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.

In accordance with exemplary embodiments, methods and systems are provided for controlling knocking for an engine of a vehicle having a plurality of different types of fuel injectors and a combustion chamber. In an exemplary embodiment, the system includes one or more sensors of the vehicle and a processor. The one or more sensors are configured to measure an intensity of engine knocking for the engine. The processor is coupled to the one or more sensors, and is configured to at least facilitate adjusting a fuel injection ratio of respective amounts of fuel provided by the plurality of different types of fuel injectors to the combustion chamber, based on the intensity of the engine knocking.

A method provides for operating an engine configured to use a plurality of differing fuels. The method includes determining a fuel combustion ratio of the plurality of differing fuels associated with at least one engine cylinder of the engine based at least in part on one or more of a plurality of characteristic profiles. This maintains one or more of a plurality of actual values associated with usage of the plurality of differing fuels relative to defined corresponding threshold values. The fuel combustion ratio includes a ratio of the plurality of differing fuels to be delivered to the at least one engine cylinder. A fuel delivery system delivers the plurality of differing fuels to the at least one engine cylinder based on the fuel combustion ratio.

A determination device for an internal combustion engine executes a partial fuel cut-off process. The determination device determines that exhaust gas characteristics have deteriorated when the misfire rate of the internal combustion engine is greater than or equal to a determination threshold. The determination device sets the determination threshold to a first determination threshold when the calculated misfire rate is a misfire rate in a period of non-execution of the partial fuel cut-off process. Also, the determination device sets the determination threshold to a second determination threshold, which is less than the first determination threshold, when the calculated misfire rate is a misfire rate in a period of execution of the partial fuel cut-off process.

An engine includes a first injection valve, which is one of port and direct injection valves, and a second injection valve, which is the other. When operating only the first injection valve based on a base injection amount, which has been corrected using a feedback operation amount and a first learning value, an air-fuel ratio control apparatus updates the first learning value and determines that the first learning value has converged on condition that a correction ratio of the base injection amount is not more than a predetermined ratio. When the first and second injection valves are being operated, the apparatus updates a second learning value for the second injection valve on condition that the first learning value has converged and the ratio of the injection amount of the second injection valve is not less than a specified value.

A control device for an internal combustion engine is configured to carry out a lean combustion of which excess air factor is 2.0 or more by injecting fuel for creating a homogeneous air-fuel mixture from a first fuel injection valve into a combustion chamber of an engine main body, injecting ignition fuel for creating an ignition air-fuel mixture near an electrode portion of a spark plug from a second fuel injection valve, and igniting the ignition air-fuel mixture, and when occurrence of knocking is detected based on a detection value of a knock sensor during the lean combustion, apply retard correction to each of an ignition timing of the spark plug and an injection timing of the ignition fuel set corresponding to an engine operating state, and apply increase correction to an injection amount of the ignition fuel.

A control method of an internal combustion engine including an in-cylinder injection fuel injection valve arranged to inject a fuel to a combustion chamber, and a port injection fuel injection valve arranged to inject the fuel to an intake port, the control method includes: sensing or estimating a fuel temperature at a tip end portion of the in-cylinder injection fuel injection valve; sensing an intake pressure; judging whether or not a flash boiling condition based on the fuel temperature and the intake pressure; setting the in-cylinder fuel injection valve to a default fuel injection valve; and injecting an entire or a part of the fuel from the port injection fuel injection valve by decreasing an injection amount ratio of the in-cylinder injection fuel injection valve when the flash boiling condition is satisfied.

A vehicle includes a residual pressure holding valve provided downstream a feed pump of a fuel to hold a pressure in a fuel pipe leading to the port injection valve. Residual pressure holding valve is opened to return the fuel in the fuel pipe to the fuel tank when the pressure in the fuel pipe exceeds a valve opening pressure, and closed when the pressure in the fuel pipe is lower than the valve opening pressure. At the time of a request to reduce a target pressure of the fuel to be supplied to the electric feed pump, a control device refrains from causing the target pressure to decrease when a load of the engine is smaller than a prescribed value, and causes the target pressure to decrease when the load of the engine is greater than the prescribed value.

Methods and systems are provided for learning fuel injector error for cylinder groups during a deceleration fuel shut-off (DFSO), where all cylinders of an engine are deactivated, sequentially firing each cylinder of a cylinder group, each cylinder fueled via consecutive first and second fuel pulses of differing fuel pulse width from an injector. Based on a lambda deviation between the first and second pulses, a fuel error for the injector and an air-fuel ratio imbalance for each cylinder is learned. Alternatively or additionally, a difference in crankshaft acceleration between the first and second pulses relative to the expected deviation may be used to learn torque error, and adjust fuel injector error and air-ratio imbalance for each cylinder.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, estimates of engine fuel consumption for operating the engine with a plurality of cylinder modes or patterns while a transmission is engaged in different gears are determined and are used as a basis for deactivating engine cylinders.