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I have done some tests to determine the effectiveness of the fuel heater which I have installed in one of my 300Ds. I fitted this car with a '78 OM617 engine (was a 280E before the rings went south). It has a 20 plate FPHE immediately before the IP and return to tank on both fuels.
The start-up tank (stock tank) has biodiesel in it and uses the stock fuel lines.
The veggie tank is a custom made 70+ litre steel tank, using 8mm nylon air line for supply and return, wrapped (as a Hose On Hose) with the coolant lines going to the tank heating coil, which is brazed under the bottom of the mild steel tank. This does not provide significant heating to the tank, but allows any solidified oil to be melted and mixed with the liquid oil and therefore consumed in the engine.
Both fuels pass to a Pollak valve which selects the fuel in use, to go to the stock fuel pump, the output of which is steered to the respective filter by the second part of the Pollak. A second Pollak valve switches the selected fuel to the IP (via the FPHE) and the IP return line to the appropriate tank. by the second part of this Pollak
The stock filter is used for the stock fuel tank and a CAV fuel filter, with an aluminium coolant/fuel heat exchanger, is used for the vegetable oil fuel.
A MB coolant pump is used to assist coolant flow through the oil heating circuit.
I started the temperature data logger, started the car and idled the car down my driveway to the gate, where I put out the bins (rubbish day is Monday
). I then drove the car up the highway at full power for around 5 minutes, by which time, the temperature of the coolant and the oil leaving the FPHE had stabilised.
The following graph is from the recorded data for that period.
Should you wish to use the graph please contact me for permission to use it.
As can be seen, the limiting time in this experiment, is the time the engine takes to reach operating temperature. The vegetable oil follows the coolant temperature within 30 seconds once the engine was loaded and stabilised within 5°C of the coolant temperature.
All measurements were done with the thermocouples immersed in the fluid being measured.
The fuel in use during this test was biodiesel:veggie blended at 1:1, and the HOH for the vegetable oil and heated CAV filter were not in circuit.
Methinks that this is a reasonably effective heater, and that a 30 plate would not be of any real advantage on a diesel engine unless its fuel consumption (and/or fuel flow return to tank) was much greater than those parameters on this engine. I have not made any measurements of the fuel flow during this test, other than that the test was performed at maximum power setting of the IP at speeds starting at standstill and reaching 90 Kmh at the 7 minute mark, at which time I eased off the power to remain within the speed limits. The road has a moderate slope and it is difficult for the 300D to accelerate to the speed limit on this road.
I have a 10 plate FPHE which I will try to get time to fit to this car, to test for it's heating performance. I will post the results as they are recorded.
I will look at adding the 4th thermocouple to the IP return line, to measure the temperature rise of the IP, as the return fuel would be indicative of the IP internal temperature.
Regards,
Tony
The start-up tank (stock tank) has biodiesel in it and uses the stock fuel lines.
The veggie tank is a custom made 70+ litre steel tank, using 8mm nylon air line for supply and return, wrapped (as a Hose On Hose) with the coolant lines going to the tank heating coil, which is brazed under the bottom of the mild steel tank. This does not provide significant heating to the tank, but allows any solidified oil to be melted and mixed with the liquid oil and therefore consumed in the engine.
Both fuels pass to a Pollak valve which selects the fuel in use, to go to the stock fuel pump, the output of which is steered to the respective filter by the second part of the Pollak. A second Pollak valve switches the selected fuel to the IP (via the FPHE) and the IP return line to the appropriate tank. by the second part of this Pollak
The stock filter is used for the stock fuel tank and a CAV fuel filter, with an aluminium coolant/fuel heat exchanger, is used for the vegetable oil fuel.
A MB coolant pump is used to assist coolant flow through the oil heating circuit.
I started the temperature data logger, started the car and idled the car down my driveway to the gate, where I put out the bins (rubbish day is Monday
). I then drove the car up the highway at full power for around 5 minutes, by which time, the temperature of the coolant and the oil leaving the FPHE had stabilised.The following graph is from the recorded data for that period.
Should you wish to use the graph please contact me for permission to use it.
As can be seen, the limiting time in this experiment, is the time the engine takes to reach operating temperature. The vegetable oil follows the coolant temperature within 30 seconds once the engine was loaded and stabilised within 5°C of the coolant temperature.
All measurements were done with the thermocouples immersed in the fluid being measured.
The fuel in use during this test was biodiesel:veggie blended at 1:1, and the HOH for the vegetable oil and heated CAV filter were not in circuit.
Methinks that this is a reasonably effective heater, and that a 30 plate would not be of any real advantage on a diesel engine unless its fuel consumption (and/or fuel flow return to tank) was much greater than those parameters on this engine. I have not made any measurements of the fuel flow during this test, other than that the test was performed at maximum power setting of the IP at speeds starting at standstill and reaching 90 Kmh at the 7 minute mark, at which time I eased off the power to remain within the speed limits. The road has a moderate slope and it is difficult for the 300D to accelerate to the speed limit on this road.
I have a 10 plate FPHE which I will try to get time to fit to this car, to test for it's heating performance. I will post the results as they are recorded.
I will look at adding the 4th thermocouple to the IP return line, to measure the temperature rise of the IP, as the return fuel would be indicative of the IP internal temperature.
Regards,
Tony
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