Recovering lost heat energy in engine coolant...

[t vago]

I have made a vehicle entry in the garage here, "Dakota A-B-A HAI", specifically to capture trip data related to my hot air intake. I have written down the rules for trip acquisition, which happen to be based on how I would normally drive home. These rules further restrict trip acquisition based on events that would affect fuel consumption (rainy or windy weather, delays due to road construction, elephant races, etc.) The rules below should minimize most of the variables that could significantly affect trip data.

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Each fill-up entry represents one commute from work (or co-worker's house) to home. Three different paths are considered.

• Route A - Work to I-480E to I-77S to home (58.7 miles)
• Route B - Work to I-480E to I-271S to SR 8 to co-worker's house to SR 8 to I-77S to home (61.8 miles)
• Route C - Co-worker's house to SR 8 to I-77S to home (26.5 miles)

Temperature snapshot will be taken at I-77S exit 109, where there is a large sign present that alternates between outside air temperature and the time. The display temperature has been verified to read within one degree F of the vehicle's outside air temperature reading on it's overhead display. The installed ScanGauge II shall be used to record the vehicle's intake air temperature.

Fuel consumption will be recorded with installed ScanGauge II.

All entries are generated between 12:30 AM and 2:00 AM, where there is little traffic present. Each trip begins at work (or co-worker's house), and ends at home.

Vehicle will have sat at work (or co-worker's house) for at least 8 hours prior to trip.

Vehicle does not have any aerodynamic mods, save for a chin spoiler.

The stock cruise control is used, to the maximum extent possible. Speeds to be kept to 7 MPH over the posted speed limit while the vehicle is on the highway, and shall be kept at the speed limit when the vehicle is off the highway. Lane changes to be kept to a minimum. Any attempts to pass slower vehicles to be made only with cruise control set at speed, with no additional acceleration, and by using lane changes as necessary.

Vehicle air conditioning will not be used.

Vehicle to make interim stops only at traffic lights, toll booths, the gas station, and at co-worker's house.

The following will invalidate a trip from being recorded: Road construction along route that spans over 0.5 mile. Delays that reduce vehicle speed to below 50 MPH on the highway. Rainy weather. Wet highway roads. Noticeable winds with windspeeds over 5 MPH, as verified by weather website. Stops made for any purpose other than described above. Driving vehicle for any reason during 8-hour work period. Use of vehicle air conditioning.

[JRMichler]

YES!!
Finally, an ABABABABABAB test of HAI under controlled conditions.

[Daox]

Originally Posted by JRMichler

The heat used by the intake heater goes right back into the engine, so should have no effect on warmup time. Theoretically.

On the other hand, an intake heater that uses exhaust manifold heat should theoretically warm up faster.

Somebody want to run some tests of warmup time?

Done, a few years ago.

http://ecomodder.com/forum/showthrea...-up-11471.html

[t vago]

Okay, some good news and some bad news:

First, the good news: I could do a run with the HAI turned off.

Route C Data Set (26.5 mile distance)

Label	Date/Time Stamp	Consumed	FE	Outside Temp	Intake Temp	HAI Status	%Change
B	2012-05-16 1:40 AM	1.40 gal	18.93 MPG	62 F	104 F	Active
A	2012-05-17 1:47 AM	1.49 gal	17.79 MPG	42 F	58 F	Off	-6.04%

This B-A test set shows a decrease of 6.04% from B to A. (and apparently we can use table bbcodes... cool!)

Now, the bad news: The heater valve, used to control the intake heater, allows a little bit of hot engine coolant to the intake heater when the valve is switched off. The supply line was warm to the touch at the end of the test route, but the return line was cool. This caused the warmer-than-expected intake air temperature observed during this night's run. If pure results are desired (HAI turned absolutely off), then I might have to invest in some sort of globe valve to install in-line with the heater supply.

[t vago]

Route A Data Set (58.7 mile distance)

Label	Date/Time Stamp	Consumed	FE	Outside Temp	Intake Temp	HAI Status	%Change
B	2012-05-12 1:40 AM	3.04 gal	19.31 MPG	55 F	98 F	Active
A	2012-05-18 1:27 AM	3.12 gal	18.81 MPG	49 F	68 F	Off	-2.56%

Another B-A set, though I don't think I will be doing any more for a bit.

As can be seen, there's a small difference between the 58.7 mile run with the HAI active, and with the HAI turned "off." I put "off" in quotes because there's still a 19 F difference between outside air temp and intake temp. Apparently, that heater valve leaks more than I had thought. I must put in a heater valve that doesn't leak when closed (preferably one that can be electrically controlled from the cab).

[Daox]

It would be great if you could get a few more runs in with the same ambient temperature.

[t vago]

Yes, yes, it would. If only this weirdo weather will cooperate... One night it's sultry, the very next night it's practically near freezing.

In the meantime, I will try to find a heater valve that will actually, you know, shut off flow. I think that will also help.

[t vago]

Route A Data Set (58.7 mile distance)

Label	Date/Time Stamp	Consumed	FE	Outside Temp	Intake Temp	HAI Status
B	2012-05-12 1:40 AM	3.04 gal	19.31 MPG	55 F	98 F	Active
A	2012-05-18 1:27 AM	3.12 gal	18.81 MPG	49 F	68 F	Off
B	2012-05-19 1:33 AM	2.99 gal	19.63 MPG	58 F	104 F	Active

Hopefully, this weekend I'll be able to install a heater valve that doesn't leak. If so, I'll throw out the "A" data gathered so far, and recollect more "A" trips.

[ksa8907]

This sounds like something ill have to try.

[t vago]

More good/bad/indifferent news...

Good news: I redid the heater hose plumbing, replacing the heater bypass valves that I was using, with heater shutoff valves that are specified for a late model Chrysler K-car. I tested them before installation, and they do appear to completely shut off coolant flow when they close. So, perhaps I can get better A-B-A data.



Along with that, I replaced the tube-and-fin heater element with a plate-and-fin element. Instead of a 45 F differential between outside and intake air temperatures, there is now about a 60 F differential. It reflects favorably on the test drive, too. On an all-city driving test run of about 8 miles (between my home and my parent's house), I am estimating a 15% improvement in fuel economy. (That's all in-town miles, there. My commutes will doubtlessly show a smaller increase than 15%.)

The indifferent news: I did not test the heater shutoff valve, because I wanted to do a leak test of the reworked heater hose plumbing.

Now, the bad news: All that A-B-A test data above? Say buh-bye to it... I'm starting over from scratch.