Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Utility Patent
1998-11-03
2001-01-02
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C251S129010
Utility Patent
active
06167852
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electromagnetically operated valve for an internal combustion engine and more particularly to an apparatus and a method of detecting opening and closing time of the electomagnetically operated valve.
2. Prior Arts
In recent years, techniques in which intake and exhaust valves of internal combustion engines are electromagnetically operated and their opening and closure timings are electronically controlled, have been developed.
This electromagnetically operated valve has an advantage in that valve opening and closure timings can be established in a wide range and also can be selected properly in accordance with engine operating conditions, however, on the other hand, it has a disadvantage in that the valve is accelerated by the electromagnetic force of solenoids and the biasing force of the spring and as a result a large impact occurs when the valve is seated on a valve seat or when the valve fully opens.
To overcome this disadvantage, numerous techniques such as retarding the valve speed immediately before the valve is seated on the valve seat or fully open, have been developed. For example, Japanese Patent Application Laid-open No. Toku-Kai-Hei 7-332044 discloses a technique wherein a piezoelectric element is fixedly disposed at the position receiving pressure from an armature or an interconnecting member integrally moving together with the armature to detect a valve position based on the change of an output characteristic of the piezoelectric element.
However, in this technique, since the valve position is detected by applying a pressure directly on the piezoelectric element, it is a problem whether or not the piezoelectric element is endurable. To solve this problem, as an alternative means, the use of contactless sensors such as an eddy current position sensor and the like can be considered. However, these contactless sensors can detect a relative displacement of the valve but have a disadvantage that it is difficult due to the effect of noises contained in output signals of the sensors to detect an accurate instant when the valve is completely closed, i.e., seated on the valve seat or when the valve is fully open.
SUMMARY OF THE INVENTION
With the above described problem in mind, it is an object of the present invention to provide an improved valve opening and closing time detecting apparatus for an electromagnetically operated valve capable of accurately detecting a time of a valve fully open or completely closed. By detecting an accurate time, it becomes possible to control more correctly the velocity of the valve when the valve is seated on the valve seat or is fully open.
To achieve the object, the valve opening and closing time detecting apparatus for an electromagnetically operated valve reciprocating between a valve fully open position and a valve seated position in an engine, comprises vibration detecting means for detecting a vibration generated when the valve reaches the open position or when the valve reaches the seated position and judging means for comparing a comparison data obtained from the vibration detecting means with a threshold level and for judging that the valve has reached the open position or the seated position when the comparison data exceeds the threshold level.
REFERENCES:
patent: 5765514 (1998-06-01), Sono et al.
patent: 5797360 (1998-08-01), Pischinger et al.
patent: 7332044 (1995-12-01), None
Ishii Mitsunori
Kamimaru Shinji
Farber Martin A.
Fuji Jukogyo Kabushiki Kaisha
Lo Weilun
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