Claims
- 1. In a hydraulic valve lift device including a lifter having therein an oil pressure chamber for introduction of oil and slidably disposed in a cylindrical bore of a housing with its one end engaged by a cam on a cam shaft and a plunger slidably disposed in said lifter for opening and closing an intake or exhaust valve, of which a valve lift is made variable depending on the rotational speed of said cam due to discharge of oil from said oil pressure chamber through a throttling port, the improvement comprising a braking chamber defined by a flange portion of said plunger and said cylindrical bore, a slit adapted to communicate said braking chamber with an oil feed chamber of said plunger for flow-in of oil and to be reduced in its opening area depending upon the downward movement of said plunger, a relief valve provided in association with said braking chamber for controlling an oil pressure therein so as to cause it to be below a set value, a sensor for producing an electric signal representing a braking force generated by said braking chamber, an electromagnetic means for regulating a set working pressure of said relief valve, and a computer for energizing said electromagnetic means depending upon the output signal of said sensor to control said relief valve such that its set working pressure corresponds with a desired value, and wherein said computer comprises an amplifying circuit for amplifying a signal from said sensor, a condition setting circuit for setting a valve seating impact load depending upon running speeds of the engine, a comparator circuit for comparing the output of said amplifying circuit with the set value of said condition setting circuit and an output amplifying circuit for amplifying the output of said comparator circuit and outputting the resulting value to said electromagnetic means.
- 2. A hydraulic valve lift device as claimed in claim 1 wherein said sensor is mounted on a cylinder head of an internal combustion engine for detecting valve seating impact loads of the intake or exhaust valve to output a signal representing a braking force.
- 3. A hydraulic valve lift device as claimed in claim 1 wherein said sensor comprises a casing, an inertial mass body threaded into said casing and a piezo-electric element interposed and compressed between said casing and said inertial mass body, said casing being provided with a mounting bolt and an output terminal.
- 4. A hydraulic valve lift device in accordance with claim 1 including means for detecting a valve seating impact load of said intake or exhaust valve and means for controlling a set pressure of said relief valve such that the output of said detecting means corresponds with a set value which is determined by the operating conditions of the engine.
Priority Claims (2)
Number |
Date |
Country |
Kind |
54-108471 |
Aug 1979 |
JPX |
|
54-109510 |
Aug 1979 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 178,285, filed Aug. 15, 1980, now U.S. Pat. No. 4,408,580.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
178285 |
Aug 1980 |
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