The heat exchange unit extends the range of applications of the flowtronic systems 206/S60 or 206/207/S60 and 215/S60 or 215/217/S60. This unit can is designed for a maximum fuel pressure of 5 bar.

The heat exchanger 4703X-10 which is in preparation will be suitable for fuel supply systems working with a higher pre-supply pressure.

Fuel consumption measurement needs to meet the requirement that surplus fuel cannot return from the engine back to the tank. Otherwise this volume could pass the flow sensor again which would distort the measurement.

To solve this requirement, the fuel circuit has to be modified to an engine-related fuel circuit that supplies the engine with fuel and avoids the fuel return flow to the tank at the same time. Only the volume of consumed fuel will be supplied from the fuel tank into the engine-related fuel circuit and measured by the flow sensor.

To avoid an overheating of and gas bubbles within the engine-related fuel circuit this circuit is cooled down by a second fuel circuit (tank related) via the integrated heat exchanger. The tank related circuit is supplied by the fuel pump within the heat exchange unit.

Depending on the design of the engine’s fuel supply system (original fuel pump located at the engine or at the tank) the heat exchange unit is used as described above or with a modified connection scheme. The second scheme offers same functionality but considers that the original pump is located close to the fuel tank. In this configuration the fuel pump within the heat exchange unit provides the required pre-supply pressure at 5bar.

The former Flowjet valve 4703 is no longer available and has been replaced by the 4703X-F heat exchange unit. It has been completely redesigned and updated to the latest state of development.

The heat exchange unit 4703X-F can be used instead of the old Flowjet valve 4703 without problems.

The former flowtronic assembly 4705 is no longer available. The at that time integrated Flowjet valve 4703 has been completely redesigned and updated to the latest state of development.

To achieve the functionality of the old assembly flowtronic 4705 the new unit flowtronic 4703X-F and the separate sensor S60 are required. Please consider the system component list of the heat exchanger unit 4703X-F for further details on the required components.

When using the heat exchange unit 4703X an additional pressure regulator (flow-0064) is required if the fuel supply pump (*) does not work with a pre-supply pressure of approx. 5bar. (*) Please note: The fuel supply pump is located close to the engine.