Heat engine block for efficiency?
 

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?

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. :)

PS: In praise of the lowly block heater

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.

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.

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

This is actually one of the big attractions for me.

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.

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.

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

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

Probably not - most transmission cases are aluminum...

EBH (transmission boost too?)
 

I'll tell ya -- if it wasn't for the engine block heater plug-in, my tank average in the cold Winter would be about 5 MPG lower. (This is the direct, factory addition).

I too suffer from auto-trans, Arctic inefficiency. The torque converter is VERY hesitant to engage, and it won't upshift lower than 2500 RPM after a cold-soak start.

Since the rad has a built-in tranny-cooler, I assume a quick burst of warm transmission fluid is sent through the system on startup after plugged-in. That's it, I bet.

My guess is that your TC is acting-up in the cold. It can engage and disengage without change in speed, but the engine effort changes. Chrysler trannies are pretty particular to cold. This is followed by foreign brands, and finally by GM (they'll lockup at -40F, 2 miles after startup). Ford? Well, it varies...

RH77

Great resource page, Metro, but it is missing one very effective and inexpensive style of block heater...the adhesive pad heater.

For example: http://www.spiderautomotive.com/oilpanheater.html

I installed three of these on side of the block, dry sump tank and to the bottom of the transaxle of a customer's car, and we were both extremely pleased with the results. :thumbup:

They easily conform to non-flat surfaces, attach to aluminum, plastic, iron, whatever with hi-temp silicone adhesive (usually included)...and they really work well! Start the engine up after 30 minutes of being plugged in and the temp needle was instantly in the green arc. It might need an hour in colder climates.

You don't need a Moroso brand, either. Lots of folks make and sell them. Just do a search on 'adhesive oil pan heater' in your favorite search engine and you will get tons of hits.

Stan

Stan - great find. I hadn't seen those before. Thanks for posting.

IMO the block heater is very much worth it. I just put one in my Matrix (wife's car) a few weeks ago. She loves that its blowing warm air seconds after pulling out of the driveway. That alone is worth it, but there are numerous benefits.

I like to do the timer thing with mine so it warms for a few hours before i take off. It really does make a difference in FE. I've been debating getting one for the wife's 08 civic. The dealer installed optional heater is $130 ish installed. I would normally just buy one and do it myself, but her car is so new I'm hesitant :o.

In a better world, the EBH and some electrical interior pre-heating could be better integrated. As you exit the vehicle the night before you simply set 7am on a screen and then plug the vehicle in. It could then determine based on block temperature and ano utdoor temperature sensor when to start heating up the vehicle to have everything ready for you at 7am. Totally green comfort and luxury as compared to remote starters.

My EBH gets the coolant temp up to about 30°C (86°F) and after that I'm just wasting electricity so it gets tough trying to figure out how long to set the timer for. That gets you thinking...

Check Your Warranty
 

;) After you finish your debate and decide to get one, check with your dealer first about DIY additions to the car. Having worked for several different Dealers, (Different brands), they all have their own hangups about WARRANTY. It would probly be worth it in the long run to allow them to install the heater. Then there is no question of warrant-ability.
I would not want to see your warranty toileted because of "Un-Authorized Modifications". S.

My car has 200,000 miles on it. I am not concerned about a warranty.
I am not concerned about how pretty it is. I am not concerned about (low-speed) deer collisions.

It is amazingly liberating to not care what other people think.

Also, why not tinker with such a vehicle? I think the block heater on mine is a frost plug one. It came with the car, but I have really never used it. It may even have been factory installed.


On the photo of my car, that is right after I hit a deer. (Those things are crazy! Hard to dodge them!) Soon after that, I replaced the front of the headlight with a piece of plexiglass and lightly sanded it. It looks almost factory original!

And itsa "K" car too boot, I may have a headlight around here for you.
What year and model is it? I'll go look see. S.

Here is the other car I did't let people's opinion of me stop from happening.

This car was half '87 Geo Spectrum and half '89 Chevy Spectrum.

It was the first time I ever did any body work on a car. Mostly grinding rust and screwing on aluminum sheets. I wanted to do something with the paint that would camoflage the work done on it. The car was mostly white already, so I painted the hood white and cut out contact paper to make a cow spot template.

Everyone in public loved the cow car! It was anti-road rage! People would smile and wave at me on the road.

The car was retired on Sept 11, 2002 after the engine self-destructed on the interstate.

Last summer, I was at a friends bar-b-q and he told me he saw the cow car just a mile or two from his house. We drove over and found it parked in a driveway. Nobody was home, so we couldn't stop and say hello.
I am assuming that somebody loved the paintjob and bought it from the scrapyard. I have no idea if it runs or not, but I hope somebody else is enjoying it now.

I get the impression one or some of you are thinking of using block heaters to prevent the engine from cooling down overnight, instead of letting it cool down then heating it briefly before you go the next morning... well, DON'T!

It will take more energy to maintain that warmth all night than it will to warm it from cold in the morning. Why? Because the greater the temp differential between object (engine) and ambient temp, the greater the heat transfer (loss). So the most efficient way to use the block heater is to know how long it takes for it to warm the engine from cold to as warm as the heater is going to heat it, and turn it on that long before departure.

Right,

I was thinking some sort of a timer so that it turns on a certain amount of time before leaving in the morning. That was it isn't running all night, just runs long enough to get the engine warm.

Not sure how long that would be. I suppose some experimenting is the next step.

My experience: no more than 2 hours (my small 3-cyl engine = small heat sink, though). YMMV.

OK - it's freezing out right now.

I broke out my Killawatt and plugged in the block heater.

Turns out it is a 500 watt. Seems like a lot of heat. I can hear it running!

Is that a bad thing? I am always afraid anytime I hear weird noises from my car.

That sound means it's working :thumbup:

Mine does the same. Consider your vehicle as a very inefficient Power Plant upon cold-soak, vs. the more efficient grid to get that vehicle up to temp sooner with the EBH, so that the sum total of energy used and emissions is fewer to get that vehicle up to optimum efficiency (or normal operating temperature).

For my car, that is about 2-3 hours. I can hear the heating element sizzling the coolant shortly after plug-in, but that's normal. With the automatic, torque converter lock-up happens so much faster, which equals higher efficiency. The same should apply for the manual folks...

RH77

I just found my spare lamp timer.

This one says it is rated for 15 amps! Most of the cheap-o lamp timers are only rated at a few hundred watts at most.

My engine block heater is 500 watts.

I am planning on now plugging: my block heater into an extension cord, that cord into the timer, and that timer into the KillaWatt.

That way I measure the combined electrical usage of the block heater and timer (yeah, I know the timer should use almost NONE, but I want to measure it anyways.)


Who can suggest how long I run the block heater timer for in the morning? The engine is a 2.2L 4 cylinder - and the car is parked in the driveway, not a garage.

Also, how much of the year does it make sense to run the block heater? Would it help in efficiency in the spring and fall too? Is there a certain temperature, above which, one stops using the block heater as an engine pre-heat?

-Ben

Have you seen this thread?

Mini experiments: 300w vs. 800w block heater warm up time ...

I'd wager that anything more than 2 hours is overkill.

As to question #2, I'd use the block heater year round (though you can likely cut the plug-in time down dramatically in the summer - I'll have to chart that this year).

There's a reason the Prius stores some of its hot coolant in an insulated tank and circulates it back into the engine... regardless of whether it's January or July. :)

Agreed, I only run my EBH for ~1-1.5hrs depending on outside temps during winter. This summer, I might have to cut that time down to only 20 minutes since the garage should be around 70°F all the time.

HERE is my thread on my EBH installation and results.

The first tank after installation showed a good improvement of a few MPGs, not to mention, the fact that you get heat almost instantly helps as well.

And for a few months my work even let me plug my EBH in so I could save some gas....that is, until someone complained that I was getting special treatment and had to stop. [rant]I think it's ingrained in some people not to be efficient nor to understand efficiency's effect[/rant] :rolleyes:

No kidding! Did you offer to pay for the electricity use? Or was that not the issue...

Don't forget wheel bearing pre-heaters.

I'd like an outdoor temperature controlled timer with a straight line mapping.

5hrs @ -25° C
4hrs @ -15° C
3hrs @ -5° C
2hrs @ 5° C
1hr @ 15° C


I've used 3½ hours most of the winter. It's a 400 watt heater in a 3.3L V6. It seems to top out at around 30°C (86F) if you leave it on long enough. I'll back it down to 2 hours at the end of this month and then down to an hour at the start of May.

Who - so you're saying yours "tops out" after 5 hours?

Electricity use wasn't the issue (cost less than 4¢ per day for work's electricity). It was because my car was parked near the maintenance garage, and on of the other staff thought that I was getting a special parking space closer to the building. In reality, the spot I was parked in was only 5 ft. closer to the main building than the closest parking spot.

I made sure to inform all the staff that asked me, why I was parking there and most of them understood. Although, nearly all of them asked why I was still plugging in my car when the temps were just getting above 30°F, hehe. I then had to explain that 30°F is still a long ways away from 180+°F (the temp at which the thermostat opens on most cars).

Meh, I chalk it up to ignorance and jealousy of coworkers. It's all good though because I'm the IT Guy at work, so they all respect me anyways....and think I'm a little weird. :D:thumbup:

It would take far less than 5 hours on a typical night to effectively saturate the ScanGauge reading (it is possible that the rest of the heat is still conducting to areas that help - exhaust manifolds for instance).

Those times above would be my guess on how long it takes to get to about 29° C (engine target temp is 80° C). My commute is very short and in the winter that means very high consumption rates so I've tried to max the block preheat, without using more money for electricity than the gasoline it saves. I save a nickel a night, so assuming 200 nights a year plugged in, it's only a 40 year payback.

The auto mfr.s of cars for cool climates could really help out. I'd like to see some insulation on both the block and the tranny. Let the cooling systems do the cooling, let the casings hold the heat. It wouldn't take much and could also reduce noise slightly.

I'd also like something like smart shore power. You park and plug and as you leave you set a time (maybe 7am). The car's sensor checks battery charge, engine temps, interior temps and outdoor temps. It then times everything and based on the input temperatures prepares the car so that at 7am, the battery is fully charged, the interior/seats/glass aren't freezing, and the block and tranny are pre-heated optimally. Much better than the remote starter option!

That would be great!

I'm not the best with electronics, so bear with me...

How about a temperature-based timer/cycle circuit on the EBH? Take temps off of the block and have the circuit cut the power at X-degrees, and if you're not back in time, re-engage the heater like a home furnace.

Or even, would cycling the heating process produce more even-heating with less energy over a long period of time?

RH77

Or, they all fear you, 'cause you could cause their files to dissappear, or the servers to slow down. ;)

Stew
"I don't do windows"

I read an interesting paper on block heaters yesterday.

REDUCED COLD START EMISSIONS THROUGH USE OF ELECTRIC ENGINE HEATERS

Did you know that using a block heater year round can help reduce your carbon footprint by over 500 pounds?

Did you know that by using a block heater you can reduce your overall CO and HC emissions by up to 80% on a 3.5 miles trip.

Did you know that using a block heater saves your roughly 0.07 gallon per cold start?

I bet it would on your steel paned automatic trans.