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 identifying cylinder phase in an engine with an ignition and/or injection system wherein each cylinder is individually controlled, and with a sensor cooperating with a rotary target having an indexing element indicating a reference cylinder upper dead center position. The method including the steps of generating, on the reference cylinder, a disturbance other than the interruption of the injection, the disturbance of a type capable of causing a change in the engine torque, detecting the engine torque change by a change in a signal representative of the gas torque, caused by the generation of the disturbance, establishing a relationship between the time of generation and the detection of its result on the engine torque so as to derive the reference cylinder phase at the time of generation of the disturbance, and thereafter the phase of the other cylinders. The method of the present invention being particularly useful for four stroke engines with sequential ignition and/or injection.

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.