Two MPG Questions:

The answer to your first question is one I would like to know as well. When we bought our new Prius I couldn't help but wonder how much better numbers the technology could produce if utilized in a Yaris. While I love the space of the Prius, one Prius and one much smaller (read "maybe even a two-seater") car would work. Curious to see what some of the HSD geniuses on here have to say.

 

Answer to second question: ymWv
Expect to consume 0.2 - 0.4 kwh/mile pure electric;
35 - 70 mpg pure petrol.

So e.g, if you go out for a 100 mile drive and start with say 4 kWh of useable battery,
then somewhere between 10 and 20 miles will be electric, and the remainder petrol. It doesn't matter a bit if the electric is used up as pure EV, or blended into the petrol use.

 

A hybrid Yaris would weigh about 2500 lbs. So about 500 lbs less than a Prius. It should get better mileage than a Prius, though I wouldn't expect it to be a lot better. Perhaps 50-52 overall. It doesn't have the low Cd number of the Prius.

The "new" Fit looks very aerodynamic (they don't spec a Cd for it). It would also be in the 2500 lb range as a hybrid. It would use the IMA system, so wouldn't be -quite- as efficient as HSD, but would be close. I'd guess 49-51 MPG overall.

The question is would anybody actually buy one? Remember, the hybrid components would add about $2500 to the price. Small cars are very price sensitive.

It might be possible to market one "loaded up" as a "pocket rocket". It would certainly have more oompf in hybrid form! In the city, of course. Top speed wouldn't be really high as it's limited by raw HP.

I don't think you'll see one unless they think they can sell a lot of them. It's marketing.

 

Why is this in the hybrid news forum?

 

Que ? It's in the Main forum, or was when I looked at it.

 

If you shave off ~500 lbs and reduce the effective seating capacity, then it would makes sense to also reduce the displacement slightly. That would yield some additional mpg. In doing such a retrofit I would also anticipate some cleaning up of the aerodynamics of the Yaris or Fit.

 

According to Batteries: Power, Energy and Units - X Prize Cars
The energy equivalent for gasoline is 38 KWH.

Trying to tie down the cost of a KWH is the next problem. Picking Alaska as a prime example of a problem area for power generation they have a rate of 18 cents per KWH plus a surcharge of 33 cents a KWH for a cost of $.51 per KWH we get a cost equivalent of .51 times 38 of $19.38 per gallon of gas equivalent. Using gas to generate electricity with your Prius becomes attractive and a PHEV becomes ridiculously expensive.

AEL&P predicts large drop in rates next month - Juneau Empire

At the non surcharge rate of $.18 per KWH a gallon of gas from electricity costs
.18 x 38 = $6.84. Obviously conversion efficiencies will leave all of these calculations as extreme examples. IF the gas conversion efficiency is one third or less then we are at a break even for gas and electric.

Question: Who if anyone has done the math to figure out if a PHEV is cost effective?

Edit: Is a PHEV cost effective per mile traveled as compared to a gas ICE hybrid car? No initial expenses are to be considered in this question. IF gasoline stays at a price of $3.00 or less it would seem to me that the cost of electricity alone is more than the cost of gasoline. On the other hand as energy prices go up then the cost of electricity will go up at roughly the same rate and the PHEV will be a dead issue.

http://portfolio.epri.com/ProgramTab.aspx?sId=PDU&rId=117&pId=4087&pjId=4102

 

From 2000-2006 there was an opportunity to buy a smaller hybrid good for 75mpg-120mpg. Low sales & high production costs meant the end of the line.

"#2) How will MPG be measured for PHEV? What I have seen so far tends to assume electricity is free.
Need a standardized measure that is easily understood and applies to the real world."

Yeah right. There is much grousing over the EPA's ratings now. IMO there is no way they will be able to devise a test that satisfies everyone.

 

The Prius is more aerodynamic than the Yaris so it should get better fuel economy; however, that said, when the battery on the Prius is completely drained, fuel economy in my experience doesn't get above 36mpg. Thats the same as the Yaris highway, and 6mpg more city. The Yaris might weigh less (certainly because of a lack of a hybrid drivetrain) but its aerodynamics probably are what keep it down there relative to the Prius. As well as having the engine fed gas constantly.

So....I would reckon 40mpg. IMHO.

 

I agree, but it might be fair for a test to be made of mpg over a range where the (actually any hybrid) electric mode (and regenerative braking) is disabled to get an idea of the efficiency as a gasoline vehicle, and then a range test with EV mode only.

Dave M.