A New 'Take' On Hot Air Intakes
 

As this is my first post, I would like to start by saying 'HI' to everyone. I've been following the advice from MetroMPG.com since the latter part of 2006, and now feel I must add to the discussions as repayment for all the money, and gasoline, I have saved over the past year and a half. I have been toying with the idea of a HAI for quite some time now, and would like some feedback on on my design. It utilizes a fairly simple design using easy to find parts that are relatively inexpensive. The following design is not patented (though it might be wise to do so) but I want everyone to benefit from this, so here's the Image I drew up. The theory behind this is that as the air is drawn through the oil cooler and heated, it will cool the oil preserving the engine's bottom end. However, this may pose a problem with thermal efficiency. It may allow a higher temperature to be reached inside the intake, while keeping the engine at a more controllable temperature. Please feel free to comment.

Hey, welcome to ecomodder!

While a warm air intake is a good idea, I don't know that sucking heat out of your oil is the best way to accomplish it.

Essentially you'd be gaining a bit by reducing pumping losses with the WAI. But, I'd be worried about that heat loss in the oil reducing your oil's viscosity, thereby increasing losses in the engine.

Given, the losses from oil viscosity aren't going to be much, but if you don't need oil cooling anyway (if you don't have a high-performance high-powered car) then there are much better places to get free heat, like the exhaust manifold.

Hi -- cool (I mean Hott) idea -- and welcome to EM.

First, I would make sure that you've done your research on the ideal temperature. I've experimented with WAIs, HAIs, and CAIs for the last 3 years. For my Honda-based engine, the target is 100F.

I commend you on the design, but perhaps a simple tube to the exhaust manifold area could yield excellent results.

My WAI this Winter was essentially a 3-foot section of flex-pipe exhaust tubing, with the air source being just above the exhaust manifold. It was simple to install and relocate to source cooler air for Summer (which is essentially 90-100F as temps heat up). As ambient temps warmed up, congested traffic yielded 140-150F intake temps (which is bad -- the ECU dumps more fuel to cool the charge, and retards timing to prevent detonation).

Best FE to you and welcome to EM! :thumbup:

RH77

Welcome from me as well.
Enjoy your stay.

To the oil cooler design...the idea is workable since all the factors and technology already exists on many cars.

You may find some level of restriction on the air intake with the cooler in place.
Oil tends to heat up less slowly (although an early Subaru used it for cabin heat many , manyy years ago) than the exhaust system so you may want to consider using some form of exhaust heat collector (old air cooled VW's had the cabin heater taken from the exhaust) as has been suggested by RH 77,

Regardless I hope it works as well as you want if / when you decide to build it.

Cheers , Pete.

Thanks for the feedback guys.

The temperature of the oil would remain relatively constant, because of the way we (Hypermilers) drive, with almost no WOT. As the throttle opens, the air drawn past the oil cooler would cool the oil. The oil, once it has recirculated back to the sump, would then cool the remaining oil, thus reducing the the temperature at the oil cooler, in theory, of course. The only time I would be concerned, would be in bumper-to-bumper traffic.

The problem I'm foreseeing is thermal efficiency. The gains I make with the HAI may be counteracted by the loss of heat in the engine block. I Might just have to try this and see where it gets me. (Don't worry, I'll take pics when I do :thumbup:)

I live in Massachusetts, so we see the full gambit of temperatures and conditions, -30* to +110*F and every type of precipitation known to man ;).

Hi Funny - glad to see you arrived at EM.

Thanks for your help Darin. I enjoy sharing ideas and getting involved with something important to everyone.

Funny -

Welcome to EM! Another interesting way to look at W/HAI.

When I was doing my HAI I inserted an inline (PLASTIC) marine bilge fan rated at 5 Amps (about the power of one DRL ... Daytime Running Light) into the HAI tubing. I controlled it with a DC motor controller (Ramsey Electronics Kit) in order to control it's RPMs. The idea was to suck more hot air into the air intake.

I couldn't get it to work very well, because when I did get the temps up, I was in danger of melting the fan, :o . If I ran it too fast, I think it "outran" the hot air and pulled in more unheated air. Also, when it was off, I think it acted as a constrictor. Finally, a screw came loose (No, in the fan mount, not my head, :mad: ) and I took it out.

If I were to try it again, I would use a "snail shaped" metal fan. With a DC motor controller and a metal "snail fan", you may be able to control the RPMs and modulate the IAT temp.

CarloSW2

If you're going to work with WAI or HAI get some kind of intake air temperature monitoring (I did, for $10). You want to know the outside temperature and the temp of air going to the engine.

If you have a ScanGauge I think it might offer intake air temp monitoring.
Otherwise, get yourself down to your local big box auto parts stores and find an interior/exterior thermometer. Mine was $10, runs on 1 AAA battery. Plant the "exterior" sensor inside your air box, or if you dare, in the intake hose before the air mass meter (or whatever your car calls it). I take a look at it before starting my car; that's the outside air temperature. Then I watch it go up as the WAI goes to work.

You'll need to cut the wire lead, drill a roughly 1/8 inch hole in the airbox, put the sensor inside, run the lead out the hole, and solder it back together. Since the sensor has very high resistance just twisting the wires back together isn't enough - over time, accumulated resistance in the connection (dirt/corrosion etc) will throw off the readings. So solder.

I understand what your saying, but the HAI (In Theory) would be self maintaining, and linear in its temperature range after the initial warm-up. As the oil heats up, it would be perpetually cooled (I use this as a relative term, because the outside air temps will always we colder than the oil temperature, unless I'm driving through fire :rolleyes:), by the incoming air, thus allowing for a greater capacity for grill blocks, high temperature thermostats (still have yet to find one for the Lemon) and other such thermal efficiency modifications.

As a research and development technician, it's my job to look at all aspects of the experiment before performing it to see if my hypothesis is indeed correct. It's one of my flaws I think, not being spontaneous. I also don't want to ___ up my car :).

Thanks for the input Bruce, I do have a Scangauge I. I just implemented a grill and radiator block this evening and took her for a spin. The outside air temp was 50*F and the intake temps after warm-up were 63*F. The problem I was having was the coolant temps were bouncing between 207*F and 198*F (the radiator fans were going on and off. I could hear those mileage robbing beasts going a few times when I was at stop signs.) I still got 45.9 MPG on the trip :). I think if I do a partial grill block, it will solve that issue, at least for the most part (she won't fluctuate as much).

Funny -

I agree, a self-regulating "passive" solution is always better. Nothing to break (or melt, ;) ).

Since I am not a car-person by experience, I am super-cautious too. I only have my daily driver, so I can't afford to ____ up either.

In terms of high-temp thermostat, I think this is an option for you :

High Range Adjustable Temperature Switch with LCD
http://www.jaycar.com.au/productView...=&SUBCATID=347
http://www.jaycar.com.au/products_up...oduct_7565.jpg
This could be used to monitor engine temps.

CarloSW2

Thanks, mine is a daily driver too and I believe in passive solutions, with the exception of transmissions (got to have a manual!) :rolleyes:.

By thermostat, I meant in-line with the radiator hose to regulate the coolant flow. This is an interesting idea though, having a temperature of the exhaust manifold or even the oil cooler in the HAI would be real nice, especially If I do make that into a mod on my vehicle. That would tell me how consistent the oil temperature is. I'm making note of the site right now for later use :thumbup:. I have a Scangauge I to take care of my internal monitoring. If you haven't picked one up yet, they are by far the best $139-169 bucks you can spend on instrumentation/diagnostics.

Why not use engine coolant? Tee into the heater hose at the water pump and throtle the flow with the same type of controls that you use on your existing heater. Water temp is much more stable than oil temp and would be easier to control I would think.

I had already thought about coolant, Duffman, as the coolant in the average auto is about 200-220*F. I like your idea though. Thermal efficiency of a heater core or oil cooler is not 100% by any stretch, and the addition of other pipes that would lose heat and more coolant to warm up seemed to me to be the deciding factor against that.

That is why was searching for a "warmer" heat source. I thought about the exhaust system, as that is a huge waste of potential energy, but after further inspection of my car, I realized how difficult it would be to make and mount a system that wouldn't lose most of its heat from the back of my engine bay to the front (my engine's turned 180 degrees from you Honda guys :D)

I got this idea a few weeks ago, when I was browsing an online catalog that sold battery relocation kits. I wanted to even out the weight distribution in my car, so naturally, I sought to move one of the heaviest objects to the trunk. Then I realized all the unused space up front could be used to engineer a more fuel efficient air intake.

In the same online catalog, I found oil filter relocation kits and oil coolers. A gear in my mind must have up shifted and that's where I got the idea of using the oil for a heat source. Often at upwards of 250-300*F (not sure of the exact temps, please correct if I'm wrong), and the oil being a fluid so it was more likely to hold energy longer, it seemed to me to be an ideal solution to "where to get the heat?"

The other reason I wanted to get the oil filter relocation kit was because of the nature of the Rolling Lemons current filter to be high and recessed. I just wanted to make it easier to do oil changes :thumbup:.

Maybe I should make a hybrid Oil/Coolant based HAI :eek:. That seems like more of an engineering challenge (nightmare) to me.

The thing of it is, oil temp is very dependent on the engine load, so at low load when you can use more heat you have less and at high load when more heat is in the oil, engine pinging may be a problem. Its true that engine coolant behaves the same way but it has a thermostat that partitions the engine coolant from its reservoir (radiator) holding it at a much more consistent temp. I would think it would get hotter faster as well with coolant.

One thing that I don’t like about the oil idea is you go allot farther on a coolant leak than you will on an oil leak. The potential for catastrophic failure from a busted oil line is a lot higher when you are low on oil than low on coolant.

You make a lot of good points :D.
I think I'm just a little leary of playing with the coolant system, but I think I can adapt this idea to work with coolant.
I just wanted to use a higher temperature fluid (oil) because I can't find a high-temp thermostat for a 2002 Corolla anywhere. There is also the issue of making a system with a thermostat for the HAI so that the heater core/oil cooler doesn't overheat, stays at a stable temperature, and doesn't affect the drivability of the car. Maybe now I can make a system that uses the Prius Radiator Theremos ;). I may be overthinking this just a bit. Please pull me back down to earth.

Maybe someone can jump in here and help on the oil temp issue but I dont think it will be any hotter than the coolant temp under moderate loads.

If you go with the coolant method, thermostatic controls are not an issue, it will not get higher than your coolant thermostat temp and you can use a heater control slider to control your valve to the HAI heat exchanger.

I am a little puzzled that you say you dont want to mess with the coolant side. Where are you going to tap into for the oil for a high pressure oil supply? For a coolant system I would buy one of those tees that you get to flush your coolant and just tie it in paralell with your heater core. For the heat exchanger I would just use a heater core. I dont for see more than $30 on parts if you get a used valve, heater core and new hose.

I believe oil temperatures hover around 180-220 degrees fahrenheit. I'm pretty sure oil viscosities are measures at 100 degrees celsius (212 F).

I wouldn't tap into the oil line simply because lowering the oil temperature is going to increase the viscosity of the oil. The coolant line setup would work well, but at the cost of added complexity.

I would just get an aluminum heater duct, route it from the front of your car, to the rear of the engine (touching the headers), and back to the throttle body. Your engine is reversed, but it should still be doable.

You could also create a heat muff through a similar method, but instead leave the heat output angled towards the throttle body rather then directly attached...no need to create a throttle restriction.

- LostCause