hot fuel vs. cold air

[EdKiefer]

Originally Posted by mechman600

That would be bad. Systems with return lines need the flow for cooling and fuel pressure regulating purposes (I think). It probably would not run if you blocked it off, or it would run poorly. New cars do not have return lines, so maybe something could be done there. But I wonder what hot fuel will do to the life of a fuel injector.

I would listen to mwebb - heating fuel will probably have little effect on anything.

the only thing you could do is move the pressure regulator to the tank, where the pump is (if it is there) . this way you would have one line to fuel rail, dead ended . this still has return line but it is real short, just going into tank .
This is what Honda does in later models . the pump, regulator are all one unit with sender in it .
This would or could have a tendency to vapor lock more than with regulator at rail .

[mwebb]

Originally Posted by mechman600

That would be bad. Systems with return lines need the flow for cooling and fuel pressure regulating purposes (I think). It probably would not run if you blocked it off, or it would run poorly. New cars do not have return lines, so maybe something could be done there. But I wonder what hot fuel will do to the life of a fuel injector.

I would listen to mwebb - heating fuel will probably have little effect on anything.

you can not bypass the return line on cars that have return lines .
new er cars have fuel pressure sensors and they duty cycle current to the fuel pump to regulate fuel pressure using a feedback system with the fuel pressure sensor.... but
why not just heat up the air ? tap into the radiator shroud , the air will be regulated at whatever coolant temperature is ... low tech ... easy ....
and you are heating up 14 times more mass of combustion charge without any drama or safety issues .

will there be any benefits ?
a definate maybe or ,
i dunno . but if not the modification will be easy to un modify .

there are no significant "suction throttling losses" on diesels as they do not have , throttles .
unless they have EGR
and are computer controlled then there is a throttle of sorts that is used to lower pressure in the intake and some have a throttle in the exhaust to increase exhaust pressure at the same time so that
EGR will flow from hi pressure to low pressure ..
and
they all have EGR

[mechman600]

Originally Posted by mwebb

tap into the radiator shroud , the air will be regulated at whatever coolant temperature is

Unfortunately, the radiator temp varies wildly even when the engine coolant temp is steady, depending on engine load, ambient temp and vehicle speed. The thermostat regulates engine coolant temp by regulating the flow of coolant through the radiator to maintain engine coolant temp, say 195F. Only during high load and/or slow vehicle speeds will the radiator temp equal engine coolant temp. At this point, the thermostat is 100% open and the coolant bypass is 0% open. During most situations when the engine coolant temp is "warmed up" at, say, 195F and the engine load is relatively light and air flow sufficient, the thermostat is a tiny bit open and the bypass is mostly open, as engine heat rejection is low relative to airflow. Common exceptions are stop and go traffic and higher engine load situations when there is insufficient airflow through the radiator and/or relatively high engine heat rejection. In this situation, once the radiator temp rises to where the radiator and engine coolant temps are equal and the thermostat is 100% open, both temps will continue to rise up to fan on temp, say 210F, when the fan will turn on to cool the entire cooling system down. Once airflow increases because of sufficient vehicle movement and/or engine load is reduced and radiator temp falls below 195F, the thermostat will once again be partly open, regulating coolant flow through the radiator to regulate engine coolant temp at, say, 195F.

I would pull air from the exhaust manifold heat shield for a HAI. Use tin foil to channel as much air around hot things as possible. Much hotter and steadier temps than the radiator shroud.

[mwebb]

i would swag that
exhaust manifold temps are too high , can be upwards of 800f under load ,

OEM systems that used to draw hot air from the exhausts had simple bimetalic spring loaded flaps to regulate temperatures to the intake
UN regulated heat from the exhaust manifold is probably not a good idea

hot air from the radiator shroud will never exceed about 250f to 300f and while it may vary , it will be pretty stable at cruise .

[tortoise]

Is there an optimal IAT for best BSFC?

[brent777]

Originally Posted by mechman600

That would be bad. Systems with return lines need the flow for cooling and fuel pressure regulating purposes (I think). It probably would not run if you blocked it off, or it would run poorly. New cars do not have return lines, so maybe something could be done there. But I wonder what hot fuel will do to the life of a fuel injector.

I would listen to mwebb - heating fuel will probably have little effect on anything.

darn im just trying to thank out side of the box

Q what is the best mod you have ever done?

[t vago]

Originally Posted by mwebb

10% improvement .... not very likely

I did a little Excel heat energy calculation, using a specific heat of 1 kJ/(kg K) for air, and 2 kJ/(kg K) for gasoline. The air was assumed to be at 30 C (86 F), and the gasoline was assumed to be heated up to 90 C (194 F, and presumably heated up by engine coolant). A 14.7:1 mass ratio was assumed, too.

(1 kJ/(kg K)) * (14.7 parts air) * (30 C + 273.15 C) + (2 kJ/(kg K)) * (1 part gasoline) * (90 C + 273.15 C) =

(1 kJ/(kg K)) * (14.7 parts air) * (303.15 K) + (2 kJ/(kg K)) * (1 part gasoline) * (363.15 K) =

4456.305 kJ/kg + 726.3 kJ/kg =

5182.605 kJ/kg

Now, to find the final temperature of this mixture:

5182.605 kJ/kg / (1 kJ/(kg K)) * (14.7 parts air) + (2 kJ/(kg K)) * (1 part gasoline)) =

5182.605 kJ/kg / (16.7 kJ/(kg K)) =

310.3 K

or

37.2 C (98.9 F). This is a 12.9 F difference between the initial and final temperatures.

Given that my documented HAI gain of around 5% is done with an intake air difference of about 45 F, I would have to agree that 10% improvement with fuel heating seems rather unlikely.

[mechman600]

Originally Posted by brent777

darn im just trying to thank out side of the box

That's a good thing. Most great ideas have come from this type of thinking. But I have found for myself that a lot of outside the box thinking leads to disappointment. But thanks to this forum we have some guidance - what should work and what definitely will not. If my "tone" has implied that I think I am an expert here and my word is that last word, I apologize, because I am definitely not an expert. I will be the first to set that one straight.

Q what is the best mod you have ever done?

Nothing of substance. Unfortunately, my wife and I share the car that gets driven the most, so any mod that requires any extra driver input is out of the question because she is NOT interested. This is also the reason our car is an automatic instead of a manual. BUT...I am on the verge of doing a mega-eco-mod: converting my lowly MX3 to an EV. All the parts are in the garage and I only have a living room wall unit to complete before I rip and tear!

[brent777]

Originally Posted by mechman600

That's a good thing. Most great ideas have come from this type of thinking. But I have found for myself that a lot of outside the box thinking leads to disappointment. But thanks to this forum we have some guidance - what should work and what definitely will not. If my "tone" has implied that I think I am an expert here and my word is that last word, I apologize, because I am definitely not an expert. I will be the first to set that one straight.



Nothing of substance. Unfortunately, my wife and I share the car that gets driven the most, so any mod that requires any extra driver input is out of the question because she is NOT interested. This is also the reason our car is an automatic instead of a manual. BUT...I am on the verge of doing a mega-eco-mod: converting my lowly MX3 to an EV. All the parts are in the garage and I only have a living room wall unit to complete before I rip and tear!

i thank you for the guidance

a EV cool how may deep cycle battery's are you going to use?

[mechman600]

Probably 12. Here's the thread:
http://ecomodder.com/forum/showthrea...gun-19957.html