improving cold start FE [throwing around ideas]
 

There are a lot of great ideas on the site that deal with aerodynamics, driving techniques, modifications, and other FE-related things. The one thing that I haven't seen much interest in (perhaps I just missed it though) is overcoming the low FE that is inevitable after first starting your car.

Diesels have long employed engine warming blocks to help get heat ciruculating in the car faster, and to improve cold winter starts. This of course helps the engine avoid some damage that it would have incurred if it had been started without any assistance from a heat-producing device.

Are there any other things that we should be looking at which might help even out the FE you get while driving your car?

The fact is, long trips yield better MILEAGE than short ones (think 100 miles compared to 5 miles), but you end up using WAY MORE FUEL on the long trip. Let's say you get 10mpg and drive 5 miles. You end up using half of a gallon of fuel. Now let's say that you get 50mpg. You drive 100 miles. You end up using 2 gallons of gas.

While this may not be a great example, it is only for demonstrative purposes. If we could improve the 10mpg cars economy even by a little, there would be marked fuel savings.

I believe that if we were able to get that 10mpg car up to optimal operation conditions right off the bat, that the FE of said car would be much better.

So the question is... what do we need to change to make this happen?

For a diesel, it ends up being a block warmer. Some people swear by low weight synthetic oils. We need to think outside the box though, and come up with entirely new ways of approaching this FE robbing part of our journey.

Any ideas??

Engine block heaters are not just for diesels. I had one on the Maxima and it made a hugh difference, around 10% if i remember. You're right the shorter the trip the bigger gain you'll see with the EBH( do a search for EBH). I've tried warming the engine oil on the stove to 200 degrees and then reinstalling with some sucess but it is a bit of a hassel. You're on the right track there is about 3 MPG on my 25 mile commute between cold and warm engine temps.

Engine heaters and insulation.
 

I copied this from a Challenge FE report I made in April. I have been using this procedure ever since. I am in closed loop in about 1/4 mile, used to take 3-4 miles. Get your car headed the direction you want to go the nite before.
No engine warmup....get moving as soon as possible.

April 1, 2007 9:37 PM MDT

Winter is not over yet here in Colorado. It has been snowy and 15-20 degrees at night for the past week. I have not driven the car at all this week till yesterday.

Scanguage readings for week March 26 thru Apr 1, 2007: Trip to neighbor's garage 6.2 miles 122 mpg. One way because car is still there. Saturday morning temp 16 degrees. Our places are close to equal elevations but there is a 200 ft. gradual drop and a 200 ft. steeper rise between us. The balance of the distance is fairly level. The best previous mpg I remember seeing at this distance is 82 mpg(summer). So the belt and component deletions with the added cold-start-warm-up techniques are responsible for considerable gain for this stretch.

I have taken the time to make room in the garage for Old Reliable. I have been working on making my cold starts and the first part of my trips more mpg productive. The past few days I installed a block heater I have had for months and installed a heater in the water hoses. Also put on an oil pan heater, this may end up on transmission later. All were on for about 8 hrs overnight Friday. Also put R-30 insulation batts between engine and hood overnight to help hold the heat. Used R-30 batts all around the bottom of the car from the garage floor up around the body. Made sure my battery was fully charged as alternator is still off car.

Check out www.summitracing.com I believe they sell oil warming pads. It basically sticks to the bottom of your oil pan and plugs into the wall to pre warm the oil.

Is this actually cost effective?

lol @ warming the oil on the stove

Ebh
 

I second the motion on the Block Heater. I've been using one for about a year now, and it helps tremendously, even while garaged (if I can only figure out how to heat up the car as it's parked away from home for extended periods :rolleyes: )

The Automatic Transmission is my biggest problem with cold starts (and, well, I guess overall). I'd like to heat up the fluid somehow -- perhaps that stick-on heater would work on the transaxle as well -- or a dipstick-style heater?

They say it's more efficient to use the power grid than your own engine to heat itself up. I'm sure there's a cutoff point, but it have to draw quite a bit of juice to do so...

RH77

Block heaters are good - especially a 2.7kw one like mine. When it is working! Because it heats the engine up in 15-20 minutes, it means that you don't 'vent' heat to atmosphere all night as you would with a 300 watt one.

If you get a wideband lambda sensor, you may find a certain throttle position that puts the mixture to 14.0:1 even when cold - my car does this, and it is better than flooring it (10.0:1), or driving along very gently (10.0:1 ratio). Driving with the right load can help the economy a lot by avoiding wastage of fuel.

Rick, I am using the oil pan heater on my transaxle now. Works good.

I would not recommend a dipstick heater at all. They just do not have the heating capacity to do much.

I have a block heater in my Prius and it works great. I can reach 150*F(min temp for stage 4) in ~1/8 mile. When I come to the stop sign about 3/4 mile from my house, all I have to do is come to a complete stop and let the engine stop on it's own to to reach stage 4 which means that all of the hybrid functions are in operation.

which oil pan heater are u using?? i was looking into on this past winter but seeing as most of my trips are shorts one it might be good for year round. might even get 2 1 for oil pan and one for tranny pan??

If you don't have a garage you can't use the electric heater. Would anyone attempt a small homemade kerosene lamp under the oil pan?

would there be any gains from a reflective inner hood surface or another kind of insulation? recently while checking out in house energy saving tips i came around the sugestion of placing reflective shields behind heating radiators. perhaps simply painting the inner surface white or silver might make a small differense?

my car sleeps outside to my winter FE is considerably lower

landspeed wrote:"If you get a wideband lambda sensor, you may find a certain throttle position that puts the mixture to 14.0:1 even when cold - my car does this, and it is better than flooring it (10.0:1), or driving along very gently (10.0:1 ratio). Driving with the right load can help the economy a lot by avoiding wastage of fuel."

I've noticed the same thing. I've also read in the ecu disassembly for my car that cold enrichment is reduced as airflow levels increase. I imagine this is a characteristic of the needs of a cold engine, and similar to other modern computer controlled fuel injected engines. I tried leaning out the cold enrichment settings, but the motor doesn't run as well at light throttle. So I've adjusted my driving style to suit. When I'm driving with a cold engine I'll accellerate briskly in the stoich range in between light throttle/cold enrichment and heavy throttle/accelleration enrichment. I get up to speed quickly, then shut the motor off and coast. This way I avoid high idle speeds at rich settings, which wastes more gas than if the engine was warmed up.

Since I park on the street, I try to find a spot on the side of the street that gets sunshine earliest. Coincidentally that side of the street lets the engine face the sun, too. It might add an extra 5 or 10 degrees at most.

I live in a rural area, so security is not much of an issue. When my block heater was broken, on a sunny morning, I would open the bonnet, and let the sun shine on the engine! It made the engine go from 'stone cold' to the touch, to 'luke warm' to the touch, and I'm sure it help economy too.

Just dont do what I did - let a tiny bit of water get into the electronics of your block heater. I just managed to blow a hole through 3mm of Aluminium plating (part of the block heater container) in a split second - impressive!. I have now dried it off completely, and checked it, and it still seems to work. I don't trust it as much now though :(.

For those without a rad block, a rad block (especially at the top of the radiator air vents) will make a difference - as a lot of hot air will convect from here when parked (or when using a block heater etc), and if you reduce the convection air flow (drawing in cold air underneath the engine, and letting hot air out through the top), the engine will cool more slowly.

I'm now going to see if it works for longer (fire extinguisher at the ready) :O

People did use to have oil pan heaters, and it should make a difference! I guess the important things are to ensure the flame itself is shielded, so only hot air goes towards the oil pan, also ensuring that it isn't giving off too much heat to boil / char the oil in the oil pan, and parking your car away from other cars, buildings, just in case the worst happens (and having a fire extinguisher to hand).

I suppose you would have to check carefully for minor fuel leaks from the engine bay fuel lines too - or these could cause a disaster!

I think I am going to take landspeed's advice. I can't keep my hood open in my neighborhood, but when I am school that should work great. I park with the sun coming in through the windshield, which heats up the car interior.

So, by propping open my hood, it will both a) heat up my engine with passive solar heat and b) keep my cabin from getting too hot while the car sits in the sun.

Hope to see some improvements, but I have no SG II (can't be used in a Japanese domestic car) so I can only rely on fill-up to fill-up. Pretty much all stations in Japan are full-serve too, so I can't control how much fuel I get at fill-up time either. Man.. there is no way I can gauge whether I get any benefits out of this method. Oh well...

Get a SuperMID :) Look at my gaslog - there was a gradual increase, the next 'jump' (quite major) was the competition, and the next 'jump' after that was the SuperMID! With SuperMID, I am getting 20% better economy straight away! Should be easy to get, as you are in Japan, and it has loads of info (and, actually, seems to be more accurate than the ScanGauge, which seems to have some inaccuracy, I think when it in fuel cut mode or something?)

By the way, I only prop up the hood, outside my house, which is down a 3/4 mile dirt road - don't leave it unattended for more than a few minutes - you don't want anyone messing it up!.

Edit - I see that it is your company's car, so maybe you can't fit a SuperMID. Are you sure the car doesn't have an OBD-II gauge somewhere?

I've always been a little concerned about the additional energy costs of heaters and I don't know how many are left plugged in all night and how many are on timers so they don't waste more energy than necessary.

Having said that, I have heard that some hybrids pump coolant into a large "thermos" (like 3 gallons) when the engine shuts down. I imagine a fitting could be made to a well insulated bottle sitting in the garage (or trunk) that stores hot fluids when appropriate (might be worth doing the gallon of oil in the engine block and the tranny too).

The block heater in my Prius is 400W. I have it on a timer that is set to come on ~4 hours before I'm going to go anywhere. At ~$.10/KWH that would be ~$.16 and the gas saved is significantly more than the cost of running the EBH.

As for the "thermos," it is only 3 quarts instead of 3 gallons and it only keeps it "warm." In fact, when I start out in the morning after unplugging the EBH(when I don't forget to un-plug it:o -another story), the coolant temp will actually decrease(from ~140F down to ~125F or lower) slightly for a few seconds when the "thermos" empties into the system. I end up being up to the temperature at which I have full use of the hybrid features(~155-160F) within 1/4 mile of my house and usually to the full 190F within 1/2 mile. Without the EBH it took nearly 1 mile longer to reach the above mentioned levels.

Love that EBH
 

That's why I implement the same. For the average workday, I have it set on a cheapo timer from the hardware store, to begin heating about 3 hours before departure. For me, cold-start emissions and fuel consumption on a 10 year-old vehicle is significant -- much less is emitted, more $ and fuel is saved by using the power grid to warm the car.

Simple timing tests with the SG show a significantly quicker time to Closed-Loop operation -- so you know it works.

Yeah, same here -- it just pulls loose, but now it's in the path of parking later-on -- can't roll in under zero-power, have to stop, etc.

For me, it's remembering to plug it in after driving in 90-degree weather, for the next morning...

Which is another point -- even if it's warm outside, block-heating still helps get that coolant temp up to the most efficient temperature range (190-210F in my case). It's still a 100-degree difference, which takes energy (fuel or grid), to get to.

RH77

I've done forgotten to unplug 3 times now.:o The first time, it destroyed the timer, severely cracked the plastic in the wall outlet, and mangled the prongs on the extension cord which took several minutes with needle-nose plyers to straighten out. The second time, it pulled all but the ground plug of the cord out of the timer before the EBH cord came unplugged. The 3rd, and last time,:crosses fingers: I was turning so the right front tire ran over the extension cord and unplugged the EBH rather quickly. I have developed a new strategy to help prevent this: After I plug in the EBH, I take the extension cord and lay a loop over the hood and lay it so that it rests against the windshield wiper. The extension cord is bright yellow so it should be very noticeable if I forget again.:rolleyes:

I've been thinking about doing that type of testing. I need to find a setting that will allow me to reach operating temp in the same distance as I do now. Most EBH's are a higher wattage than mine(400W) so I may end up having to leave mine on a bit longer than most people do. I'll start trying that tomorrow morning. I'll back it off to 3 hours before I leave and see what happens.

landspeed: I am only going to be in Japan for another half year, and it is (as you noticed) my company's car. I actually don't pay a cent (or yen rather) for my fuel costs. In fact, I don't pay for anything on my car. 100% cost reimbursement. So, buying something like the Supermid would be a waste of money, especially since I could only use it for another half year or so. I spoke with Mitsubishi of Japan, and they confirmed that there is no OBDII port on the car.

As for the sun-warming technique, I wouldn't dare keep it open in front of my house, but the school that I teach at is very safe. We are on the top of a mountain and there are a total of like 100 people at the school. I know everyone's face and name. No one would ever mess with my car.

diamondlarry: I will be sure to use your wiper trick when I install the engine block heater on my tdi back in the states.