Robert Boschgmbh

Henning Cordes

Chi-Thuan Cao

Helmut Janetzke

Alfred Schulz

Andreas Erban

Helmut Kauff

Wolfgang Matuschek

The invention is directed to a control system for an internal combustion engine with reference to air throughput, rotational speed and lambda. In this control system, a decoupling device is provided between open loop and closed loop control signals which act with different speeds. An ignition signal is influenced in dependence upon a lambda-dependent signal via at least one dead time member. In this way, phases having unfavorable opposing influence on control branches of different reaction durations are reduced.

Control system for an internal combustion engine

The speed to be measured, either engine speed or vehicle (drive wheel) speed, is measured by a tachogenerator which trips a timer to provide a series of measurements. When the system is in use, a driver can store the actual speed at a selected moment as the desired speed. From a linearized model of vehicle speed or engine speed response to acceleration or deceleration of the engine by displacement of a control member, system parameters a.sub.1 and b.sub.1 are derived. The actual speed signal is multiplied by a.sub.1 and added algebraically (to produce a difference signal) to the desired speed signal, with the resulting signal then being multiplied by another constant derived from the system parameter b.sub.1 by reference to weighting factors p and q of a cost minimizing equation relating to the relative significance of obtaining a small control deviation and of limiting or increasing the amplitude of the control signal. An output signal is then provided by the second multiplying stage. The system can be constituted in an analog fashion or it may operate digitally by means of a microprocessor. Smoothing of the input and output signals may be provided by low-pass filtering in the analog case and by providing a moving average with the preceding value in the digital case. This type of regulation, which may be referred to as cyclic or as single-step control, assures an aperiodic run-in characteristic and is stable in all speed ranges.

Speed control for motor vehicles with microcomputer step-by-step control

Growing community of inventors

Eberdingen, Germany

Henning Cordes