Engine Block Heaters

I live in Northern Maine. We got our Prius last fall, and we did not find that it needed the EBH.

Read the threads. There is a warm-up cycle that the car must go through, so just let it do it's thing.

Always remember that in winter if you start the car for less than a minute, it leaves the engine in such a condition that make cause hard starting the next time. So if you only need to move it a few feet, use EV.

 

You park your Prius in a garage; which is the biggest factor in smooth starting a vehicle when it is below -10F.

Would the extra dollars spent in electricity to pre-heat the engine; come back to you via less fuel burned? I do not know.

I suspect that 'no' you would spend more to pre-heat than you would by not pre-heating. But to know for certain would require testing, at a wide array of temps.

 

Living in tropical buffalo NY I spent an hour installing one last month. ($45.00 from Ebay)
I plan on having a timer fire it up two hours before the morning comute.
My only question is durring the first week of use will I be dragging just the cord or the timer as well when I forget to unplug it?

 

Last winter I read a bunch on this topic. Though I am having difficulty finding the threads right now, and I need to get back to work.

The ICE needs to warm itself, plus it is responsible for keeping the main battery temp within spec. A EBH only addresses one of these topics. In terms of fuel economy you might be better off to consider grill-blocking instead.

 

Mark, no, the engine cannot skip the warm-up stage, the EBH can only reduce the time needed to bring it up to temp. I use my EBH year round and have found that it decreases the warm up time by half. More accurately, it reduces the warm up distance by half.

Also, grille blocking and EBH complement each other. The EBH reduces warm up time, and blocking the grille helps the engine maintain operating temp. (I do not block my grille when temps are greater than 60F.)

As far as FE gains, probably not a lot. But it's worth experimenting.

 

The Gen 2 Prius had a thermos that tried to keep some radiator fluid warm between starts, I think it works in terms of hours but not overnight. Gen3 like yours does not have the resevior.

 

The engine also needs to warm up the catalytic converter. The EBH cannot bypass that.

If you use it only in winter, I doubt that it can save enough fuel to pay back the installation, at least at recent fuel prices. Hardcore competitive hypermiling going for high score will use it year round. Far Northerners use if for reasons other than raw $ savings. Drivers with environmental, political, or national security reasons to further reduce oil consumption, and are willing to pay a bit more for it, may find it useful.

My assumption (does anyone else have a better rule of thumb? Or even a real measurement?) is that each full warmup cycle costs about 2 miles worth of fuel. For a Prius, that would be about 0.04 gallon per driving day, assuming it gets plugged in only at home, not at the office. You do your own math from there, including the cost of electricity. And a timer, to insure that the plugin cycle doesn't run so long that it burns more electricity than is saved in fuel.

 

I would jump at that $120 charge for installed Block Heater. It is not a fun job, and the part alone is somewhere between $50 and $100 I think.

I got the Block Heater installed when we got our 2010 (for a lot more $'s). We use it almost without fail, before the first start of the day, for around 2 hours. A timer is helpful. Don't care the time of year: raising coolant temperature before startup is always going to get the engine wamed up sooner.

Also, in winter, the car interior temperature warms up sooner. And I suspect the engine will last longer, due to less severe cold starts.

 

I had engine block heater installed in my vehicle. I had my son install it (I helped...) and was I glad someone else installed it... We had a mild winter but I think it was worth it. I also block the grill, but not completely like others here.

 

From a purely hypermiling standpoint this is a good mod. In my racing days we spent thousands of dollars on mods to decrease 1/4mile time and never cared about things like payback or ROI. You did the mods because you wanted to. Period!

Lincoln suffers from enough cold winter days that I think you would benefit from an EBH in terms of mpg. Will you make your money back in saved fuel? Maybe or maybe not. Will the mod make you happy if it helps boost your winter mpg? Will it give you something else to monitor and play with on your commute? I think we both know the answer to those questions.

BTW, start monitoring your warm up times and ambient temps now so when winter comes you can start measuring the warmup times then with colder temps. Then you can perform the EBH and grille block mods and see how those affect your warm up times.

 

To help determine if heating can help FC, check this thread under Gen III technical discussion: HSD behaviour during S1a & S1b warming stages | PriusChat FrankTiger's infoporn records start ups while moving slowly electrically (but not in EV mode, strictly-speaking) in an underground car park. So it is similar to stationary idling in that the engine was doing little other than running to warm itself up.

In FrankTiger's car, for every Celsius degree below 28°c (82F) the engine ran for 4.5s and used 2.79ml (0.000737 US gallons) of fuel.
Example: If the coolant is 10°c (50F) at start up, the car will burn 50ml of fuel worth 6.5¢ ($1.30.5 / litre of 91 RON in Australia or $4.96 per US Gal of 87 AKI) and run the engine for 81s, compared to a car at or above 28°c.
How much? I pay 16.5¢/kWh for electricity (Australian electricity is much more expensive than USA) so if I run the EBH for 3 hours, that would be 400W * 3 hours *16.5¢kWh= 19.8¢ or 3 times as much as the fuel I'd save. Note: If the EBH reached 28°c in 1 hour, it would be evens.

However, that is the FC at start up and idle. If I drove the car and asked the engine to get me up a hill or into traffic, the FC would be far worse starting from 10°c. That's because the engine is running at inefficient settings to maintain low emissions and warm up as best it can. In this state I can't start-stop or glide and stealth is out of the question. And please don't switch on heater!
If the EBH gets the coolant up to 40°c (104F) after 3 hours as some report, then you get through the stages much faster.

10°c (50F) or lower would be the morning start up coolant temperature of my car for about 4 months of the year. I just imported a Norwegian DEFA EBH from Germany, so somehow I convinced myself that it was worth it. Perhaps the 9 consecutive nights below 0°c (32F) including a few at -6°c (21F) in Canberra played a part.

Disclaimer: Now, I am just learning this myself, so I'm happy to have the logic and maths (math) pulled apart. Suffice to say that the fuel saved is only 1 consideration of many. There's also emissions and wear and tear. And the heater.

 

I have not installed one.

I spoke with the dealership about them. They install EBHs in a very tiny percentage of Prius'.

Last winter we did not see any behavior that indicated to us that an EBH was needed. We normally expect to see low temps in the -15F to -25F range every January; but never anything really cold.

You are likely to see much cooler weather than what we see here. So your need for EBH may be more pronounced.

 

Does using a block heater year 'round, right through the heat of summer, mean I need to be commited, then?

 

I have no idea what you mean. If your vehicle is hard to start in the summer, and is exhibiting the typical behavior of a vehicle that NEEDS a EBH; then commit yourself to using a EBH in the summer. I guess.

I have used EBHs in the past. I have one now for my tractor. Some vehicles need them.

 

It's not a question of needing an EBH because of a difficult-to-start engine.
It is that a Prius can run very much more efficiently if the engine is warm. Or rather, the engine does not need to run, which means it more efficient. And for a PiP that would go double.
I'm still using my EBH as I move into Summer. Night-time temperatures of 5°c (41F) are common in Canberra during early Summer. Warming the engine even a little helps.
The DEFA Technical Handbook (PDF) has several graphs of fuel consumption, emissions and engine wear for various temperatures from -20°c (-4F) on pages 5-7.

BTW, after 3 hours my 300W DEFA EBH heats the block to 45°c (113F). After the engine starts the coolant temperature actually drops to 40°c (104F). But once the coolant has done a lap, it shoots up to 60°c (140F) very quickly. Unlike the Canadian EBH, mine is located between cylinders 1 & 2 (or 3 & 4) so the oil is probably warming too.