Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2000-01-07
2001-05-15
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
Reexamination Certificate
active
06230687
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The subject of the present invention is a method for fuel injection for starting an internal combustion engine and, more specifically, a method allowing quick jolt-free starting even at very low temperature.
Multi-cylinder four-stroke internal combustion engines are currently operated on the so-called sequential injection principle. In this method, one injector is associated with each cylinder and this injector is operated on the basis of the angular position of the engine in the cycle so that a predetermined amount of fuel is injected into each cylinder at a precise phase in the engine cycle. To achieve this, the position of the engine is recognized on the basis of signals supplied by sensors associated with targets linked to the crankshaft and to the cam-shaft. The cylinder which is to begin its induction phase is determined, and the injector associated with this cylinder is operated in such a way that the desired amount of fuel is injected before the start of the induction phase.
However, during engine starting, the exact position of this engine is not known. A device designed to implement a method for injection for an internal combustion engine in such a way that on closure of an engine starting contact a first amount of fuel is injected simultaneously into all of the cylinders and when an engine synchronization signal is recognized the fuel is injected sequentially, one cylinder at a time, once per cycle and in a predetermined order is known from French Patent Application 2 516 982.
It has, however, been observed that misfires could occur in one of the cylinders and lead to the engine slowing down and even sometimes stalling, particularly under extreme cold start conditions.
SUMMARY OF THE INVENTION
The present invention therefore proposes a method for controlling the injection of fuel into an internal combustion engine which does not carry this risk of misfires and thus allows quick and assured engine starting regardless of the operating conditions.
These objects of the invention, together with others which will become clear in what follows of the present description, are achieved by means of a method for fuel injection for starting an internal combustion engine in which, upon closure of a starting contact, fuel injection means are operated simultaneously to deliver a first amount of fuel to a number of cylinders and, after a synchronization signal has been recognized, said injection means are operated sequentially. According to the invention, an angle of rotation separating the angular position of the engine upon closure of the starting contact from the angular position reached upon recognition of the synchronization signal is measured, this angle is compared with a predetermined value, and when the angle of rotation is greater than the predetermined value, an additional amount of fuel is injected into a cylinder determined on the basis of the cylinder in respect of which the synchronization signal was recognized.
According to an important feature of the invention, the predetermined value is calculated on the basis of the angular advance of a mark identifying the top dead center position of a cylinder with respect to the actual position of this top dead center and of a delay in the closing of an inlet valve of this cylinder.
According to another feature of the invention, the additional amount of fuel is injected into the cylinder which, in the cycle, immediately precedes the cylinder in respect of which the synchronization signal was recognized.
According to another feature of the invention, the additional amount of fuel is a function of the first amount delivered and of the angular difference between the angular position of the engine upon closure of the starting contact and the angular position reached upon recognition of the synchronization signal.
REFERENCES:
patent: 4508083 (1985-04-01), Hasegawa et al.
patent: 4732122 (1988-03-01), Scarnera et al.
patent: 4941449 (1990-07-01), Hoptner et al.
patent: 4998522 (1991-03-01), Achleitner
patent: 5245972 (1993-09-01), Denz et al.
patent: 5390641 (1995-02-01), Yamada et al.
patent: 4317635A1 (1994-12-01), None
patent: 2233709A (1991-01-01), None
Argenbright Tony M.
Greenberg Laurence A.
Lerner Herbert L.
Siemens Automotive S.A.
Stemer Werner H.
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