Pierburg Gmbh & Co Kg

Eckehard Schmitz

Hans Baumgartner

Rainer Sudbeck

A method and an arrangement are disclosed for regulating a path length defined by a pressure-responsive unit. Whenever a coarse positional adjustment has been made, a pause period is made to elapse before a fine adjustment (if any) is carried out. This arrangement does not, due to the pause period, require any accommodation or tuning to regulating stages having different decay behaviors.

Method and arrangement for regulting a path length in dependence upon a

A method and an arrangement for controlling exhaust return quantities of an automatic-ignition, internal combustion engine comprising a camshaft-driven piston injection pump and an exhaust control element in an exhaust return pipe. Pressure pulses occurring in an output pressure line of the injection pump during the injection-active delivery stroke are directly or indirectly detected as regards their pulse duration as the injection duration T.sub.E and their pulse intervals as the injection period T.sub.P. A certain injection stroke or a certain quantity of fuel to be injected per work cycle may be assigned, pump-specific, to each pair of values of these quantities through a known pump stroke curve. To control the return quantity of exhaust in dependence upon the quantity of fuel injected, the dependence between the pairs of values of T.sub.E, T.sub.P on the one hand, and control quantities for the return quantities of exhaust on the other hand, are stored in an at least two-dimensional identification field. Accordingly, it is possible for each pair of values of T.sub.E, T.sub.P determined in operation to retrieve the associated control quantity for the return exhaust quantities and to use that control quantity for controlling an exhaust control element. If the reciprocal value of the injection period T.sub.P is proportional to the rotational speed, other operating parameters, such as pressures and/or temperatures, may also be taken into consideration in the determination of the particular control quantity for the return quantities of exhaust.

Method of and an arrangement for controlling return quantities of exhaust

In a reciprocating internal combustion engine of the spark ignition type the idling rotational speed of the engine is controlled by a system in which a secondary air flow through a passage bypassing the main air intake throttle valve (1) of the engine is controlled by a valve having a conical valve member (3) co-operating with a seat (2) to form a Laval nozzle at all open positions of the valve. The valve member (3) moves in response to the pressure difference across a diaphragm (9) separating two chambers (6) and (7). The chamber (7) communicates through a throttling element (8) with the pressure P.sub.s downstream of the throttle valve (1) and contains a spring (11) biassing the diaphragm (9) to open the valve (2, 3). The chamber (6) communicates through a throttling element (12) with the pressure P.sub.a upstream of the throttle valve (1) and also communicates through a more restricted throttling element (13) with the downstream pressure P.sub.s . The communication of the chamber (6) to the pressure P.sub.a is also controlled by an electronic control valve (14) which operates and regulates a mark space ratio communicating the pressures P.sub.a and P.sub.s to the chamber (6) alternately and in response to the difference between the actual engine idling speed and a set-point idling speed.

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Monchen-Gladbach, Germany

Eckehard Schmitz