View of engine from front |
R48 | Coolant thermostat heating element |
P07.70-2551-76
Location
The coolant thermostat heating element (R48) is mounted below the charge air distributor.
Task
The coolant thermostat heating element (R48) is used as actuator for electronic control of the coolant thermostat for the heat management.
Electronic control of the coolant temperature offers the following advantages:
Operating temperature is reached faster
Reduction of fuel consumption
Improved heating comfort
Function
The coolant thermostat heating element (R48) is triggered by the ME-SFI [ME] control (N3/10) on the ground side.
Opening and closing of the coolant thermostat is accomplished by the temperature-influenced expansion of the wax expansion element.
Additionally opening and closing of the coolant thermostat is performed variably and dependent on the motor requests dependent on actuation of the coolant thermostat heating element (R48) .
The function of the coolant thermostat is subdivided into the following partial functions:
Closed position
Position opening (mixed-fuel mode)
Open position (radiator mode)
Closed position
Coolant flow in engine only, the heater heat exchanger can be flooded-through.
Position opening (mixed-fuel mode)
The coolant thermostat opens, coolant begins to flow (for load request below the full-load threshold).
Open position (radiator mode)
The coolant thermostat is open and the engine radiator is fully flowed through.
View of engine from the rear |
Y133 | Coolant pump switchover valve |
P07.70-2549-76
Location
The coolant pump switchover valve (Y133) is mounted over the gear housing on the engine.
Task
The coolant pump switchover valve (Y133) switches off after triggering the coolant pump. The absent coolant circulation enables faster warming up of the engine and reduction of the exhaust emissions.