Robert Boschgmbh

Pierburg Gmbh & Co Kg

Bosch Und Pierburg System Ohg

Manfred Henning

Wolfgang Misch

Gunter Hartel

Gunter Gilz

Franz-Josef Ehrentraut

Adolf Freytag

To zero or reference-set or null-set a signal source, typically a distance or rotary angle transducer (10), a closed control loop (11, 12, 13) is connected in the output (E) from the signal source, which includes feedback of the system output signal (A) and comparison thereof with a reference or null or zero-set signal (W) when the signal source or transducer is at the reference position, the closed control loop including a correction element (11), such as an adder, to correct the zero or null-set signal derived from the signal source in accordance with the operation of the control loop. This eliminates individual adjustment of the zero or null-set of the signal source, reducing costs and increasing accuracy of the zero or null-set. The correction signal is introduced at the time the signal source or transducer is at a zero or reference position, or the transducer can be preset to provide, initially, a signal which requires correction, and a diode (15) is introduced in the control loop so that the correction signal is effective only in one direction, thus permitting deviation of the transducer from its zero or reference position and not requiring a special switch (14) which renders effective the control loop when the transducer (10) is at the zero or reference position.

Method of setting a reference value, for example to zero-set a signal

Two magnetic valves, one of which reduces the pressure and the other one of which increases the pressure by which the displacement of a positioning member is controlled, only one of them operated at a time in accordance to the sign of the error signal, are operated in a pulsed mode with variable pulse width when the error signal is within a range of low absolute value and in a continuous mode of operation when the error signal has a higher absolute value. Variation of the magnitude of the error signal within the intermittent valve operation range controls pulse width variation. Hysteresis is provided in a transition between operating modes of a valve by a time delay of the mode change after the error signal has risen or fallen past a threshold value of signal. High displacement resolution is obtained as well as independence from effect of temperature drifts and magnetic valve characteristics.

High resolution control system for a pressure-responsive positioning

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.

Idling speed control for internal combustion engines

Regulation of idling speed involves the production of a first error signal by comparing engine speed with a reference idling speed, and then deriving from the first error signal in an amplifying PI controller, proportional and integral components that are added together, for use of the PI sum signal as a reference value signal for the displaceable stop position. The latter is compared to the actual stop position to provide a second error signal for control of electro-pneumatic valves of a positioning device that displaces the stop. Both the proportional and integral components produced in the controller vary assymetrically about the reference idling speed, so that regulation operates more strongly when the engine speed is too low than when it is too high, except for a dead zone on either side of the reference idling speed. When the driver actuates the throttle, a switch signal designates that the idling condition is no longer present and a lower engine speed threshold defines a starting mode of operation at lower speeds and a higher engine speed threshold distinguishes the 'drive' mode from the partial load mode. Suitable operations of the displaceable stop during mode transitions and during operations in non-idling modes are provided. The controller output at the end of the last idling interval is stored for use when the engine returns to the idling mode.

A method for varying the phase spacing of sequential ignition control pulses emitted by an ignition pulse transducer and an apparatus for performing the method are proposed, wherein it is ascertained in the case of the sequential ignition pulses whether their phase spacing has become shorter. If a shortening of the phase spacing is ascertained, then the ascertained phase difference, or a maximal value of the phase difference, is added to the phase spacing of the ignition pulse at that particular time. In this manner, jerking which occurs particularly at constant rpm, when internal combustion engines with externally-supplied ignition used to operate a motor vehicle are driven in the vicinity of the idling rpm, is avoided by simple means.

Method and apparatus for varying the spacing of sequential ignition

A method of varying the phase spacing of sequential ignition pulses emitted by an ignition pulse transducer and an apparatus for performing the method are proposed, in which with the aid of a phase control circuit a corrected ignition control pulse train of average frequency is formed on the basis of an actual ignition control pulse train. The corrected pulse train being held constant so long as a given phase difference is maintained between the two control pulse trains. As a result, brief rpm fluctuations, which in an rpm range in the vicinity of idling rpm are perceived as jerking, are compensated for. When there are changes in rpm which cause larger phase deviations, the corrected ignition control pulse train is synchronized with the actual ignition control pulse train.

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Kaarst, Germany

Manfred Henning