Recovering lost heat energy in engine coolant...

[t vago]

Originally Posted by ProDarwin

Unfortunately, there is really no reliable way to A-B-A test anything around here since the nearest traffic free section of road is probably over an hour away, unless I feel like doing my testing at 3:00AM. I'm happy with just logging my mileage as usual for now - after all, its gas usage that I'm really after. Even if its a placebo that makes me subconsciously drive better... I'll take it

I am lucky in this regard. My nightly return commute is usually pretty stable. The highway's pretty empty, and it's really easy to just set the cruise to 72 and do a good 25 mile stretch without even having to change lanes. That takes out a good number of variables, right there. Of course, outside temperature and humidity still factor in...

When I get this thing working tomorrow, I am going to monitor throttle position and manifold air pressure, in addition to intake air temperature.

[pete c]

I wonder if the engine will make enough heat to get to proper running temp during cold weather if you are using the intake heater and the cabin heater.

[JRMichler]

Originally Posted by pete c

I wonder if the engine will make enough heat to get to proper running temp during cold weather if you are using the intake heater and the cabin heater.

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?

[Christ]

It'll warm up faster with a core in the intake, too. Using warmer air changes the ratio of heat dispersion from the cylinder into the cold air that's taken in. If the air is already warm, no heat is lost from the engine to warm up the air.

Thereby, decreasing warmup times, albeit slightly.

[t vago]

Coolant, vacuum, and electrical work were completed this afternoon. I temporarily re-wired my foglamp switch to control the vacuum solenoid to open and close the 4-way heater valve.

Initial observations:
Outside temperature: 78 F
Intake air temp with no heat: 90 F
Intake air temp with heat: 115 F

When switched on, the air temperature takes about 30 seconds to stabilize at the higher value. When switched off, the air temperature takes several minutes to stabilize at the lower value.

I think that's a good start, considering that the intake heater only covers about 70% of the air filter area. Air is free to flow around the remaining 30% uncovered area, without getting heated. Fuel economy observations will be conducted during the next run.

[Christ]

Looking forward to results.

[Ford Man]

Originally Posted by drmiller100

I'm a bit puzzled why you would want hot air in the intake.

The adiabatic expansion implies the colder the air you can use, the more delta T you get.

The greater the delta T, the more effiicent the 4 stroke engine?

I guess I'm curious why you would want a hot air intake.

Warm air is less dense and has less oxygen molecules therefore less oxygen in the exhaust stream for the 02 sensor to detect and the IAT sensor sends a warmer temperature reading to the ECU, which fools the ECU into thinking the outdoor temperature is hotter than it actually is and leans out the mixture. All cars run richer when cold air is being introduced into the engine. Many have found that warmer IAT's increase their mileage.

[Christ]

Originally Posted by Ford Man

Warm air is less dense and has less oxygen molecules therefore less oxygen in the exhaust stream for the 02 sensor to detect and the IAT sensor sends a warmer temperature reading to the ECU, which fools the ECU into thinking the outdoor temperature is hotter than it actually is and leans out the mixture. All cars run richer when cold air is being introduced into the engine. Many have found that warmer IAT's increase their mileage.

They don't run richer, they just add more fuel to compensate for the presence of more available air. "Richer" suggests an AFR different than desirable, as in "too much fuel for available air mass".

[drmiller100]

Originally Posted by Ford Man

Warm air is less dense and has less oxygen molecules therefore less oxygen in the exhaust stream for the 02 sensor to detect and the IAT sensor sends a warmer temperature reading to the ECU, which fools the ECU into thinking the outdoor temperature is hotter than it actually is and leans out the mixture. All cars run richer when cold air is being introduced into the engine. Many have found that warmer IAT's increase their mileage.

ummmmm,,,,, well, no.

it takes a certain amount of oxygen molecules to make a certain amount of power. If the molecules are warmer, they take up more space, so you have to give more throttle position to get the same amount of power.

But when done, it still takes the same number of molecules to make a certain amount of power.

If the molecules were colder to begin, expansion ratio would be higher, making the engine more "efficient" = more power with identical amounts of fuel and air.

[toc]

Originally Posted by drmiller100

ummmmm,,,,, well, no.

it takes a certain amount of oxygen molecules to make a certain amount of power. If the molecules are warmer, they take up more space, so you have to give more throttle position to get the same amount of power.

But when done, it still takes the same number of molecules to make a certain amount of power.

If the molecules were colder to begin, expansion ratio would be higher, making the engine more "efficient" = more power with identical amounts of fuel and air.

Ehh??
CAI or WAI? Which one!
(The age old topic that never gets any solid data for or against).