The electronic control system consists of sensors, an electronic control unit that includes one or more microprocessors, and actuators that directly affect the engine systems.
Information about the operating mode and state of the engine is received by the control system from a number of sensors. The sensors convert the monitored (measurable) engine parameters into electrical signals that are convenient for processing and transmission in the electronic control system. Signals from the sensors are sent to the inputs of the electronic control unit. The electronic unit, processing the received information according to specified algorithms, issues control signals to the actuators. Control algorithms implemented by the microprocessor of the electronic unit, in each engine operating mode generate an optimal (best) combination of fuel injection parameters in terms of fuel consumption (cyclic feed and injection advance angle) and air charge (boost pressure and exhaust gas recirculation ratio). The actuators, which receive control signals from the electronic unit, are located respectively in the high-pressure fuel pump (HPFP), in the intake manifold, between the intake and exhaust manifolds, in the turbocharger. The diagram of the electronic control system of the Toyota diesel with a VE-type HPFP is shown in Figure 2. The block diagram of the electronic control unit is shown in Figure 1.
Fig. 1 Block diagram of the electronic control unit
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Fig. 2 Electronic control system diagram of Toyota diesel engine with VE type fuel injection pump