1.9-ltr. TDI Engine with Pump Injection System - Volkswagen ...
1.9-ltr. TDI Engine with Pump Injection System - Volkswagen ...
1.9-ltr. TDI Engine with Pump Injection System - Volkswagen ...
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The fuel cooling circuitThe fuel returning from the pump injector flowsthrough the fuel cooler and transfers its hightemperature to the coolant in the fuel coolingcircuit.The fuel cooling circuit is separate from theengine cooling circuit. This is necessary since thetemperature of the coolant is too high to cooldown the fuel when the engine is at operatingtemperature engine.The fuel cooling circuit is connected to the enginecooling circuit in the vicinity of the expansiontank. The fuel cooling circuit can thus be filledand changes in volume due to temperaturefluctuation can be compensated. The fuel coolingcircuit is connected so that the hotter enginecooling circuit does not have a detrimental effecton the fuel cooling circuit.Fueltemperature senderThe fuel coolerThe fuel and coolant flows through the fuelcooler. The temperature of the fuel istransferred to the coolant.Fuel tankFuel pumpExpansion tank209_48The auxiliary water coolerreduces the temperature of the coolantin the coolant circuit. It dissipates theheat of the coolant to the ambient air.The fuel cooling pumpis an electrical recirculation pump which circulates thecoolant in the fuel cooling circuit. It is switched on bythe engine control unit via the fuel cooling pump relayat a fuel temperature of 70°C.<strong>Engine</strong> coolingcircuit25