Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2000-03-03
2001-03-20
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S179300, C123S1980DA
Reexamination Certificate
active
06202608
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control system for an internal combustion engine, and particularly to a control system for an internal combustion engine including electromagnetically driven intake valves and/or exhaust valves.
A control system for an internal combustion engine including intake valves and exhaust valves in each of which a valve body is electromagnetically driven by a spring and solenoids, characterized in that power consumption caused by operation of the solenoids upon start-up of the engine is reduced by making use of the resonance phenomenon of the spring, has been known, typically, from Japanese Patent Laid-open No. Hei 9-195736. Such a reduction in power consumption caused by operation of the solenoids is effective because, upon start-up of the engine, a power for operating the electromagnetically driven valve, which is supplied from only a battery because no power is supplied from an alternator thereto, is required to be made as small as possible. Another control system of the type making use of the resonance phenomenon, characterized in that a drive starting timing of a valve is determined depending on a crank angle position in order to prevent interference between the valve and a piston upon start-up of an engine, has been known, for example, in Japanese Patent Laid-open No. Hei 9-303122.
A further control system of a type in which initial attraction for closing all of electromagnetically driven intake valves and exhaust valves is executed before start-up of an engine and then the start-up of the engine is permitted in order to prevent interference between the valves and pistons, has been disclosed in Japanese Patent Laid-open No. Hei 8-170509.
The control system disclosed in Japanese Patent Laid-open No. Hei 9-195736 or Japanese Patent Laid-open No. Hei 9-302122 is advantageous in reducing the power consumption by making use of the resonance phenomenon of the spring; however, such a control system is disadvantageous in that since the operation of the valves is started while the starter is operated, the output current of the battery is increased, and accordingly, if the battery is degraded, the output voltage is reduced, to cause a possibility that it fails to certainly start up the engine.
The control system disclosed in Japanese Patent Laid-open No. Hei 8-170509 is advantageous in that since the closing operation, that is, the initial attraction for the valves is executed before the cranking of the engine is started, the initial attraction is not overlapped to the operation of the starter; however, such a control system is disadvantageous in that since all the valves are simultaneously closed, the output current of the battery is temporarily abruptly increased, and accordingly, the output voltage is reduced, to cause a possibility that it fails to sufficiently perform the initial attraction.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a control system for an internal combustion engine, which is capable of suitably controlling the operation of electromagnetically driven intake valves and/or exhaust valves upon start-up of the engine, to reduce the output current of a battery and suppress a reduction in output voltage at minimum, thereby accurately operating the electromagnetically driven valves.
To achieve the above object, according to the present invention, there is provided a control system for an internal combustion engine including an electromagnetic drive means for electromagnetically opening/closing intake valves and/or exhaust valves of the engine, the control system comprising: a start-up signal detecting means for detecting a start-up signal for starting up the engine; and an initial attraction executing means for sequentially executing initial attraction for a plurality of valves driven by the electromagnetic drive means in such a manner that the attracting operations for the valves are not overlapped to each other; wherein the start-up of the engine is performed after the initial attraction for all of the valves driven by the electromagnetic drive means is completed.
With this configuration, after a start-up signal is detected, the initial attraction for a plurality of valves driven by the electromagnetic drive means is sequentially executed in such a manner that the attracting operations for the valves are not overlapped to each other, and the start-up of the engine is performed after the initial attraction for all of the valves driven by the electromagnetic drive means is completed. This is effective to reduce the maximum consumption current caused by the initial attraction for the valves and suppress a reduction in output voltage of a battery at minimum, and hence to accurately operate the electromagnetically driven valves. As a result, even if the battery is slightly degraded, both the initial attraction and the start-up of the engine can be certainly executed.
The above control system, preferably, further includes a valve position detecting means for detecting the position of each of the valves driven by the electromagnetic drive means; wherein when a specific time has elapsed after the full-close state or full-open state of the valve is detected by the valve position detecting means, it is determined that the initial attraction is completed.
Here, the term “specific time” is defined as a time required for stabilizing the state of a valve driven by the electromagnetic drive means after the valve body of the valve is electromagnetically moved from the neutral position to the full-close position or full-open position, and is experimentally determined.
With this configuration, when the specific time has elapsed after the full-close state or full-open state of the valve is detected by the valve position detecting means, it is determined that the initial attraction is completed. Accordingly, an initial attraction current is held for the specific time after the state of the valve is shifted to the full-close state or full-open state, with a result that it is possible to certainly perform the initial attraction.
The control system is also, preferably, configured such that a current supplied to the electromagnetic drive means is reduced when it is determined that the initial attraction for each of the valves is completed.
In the control system, preferably, the electromagnetic drive means includes a valve opening coil for driving each of the valves in the valve opening direction, a valve closing coil for driving the valve in the valve closing direction, and a spring for supporting the valve; and the electromagnetic drive means is configured to execute the initial attraction by shifting the state of the valve to the full-close state or full-open state by making use of the natural vibration of a vibration system composed of the valve and the spring.
REFERENCES:
patent: 5003938 (1991-04-01), Erickson et al.
patent: 5596956 (1997-01-01), Ogawa et al.
patent: 8-170509 (1996-07-01), None
patent: 9-195736 (1997-07-01), None
patent: 9-303122 (1997-11-01), None
Hatano Harumi
Suzuki Osamu
Torii Minoru
Yamaki Toshihiro
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
Lo Weilun
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