Sealing up the nose to retain engine heat

[Recumpence]

Hello All,

 

I have been doing alot of FE reading and one thing that the guys at Ecomodder continue mentioning is that gas engines are more fuel efficient when run at their upper temperature. They go to great lengths to make sure their engines run nice and hot in the winter. Well, with our hybrids, we suffer from the fact that our engines do not run much of the time. Consequently, the temp drops quickly once the engine cycles off. This has been discussed in relation to grille covers. However, I found that, though my grilles are blocked (upper and center grilles are completely blocked and the lower has just a small opening in it), I still was seeing engine heat shedding rapidly when running in EV mode. So, I picked up some weather stripping and sealed up the border of my hood, around my headlights, and various little nooks and cranys I found.

 

What a difference! It turns out, the gap round the edge of the hood allows cold in and heat out. So, does the gap around the headlight lenses. Once I sealed those up, I found my engine stayed hot all the time. In fact, letting the car sit does not drop engine heat nearly as much as before.

 

This has, not only helped my heater, but it is good for FE. One side benefit is, my intake temperature went from 3 degrees over ambient, to 40 degrees over ambient! This increase in intake temperature is supposedly helpful for better MPG (when the engine is running). This may be a very small FE increase. But, hey if my heater works better, warmup time is faster and I get a tiny bump in MPG, it is a win-win.  :)

 

Matt

[CMax-Traveler]

Very interesting... I was wondering about doing something like that myself since I noticed engine heat bleeding off so quickly.

 

Only question: Is there any concern with having the engine compartment sealed off like this during the hotter/summer months?

[drdiesel1]

What are the ECT's and is the coolant fan coming on ?

[C-MaxSea]

Matt, I certainly agree that keeping the engine warm / hotter in winter is going to make a large difference.  Combined with all your aero mods, and you are really maxing your C-Max out, to be sure.  isn't this what Frank was doing, more or less, sealing off the hood gaps for aero & heat loss?  Nick

 

PS  I ran into the same limit when I lowered my hood, could only go down a scosh before needing to lower the latch mechanism, so I bailed. 

Edited November 26, 2013 by C-MaxSea

[Recumpence]

Lowering the latch is easy with a Dremel. You just need to oval out the 4 holes. It literally takes 20 minutes, tops.

 

At this point, I am looking at a Kammback, and lower air dam (extended chin spoiler). Honestly, I have assumed my MPG was up around 7mpg. However, I have been doing a bit more testing and it looks like I have gained around 5mpg tops. That is nothing to complain about. But, I have to tell you, it is not easy increasing mpg. I bet sealing off the hood and lowering it with the slight aero increase and temp increase in the engine compartment is only good for 1/10 mpg. That is so hard to measure that it is purely conjecture. But, it is universally agreed by all the engineers and tinkerers at Ecomodder that everything I have done will net a gain. The quesiton is, how much?

 

The engine runs at 175 to 180 degrees right now pretty much all the time. The fan does not kick on at all. I can still do a couple things to seal up the engine compartment further such as the lower vents in the belly pan. But, I think this is good enough at least for now.

 

I am hoping to gain 1mpg more with the air dam and kammback (1mpg with the two combined). At that point, I would need to go to some pretty extreme measures to gain any more efficiency without making it look hideous.

 

Matt

Edited November 26, 2013 by Recumpence