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.

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.

Provided is a control device for an internal combustion engine, which can control an injection amount of water injected into each cylinder of the internal combustion engine to a minimum injection amount that allows knock to be suppressed for each cylinder. Therefore, in a control device 1 that controls water supply valves 35 (water supply devices) that supply water into each of combustion chambers of a plurality of cylinders R (cylinders R1 to R3 in the embodiment) of an internal combustion engine 100, the control device 1 includes a water supply amount calculation unit 2 that calculates a supply amount of water supplied to each of the combustion chambers of the plurality of cylinders R1 to R3 for each cylinder, and a water supply control unit 3 that controls the water supply valves 35 based on the supply amount of water calculated by the water supply amount calculation unit 2 for each cylinder.

Optimized alcohol and plasma enhanced prechambers for engines powered by gasoline and other fuels are used to increase the range of prechamber operation and to reduce soot. The increased prechamber capability is employed to extend the limit of lean operation of the engines. It can also be used to extend the limit of heavy EGR operation and to enable higher RPM operation. The amount of alcohol used in the prechamber is preferably less than 2% of the fuel that is used in the engine cylinder. The alcohol for the prechamber can be entirely provided by onboard separation from a gasoline-alcohol fuel mixture.

Methods and systems are provided for calculating a fuel aging of fuel in a fuel tank. In one example, a method may include alerting a vehicle operator and/or adjusting engine operating parameters in response to a fuel aging being greater than a threshold aging.

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.

A device that enables gasoline internal combustion engines to efficiently use fuel with higher ethanol content. The device measures various data such as ethanol content, RPM, temperature, intake air pressure, mass airflow, exhaust gas, crank sensor, among other data, to determine to an ideal enrichment pulse duration to apply to the fuel injector.

Various embodiments include a method for starting an internal combustion engine comprising: in a first phase after a starting process, setting a throttle valve to a value near to zero so the pressure in the intake tract is lowered below the ambient pressure and injecting a fuel into the intake tract above a rich combustion limit at which the fuel/air mixture would still just be combustible; in a second phase, reducing the fuel mass as a function of the pressure; in a third phase shorter than the second phase, further reducing the fuel mass and increasing the opening of the throttle valve to increase the pressure in the intake tract; and in a fourth phase, increasing the fuel mass as a function of rising pressure in the intake tract.

The present invention relates to a diagnosis method for an ethanol sensor of a flexible fuel vehicle, the diagnosis method including: a) the fuel refilling detection step of detecting whether fuel is filled to a fuel tank; b) the maximum changeable content range calculation step of calculating a content range of ethanol in the fuel stored in the fuel tank; c) the ethanol sensor value acquirement step of determining whether the data detected from an ethanol sensor converges into a given value; d) the oxygen sensor value acquirement step of determining whether the data detected from an oxygen sensor converges into a given value; and e) the ethanol sensor abnormality determination step of determining that an error is generated from the ethanol sensor if the data acquired at the ethanol sensor value acquirement step or the data acquired at the step is not a value in the calculated range.

Methods and systems are provided for improving efficiency of an exhaust gas after treatment system of a vehicle. In one example, a first group of engine cylinders is operated with a rich air-fuel ratio continuously while a second group of engine cylinders is operated with a lean air-fuel ratio continuously. The rich and lean exhaust gases from the two groups of engine cylinders may be oxidized within an exhaust gas after treatment system to improve catalyst efficiency.