Idling speed control for internal combustion engines
First Claim
1. Apparatus for controlling, especially in idling, the speed of a vehicular internal combustion engine having a throttle imposed in an engine intake duct for controlling the engine speed, and an accelerator control for said throttle actuatable by a vehicle driver, comprising:
- means for producing a signal representative of actual engine speed;
means for producing a reference idling speed signal;
means for comparing said actual engine speed signal with said reference idling speed signal to produce a first error signal;
means for modifying said first error signal by blocking out any portion thereof corresponding to deviation of actual speed from said reference idling speed which is equal to or less than a predetermined extent of deviation and thereby providing a first modified error signal;
means for modifying said first modified error signal by adding at least one other signal thereto including a signal proportional to said signal representative of engine speed, and thereby producing a second modified error signal;
means including a proportional amplifier of unsymmetrical amplification with respect to error signal sign for processing said first modified error signal;
means including an integrator of unsymmetrical characteristics with respect to error signal sign for processing said second modified error signal;
means for adding together the process signal respectively produced by said processing means and thereby producing a throttle position reference signal;
a displaceable stop for said throttle for defining a condition of said throttle when said accelerator control is not actuatedmeans for producing a signal representative of the actual position of said displaceable stop;
means for producing a throttle actuation signal when said throttle is actuated so as to remove it from said displaceable stop;
means for comparing said signal representative of actual position of said displaceable stop with said position reference signal provided by said means for adding the signals produced by said processing means, and thereby producing a final error signal;
means for displacing said stop in accordance with said final error signal;
means for disabling said displacing means responsive to said throttle switch signal, andmeans for disabling said means for processing said first modified error signal in response to said throttle switch signal.
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Accused Products
Abstract
A first error signal produced by comparison of actual engine speed value with a reference speed value is modified by blocking out of it a component corresponding to speed deviation within a dead zone speed range. The modified signal is then processed separately by proportional and integrating amplifiers of a PI controller each having a characteristic unsymmetrical with respect to the sign of the error signal. Before processing by the integrating amplifier, the modified error signal is further altered by a contribution from a signal proportional to engine speed to compensate for drifts caused by gradual temperature or atmospheric pressure changes. When the engine is not in idling operation, a fedback contribution is supplied at the same place for preloading the integrator for the next idling operation. The separately processed signals are added together to produce a position reference signal for a displaceable idling speed stop for the engine throttle. A final error signal for control of the displaceable stop is obtained by comparing the position of the reference signal with a signal representing actual stop position. When the throttle is actuated by the driver and engine speed rises out of the drive range, the proportional amplifier is blocked and also the stop displacing mechanism, but an addition is made to the stop position reference signal by which the stop controller causes the stop to set a gap between it and the throttle preventing the throttle switch from returning to idling position until another speed comparison showing exit from the drive condition releases the idling speed control.
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Citations
13 Claims
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1. Apparatus for controlling, especially in idling, the speed of a vehicular internal combustion engine having a throttle imposed in an engine intake duct for controlling the engine speed, and an accelerator control for said throttle actuatable by a vehicle driver, comprising:
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means for producing a signal representative of actual engine speed; means for producing a reference idling speed signal; means for comparing said actual engine speed signal with said reference idling speed signal to produce a first error signal; means for modifying said first error signal by blocking out any portion thereof corresponding to deviation of actual speed from said reference idling speed which is equal to or less than a predetermined extent of deviation and thereby providing a first modified error signal; means for modifying said first modified error signal by adding at least one other signal thereto including a signal proportional to said signal representative of engine speed, and thereby producing a second modified error signal; means including a proportional amplifier of unsymmetrical amplification with respect to error signal sign for processing said first modified error signal; means including an integrator of unsymmetrical characteristics with respect to error signal sign for processing said second modified error signal; means for adding together the process signal respectively produced by said processing means and thereby producing a throttle position reference signal; a displaceable stop for said throttle for defining a condition of said throttle when said accelerator control is not actuated means for producing a signal representative of the actual position of said displaceable stop; means for producing a throttle actuation signal when said throttle is actuated so as to remove it from said displaceable stop; means for comparing said signal representative of actual position of said displaceable stop with said position reference signal provided by said means for adding the signals produced by said processing means, and thereby producing a final error signal; means for displacing said stop in accordance with said final error signal; means for disabling said displacing means responsive to said throttle switch signal, and means for disabling said means for processing said first modified error signal in response to said throttle switch signal. - View Dependent Claims (2, 3, 4, 5)
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6. Method of controlling, especially in idling, the speed of a vehicular internal combustion engine having a throttle disposed in an engine intake duct for controlling engine speed, and an accelerator control for said throttle actuatable by a vehicle driver, said method being automatically operated by means of a displaceable stop for adjusting the idling setting of said throttle during particular conditions of operation of said engine, said method comprising the steps of:
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comparing a signal representative of actual engine speed (Un) with a reference idling speed signal (Uno) to produce a first error signal; modifying said first error signal by blocking out any portion thereof corresponding to deviation of actual speed from said reference idling speed which is equal to or less than a predetermined extent of deviation to provide a first modified error signal; modifying said first modified error signal by adding a further contribution thereto including at least a signal proportional to said signal representative of engine speed to produce a second modified error signal; processing said first modified error signal by a proportional amplifier of unsymmetrical amplification with respect to error signal sign; processing said second modified error signal by an integrator amplifier of unsymmetrical characteristic with respect to error signal sign; adding the processed first and second modified first error signals to produce a reference position signal (Ls) for said displaceable stop; and comparing a signal (Li) representative of actual position of said displaceable stop with said reference position signal (Ls) to produce a final error signal, and displacing said stop in accordance with said final error signal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification