US 6,668,791 B2Granted

Control system for in-cylinder direct injection engine

AssigneeMazda Motor Corporation

InventorsMasayuki Tetsuno, Kiyotaka Mamiya, Takeo Yamauchi

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Abstract

In a control system for an in-cylinder direct injection engine, during idling operation, the fuel injection timing is compensated to the advance side for each cylinder so that the rate of change in crank angular velocity becomes smaller than a preset criterion while the fuel injection pressure of an injector is gradually reduced from a reference target fuel pressure to a preset lower limit. If the rate of change in crank angular speed becomes smaller than the criterion as a result of the above compensation, the fuel injection timing is compensated to the retard side so that the rate of change in crank angular velocity becomes smaller while the fuel pressure is gradually increased to the preset upper limit. Consequently, the unbalance of fuel spray and tumble due to deviations of fuel spray penetration and the like can be eliminated thereby providing suitable mixture stratification.

Claims9

Dependent claims

A control system for an in-cylinder direct injection engine which comprises:

a fuel injection valve for directly injecting a fuel into a combustion chamber in a cylinder of an engine;
and a 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 a spark plug at the ignition timing for the cylinder, the control system further comprising:
a fuel pressure control means for controlling the fuel injection pressure of the fuel injection valve;
a fuel pressure forcibly changing means for forcibly changing the fuel injection pressure to be controlled by the fuel pressure control means from a reference injection pressure corresponding to operating conditions of the engine;
a combustion variation detecting means for detecting the degree of combustion variation in the engine when the fuel injection pressure has been changed by the fuel injection forcibly changing means;
and
an injection timing compensation means for compensating the fuel injection timing of the fuel injection valve so that the degree of combustion variation in the engine detected by the combustion variation detecting means becomes smaller than that in a preset reference condition.

4 more elements

An in-cylinder direct injection engine system comprising:

a fuel injection valve for directly injecting a fuel into a combustion chamber in a cylinder of an engine;
an intake port capable of generating a tumble flow in the combustion chamber;
a regulator for regulating the fuel pressure of the fuel to be supplied to the fuel injection valve;
a revolving speed sensor for detecting the revolving speed of the engine;
a crank angle sensor for detecting the rotational angle of a crank shaft;
a fuel pressure sensor for detecting the pressure of the fuel being supplied to the fuel injection valve;
and
a control unit for controlling the fuel injection timing and fuel pressure of the fuel injection valve based on a signal from at least one of the revolving speed sensor, the crank angle sensor and the fuel pressure sensor,
wherein the control unit is adapted to set based on at least the engine revolving speed a reference target value for control on the fuel pressure to be regulated by the regulator, set based on at least the engine revolving speed a reference target value for control on the fuel injection timing of the fuel injection valve, change the setting of the reference target value for control on the fuel pressure to increase or decrease the target value followed by controlling the regulator so that the value detected by the fuel pressure sensor reaches the changed target value, retard the fuel injection timing of the fuel injection valve behind the reference target value for control on the fuel injection timing if the rate of change of values detected by the crank angle sensor becomes larger than a preset reference value as the result of an augmentative setting of the target value for control on the fuel pressure, and advance the fuel injection timing of the fuel injection valve ahead of the reference target value for control on the fuel injection timing if the rate of change of values detected by the crank angle sensor becomes larger than the preset reference value as the result of a reductive setting of the target value for control on the fuel pressure.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/095,090Filed 12 Mar 2002
Priority: JP 2001-07763419 Mar 2001
Published: US 2002/0129785 A119 Sep 2002
Granted: 30 Dec 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification21 codes

F02D 41/3029
A mode being the stratified charge spark-ignited mode: further comprising a homogeneous charge spark-ignited mode
F02B 17/005
Engines characterised by means for effecting stratification of charge in cylinders: having direct injection in the combustion chamber
F02B 23/104
With separate admission of air and fuel into cylinder: the injector being placed on a side position of the cylinder
F02B 31/085
Having multiple air inlets: having two inlet valves