Engine Preheater?

Well let's just look at some math.

If we consider a "few" to mean 3 miles, then 3/32 = 0.09375 (the fraction of a gallon your engine uses in those 3 miles).

We can then divide that fraction by 2 because you are getting half of your mileage.

So if fuel is $4.00/gallon....4 x 0.046875 = 0.1875 cents.

The electricity to heat the engine will likely cost more than 19 cents, not to mention trying to recoup the cost of the heater.

I know....math just sucks...

- - - - doesnt gas consumption INCREASE with poorer MPG ?

so not to divide by 2 but multiply ?

I agree that that is confusing so I'll lay out a different calculation, assuming cold MPG 14, warm MPG 30, warmup mileage 10, linear improvement in fuel consumption.

Average MPG over warmup 10 miles = (30+14)/2 = 22. Fuel consumed = 10/22 = 0.45 gall
Average MPG over 10 miles when warm = 30. Fuel consumed = 10/30 = 0.33 gall
Fuel difference = 0.13 gall, costing me 1.35 of your dollars. A typical UK kWh price is about 20 of your cents.
Thanks, by the way, for all the responses so far.

You guy's are in serious need of electric cars.

We can get beer here for $10.00/gallon.

We may be more in need of cheaper beer. An English pint of beer is about £2.90, coming to about $32/US gallon.

I buy 15.5 gallon half kegs for $92.00....less than $6.00 per gallon.

Yes, but I am long past 18 and quality beats quantity.

We pay around €0.40 for 0.5 Liter good beer in the Supermarket....quality beer with around 5% alcohol.....I actually only pay €0.37 in a local shop!!!

1 US Gallon of Beer = 3.78541178 Liters = €3.03 = US$4.12.

Pretty cheap in comparison to the UK for example......they pay more for a two Pints in a pub for example....not a good comparison, but I have no idea what Beer costs in Tesco or Asda...

I agree math sucks, but I'm in the UK, where the petrol costs the equivalent of over $10 (admittedly we also have bigger gallons). However, the increased fuel consumption in the early stages is also a marker for increased engine wear, so there are other costs than purely the fuel.

The cost of energy is far more expensive in automobiles than most companies selling you electricity. 1 KW-hr is less than 20 cents in many places, which is far less than the cost of running a 1.3 HP load for an hour powered by an automobiles ICE.

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Adding an electric oil heater would be minimal costs in parts and very little electricity, and might be a worthwhile endeavor.

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It is important to realize that a good portion of the fuel economy gains you notice are not due solely to the engine warming up. There are a number of other possibilities.

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Tires offer reduced rolling resistance once warmed-up.

Warming up the transmission may also yield increased efficiency.

Roads and traffic patterns for short trips or at the beginning of more lengthy trips may be more demanding and degrade efficiency.

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How are you gauging the MPG?

How are you gauging the MPG?

That's another story. The on-board computer calculates MPG from the fuel consumed during the previous N miles, where N is a number I have yet to determine. This leads to the interesting feature that the calculated range more than doubles when the engine has reached full temperature.

It sounds like it will be difficult to distinguish between actual increases in fuel economy versus increases in just calculated/displayed fuel economy relying on that indication alone.

I have to say at this point that Mercedes seem to have a very primitive algorithm for the range calculations. It should be fairly obvious that the fuel consumption is poor in the first 10+ miles, but that it is better thereafter. The range calculation does not make that assumption, but assumes that the fuel consumption of the previous N miles will continue until the tank is drained.

"....The range calculation does not make that assumption, but assumes that the fuel consumption of the previous N miles will continue until the tank is drained....."

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Is this something you know, or that you assume?

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I suspect the range calculation takes more into effect than simply the most recent fuel consumption over N most recent miles. Otherwise, right after you strt it cold, the range would not be around 1/2 what it is when fully warmed up.

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If the consumption over the previous N miles were the only, or even dominant effect in the calculation, when the car was started cold, it would initially indicate normal, warm temperature range, since no higher consumption has taken place. The range would then decrease steadily as more inefficient consumption gets averaged in. Then when the engine beings to warm up, the range would begin to rise from its lows.

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That doesn't fit the descriptions you have provided thus far.

But your thoughts do fit my Mitsubishi quite well....

The only problem with my car is that it resets the meter once every day (once in 24 hours, usually at night unless driving), I would like to be able to select when myself, but not possible!!!

So there are always differences between real usage/mileage and what the meter says.....

Thankfully usually it uses less Diesel than the car meter thinks it has....up to 20% less...

To me, the meter is totally useless.....I almost never look at it nowadays....

If the consumption over the previous N miles were the only, or even dominant effect in the calculation, when the car was started cold, it would initially indicate normal, warm temperature range, since no higher consumption has taken place.

On the contrary, the indicated range is low during the first cold N miles, and steadily improves as the N includes warmed up miles. Unfortunately the display does not include instantaneous fuel consumption, which my bike does.

"....On the contrary, the indicated range is low during the first cold N miles, and steadily improves as the N includes warmed up miles. Unfortunately the display does not include instantaneous fuel consumption..."

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Do you see that these two statements and the idea that the MPG displayed is a simple function of fuel consumption over the previous N miles are incompatible?

If the MPG displayed were just a simple function of consumption over a set number of previous miles, it would not be lower when you initially started the car than immediately prior to shutting the car off.

I'l try and express it another way. At the start (engine cold) the indicated MPG is low and the indicated range is low. As the engine warms up, the indicated MPG increases and the indicated range increases. That is entirely consistent with the postulated primitive algorithm.

"...That is entirely consistent with the postulated primitive algorithm...."

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Nope. If the primitive algorithm to display MPG is, for example 'gallons consumed over the last three miles divided by three', then there should be very little change from shutting the car off to the next cold start, because the fuel consumed over the previous three miles would be pretty close to the same.

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You have indicated that when you start the car the mileage and range are lower than when the car is warmed up. Presumably the car is typically warmed up when you shut it off. If the range and MPG differ markedly between just before shutting the car off and the following presumably cold start, the algorithm is more complex than 'consumption over x miles divided by x'.

I take your point. The algorithm is at least clever enough to forget the previous journey, if the previous journey is far enough in the past. Overnight is enough.

Not sure what thread size would be required, but most preheaters heat the oil and the element screws into the drain plug, I think.....kind of a hassle to plug in and out though I would think...

http://www.ebay.com/itm/MOROSO-23980-ENGINE-OIL-PRE-HEATER-ALUM-FITTING-/390806086868?pt=Motors_Car_Truck_Parts_Accessories&hash=item5afddba4d4&vxp=mtr

How about just wrapping it in an electric blanket....I've heard that done before, but no firsthand knowledge....

http://www.northerntool.com/shop/tools/category_auto-suv-truck-accessories+engine-heaters-blankets

The one I had on my Thunderbird years ago went in the lower radiator hose. Made it much nicer on freezing mornings since the coolant was warm when you started out so the heater and defroster would work. -- JHF

In the us there are several types of heaters for this---dip stick heater, block heater,and water heater

Try a dip stick heater. They are not expensive. If it doesn't work good, throw it out and try something else but it will be more expense to play around with. If the dip stick heater works use it. If it helps but not enough get something else with more heat generation capacity such as a block heater or coolant heater. At least you know that this more expensive unit is going to work for what you want it to do.

Good Luck, Old Salt

I would be very hesitant about installing any heater element in direct contact with the engine oil as doing so presents a high risk of burning the oil and causing severe engine damage.

Most engine heaters are designed to be installed in the engine coolant system and the better quality devices have temperature control and a circulation pump.

I have one on my truck that is 10 years old and it still functions very well.

Any dealership or third party auto parts sales can provide an engine block or in-line coolant heater system for a reasonable price.

Very good observation. I don't advocate using them as a long time cure but only as a short time "Band-Aid". I personally haven't used them in many years but it worked on extremely cold nights sufficiently. The one I used had an overtemp cut-out on it to stop any heater over-runs. It also barely fit into the dip-stick tube because of all the safeties plus the heater. It was stolen off the truck, the only thing they took. They left the electronics!

At this time all my gasoline vehicles don't need them. All the diesel trucks and SUV's that I drive are in a heated multi-bay garage. Several others have the dip stick type and like them.

Good Luck, Old Salt

There is big difference between just warming the engine and getting it up to operational temperature where the electronics will give you optimal fuel mileage. There can be pre-heaters on the O2 sensors which are in the exhaust system that would not be much effected by warming the engine. There are are also temperature sensors that have input to the computer that until the operational temperature is reach will not optimize fuel mileage. So there would still be a delay until the engine reaches operational temperature. Would warming the engine shorten this time I'm sure it would. But by how much to make it cost effective is the question.

Carpooling could cut your fuel costs in half.

Plus you arrive at your destination refreshed....

Plus, surfing in stop and go traffic.

Doesn't like a very safe thing to do ???

http://www.dailymail.co.uk/news/article-2627194/Father-coma-car-surfing-stunt-balanced-roof-van-driven-went-wrong.html

or how about this Einstein?

http://www.bizjournals.com/phoenix/stories/2004/12/06/daily43.html

There's a downside to everything...

http://www.thedieselstop.com/forums/f24/engine-fire-block-heater-292410/

Good answer. I like the first hand knowledge.

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When you mention cooling a hot car in the summer, are you referring to ventilating a car that has been sitting in the sun, or is there some refrigeration process involved?

Good question, sorry I didn't make it clearer. It only runs the cars ventilators and blows outside air through the passenger compartment. No A/C is running.

Its still better than nothing on a hot day and 50-60°C in the car!!! But I still left a white towel on my black leather car seat!!! And a front widow cover....

I have an excellent engine coolant heater unit on my truck that has been in service for over 10 years and is still functioning well.

Any dealership or third party auto parts store can provide what you are looking for.

I would avoid any heating device that makes direct contact with the oil unless it has a reliable surface temperature control that will prevent the oil from being burned.

The lower gas mileage you are experiencing is normal as all OBD I and OBD II system control vehicles operate in a "rich" fuel mixture mode until the engine reaches optimum operating temperature.

This is required with all internal combustion engines to operatate at colder temperatures without experiencing stalling.

The displayed gas mileage is a calculated resultant based on fuel injector pulse width, quantity of fuel pulses, engine RPM, and vehicle speed.

Mercedes diesels typically have electrically driven block heaters available, my 300SD came with one. You may be able to buy one from peachparts.com. They also run a mercedes forum where a lot of knowledgeable users post, formerly me.

With diesel running $4 a gallon due to the low sulfur requirements, and coal fired electricity going for $.19 in my area, preheating may save you money. It sure puts less unburned hydrocarbons out the tailpipe, unless you have a cat converter.