Diesel duel preheater heat exchanger

[somerandomguy1]

hi,

Has anypne tried a diesel fuel heat exchanger and if yes, how many mpg of improvement.

Something like this


Cheers

Jorge

 

[JHZR2]

My 1993 300SD has a thermostat actuated fuel heater. It makes little sense to me. When I need warm fuel most is at cold startup, and at that time the coolant is cold and not exchanging heat.

I want more viscous fuel to improve lubricity.

I can’t see how recuperating heat in the fuel is going to provide mpg level improvements.

 

[somerandomguy1]

My 1993 300SD has a thermostat actuated fuel heater. It makes little sense to me. When I need warm fuel most is at cold startup, and at that time the coolant is cold and not exchanging heat.

I want more viscous fuel to improve lubricity.

I can’t see how recuperating heat in the fuel is going to provide mpg level improvements.

According to some websites and the video on youtube a warmer fuel allos for better atomisation and combustion allowing better fuel efficiency.

 

[b4autodark]

My JCB skidsteer has a radiator with 3 separate sections, one for engine coolant, one for hydraulic fluid, and one for heating diesel fuel. I would imagine it eliminates fuel gelling. All welded aluminum construction, hope I never have to replace it.

 

[TnT_M]

My JCB skidsteer has a radiator with 3 separate sections, one for engine coolant, one for hydraulic fluid, and one for heating diesel fuel. I would imagine it eliminates fuel gelling. All welded aluminum construction, hope I never have to replace it.

Are you sure the fuel cooler isn't for cooling the fuel? Most modern emissions construction equipment I see has a fuel cooler not a fuel heater.

just my $0.02

 

[b4autodark]

Are you sure the fuel cooler isn't for cooling the fuel? Most modern emissions construction equipment I see has a fuel cooler not a fuel heater.

just my $0.02

It's a fuel heater when the diesel is cooler than the engine operating temperature, ( which is certainly most of the time) and a fuel cooler when the diesel is warmer than the engine operating temperature, which is never. I don't know how the fuel in the fuel tank at whatever temperature it is outside, could ever need cooling, what am I missing here?

 

[TnT_M]

It's a fuel heater when the diesel is cooler than the engine operating temperature, ( which is certainly most of the time) and a fuel cooler when the diesel is warmer than the engine operating temperature, which is never. I don't know how the fuel in the fuel tank at whatever temperature it is outside, could ever need cooling, what am I missing here?

Is your JCB a Tier 4 unit (DEF unit)? Fuel cooling is part of the emissions strategy with the latest emissions levels of equipment for many manufacturers. If you look at the hose routings to the cooler I'd guess the hose is probably coming off the return line of the injection pump to the cooler then to the fuel tank.

just my $0.02

 

[b4autodark]

Is your JCB a Tier 4 unit (DEF unit)? Fuel cooling is part of the emissions strategy with the latest emissions levels of equipment for many manufacturers. If you look at the hose routings to the cooler I'd guess the hose is probably coming off the return line of the injection pump to the cooler then to the fuel tank.

just my $0.02

No DEF. Just regular diesel. The return line goes directly to the tank, the supply line to the injection pump come out of the tank, to the lift pump, then the radiator, then to the injector pump.

 

[Jetronic]

I doubt it does much once the engine is hot, the fuel gets compressed which adds some heat, then travels near the engine in steel lines to the injectors which could add or subtract heat depending on the temperatures where the lines run.

The injectors are in the head and at head temperatures. The fuel is getting quite hot at the tip which is exposed to the in cylinder temperatures.

Cars often run fuel coolers in the return lines, but it depends on the injection equipment used. My previous diesel had a cooler, the new one doesn't and doesn't need it as the high pressure pump is much more efficient (not compressing excessive fuel). Some people have melted plastic fuel tanks because they went too high on fuel pressure and no cooler.

 

[somerandomguy1]

I measured temps in my engine with engine almost at regular operating temperature.
Fuel rail before entering head: 50 celsius
Radiator hose: 70 celsius
Exhaust manifold 80 celsius

I think the best location would be at the exhaust manifold to coil some copper tubing around the exhaust manifold pipe and connect to fuel system delivery line.

Diesel auto ignites at ariund 200 celsius so it will probably be safe. Will see how much mpg improves.

The exhaust manifold pipe also gets hotter and hetas up quicker than the radiator hose.

 

[Jetronic]

The fuel flow is very slow, the fuel will get to head temperatures inside the injectors, and more around the pintle.

If the fuel injectors are electrically operated (common rail) I'd be very concerned about heat degrading their lifespan.

I would not expect any fuel efficiency improvements if the engine runs as it was designed, but power loss is definitely likely

 

[somerandomguy1]

Study that supports the claim that preheating diesel fuel increases efficiency
One

 

[Jetronic]

you do realise this is on a research engine or maybe a generator engine? your own diesel will already have preheated the fuel beyond 60 degrees by the time it gets injected, except on a cold start.

I see something much better to save fuel in those graphs. Get a smaller engine and work it harder to get improved BSFC