Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
1999-11-04
2001-01-30
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S090150
Reexamination Certificate
active
06178934
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to control systems for controlling internal combustion engines equipped with a variable valve timing mechanism, and more particularly to the control systems of a type which can appropriately control the engine when the variable valve timing mechanism fails to operate normally.
2. Description of the Prior Art
Hitherto, in the field of internal combustion engines, for actuating intake and exhaust valves, various types of variable valve timing mechanisms have been proposed and put into practical use in place of conventional cam type mechanism. Japanese Patent First Provisional Publication (Tokkai) 61-247807 shows a variable type using electromagnetic solenoids, and Japanese Patent First Provisional Publication (Tokkai) 7-317516 shows another variable type using hydraulic actuators. In these variable types, the control for timing the valve opening and closing is carried out without providing the engine with a cam shaft. Japanese Patent First Provisional Publication (Tokkai) 10-47028 shows a measure for dealing with a malfunction of the variable valve timing mechanism which would occur in the type using the electromagnetic solenoids. That is, in the measure, upon detecting a malfunction of the valve actuating mechanism for one cylinder, operation of the intake and exhaust valves of the cylinder is stopped and the amount of air/fuel mixture fed to the remaining cylinders is increased. That is, in such case, operation of the engine is continued by the remaining cylinders.
However, when the engine operates with one cylinder being at rest, smoothed rotation of the engine is not obtained because of lack of balance of the rotation and thus marked vibration of the engine tends to occur. That is, when, upon detecting a malfunction of the variable valve timing mechanism, one cylinder is made inoperative, a torque that is to be produced by the cylinder is not actually produced during operation of the engine. This causes discontinuous production of engine torque and thus brings about the non-smoothed and vibratory operation of the engine.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a system and a method for controlling an internal combustion engine equipped with a variable valve timing mechanism, which can smoothly operate the engine even when the valve timing mechanism fails to operate normally.
According to a first aspect of the present invention, there is provided, in an internal combustion engine equipped with a variable valve timing mechanism which variably controls operation timing of intake or exhaust valves of respective cylinders, a system for controlling the engine. The system comprises a first unit which detects a failure of the variable valve timing mechanism; a second unit which discriminates a first cylinder which is associated with the variable valve timing mechanism in failure; a third unit which discriminates a second cylinder whose inoperative condition would cancel a possible unbalanced rotation of the engine which would be caused by an inoperative condition of the first cylinder; a fourth unit which causes the first and second cylinders to take the inoperative conditions; and a fifth unit which increases the amount of air/fuel mixture fed to the remaining cylinders.
According to a second aspect of the present invention, there is provided, in an internal combustion engine equipped with a variable valve timing mechanism which variably controls operation timing of intake or exhaust valves of respective cylinders, a method for controlling the engine. The method comprises detecting a failure of the variable valve timing mechanism; discriminating a first cylinder which is associated with the variable valve timing mechanism in failure; discriminating a second cylinder whose inoperative condition would cancel a possible unbalanced rotation of the engine which would be caused by an inoperative condition of the first cylinder; causing the first and second cylinders to take the inoperative conditions; and increasing the amount of air/fuel mixture fed to the remaining cylinders.
According to a third aspect of the present invention, there is provided an engine controlling system in an internal combustion engine including a plurality of cylinders, a variable valve timing mechanism for each cylinder, a fuel injector for each cylinder and an ignition plug for each cylinder. The engine controlling system comprises a first unit which detects a failure of the variable valve timing mechanism; a second unit which, upon detection of the failure by the first unit, selects a first cylinder of the cylinders, which is associated with the variable valve timing mechanism in failure; a third unit which, upon selection of the first cylinder by the second unit, selects a second cylinder of the cylinders, whose operation has a phase substantially symmetrical to that of the first cylinder with respect to the stroke cycle of the engine; a fourth unit which, upon selection of the second cylinder by the third unit, makes the first and second cylinders inoperative; and a fifth unit which, upon making the inoperative condition of the first and second cylinders, increases the amount of air/fuel mixture fed to the remaining cylinders.
REFERENCES:
patent: 5060604 (1991-10-01), Seki et al.
patent: 5072700 (1991-12-01), Kawamura
patent: 5190013 (1993-03-01), Dozier
patent: 5596956 (1997-01-01), Ogawa et al.
patent: 5738053 (1998-04-01), Kato
patent: 5934231 (1999-08-01), Schmitz et al.
patent: 0 367 448 (1990-05-01), None
patent: 0 777 038 (1997-06-01), None
patent: 0 915 236 (1999-05-01), None
patent: 61-247807 (1986-11-01), None
patent: 7-317516 (1995-12-01), None
patent: 10-47028 (1998-02-01), None
Hirasawa Takahiko
Matsumoto Mikio
Nagaishi Hatsuo
Foley & Lardner
Lo Weilun
Nissan Motor Co,. Ltd.
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