An adjustable thermostat allows the coolant temperature to rise faster for a faster start of exhaust gas aftertreatment. In addition, higher engine temperatures reduce friction, resulting in lower fuel consumption.
The wax which is in the thermostat melts at a temperature of 105°C. Usually, the electronics do not interfere with the operation of the thermostat, it itself maintains the temperature at this level.
For full loads, the fuel injection ECU controls the thermostat control at 89°C. The ECU controls the heating resistor (16) controlled thermostat to add 16°C, which is not enough at a coolant temperature of 89°C to melt the wax (15).
The thermostat control is also determined depending on the following parameters:
- vehicle speed and intake air temperature, which ensures the operation of the cooling system;
- ambient air temperature, providing a good thermal condition in the engine compartment, allowing the engine to cool and not worsening in countries with a cold climate.
Controlled thermostat operation phases
Note. The cooling requirement of an automatic transmission takes precedence over other cooling requirements. When the automatic transmission commands cooling, control by the thermostat is carried out at 89°C.
Attention. To remove air from the cooling system, a special mode of operation of the injection system processor is provided. In order to send information to the fuel injection ECU that is entered during a specific bleeding phase of the cooling system, it is necessary to be in the following conditions for 10 seconds: vehicle speed is zero, engine speed is above 1450 rpm, engine torque is below 50 Nm.