has anyone tried making an intake heater?
 

I tried searching the forum but didn't see anything.

My idea is to put something like this into a metal intake tube to heat the air going into the intake. Similar to a diesel setup.

Ford Thermostart Intake Manifold Heater 2000 3000 4000 5000 7000-7710 C5NE9A436A | eBay

In this cold climate of mn I think it might help in the winter time for mileage.

What do you think?

Might be nice for pre-heat but I wouldn't plan on driving with it.

Been there done that on my diesel.
Glow coils - Diesel Place : Chevrolet and GMC Diesel Truck Forums

I realize that diesels have been doing it for years, has anyone done it on a gas car?

I've not seen anyone try this on a gas engine. I don't expect it would help fuel economy. You'd end up burning more gas to keep the heater running than you'd save with warmer intake temperatures. Many people here have used "warm air intakes," which scavenge waste exhaust heat. A search for that phrase on the forum should turn up a number of results.

Correct me if I'm wrong, but with gasoline engines the idea is to preheat the fuel for easier ignition, and to chill the air to make it more dense.

What I posted back on a similar topic.

http://ecomodder.com/forum/showthrea...cus-18020.html
Ford has a patent using the A/C system to pre-chill the intake air.

In a gas engine you have the EGR, and you want to keep it so why bother with an electric heater?
(in a diesel one of the best things you can do is block or delete the EGR)

Thats the idea for more power but we are after more MPG. Cold, dense are will make the ECU use more fuel, resulting in more power. In our world we want the opposite. Warmer air would require less fuel to burn, making less power but more MPG.

Maybe I'm faulty in my logic, but if you make more power, aren't we talking about efficiency?

A more efficient engine gets better MPG, right?

I know that there are always exceptions to the rule, just talking comparables here.

Yes, but it's less thermally efficient to pre-heat the intake air (or petrol/gas).

However, prior to directly-injected/near-TDC injection engines the ambient air temp is a measurable influence on capability of the petrol to mix completely with the air. - This is why heating the charge is good, ie. the -ideal- thermal efficiency drops a little but it's negative effect is far outweighed by the gains of better fuel evaporation.

I have been shown (back-of-the-envelope) that trying to get this effect by heating fuel is a no go. Petrol just has too little heat capacity (ie. the very fact that it evaporates so easily is the problem). So if the petrol is the medium that's carrying the heat it will be totally swamped when it meets the coldness of the air.
<though I'm still not 100% convinced I must say!>

This is what I was thinking, I may try it but don't have a good way to a b a it yet.

instead of an electric heater why not do it like they did on the old cars? a tube coming from the exhaust manifold heat shield into the airbox. with an on/off controlled by vacuum

at the least it wouldnt cost more energy to heat the intake. it would just use the excess heat.

I do know my intake manifold has coolant running through it (people block it off for performance)

I was thinking for initial start up, until the car reached normal operating temp. Have it on a switch and use it the first 5 to 10 min of my commute. A tube off of the exhaust manifold isn't going to produce heat that fast.

Alls Y'alls know this is a mini fuel burner right? It's not an electric heating element.

Wouldn't want to use it with a plastic intake manifold!

I didn't thank of that, I dont have that problem (got a sheet metal intake and cast aluminum intake manifold).

If you are worried about the exhaust not warming up fast, cold start it one morning and see how long you can hold your finger on the exhaust manifold, or dump a little water on it and see how long it takes to go from dripping to completely dry.

Really? because my first two cars had exhaust heat for preheating the air and it was warming up the intake air in less then a minute of the engine running, the exhaust is the first thing to get hot, even the Honda N600 that we have uses the exhaust for cabin heat and you get heat by the time you get out of the drive way!

From what I have read the denser air will make more power because your ECU senses the better air and adds more fuel. Yes it is more efficient because you are making more power with the same displacement. But it won't really increase MPG because your ECU compensates the dense air with more fuel. If you could tell your ECU to allow the engine to run lean (not adding more fuel to the mixture) then your MPG would go up. This is why the lean burn engine in a civic HX gets better MPG than a standard civic.

At least thats what I understand. If you google this question you see many opinions but you cannot trust all of them.

many things come into play with making an efficient car.

for instance. compare my 2010 honda element SC 2.4L 166hp
to someone I know with a 2003 honda element 2.4L turbo 463 WHP

when driven in a normal manner why do I avg 17.5mpg but he avgs 26mpg

epa is 20/24

even if my best was 24.4 still it goes against the logic.

so I guess it all comes down to doing it right. not just half way.

hi Im new here, searching this subject brought me to the forum so Im starting here. First off, I have an RX8, incredible little potent engine with a very modern emissions setup. But for those that never knew... city driving yields about 12-14 mpg out of that 1.3L engine. I have over 80k miles, and it runs very clean. It's internal seals are also incredible. Ive pulled vacuum lines to find it still holding high vacuum over an hour after shutting down.

On to the subject. Heating an intake charge is not what we look for to increase performance and thats proven on the drag strip by boosted cars using ice water in air/water intercoolers. Also proven by dyno testing when heat soak consistently lowers horsepower. Now the RX8 uses coolant to heat the throttle body. I suspect this is one of the late additions that lowered its horsepower rating upon release. Attempts have been made to bypass the throttle body in order increase power. Ive never seen dyno results of this but I think it would give a very small gain but show resistance to power fade due to heat soak in repeated testing. The side effect of the bypass is that MPG suffered greatly (some reported 1/3 total mpg losses). Here's my reference for that, note user comments at the bottom. Never mind I need 5 posts to post a link here.

now racerc2000 brings up a good point about turbo cars. Ive personally seen several turbocharged cars pulling mid 30s for mileage and several of these are 80's cars that bleed oil like its cool. There are 2 reasons a turbo car gets awesome mpg, first the turbocharger heats the intake charge a LOT. Intercoolers are widely utilized to cool this down to increase power and reduce detonation risk. Also note that a critical element to creating boost is load and the heat generated on the turbine side of the turbo increases load. Methods are employed here to coat and wrap the metal so that the heat gets to the impeller and is not soaked into the metal and lost into the engine bay.

These 2 together are about all the proof I need that a heated air charge does indeed raise your mpg. Yes this comes at the risk over power output but probably not greatly so and ultimately im talking highway driving very city/spirited driving for when you want this heat.

I wanna get a few things outta the way as well for future conversation. This is the only (green) forum I have ever joined due to my view conflicting with the politics and many of the users that push such "green"ness. I wish to not discuss the politics and simply put out that I am strictly against any method of energy "saving" that uses one form of power output to convert something else into power for and engine. Gasoline is proven to be the most potent way to produce energy that can be harnessed by a street driven vehicle. There are some small exceptions like acetylene dual fuels for example that are better but simply impossible or impractical. If this werent the case I'd be lobbying for nuclear powered cars. My existence here is to aid in the discussion of ways to convert lost energy into used energy.

I sealed off my engine compartment and put the air intake in side with the engine, it's good for +75 degrees F (my car is a turbo diesel so YMMV). I believe preheating the intake air improves fuel economy, as I believe cooling the intake air improves horsepower. Economy is about maximizing the energy recovery from the fuel, horsepower is about maximizing the energy recovery from the oxidizer. Since when shooting for max horsepower one can easily add fuel to the system, the limit on horsepower comes from running out of oxygen. When shooting for max mileage, you're not running full throttle anyway so you aren't limited by air density.

Pre-heat the fuel is more usual in few flexfuel cars. I've never seen a pure gasser with this feature. It's a stock feature in some versions of the Volkswagen Polo made in Brazil and the Peugeot 308 made in Argentina, since Brazilian ethanol doesn't have the gasoline blend to ease the cold starts.

Did you test it?
Diesels tend to lose power and fuel economy with warm air intakes.

Diesels seem to like their air intake temperatures at the manifold between 30F to 120F.
Below 30F and it seems to delay fuel ignition and above 120 and you cant pack enough air into the cylinders.

Every +1 degree C or F increase in intake temperatuers increases EGTs by that amount, so you are running 75 degree higher EGTs than nessary for no reason.

i can't speak for diesel in particular, but with a gasoline enigne, a hotter intake charge is the way to go for fuel economy.

hotter air is less dense, which provides a couple of benefits, mostly being the reduced pumping losses due to having to open the throttle more to achieve the same cylinder airmass and a less dense air charge providing less resistance to movement. hotter air, i would assume also helps gasoline vaporization.

Hot air provides not benifet to diesels, unless its really cold out.
The different processes at work between the gas and diesel engines are very different.

Only in extreme cases some intake heating is desirable with a Diesel, like the grid-heater used in Cummins engines.

I have my intake pipe touching one of my I take hose taking air from the radiator. I don't have any hard mumbers but it seems like it works. I've heard of pre heating gas. It seems like a potentially good way to get huge milage. Obviously it's kind of dangerous and you may be taking a risk by doing it but I want to find a way. Maybe by running the fuel line near the exhaust or coolant lines.

I have found that because ECO modding is somewhat new on the car scene. And because the US car scene has really always been about bigger louder faster is better. There is quite a bit of mis-imformation out there. For so long all "tuners" and "gear heads" were only interested in power and speed. This shaped most if not all of car modifications and tunning concepts. It can be hard to find good ECO modding information out there. So i can understand the hot air vs cold air debates ect...

Oddly I ran one test on my cobalt where I heated the fuel tank up to about 150 degrees (average temp was probably only 100-120) when it was very cold out. The results I got where quite impressive, my engine temperature climbed to 110 in about 1 minute when it normally takes a while to get there, my fe was also much higher per the lie o meter.

It impressed me enough that I would like to locate a well controlled heating system (as oppossed to a magnet I have to watch like a hauk with the infa red)

Cheers
Ryan

There is no debate.
Most people don't understand how fundamentally different gas and diesel engines are.
Diesels need cool air (not bitterly cold air) for better milage, gas engines usually need warm or hot air for better milage.
Simple thermodynamics lays it all out for us.
Factory manuals spell it out for the no so thermodymanicly inclined, cummins has recommendations that their engines draw air from out side the engine enclosure in all but the coldest climates "for the best fuel economy and performance".

I've been pondering on an idea for a while. Basically, make an "intake box" for my filter on my car, then have 2 pipes/ducts go to two different places: The exhaust manifold and pipe into the fender.

The duct going to the exhaust manifold would have a heat shield or tray surrounding the exhaust manifold and the duct would connect to that, like a vacuum cleaner fitting. Within a few seconds of startup, it would start pulling in hot air.

The pipe from the fender that goes to the air box would have a throttle body attached in line, so it keeps closed when not needed. When WOT occurs, it would open up via an actuator. This would force cold air in when power is needed. Then, it would also have some sort of brains to monitor intake temperature and open up as needed to regulate the temps for optimal fuel mileage.

Great idea, eh? Maybe one day I'll actually get off my butt and try it! :)

my father in law's 92 ranger (2.3, 5 speed) is similar to that....

it uses a combined thermo-vacuum switch to switch between drawing air that is run right next to the exhaust manifold or drawing air through the grill.

the switch is mounted in the topside of the aircleaner box, so it gets exposed to roughly the same temperature air that will hit the MAF. there is a little "flapper" door that gets driven by the switch to constantly blend between full "cold" and full "hot" air to make the switch hit whatever target temperture Ford set it up to be.

i've manually adjusted the flapper door actuator using a handheld vacuum pump before, it does make a noticable difference.

so, there's a "no brains" option for you, if you're interested and want to scavenge parts from a junkyard vehicle.

What controls the switch, exactly?

the switch itself is connected to a vacuum line coming from the engine. the switch has an element in it that is effected by temperature to control the amount of vacuum that then reaches the flapper door actuator.

it's actually a pretty neat little system. from what i can tell, regardless of temperature, if there is no vacuum(large amounts of throttle or engine stopped), the door is always going to be held to the full cold position, but when there is vacuum, the amount of vacuum and the temperature of the air coming into the engine effects how far towards the hot and cold air sources the flapper door is moved to.

Ah! Ok, that makes sense... sounds a lot easier than the route I was planning :) Will be junk-yard hunting very soon.. Looks like power for the switch and a tap into the vacuum system is all that is required for the actuation of the flap. From there, it's all plumbing up the air intake systems. Thanks for the heads up on that! Wonder what temp it aims for...

no power, it's all old-school mechanical for both the actuator and the flapper.

i have no idea what it aims for, since i have no experience with trying to datalog early ford stuff, but i imagine someone with that kind of information might know if they were to watch the reported IAT for a given amount of vacuum after a long cruise.

if you wanted to simpify the system further.... you might be able to bypass the switch entirely and just have the flapper driven off of vacuum. the flapper would then move towards hot and cold based entirely on engine load, regardless of the incoming air temp. it would allow for a greater range of air temps, since the switch itself doesn't limit the cold side of the equation, just prevents the intake air from becoming hotter than whatever it was designed to limit it to.

got some more interesting info for you from the factory service manual...

with the ranger system, vacuum above 8" mercury(27kPa of vacuum, so roughly 73-77kPa MAP) is supposed to hold the door to the full heat position. less vacuum than that, it starts transitioning to the full cold position.

the temperature component is called a "bi-metal temp sensor" and seems to be used for keeping the intake temp at AT LEAST 75*F at 16" mercury(54kPa vacuum, so roughly 46-50kPa MAP).

i imagine the amount of vacuum determines the temperature it regulates to, but i'm not 100% on that.

http://i.imgur.com/9PpAJ.png

some of the info is gleaned from that, others from another diagnostic test.

HEATER BOX, T-1 THRU 74 LEFT T-2-71: VW Parts, Volkswagen Parts, VW Bug Parts, VW Bus Parts

Put that on your exhaust downpipe, and have a branch off the air box sucking through it with a vacuum to actuate the heater lever built in as a mixing valve, and voila (dunno what your exhaust pipe looks like though... probably too small).

Sam