Abstract: Gas torque (Cg) is determined for each cylinder combustion. Engine speed (N) and air admission manifold pressure (Pca) are measured during the corresponding prior admission phase. A reference torque (Cref), which is a function of N and Pca, is cartographically calculated by interpolation. The reference torque Cref, for example, is corrected by multiplication with a coefficient (KM) associated with the corresponding cylinder in a stabilized engine operating mode. In a transient mode, an additive correction (KA) is also made to derive the expected theoretical torque (Cpr), which is compared with the gas torque (Cg) so as to determine that misfire has occurred if Cpr/Cg>S2, where S2 is a threshold value. The process and device are suitable for generating signals representative of engine operation or indicating that the threshold level of harmful components discharged into the exhaust gases is exceeded.

Abstract: Method for producing of catalytic converter diagnostic signals and/or signals indicating that the harmful component emission threshold in exhaust gases has been exceeded. To produce the signal, the gas torque (Cg) for each combustion stroke in each cylinder is determined; the engine speed (N) and air inlet manifold pressure (Pca) during the corresponding previous inlet stroke is measured; the reference torque (C ref), which is a function of N and Pca, is calculated by interpolation from a map; C ref is weighted, for example, by multiplication with a coefficient (K) associated with the corresponding cylinder and/or with the steady or transient engine running mode in order to deduce the expected theoretical torque (Cpr) which is compared with the gas torque (Cg) to ascertain a combustion misfire if Cg/Cpr is less than S2 and if Cpr-Cg exceeds the S3 or S4 threshold, depending on whether the engine is in transient or steady mode.

Abstract: An engine control system for a spark ignition internal combustion engine of a vehicle equipped with a fuel injection system, including a motorized butterfly unit having a body, a butterfly rotatably mounted on a spindle in a passage through the body, a butterfly position sensor mounted on one end of the spindle and a butterfly actuator mounted on the other side of the spindle. An engine control unit, which is connected to sensors for detecting engine operation parameters and to the accelerator pedal, generates injection and ignition commands as well as a reference position of the butterfly, which is transmitted by a connecting line to the butterfly control unit. The butterfly control unit sets the position of the butterfly to the reference position and transmits the butterfly position signal via the connecting line to the engine control unit.

Abstract: The device controls a throttle member of an induction passage in a fuel supply system. It comprises a first electric sensor for delivering a signal representing the position of a driver actuated member, an electric actuator and a second electric sensor providing an electric signal representing the actual position of the throttle member. The actuator and the sensor are mechanically connected to the throttle member. An electric control circuit receives signals from the sensor and gives the throttle member a position which depends on the position of the driver actuated member. A movable stop is mechanically connected to the driver actuated member and has a one-way connection with the throttle member which limits its degree of opening.