Consider yourself lucky with 45mpg. Here in Chicago in the past week when we had subzero temps I only got 36mpg for the tank, the lowest ever.

I think much of this mpg hit was due to me warming up the engine before driving (takes ~7 minutes) as well as the heat being on full blast, but probably not the entire mpg hit as I think these lower temps affect the battery too. Afterall the nickel in there isn't going to warm up instantly.

For the life of the car I've only gotten 41mpg and this consists of mostly flat driving. Being stuck in stop & go traffic definitely takes a toll on mpg too I've found.

 

The NiMH battery temperature is not the main determinant of your fuel economy performance in cold weather. In fact, it plays a very small role unless you live MUCH further north...

The critical FE determinants are the engine coolant temperature, Air intake temperature and Outside air temperature. That is it !

Idling the car for warm-up only is a sure way of sinking your fuel economy and polluting more... in addition to shortening the life of the engine and your emission control system among several other losses. Anyway, Too big a list to mention here.

Operating the climate control at full blast for the first 10 minutes is yet another way of preventing the engine from arriving to its optimal zone sooner.
Instead, it is best that you set the cabin temperature more conservatively for the first 5 minutes and then gradually raise it as the FE performance improves. The opposite is also advisable in the hot summer months.

A couple other things we can do is to block the front intake grille and install a block heater. The later is often well worth it for folks in your area.

Cheers;

MSantos

 

Could you explain why idling the car for warm up would shorten the life of the engine and emission control system? The primary reason I let it idle and warm up is to extend the life of the engine. Is this logic erroneous?

I thought it was best to treat a car with a very cold engine with as low rpms as possible until it gets warmed up (to at least 2 bars in my example). Is this counterintuitive and why?

I am not as concerned about pollution I really want the car to last as long as possible.

 

Sure. This is perhaps one of the saddest myths out there, mostly because so many people do it under the assumption that warm-up idling is good for the car. Here's one quote from the Government of Canada web site:

"

• First, since an idling engine is not operating at its peak temperature, fuel combustion is incomplete.
• As a result, fuel residues can condense on cylinder walls, contaminate oil and damage engine components. For example, these residues tend to deposit on spark plugs. With more engine idling there is a drop in the average plug temperature and accelerated plug fouling. This can increase fuel consumption by 4 to 5 percent.
• Excessive idling can cause water to condense in the vehicle's exhaust. This can lead to corrosion and reduce the life of the exhaust system.

There's another good reason for motorists to drive away soon after starting a vehicle. The engine is only one component of a vehicle. Other parts, such as the wheel bearings, steering, suspension, transmission and tires, also need to be warmed up, and the only way to do that is to get the vehicle moving."


Here's the link to this and a lot more information describing why idling is not only bad, it is VERY bad and without any benefits whatsoever. (Please follow the links on the page):

http://oee.nrcan.gc.ca/transportatio...ing.cfm?attr=8

But to be even more specific: On the HCH-II, idling can cause an early failure of the VERY expensive 3-way catalytic converter, the expensive O2 sensor and can cause an excessive amount of impurities in the fuel system to deposit in the injectors, combustion chamber, valves, seals, sensors and so on ...

Not nice. Not nice at all.


Cheers;

MSantos

 

I find that it happens when I try going into either Pulse & Glide mode or all EV mode. The km/l (MPG) gauge may swing all the way down to zero and climb back. I believe the car is taking lots of parameters into computing the km/l. As such, I think when it swing to zero, it is resetting (recalibrating) the system.

 

ChicagoHCHII,
MSantos is right (as usual, as you'll soon discover!). BTW, welcome!

Idling for warm-up does no good.
If you feel you must, only let it idle for 5-10 seconds - after a COLD START only.
Take it easy on the acceleration for the first few minutes of driving (as the car IS warming up), and you will have done your engine MUCH more good than idling until it's warmed up. Not to mention your MPG and the environment.

If you can resist the urge to blast the heater before it's really ready to put out much heat, the car WILL warm up faster. Then you can get yourself toastier, quicker. This also is better for the car and MPG and the environment.

Bottom line is that getting the car up to normal operating temperature as quickly as possible is the best thing for your car, your MPG and the environment. And the best way to do that is to DRIVE it, and limit the heat-loss (by limiting your heater usage) for the first couple minutes.