16-03-2017, 04:35 PM
Hi.
I'm intrigued by the version of the Diesel engine that has been converted to marine use.
It is unlikely to be a modern common rail version as trying to rig these up with ECU etc is a nightmare.
The older types use the Common enough Bosch pumps that require no fuel lift pump in a car but if the fuel tank is lower than 1-2 meters than the engine (fuel pump actually) then a supplementary low pressure pump will be required.
All of the Bosch pumps will have a 12 volt connection to the "stop" solenoid, 12 volts on it and the engine runs, cut the 12v and it stops.
On this pump it needs a feed in (suction) of fuel and a return back to the tank, this is for bleeding and part of the design, the fuel filter is in the feed line.
Your other statement "Most use crankcase pressure to power a mechanical fuel pump" I'm sorry you are wrong. A diesel fuel pump has to be timed correctly to the relative camshaft and crankshaft positions and this can only be done either electronically or on older engines by running the pump off the timing belt or chain or by using a toothed auxiliary belt.
The only other time you will see a pump on the side of a crankcase is a mechanical fuel lift pump (usually on petrol engines or very old diesels) that is driven from an eccentric on an auxiliary shaft (in OHC engines) or from the camshaft in OHV engines, nothing to do with crankcase pressures, If you had enough crankcase pressure to run a pump you have all the seals leaking oil!!!!!
I'm intrigued by the version of the Diesel engine that has been converted to marine use.
It is unlikely to be a modern common rail version as trying to rig these up with ECU etc is a nightmare.
The older types use the Common enough Bosch pumps that require no fuel lift pump in a car but if the fuel tank is lower than 1-2 meters than the engine (fuel pump actually) then a supplementary low pressure pump will be required.
All of the Bosch pumps will have a 12 volt connection to the "stop" solenoid, 12 volts on it and the engine runs, cut the 12v and it stops.
On this pump it needs a feed in (suction) of fuel and a return back to the tank, this is for bleeding and part of the design, the fuel filter is in the feed line.
Your other statement "Most use crankcase pressure to power a mechanical fuel pump" I'm sorry you are wrong. A diesel fuel pump has to be timed correctly to the relative camshaft and crankshaft positions and this can only be done either electronically or on older engines by running the pump off the timing belt or chain or by using a toothed auxiliary belt.
The only other time you will see a pump on the side of a crankcase is a mechanical fuel lift pump (usually on petrol engines or very old diesels) that is driven from an eccentric on an auxiliary shaft (in OHC engines) or from the camshaft in OHV engines, nothing to do with crankcase pressures, If you had enough crankcase pressure to run a pump you have all the seals leaking oil!!!!!
