DD15 Engine

Section 3.8 Fuel Rail

Section 3.8
Fuel Rail

The fuel rail incorporates the Fuel Rail Pressure Sensor and pressure limiting valve. The fuel rail attaches to the side of the camshaft frame with brackets.‪

Section 3.8.1
Fuel Rail Pressure Sensor

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 1. Fuel Rail Pressure Sensor‪

 3. Injector‪

 2. Fuel Rail‪

 4. Pressure Limiting Valve‪

The Fuel Rail Pressure Sensor (1) uses a sensor element and a hybrid element. As pressure increases the sensor membrane will distort. There are four pressure-dependent resistances (strain measuring resistors) on the sensor membrane. Its bridge circuit is supplied with voltage by an electronic analysis system which also serves for signal amplification and signal correction. The electronic analysis system itself is supplied a 5 V DC voltage by the MCM. The resistors in the sensor membrane are arranged in a way that when deforming the sensor membrane two resistors will contact and two resistors will expand. Contracting and expanding changes the electrical resistance and in turn has effects upon the measurement voltage, which is being applied to the electronic analysis system. The electronic analysis system amplifies the measurement voltage, compensating for possible temperature fluctuations or balancing out possible manufacturing tolerances and passes the cleaned measurement voltage to MCM.‪

Section 3.8.2
Pressure Limiting Valve

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 1. Fuel Rail Pressure Sensor‪

 3. Injector‪

 2. Fuel Rail‪

 4. Pressure Limiting Valve‪

The pressure limiting valve (4) is a safety element which limits the maximum rail pressure in the injection system to about 1280-1380 bar. If the current rail pressure exceeds the maximum rail pressure of about 1280 -1380 bar, the push spring is pressed together by the pressure plate . A connection is opened at the same time to the cutoff bore, and the excess fuel flows into the return.‪


DD15 Fuel System Technician's Guide - DDC-SVC-MAN-0037
Generated on 10-13-2008

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