In the parametric ignition system, the optimal ignition timing is determined depending on the current engine operating mode. Control parameters are engine speed, engine temperature, intake air temperature and engine load (intake manifold vacuum, throttle position). Engine load degree refers to the current engine load (for example, there is a difference in engine performance at 4000 rpm when the car is uphill or downhill).
The required field of control parameters of the ignition system was determined as a result of research on the stands and refined in sea trials, which made it possible to obtain optimal values for fuel consumption, exhaust gas composition and driving performance. The obtained values are stored in the memory of the electronic control unit.
While driving, the control unit receives information about the current engine speed, its temperature and load, and based on these data, the optimal ignition timing for the current conditions is generated (e.g. 10°BTDC or 0°).
In the absence of information about the number of revolutions, the degree of load, etc. deterioration in driving performance, such as a reduction in engine power, may occur. It is also possible to increase fuel consumption. Serious engine malfunctions should not be feared if the defect is eliminated at the earliest opportunity.
An ignition distributor with a parametric ignition system has another task, namely the distribution of the ignition voltage to the individual spark plugs. The distributor runner is driven directly from the camshaft. In this case, inertial weights, a vacuum membrane and a system of inductive sensors are not required, since their functions are performed by a microprocessor in the control unit.