Electromechanical transducer controlling device
AssigneeHitachi, Ltd.
InventorsHiroshi Kuroiwa, Takao Sasayama
Life of this patent
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Abstract
A device for controlling an electromechanical transducer such as a proportional electromagnetic valve, in which a pulse signal having a constant period shorter sufficiently than the minimum response time required for the displacement of the plunger of the proportional electromagnetic valve over its predetermined full stroke is applied to the electromagnetic coil of the proportional electromagnetic valve to superpose a very small vibratory stroke component on the stroke of the plunger, and the duty cycle of the pulse signal applied to the electromagnetic coil is varied so as to urge the plunger in directly proportional relation to the variation of the duty cycle without substantially giving rise to mechanical hysteresis in the stroke of the plunger.
Claims12
A device for controlling an electromechanical transducer comprising:
- an electromagnetic valve including an electromagnetic coil and a movable member displaced in proportional relation to an electrical input signal applied to said electromagnetic coil thereby driving a controlled element;
- at least one switching means for chopping the electrical input signal applied to said electromagnetic coil;
- and
- means for generating an electrical pulse signal for triggering said switching means,
- wherein the electrical pulse signal generated by said pulse generating means and applied to said switching means has a constant period shorter than the minimum response time required for said movable member to make its predetermined full stroke, and the duty cycle of the electrical pulse signal applied to said switching means is varied to cause displacement of said movable member in proportional relation to the variation of the duty cycle, and
- wherein said switching means comprises two switching elements which are arranged so that said movable member is urged in a first direction when one of said switching elements is turned on, while said movable member is urged in a second direction opposite to said first direction when the other of said switching elements is turned on, and one of said switching elements is maintained in its off-state when the other is placed in its on-state.
A control device for controlling fluid flow in an internal combustion engine, comprising:
- a valve for controlling fluid flow;
- means for detecting the operating condition of said internal combustion engine;
- an electromagnetic device including an electromagnetic coil and a movable member to be displaced in proportional relation to electric current applied to said electromagnetic coil thereby driving said valve;
- an electric source for energizing said electromagnetic coil;
- at least one switching means for chopping current supplied from said source to said electromagnetic coil;
- means for generating an electrical pulse signal composed of a plurality of pulses for actuating said switching means, said pulse signal generating means comprising a digital computer for receiving the output signal from said detecting means as an input signal, and for processing quantized digital signals and for converting the quantized digital signals to pulse signals, each of said pulses having a constant period of 5-15 msec, the constant period being shorter than a minimum period of time required for said movable member to be moved by its predetermined full stroke and sufficient for said movable member to be moved;
- and
- means for changing the duty cycle of each of said pulses applied to said switching means,
- wherein said movable member is displaced in proportional relation to the duty cycle changed by said duty cycle changing means.
A control device for controlling fluid flow in an internal combustion engine, comprising:
- a valve for controlling fluid flow;
- means for detecting the operating condition of said internal combustion engine;
- an electromagnetic device including an electromagnetic coil and a movable member to be displaced in proportional relation to electric current applied to said electromagnetic coil thereby driving said valve;
- an electric source for energizing said electromagnetic coil;
- at least one switching means for chopping current supplied from said source to said electromagnetic coil;
- means for generating an electrical pulse signal composed of a plurality of pulses for actuating said switching means, said pulse signal generating means comprising a digital computer for receiving the output signal from said detecting means as an input signal, and for processing quantized digital signals and for converting the quantized digital signals to pulse signals, each of said pulses having a constant period, the constant period being shorter than a minimum period of time required for the movable member to be moved by its predetermined full stroke and the constant period being one of equal to and longer than a period for said movable member to be moved without mechanical hysteresis;
- and
- means for changing the duty cycle of each of said pulses applied to said switching means,
- wherein said movable member is displaced in proportional relation to the duty cycle changed by said duty cycle changing means.
Dependencies are inferred from the claim text.