Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Reexamination Certificate
2000-01-12
2001-07-24
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S090110
Reexamination Certificate
active
06263857
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a control system for controlling operation of an internal combustion engine, and more particularly to an intake air control system that controls the amount of intake air to a target value by adjusting an OPEN/CLOSE timing of each intake valve of the engine.
2. Description of the Related Art
Hitherto, various intake air control systems have been proposed for appropriately controlling the amount of intake air by controlling the operation timing of the intake and exhaust valves.
One of such intake air control systems is shown in Laid-open Japanese Patent Application 9-256823. In the system of this publication, for accuracy with which the open/close operation of each of the intake and exhaust valves is carried out, an electromagnetic type valve actuating unit is used that includes electromagnetic actuators for actuating the intake and exhaust valves. In the engine equipped with such electromagnetic type valve actuating unit, control of the amount of intake air is made by adjusting the time for which each intake valve is opened, irrespective of whether the intake pipe of the engine is of a type equipped with a throttle valve or a type equipped with no throttle valve. Under operation of the engine, the pressure in the intake pipe is kept substantially equal to the atmospheric pressure, and thus the engine shows a less pumping loss as compared with a conventional engine that controls the intake air by using a throttle valve. However, even such engine has failed to adequately satisfy users due to various reasons.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an intake air control system of an internal combustion engine, which can adequately satisfy users.
It is another object of the present invention to provide an intake air control system of an internal combustion engine, which assures an engine brake under a deceleration condition of an associated motor vehicle.
It is still another object of the present invention to provide an intake air control system of an internal combustion engine, which suppresses or at least minimizes the amount of lubrication oil sucked into the combustion chamber.
In accordance with a first aspect of the present invention, there is provided an intake air control system for use in an automotive engine. The engine has an air intake passage, a throttle valve installed in the air intake passage and an intake valve for selectively opening and closing a communication between the intake passage and a cylinder. The control system comprises a target intake passage pressure setting unit which sets a target pressure in an intake passage of the engine in accordance with an operating condition of the engine; a target intake air amount setting unit which sets a target intake air amount of the engine in accordance with the operating condition of the engine; a target throttle open degree setting unit which sets a target open degree of the throttle valve of the engine in accordance with both the target pressure in the intake passage and the target intake air amount of the engine; a throttle valve drive unit which drives the throttle valve in accordance with the target open degree of the throttle valve; an intake passage pressure detecting unit which detects an existing pressure in the intake passage; a target intake valve OPEN/CLOSE timing setting unit which sets a target OPEN/CLOSE timing of the intake valve in accordance with both the detected existing pressure in the intake passage and the target intake air amount; and an intake valve drive unit which drives the intake valve in accordance with the target OPEN/CLOSE timing of the intake valve.
In accordance with a second aspect of the present invention, there is provided a method for controlling an amount of intake air in an automotive engine. The engine has an air intake passage, a throttle valve installed in the air intake passage and an intake valve for selectively opening and closing a communication between the intake passage and a cylinder. The method comprises setting a target pressure in an intake passage of the engine in accordance with an operating condition of the engine; setting a target intake air amount of the engine in accordance with the operating condition of the engine; setting a target open degree of the throttle valve of the engine in accordance with both the target pressure in the intake passage and the target intake air mount of the engine; driving the throttle valve in accordance with the target open degree of the throttle valve; detecting an existing pressure in the intake passage; setting a target OPEN/CLOSE timing of the intake valve in accordance with both the detected existing pressure in the intake passage and the target intake air amount; and driving the intake valve in accordance with the target OPEN/CLOSE timing of the intake valve.
REFERENCES:
patent: 4763264 (1988-08-01), Okuno et al.
patent: 4791902 (1988-12-01), Ishikawa et al.
patent: 4799467 (1989-01-01), Ishikawa et al.
patent: 5022357 (1991-06-01), Kawamura
patent: 5870994 (1999-02-01), Kato
patent: 8-082365 (1996-03-01), None
patent: 9-256823 (1997-09-01), None
Obata Takeaki
Takahashi Nobutaka
Argenbright Tony M.
Foley & Lardner
Nissan Motor Co,. Ltd.
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