Heat engine block for efficiency?

[bennelson]

My old blue beater '93 Dodge Shadow 2.2L 4 cylinder has a plug on the front of it. (oh if that were only for recharging some lithium batteries...)

It is for an engine block heater to keep the engine warm at night so you can start it on a cold winter morning.

I plugged it in once just to see that it worked. It seemed to. I didn't pop a breaker and my car didn't explode.

I have a good battery, and it doesn't usually get so cold that I couldn't start it.


But I was thinking, if a warm engine runs more efficiently, could I use the block heater to pre-heat the engine and get better gas mileage? Or is the car warmed up two minutes after starting it, so the only fuel gains would have been for that first two minutes anyhow, plus I wasted all that electricity running the block heater?

Has anyone tried this?

[MetroMPG]

It's a common, proven method for improving efficiency. It's especially helpful if you tend to drive short distances.

You probably don't need to plug in overnight though - a couple of hours, max., is all you need.

My car has 2 heaters - one inline coolant heater, one external contact heater - and I use them both. At the same time. And not just in the winter.

[MetroMPG]

PS: In praise of the lowly block heater

[DifferentPointofView]

A car is never warmed up after 2 minutes unless it's hot outside, a block heater will warm it to operating temp before you even put the key in the ignition.

In the winter, most vehicles take a few miles to warm up. some take as little as one, but mine takes 5 miles. For your engine to be warm, your temp gauge is usually about 2/3-1/2, or if you don't have a temp gauge, you can easily judge this if the vehicle's heater is putting out hot air. if it's just warm air (compared to what it normally is) then it's not warmed up. if it's cold freezing air and your heater actually works, then your engine is cold soak. your engine may be warm enough to drive without your engine acting up after 2 minutes, but a block heater will definitely help on a winter morning. not only will your engine run smoother, and you will get better mpg's than when it's been cold soaked, but you will have hot air coming from the heater as well.

[bennelson]

I read that heater info.

That Prius idea for pumping hot coolant into a themos for later is a great idea.

How is that for true conservation!

I was thinking if I used the block heater, I would put it on a timer.

I already do that with my aquariums so save energy at night, plus fish have to sleep, and with a big lamp in my bedroom to wake me up in the morning.

The timer could just run for a while at night, then I would just unplug the car before taking off in the morning.


PS - On an electric car forum, I was asking about pre-heating an electric car (because electric cars have no engine to give off enormous amounts of waste heat, they usually have pretty poor heater)

My idea was just to put a regular 120V heater in the car and let it run for a bit plugged into the wall. The the car is nice and warm, and you can unplug the heater power cord and take off.

A guy replied that he did exactly that and it worked great.

Now an electric car does not have to "warm up" before it is effecient, that's half the fun. Great for short trips an errands. Electric car people in cold climates do tend to use battery warmers to keep voltages/capacity from dropping.

[MetroMPG]

Originally Posted by DifferentPointofView

your engine may be warm enough to drive without your engine acting up after 2 minutes

Maybe your engine! My 10 year old engine can be driven (gently, of course) without acting up within seconds of a cold soak start.

you will have hot air coming from the heater as well.

This is actually one of the big attractions for me.

[DifferentPointofView]

set the timer to turn ON at a certain time, that way the engine won't cool down if it turns off in the middle of the night. I know that within 10 minutes of my big 4.0L being off during 30 degree weather my engine will cool about 20 degrees, and in half an hour about 80. in one our my engine is cold again, not complete cold soak. it's still about 75 degrees. but cold enough to rob me of FE.

If it's set to turn off after a few hours. the engine will be totally cold again by morning.

[DifferentPointofView]

Originally Posted by MetroMPG

Maybe your engine! My 10 year old engine can be driven (gently, of course) without acting up within seconds of a cold soak start.

I think that it isn't my engine, but my TRANSMISSION that acts up when it's freezing cold. It seems that on freezing cold mornings, the Tranny fluid is so thick that the transmission seems to slip while I'm driving. I'll be gently driving it, and the rpms will surge up from about 1400 to 2000 then back again with no gain in speed. That's only when it's about 15 degreesish out side. once it warms up, it's totally fine. seamless shifts and normal operation.

This is my first winter with my Jeep. and at first when winter was just setting in I thought it was just a slight miss, but as it got colder, the symptoms got worse until I warmed up the Jeep for about a minute and a half or two. then it'd be less of a problem cause the warmer engine would warm the tranny slowly, but surely faster than if they were both freezing cold. I need to check the fluid level to see if there's any low readings from the tranny since I replaced the fluid not too long ago, I might be low.

[MetroMPG]

You need a transmission pre-heater too. (In fact we all could use one.)

[DifferentPointofView]

Would a magnetic one work for that? (would it also work for a freeze plug type?)