Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1994-03-18
1995-06-27
Nelli, Raymond A.
Internal-combustion engines
Charge forming device
Fuel injection system
F02M 500
Patent
active
054270693
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an apparatus and method for injection timing control of an internal combustion engine, and in particular to an apparatus and method for controlling the fuel injection timing of a fuel injection valve such that fuel injection is completed at a predetermined injection end timing.
BACKGROUND ART
An internal combustion engine of this type is disclosed for example in Japanese unexamined Patent Publication No. 59-29733.
With this engine, the injection end timing for fuel injection using fuel injection valves for each cylinder is timed to occur just before the intake stroke for each cylinder. This is achieved by variably setting the injection start timing which is calculated backwards for a fuel injection quantity (fuel injection time) computed on the basis of the engine operating conditions. As a result, high combustion stability can be achieved.
Engine intake flow however is influenced by engine operating conditions prior to the intake stroke due to an intake filling effect caused by intake/exhaust valve overlap, and in the case of an engine with variable valve timing, there is also an influence due to valve timing variation.
Consequently, with an allocated injection end timing adapted for steady state conditions, control to give an optimum injection end timing under all operating conditions including transient operation is not possible, so that stable optimum combustion for all operating conditions cannot be attained.
It is an object of the present invention to address the above problem, and improve engine combustion by providing an apparatus and method of injection timing control whereby an optimum injection end timing for all operating conditions including transient operation can be set by detection of the intake flow velocity near the jet of the fuel injection valve.
It is also an object to be able to complete fuel injection at a crank angle position wherein the intake flow velocity near the jet of the fuel injection valve is at a maximum.
Furthermore, it is an object to be able to stably control injection end timing by limiting a variable range of the injection end timing.
Moreover, when a variable valve timing mechanism is provided, it is an object to be able to avoid influence from variations in valve timing on the accuracy of detecting the intake flow velocity near the jet.
It is an even further object to be able to accurately determine the intake flow velocity near the jet of the fuel injection valve.
DISCLOSURE OF THE INVENTION
The characteristics of the construction adopted in the present invention to solve the above problem involves a construction wherein the fuel injection valve is driven according to a fuel injection quantity calculated on the basis of the engine operating conditions, so that the fuel injection is completed at a predetermined injection end timing. With this construction, at least engine rotational speed, engine intake air quantity and intake valve opening area are each detected as parameters. The intake flow velocity near the jet of the fuel injection valve is then obtained on the basis of the detected parameters, and a predetermined injection end timing variably set according to the obtained intake flow velocity.
With such a construction, the injection end timing can be varied to correspond to variations in conditions of the intake flow velocity near the jet of the fuel injection valve.
Preferably the construction is such that a crank angle position wherein the intake flow velocity near the jet of the fuel injection valve is greater than a predetermined value, is set as the injection end timing.
In this case, even with a change in the crank angle position for a maximum intake flow velocity, the injection can be completed at a timing corresponding to this change so that the intake flow velocity is always a maximum.
Moreover, when the crank angle interval between the intake opening top dead center (TDC) and the intake closing bottom dead center (BDC) is 100%, then preferably the injection end timing is set to be within a crank
REFERENCES:
patent: 5211147 (1993-05-01), Ward
patent: 5215061 (1993-06-01), Ogawa et al.
patent: 5226393 (1993-07-01), Nagano et al.
patent: 5284118 (1994-02-01), Kato et al.
patent: 5337719 (1994-08-01), Togai
Kitayama Toru
Sugino Shigemi
Tomisawa Naoki
Nelli Raymond A.
Unisia Jecs Corporation
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