Toyota Prius Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
117 Posts
Discussion Starter · #1 ·
Read again in the paper about the new EPA guidance on mileage tests. Apparently, Mulroney stickers will start to reflect the new test procedures in a few months. I'm just wondering if the new ratings, which may impact hybrids a lot more than conventional cars will actually help hybrid sales. Face it, noone buys a Mustang or pickup truck because of the mileage. They will buy a Prius because of mileage, but few are able to get 60 MPG in city driving, and this might disappoint some. I have seen several low-mileage 2006 Priuses sitting on used car lots--a local Honda dealer was really pushing a 5000-mile Prius on me. I can't help but wonder if the previous owner was disappointed at not getting advertised mileage. I know Prius owners get defensive on this point, but the fact is, 45 MPG is more realisitc with normal driving.
However, if EPA sticker actually shows 45MPG, a numer most could actually get, I think many folks would start realizing the Prius still gets better mileage than any other car, and I believe this would help sell the car, as well as other hybrids. Right now, local Toyota dealers are overflowing with Priuses.
 

·
Registered
Joined
·
2,243 Posts
The new EPA mileage estimates start with model year 2008. From the article, "Mileage estimates for gas-electric hybrids probably will be 20 to 30 percent lower for city driving and 10 to 20 percent lower on the highway, the agency said."
 

·
Registered
Joined
·
7,161 Posts
One thing I suppose buyers overlook is that the EPA sticker has a range of mileage that could be expected out of the car. People always seem to focus on the main, most optimistic number.

Conventional cars tend to pretty much get the same mileage no matter how you drive it. Hybrids tend to avoid waste if you drive it that way.
Another way it could be viewed is a hybrid is a conventional car getting slightly better mileage than comparable cars under average use, with the capability of achieving significantly higher mileage if allowed to do so.
 

·
Registered
Joined
·
198 Posts
DanMan32 said:
Conventional cars tend to pretty much get the same mileage no matter how you drive it.
I disagree. Just install a mileage computer on a conventional car to give you feedback and I guarantee you can improve your mileage.
 

·
Registered
Joined
·
7,161 Posts
I suppose you could work on it but it would take effort.
Such as shutting off the engine when not moving, although the time it takes to restart the car may get drivers behind you angry.
You could also reduce the drag on deceleration by going into neutral. At least the Prius only simulate the drag by using regen.
 

·
Registered
Joined
·
2,348 Posts
DanMan32 said:
I suppose you could work on it but it would take effort.
Such as shutting off the engine when not moving, although the time it takes to restart the car may get drivers behind you angry.
You could also reduce the drag on deceleration by going into neutral. At least the Prius only simulate the drag by using regen.
I know I get better mileage on our old Camry using techniques I learned on the Prius. Looking ahead to anticipate lights, coasting, gentle acceleration, trying to avoid the need to brake, driving the speed limit... all help on our other cars.
 

·
Registered
Joined
·
4,873 Posts
I suppose you could work on it but it would take effort.
Such as shutting off the engine when not moving, although the time it takes to restart the car may get drivers behind you angry.
You could also reduce the drag on deceleration by going into neutral. At least the Prius only simulate the drag by using regen.
.
.
.
I have to disagree with this statement. First you would tear a conventional car to pieces very shortly if you shut it down and restarted it continuously with a 12 volt starter. Actually completely shutting down the engine from a 600 RPM normal idle does not save all that much gas. It's just part of the big picture in the Prius and Civic hybrid.
.
.Secondly, according to the auto magazine writers, and they consider themselves experts, buyers are not as concerned with the EPA sticker milages on their choice of cars but mainly with the incentives and rebates offered by the manufacturers.
A great majority of the public are not as concerned about milage figures as Prius owners are.
.
.
 

·
Registered
Joined
·
7,161 Posts
hyperion said:
I have to disagree with this statement. First you would tear a conventional car to pieces very shortly if you shut it down and restarted it continuously with a 12 volt starter. Actually completely shutting down the engine from a 600 RPM normal idle does not save all that much gas. It's just part of the big picture in the Prius and Civic hybrid.
.
I agree with the comment about wear and tear. However about not saving gas, there are even laws stating that one needs to shut the engine down when parked. Some lights are pretty long that you probably would save gas, though probably not enough for the effort I would agree. But you would save! Then again, when the Prius doesn't shut down the ICE, like when providing cabin heat, I can see the mileage go down quickly. So the converse, shutting an engine that doesn't otherwise shut down, would save gas.
 

·
Registered
Joined
·
117 Posts
Discussion Starter · #9 ·
DanMan32 said:
One thing I suppose buyers overlook is that the EPA sticker has a range of mileage that could be expected out of the car. People always seem to focus on the main, most optimistic number.
Isn't this human nature?

Conventional cars tend to pretty much get the same mileage no matter how you drive it. Hybrids tend to avoid waste if you drive it that way.
Another way it could be viewed is a hybrid is a conventional car getting slightly better mileage than comparable cars under average use, with the capability of achieving significantly higher mileage if allowed to do so.
Dan,

I totally disagree with you on this point. I think you can see about the same percent savings in most cars as you would in a Prius. Try jackrabbit starts, gassing the engine until you are right on top of the light, speeding up to keep up with traffic etc. vs. gentle acceleration, foot off the gas coming up to a light, preserving momentum, minimize AC, slow down uphill, you will see about a 15-20% difference in mileage. We have instant and average mileage indicators on both the van and the pickup, and I can see a huge difference in mileage based on how they are driven. Of course, if you are only getting 10 MPG to start with, going to 12 MPG doesn't seem like a big deal, but it would be the same as going from 45 to 54 in a Prius!
 

·
Registered
Joined
·
7,161 Posts
Some calculations would be appropriate to use percentage, but others should use absolutes.

Case in point: if one had a fuel leak being the same in both vehicles, say 1 gallon per day, then the 'waste' would totally be dependent on how many miles you could get under that day to diffuse the waste.

We can look at it from the perspective of degrading the Prius' performance, versus improving the conventional vehicle performance. We should however, compare with a car with similar powertrain performance: similar vehicle weight and engine power. A vehicle that gets about 30 MPG would be a good place to start. The SL2 I believe was close in that respect. I attributed it to calculation error at the time but I have calculated 37 MPG at times driving my usual commute up/down US19 with no AC in moderate weather.
We can have the Prius not shut its engine down, and see how close it gets to the conventional car comparison. A tap on the gas pedal will yield this, as will heat demand, although heat demand may be a bit biased.
 

·
Registered
Joined
·
591 Posts
I can speak on "improving mileage on conventional cars", as I have a lot of experience with my vehicles. For example, with the anti-Prius (see below) I switched to synthetic oil. That made a 10% improvement. I tried driving both aggressively and conservatively and had only a minor difference in mileage (I have always kept a record book on mileage on all my vehicles). I did notice mileage decreased dramatically when speeds exceeded 125 km/hr (so I try not to). This summer I purchased a Scangauge II and used it in the anti-Prius. Sadly, I saw why I couldn't improve mileage with driving style. You'd think gearing down for stops would help - you'd be wrong. It increases fuel consumption. It would quickly destroy the starting system if I shut it off at every light so that's not an option - unless gas goes to $10/litre. ;) Shifting to neutral at a light drops the fuel consumption by 0.2 l/hr but has no effect on the calculated mileage when I fill up. I have never "warmed up" my vehicles prior to driving, I just drive gently until it starts to warm up.

I suspect the engine is set up to inject fuel to keep the cat warm and reduce NOx production when engine braking.

I think the anti-Prius gets pretty good mileage for a two metric tonne vehicle - it burns between 11 l/100 km and 17 l/100 km (summer highway to winter city driving). I used to own a Landcruiser wagon "in the day", and the best I ever got it to was 20 l/100 km, so the advanced electronic controls work! I don't want to remember what it burned in the city in winter! ;)

As to the original question, I think there will be two groups affected. Those who like reality (the minority) will be happy, and may be more likely to purchase a Prius. Those who believe anything in print, especially from a govt. test (the majority), will be disappointed and would be less likely to purchase.
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top