Control system for in-cylinder direct injection engine
AssigneeMazda Motor Corporation
InventorsTakeo Yamauchi, Masayuki Tetsuno, Kiyotaka Mamiya
Life of this patent
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Abstract
In a control system for an in-cylinder direct injection engine, an actual port intake air density ganmap is calculated based on the intake air temperature thae and the atmospheric pressure atp, a reference port intake air density ganmap* corresponding to the current operating conditions of the engine is read out of a map and compared with the actual port intake air density ganmap, and a target fuel pressure or fuel injection timing is compensatorily modified based on the comparison result. This prevents fuel spray and the tumble from being thrown out of balance due to a change in intake air temperature or atmospheric pressure thereby providing suitable mixture stratification.
Claims16
A control system for an in-cylinder direct injection engine which includes:
- a fuel injection valve for directly injecting a fuel into a combustion chamber in a cylinder of an engine;
- and tumble generating means for generating a tumble in the combustion chamber, in which the fuel is injected against the tumble in the combustion chamber by the fuel injection valve during stratified-charge combustion operation of the engine so that a flammable mixture stays in the vicinity of an electrode of a spark plug at the ignition timing for the cylinder, the control system further comprising:
- intake air density detecting means for detecting a value for density conditions of an intake air taken in the combustion chamber;
- revolving speed detecting means for detecting the revolving speed of the engine;
- intake air flow control means for controlling the flow rate of the tumble in the combustion chamber;
- fuel pressure control means for controlling the fuel injection pressure of the fuel injection valve;
- and
- control means for controlling the fuel injection valve, the intake air flow control means and the fuel pressure control means based on a value detected by at least one of the intake air density detecting means and the revolving speed detecting means,
- wherein the control means sets based on at least the engine revolving speed respective reference target values of the tumble flow rate, fuel injection pressure and fuel injection timing that correspond to the case where the value for density conditions of the intake air is equal to a preset reference value, and
- the control means compensatorily modifies at least one of the reference target values based on a value for the difference between the value detected by the intake air density detecting means and the reference value.
An in-cylinder direct injection engine system comprising:
- an intake port capable of generating a tumble in a combustion chamber of an engine;
- a fuel injection valve for injecting a fuel against the tumble in the combustion chamber during a compression stroke of the cylinder;
- an intake air temperature sensor for detecting the temperature of an intake air taken in the combustion chamber;
- an atmospheric pressure sensor for detecting the atmospheric pressure;
- a revolving speed sensor for detecting the revolving speed of the engine;
- an intake air flow control valve for controlling the flow rate of the tumble flowing in the combustion chamber;
- a regulator for regulating the fuel pressure of the fuel to be supplied to the fuel injection valve;
- and
- a control unit for controlling the opening of the intake air flow control valve, and the fuel injection timing and fuel pressure of the fuel injection valve based on a signal output from at least one of the revolving speed sensor, the intake air temperature sensor and the atmospheric pressure sensor,
- wherein the control unit sets based on at least the engine revolving speed respective reference target values of the tumble flow rate, fuel injection pressure and fuel injection timing that correspond to the case where a value for density conditions of the intake air is equal to a preset reference value, and
- the control unit calculates the intake air density based on the detected values of the intake air temperature sensor and the atmospheric pressure sensor, and compensatorily modifies at least one of the reference target values based on a value for the difference between the calculated value for the intake air density and the reference value.
Dependencies are inferred from the claim text.