Warming Up: P&G? PEOG? Steady Throttle?

[aalb1]

So pulling out of the driveway on these cold mornings got me thinking...

"What driving style is best for FE in the cold? P&G? P&EOG (Pulse & Engine-Off Glide)? Steady Throttle?"

I drive a Honda Civic and it seems that it takes longer to get to Operating Temperature than other cars. My Wife's Jeep and friend's Lexus takes much quicker to get to operating temp.

So while running rich on these cold mornings is P&EOG still the most effective hypermiling technique? Or is it better to get to operating temps quicker with P&G or steady throttle?

[dkjones96]

There are a few reasons for reduced fuel economy when the engine is cold. One of them is that the engine parts have contracted as they've cooled and you end up with increased blow-by and relatively loose clearances.

Because of this, I would personally recommend steady state. Most of the time I don't force the engine to pull further than the torque peak as long as the temp gauge is still buried in the cold.

[theholycow]

Nice job on the term PEOG. I haven't seen it before, but it's every bit as good as my idea of calling it P&EOC. No matter what, it's good to differentiate between engine-on P&G and engine-off P&G.

I think the lower temperature doesn't change what is the most fuel-efficient strategy, but it does bring other concerns such as warm-up, increased clearance as mentioned above, etc. Looking at FE only, whatever was best before is probably still going to be best.

My VW takes forever to warm up no matter what, although I suppose I could flog the hell out of it and warm it up faster. With reasonable driving, whether hypermiling or driving like everyone else, full grille block or none, it won't warm up until I get on the highway 7 miles (15 minutes) down the road...usually a mile on the highway before heat is useful.

[almightybmw]

It's -15. I let it idle 7-10 minutes, otherwise my breath frosts the window over faster than it takes to warm up enough to keep clear. I need more blockage, as even when its warm its only 175, far too cold right now. I usually drive a steady rate, keeping it around 2000rpms. I also use a large vinyl fabric--soft on one side, vinyl on the other--to keep external frost off the windshield. A nice by product is all the heat that flows out of the hood vents is it stays on the window, decreasing warm-up times slightly, and allows me to drive sooner since the window is clear.

[GasSavers_BIBI]

The 7-10 minutes of idling must be great on gas...

If you get a 30 dollar block heater, and plug it 2 hours before you use your car, u will be able to start driving it right of the bat. Get a timer if its morning use, but idling is the less FE thing u can do, also its not ecological at all.

[palemelanesian]

P&EOC or whatever you call it is the best strategy for fuel usage. If you want heat, it's the worst strategy. Take your pick - low fuel or warm engine. Any driving style that warms it up faster also burns more fuel, and it will NOT be recovered by better mileage later. I've tested this.

[GasSavers_RoadWarrior]

I'd take a look at the thermostat if it's taking that long to get warmish, possibly stuck open, or not fully closing.

I found 0W30 oil helps a lot in winter, I have only 4 blocks to drive before hitting the highway on ramp. With regular oil in cold weather, the car is still very sluggish and it feels "bad for it" in accelerating up to highway speed before the oil is fully warm and it's in closed loop. With 0W30, it feels good within 30 seconds or 1 block.

[aalb1]

Originally Posted by RoadWarrior

I'd take a look at the thermostat if it's taking that long to get warmish, possibly stuck open, or not fully closing.

Who are you talking to here? Honda's take notoriously long to warm up. But my friend's lexus takes about 1.5 minutes. I'm simply amazed at the difference.

[aalb1]

Originally Posted by PaleMelanesian

P&EOC or whatever you call it is the best strategy for fuel usage. If you want heat, it's the worst strategy. Take your pick - low fuel or warm engine. Any driving style that warms it up faster also burns more fuel, and it will NOT be recovered by better mileage later. I've tested this.

Sounds like thinsulate it is!!!

[theholycow]

Originally Posted by BIBI

If you get a 30 dollar block heater

I had no idea they were so cheap. I'll be looking for one now...