increased by increasing an engine speed.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

The present invention describes a fuel-management system for minimizing particulate emissions in turbocharged direct injection gasoline engines. The system optimizes the use of port fuel injection (PFI) in combination with direct injection (DI), particularly in cold start and other transient conditions. In the present invention, the use of these control systems together with other control systems for increasing the effectiveness of port fuel injector use and for reducing particulate emissions from turbocharged direct injection engines is described. Particular attention is given to reducing particulate emissions that occur during cold start and transient conditions since a substantial fraction of the particulate emissions during a drive cycle occur at these times. Further optimization of the fuel management system for these conditions is important for reducing drive cycle emissions.

Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

Methods and systems are described for controlling fuel injection in an engine equipped with a dual injector system including a port injector and a direct injector. A ratio of port injected fuel to direct injected fuel is adjusted based at least on intake valve temperature. The proportion of fuel port injected into a cylinder is increased as the intake valve temperature for the given cylinder increases to improve fuel vaporization in the intake port.

Methods and systems are provided for estimating ethanol content in fuel and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content and/or fuel age based on fuel temperature, a speed of sound in fuel, and an attenuation co-efficient of an ultrasonic signal in fuel. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content and fuel age.

Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on fuel rail temperature, and two or more of a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (p), and a damping coefficient () of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.

Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (p), and a damping coefficient () of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.