Abstract: An ignition system for internal combustion engine, which controls the ignition coil primary current according to the magnitude of the floating capacitance in the secondary side wiring section of the ignition coil, by determining the floating capacitance from the negative slope of rising of the secondary voltage produced in the ignition coil in response to the cutoff of the primary current and the primary cutoff current value, the slope being determined by measuring the period T until the secondary voltage reaches a predetermined voltage value. When the floating capacitance is increased, the primary cutoff current value is increased to increase the coil energy so as to increase the secondary voltage generated in the ignition coil for preventing the generation of a miss-spark.

Abstract: An improved automated engine diagnosing device employing a digital data processor and a cathode ray tube monitor for displaying individual engine cylinder numbers in separate association with correlated values of exhaust gas emissions pollutants. Engine timing data associated with the time of firing of individual cylinders of the engine being tested synchronizes select cylinder firing inhibition for orderly accumulating gas emissions data generated from an exhaust probe placed in the tail pipe of the automobile under test. An automatic sequential firing inhibition and a manually selectable firing inhibition permits dual modes of data acquisition for developing pollutant data to be utilized by the processor for generating the analysis display on the cathode ray tube monitor.

Abstract: Digital condition data corresponding to a plurality of engine operating conditions of an internal combustion engine are generated and stored in a memory system for visual display to an operator mechanic. Particular data from the memory are converted from a parallel digital format to a serial digital format for transmission to a remote site computer across telephone lines. The remote site computer analyzes the data and returns the diagnostic results for visual display to the operator mechanic.

Abstract: An automatic device comprises a complex plane analyzer of a vibration signal of a measured engine unit, electrically coupled via a switch to a computer. The device also comprises a synchronization unit whose inputs are connected to sensors of the angular position of the vehicle engine shaft and transmission shaft, an ignition sensor and a sensor of fuel injection to the cylinders of the vehicle engine. A control input of the unit is coupled to the output of a control unit. There is also an operational parameter measuring unit connected by its inputs to outputs of the synchronization unit and to the output of the control unit. An engine shaft rotational frequency adjustment unit is connected by its input to the control unit and to the synchronization unit and by its output to the actuator controlling fuel supply to the engine cylinders.