A New 'Take' On Hot Air Intakes

[Funny]

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.

[AndrewJ]

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.

[RH77]

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!

RH77

[Peter7307]

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.

[Funny]

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 )

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 .

[MetroMPG]

Hi Funny - glad to see you arrived at EM.

[Funny]

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

[cfg83]

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, . 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, ) 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

[brucepick]

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.

[Funny]

Originally Posted by cfg83

Funny -
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, . 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, ) 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

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 ), 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 .