The first kilometer/mile

[AndrzejM]

Originally Posted by PaleMelanesian

I have no experience with diesels or turbos, but I approach cold starts just like warm starts. Low rpm, high load (say medium load for the first minute), EOC. I'll let it idle a few seconds after starting, but that's it. Any deviation from that for faster warmup is extra fuel used.* My car has lived 200,000 miles, so I doubt extra wear is a significant factor.

Faster warmup does mean lower fuel usage later in the trip, but at best you get back half of what you spent warming up. Best fuel consumption is to arrive at the other end with the coldest engine you can. Grille block to make it warm up faster.

I see you're from Texas, and I presume is quite different than Poland in terms of average temperature. Low viscosity oil in winter is like a butter (almost) during the coldest part of the year. So cold wear of the engine is a factor here. I'm not saying that your engine will break after few cold starts or EO(ff)C of course, but I'm keeping that in mind.

[pmiulian]

Regarding the cold starts, I was just wondering.
Given the fact that the usual comute involves leaving home in the morning and getting back in the evening, wouldn`t keeping the engine warm for 12-14 hours be a fix for most of the start-ups ?
I was thinking that maybe adding thermal mass to the engine and a bit of thermal insulation on the top and sides of the engine bay would do the trick.
I know that there are some old threads ( about winterizing the car ), but I haven`t found any input on adding thermal mass to the engine.
I tried this ( without logging data ) by using about 0.3 kg of wax. I just melted the wax, poured it into some plastic freezer batteries and placed them on top of the engine.
How could this idea be refined ? I think that all that waste heat from the engine can be stored just long enough to have a slightly warm engine the next day.

[Piwoslaw]

That is a good idea and it's been done: The II gen Toyota Prius has a 3 liter thermos which stores engine coolant, keeping it warm for quite a few hours. A DIY version isn't easy, but is possible. Check out these threads:
Heat storage system (Prius-like insulated coolant reservoir)
Keeping Engine Coolant Hot
Mimicking Gen3 Prius Exhaust Heat Recovery
The last thread is about a different approach to quicken warmup times, used in the III gen Prius.

[redpoint5]

Originally Posted by pmiulian

Given the fact that the usual comute involves leaving home in the morning and getting back in the evening, wouldn`t keeping the engine warm for 12-14 hours be a fix for most of the start-ups ?

Keeping an engine warm for 14hrs is quite difficult. The common option is to put an electric engine block heater on a timer that turns on just before the car is needed for the morning commute.

[Patrick]

Encase your engine in Great Stuff. Spray Foam Insulation | GREAT STUFF? Insulating Foam Sealant

[serialk11r]

Maybe this is a horrid idea, but how about reducing the heat capacity of the cooling system? Higher glycol concentrations bring down the heat capacity pretty fast.

Also, I suspect that engine oil has a lot to do with short trip economy, I'm going to try to put 5W-20 in next time instead of the 10W-30 that I got from a oil change place. Supposedly not all 5W or 0W are equal, a 5W-20 is quite a bit thinner than a 5W-30 when cold. 0W would be better but I have an oil burning early 1ZZ so I'd rather not use an expensive oil.

[pmiulian]

Hei - sorry for not being clear on my idea. I was thinking that the car wastes a huge amount of heat anyway.
Even if driving eco, the gas is still being burned and the heat is wasted - is all in the way the ICE works ( the 25% efficiency for gasoline ).
I know all the threads that you provided - thank you. But I see a problem with all those approaches. The insulation on the Prius engine is fine - also the thermos. But there isn't enough heat stored. The insulation capacity is limited.
The metal from the engine and the coolant will store a good amount of heat anyway, but it still isn't enough. From my point of view, the perfect car wouldn't have a radiator.
It would maybe carry with it about 100kg of wax instead.

I did mention wax ( or paraffin wax ) for a reason. This is a common and affordable PCM ( Phase Change Material ). That means that it will melt within the engine temperature operating range. When melting, the PCM stores a huge amount of heat. Wax is cheap and easy to find, almost free compared to the Prius thermos.

I tested this with about 0.3 Kg of wax, using 3 small recipients used for portable coolers. The were filled with a glycol mix I think - because of the same principle. That glycol mix would change phase when freezing / melting - so it would absorb a huge amount of heat for it's size. With the test recipients I was able to keep the engine warm for about 4-5 hours in the summer ( to about 50 deg Celsius ) and for 2-3 hours in the harsh winter ( to about 30-40 deg Celsius ). The main problem for my test was that after a while, the wax started leaking and I was afraid for the engine not to catch fire. So I need more wax and a better recipient - a metal one.

I was saying about the perfect car. With an engineered PCM and a huge amount of it, the car would never need a radiator. Or just need it for emergency. More than that. If you could store 50% from the heat generated on a 50-100 km daily commute, when arriving home, you could just plug the car in, and have instant heat for the home.

L.E.: I guess, with this kind of tuning, the car would become a mobile co-generation plant.

[brucepick]

Originally Posted by PaleMelanesian

I have no experience with diesels or turbos, but I approach cold starts just like warm starts. Low rpm, high load (say medium load for the first minute), EOC. I'll let it idle a few seconds after starting, but that's it. Any deviation from that for faster warmup is extra fuel used.* My car has lived 200,000 miles, so I doubt extra wear is a significant factor.

Faster warmup does mean lower fuel usage later in the trip, but at best you get back half of what you spent warming up. Best fuel consumption is to arrive at the other end with the coldest engine you can. Grille block to make it warm up faster.

I agree with PaleMelanesian on his approach.
I drive in New England, where we get winters.

I use EOC as much as possible on a cold engine. Grill block helps a lot. I use my ScanGauge to indicate engine temp, and that tells me whether I have too much or too little grill block for that day's temperatures. I wear a warm jacket in winter, partially because I don't heat my car like a sauna, and it can take some time to warm up.

[Piwoslaw]

I just realized that my first few kilometers after a cold start differ from later in the trip. Since the car often waits up to 2-3 weeks between trips, I have to use the brakes to get rid of the rust that had caked on. I can hear it grinding

[ps2fixer]

Personally I normally drive ~35-40mph since #1 I don't EOC due to it being night time, #2 my auto trans won't shift into overdrive/lockup till it warms up some. 35-40mph is around 30mpg for warmup, at 45 on up mileage just drops off a cliff. P&G on the way home with EOC seems to be MUCH better than my old methods ^.^.