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Engine Specific Info and Questions => IDI Engine => Topic started by: flash319 on January 15, 2008, 09:20:37 am
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Does anyone have one of these in their cars? Do they help with starting or just to help pump the fuel? What brand have you tried?
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unless it's super cold [yellowknife cold] you don't want to heat diesel. i sell vegetherm inline heaters for vegoil systems. i wire them so they only work when using wvo
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So heating the air is better for starting, thus glowplugs? I have an old Ford tractor that does not have glow plugs and it is in the middle of the bush, so this was sort of an off topic thread. I was thinking of doing it to both engines though. I heard somewhere that cummins has some kind of an inline air heater, like a toaster on the intake. is this true?
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Many fuel filters have a built in heater element. Racor makes great diesel fuel water sperators with the option of a built in fuel heater probe.
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Ford/Navistar IDI 6.9's (probably 7.3's, also) have a heater in the fuel line. Not sure when it activates. You can find these motors in JY's so if you decide you need one you might consider it.
Brian
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fuel line and fuel filter heaters are only for extreme cold, and for tractor trailers which are being driven all day in cold weather. some diesels such as vw's have a small valve in the return line which lets some fuel back into the fuel filter to heat the fuel to a certain extent, but it won't help start the car if the filter is already frozen.normally diesel should not be heated. A4 Tdi's automatics even have fuel coolers.
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So heating the air is better for starting, thus glowplugs? I have an old Ford tractor that does not have glow plugs and it is in the middle of the bush, so this was sort of an off topic thread. I was thinking of doing it to both engines though. I heard somewhere that cummins has some kind of an inline air heater, like a toaster on the intake. is this true?
Yes, some of the Cummins engines have heaters in the intake passages. The activation is controlled by the engine ECU based on various temperature sensors in the engine.
As far as heating the fuel, our trucks actually have coolers in the fuel system so that the fuel does not get too hot. Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.
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Maybe you could put some peltiers with fins in the intake so you could flick a switch and heat the air when starting. Though people usually think of them relating to cooling, they output 150% more heat than the energy you put into them.
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I have an old Onan generator which has glow plugs and air heaters. The air heaters look like a sparkplug with a 1" diameter spring instead of the plug bit on the inside. They would be easy enough to mount in a largish threaded hole in the intake manifold. They are kind of pricy though over $100 from Cummins/Onan. Cheers Dan
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Don't the TDI's have like 3 glow plogs mounted in a circle on the intake or is it in the coolent?
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Coolant.
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fuel line and fuel filter heaters are only for extreme cold,
What do you consider extreme cold? My neck of the woods is going to be around 3 degrees F on and off this week. Thats 29 degrees below freezing.
So is diesel at it's best for power when it is just above the point where wax crystals will form?
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The cummins motor (B 5.9) is a direct injected diesel. It does not have glow plugs for cold weather starting. It does have grid heater that pre heats the intake air prior to it arriving in the cylinder.
Turn the key on, lights dim as the grid heater cycles. Grid heater shuts off, crank to start. After starting, grid heaters cycle on and off until the engine reaches a certain temp then the grid heaters stop and the motor simply runs on it's own heat. (that's why you'll see a dodge truck's lights dimming and getting brighter as it's warming up)
The cummins cold start is a slick setup. It works quite well when temps get down. The only thing is, it may not work on any thing other than a direct injected diesel....
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fuel line and fuel filter heaters are only for extreme cold,
What do you consider extreme cold? My neck of the woods is going to be around 3 degrees F on and off this week. Thats 29 degrees below freezing.
that's not all that cold. i don't plug in the block heater until it gets down -20C (-4F) and i've never needed a fuel heater or anything like that. (its -24C in yellowknife right now)
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Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.
Wouldn't a lean fuel mixture be an advantage for fuel economy, But bad for power?
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Maybe you could put some peltiers with fins in the intake so you could flick a switch and heat the air when starting. Though people usually think of them relating to cooling, they output 150% more heat than the energy you put into them.
and just reverse the polarity in the summer to get some cooling :twisted:
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Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.
Wouldn't a lean fuel mixture be an advantage for fuel economy, But bad for power?
maybe... but the car would run like crap. it might affect timing which then adversely affects fuel economy anyways. TDI's could compensate for this as the ECU gets a signal for when the injectors open (which might yield a very small decrease in fuel consumption). IDI's and mTDI's do not compensate for fuel density and therefore are affected the most.
but... as these injection pumps were designed to use the diesel fuel to 'cool' the injection pump, it just doesn't seem like a good idea to add more heat to the equation. although there are many people out there running really hot veg oil through their pumps with much success... could be due to the fact that veg is such a good lubricant? i guess it could be viewed as running thicker oil in a race engine to control heat and wear under extreme conditions? (20w50 oils etc)
i have a couple 350 watt peltier junctions i'd like to mess around with... all i need is access to a lathe to machine out a block out of aluminum with two flat sides for the junctions, and a little route for the fuel to flow through. for hot days that fuel could be cooled by at least 10C as i've played with the 350 watt junctions and they get mean cold pretty quick.. with a big enough heatsink on the other side it could probably give frostbite fairly quickly :lol:
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I'm thinking that at 350 W the peltier is going to draw 30A or so which is a lot of current. Possibly taking more energy to produce than the potential increase in power it might yield. It would be interesting to develop an objective method to test this theory. Cheers Dan
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That's .2 HP plus any losses in generating it. So it wouldn't need to help too much to make more power.
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Fuel should be cool for higher density, heating would actually lean out the cylinder air/fuel mixture.
Wouldn't a lean fuel mixture be an advantage for fuel economy, But bad for power?
Hotter fuel (less dense) will lessen the amount of energy injected per volume of fuel injected, so the only difference is that you have to push the pedal ever so slightly further down with hot fuel compared to cold fuel.
Hot fuel may atomize better due to lower viscosity and thus burn better creating better efficiency, but that's going to be a pretty slim difference I think.
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Jim it actually takes a great deal more than .2 hp to generate 30A. In days of old American Iron, guys would use a cutout switch to disconnect the alternator field at full throttle because they could actually notice a difference in the acceleration by doing so. The typical alternator in those days was a 45 Amp Delco or maybe 60Amp if you had AC. If you have ever tried one of those exercycle generator gizmos that they use to demonstrate how much pedaling energy it takes to light a 100W light bulb it becomes clear that the efficiency of mechanical to electrical conversion is not high. The amount of heat that you could remove from the fuel is limited by the gellpoint of the fuel, the actual mass of fuel injected per revolution is quite small compared to the mass of air being pumped through the engine. The temperature drop that you would be able to produce by cooling the fuel would be fairly small so the net gain would be minimal as I see it. Much easier to go with an intercooler to decrease the charge air temperature. Cheers Dan