I'm thinking I need a WAI on the Escape. 2 days ago, I filled the tank and drove home (~40 miles) and when I got home the trip average was 43 MPG as reported by the Scangauge. Ambient air temp was 60F. Last night, I drove the same route, with the cruise set at the same speed, (45 MPH) and the Scangauge reported 29 MPG for the trip. The only thing different was the ambient air temp was 29F. Could a 30 degree drop in temperature really equate to a 10+ MPG drop in economy? If so I see fantastic gains available with a WAI.
Has anyone here tried a WAI with a hybrid? What were the results?
Along with a grill block, removing the snorkel connecting the air box to outside air was a common practice on the gen2 Prius. The gains seen were mostly from shortening the warm up stage used to get the cat and engine up to temp. Block heaters were also used, even outside of winter.
Most of the drop you saw might have been do to the battery though. In the cold its performance can really drop with supplying power and charge capacity. Which leads to more use of the ICE. A WAI may help out, but if you are in the he habit of toughening out the cold, try using the cabin heat to keep the battery happier. Some also talked of using a 12 volt electric blanket to heat the battery on the Prius.
I don't think that makes a difference when you're steady state driving at 45 MPH with the cruise on. The FEH won't go electric over 40 MPH. If you're driving low speed and going in/out of electric, then it would make a difference, as there will be times the engine will start to keep warm, rather then to charge the battery.
Well, I removed the snorkel, and to do that I had to remove the battery tray. I noticed that the "eye" on the battery was red. Took it into the local auto parts store, and although it didn't test bad, it did test weak. I decided to just replace the battery as well. I should definitely see some sort of mileage gain with the snorkel removed, and a new 12V battery. Now my intake air temps are 10-30 degrees over ambient in the short run I made after replacing the battery.
You could pick up one of those battery operated wireless thermometers to monitor the temp inside the battery compartment. Then you'd know for sure what temp the battery was and wether it was having a significant effect on MPG. I bet it does have a big effect.
Most of the automakers swapped to LiFeP04 batteries in 2010. Since yours is 2008, I think it's safe to assume you have a NiMh battery pack. NiMh's are way more effected by cold temps than Lithium's.... that's one major reason for the swap.
I'd buy a 120v house current heated blanket and wrap the battery box. (pull it in summer) Run the cord up to the front of the car, tie that in with a small circulating "tank type" block heater. Then your ICE would be warm as well as your battery pack whenever you needed it.
Well, the computer system has a temp sensor in the battery pack, and I can program an xgauge to display that. I would love to be able to use a block heater, but since its usually parked on the street, and we don't have any exterior outlets either, a block heater or electric blanket are both out of the question.
Some electric cars have built in battery heaters that uses the current from the batteries to heat themselves. This can actually increase the usable charge in the batteries. I think this is less of a practical issue in hybrids since you always have the combustion engine as a power source. But it is an efficiency issue no doubt because the batteries becomes virtually unusable at very low temperatures.