Hybrids Only Excel in City Driving?

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Wrong. Over the years, I have read in a number of threads that hybrids are worthless for highway driving. The individuals who make those statements argue that a turbodiesel is far superior to a hybrid if the vehicle is used primarily for highway driving. Recently, Edmunds.com conducted a test between the new 2009 Jetta TDI, 2010 Prius and various other fuel-efficient vehicles. At the end of the test, the results proved the 2010 Prius achieved nearly the same fuel economy regardless of the driving environment-- city, highway or backroads. This test proves that a hybrid does not lose its advantage if the vehicle is used for highway driving, contrary to what some posters insist on. The Back Roads The champ: 2010 Toyota Prius with 47.2 mpg 2nd Place: 2010 Honda Insight with 44.1 mpg 3rd Place: 2009 Volkswagen Jetta TDI with 41.2 mpg 4th Place: 2010 Ford Fusion Hybrid with 39.6 mpg 5th Place: 2009 Mini Cooper with 38.5 mpg The City The champ: 2010 Toyota Prius with 48.7 mpg 2nd Place: 2010 Honda Insight with 43.4 mpg 3rd Place: 2010 Ford Fusion Hybrid with 35.1 mpg 4th Place: 2009 Volkswagen Jetta TDI with 31.6 mpg 5th Place: 2009 Mini Cooper with 30.1 mpg http://www.edmunds.com/advice/fueleconomy/articles/153866/article.html
 
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I was at the Toy dealer the other, took a close look at the Prius, that things pretty nice inside, got to give Toyota props for that car, its well put together and delivers. If they could only build a Helix size hybrid truck, or just bring the small diesel over, they'd have me for sure.
 
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In the quest of the highest milage the total cost calculation seems to be " overlooked" by most? We all would enjoy freedom from the oil cos., but at what price? As I watch the Priuss' wizz past me in traffic I guess that most were purchased for their cache... rather than true economy. For me anyway, if you need all around economy a Corolla or Civic would probably work out best in the long run as gasoline over $5/gal U.S., would totally cripple the world economy (including the KSA, HUGO, and the FSU) and therefore I view as unlikely. Purchasing a diesel pretty much relegates you to "stealership" visits for routine maintenance after the first 30,000 or so (not many will have the tools or expertise). The several Priuss' Ive seen seem to be LOADED up with "gadgets" inside and these tend not to be "shadetree" friendly? The earlier reports of battery problems with the hybrids seem to be on the back burner for now and I''ll reserve judgement until I see a repair bill posted, but I have to think that at least one change-out w/b required in the average (13.5 year) vehicle lifespan. This whole exercise for milage may turn out to be a good example of a famous general's quote: "The only enemy of a good plan is the pursuit of the perfect plan".
 
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 Originally Posted By: CATERHAM
It entirely depends on how fast you drive.
That is quite true. I am hoping the test controlled speeds as best it could. There are various ways to reduce fuel usage. One way is to plan ahead and not do as much errand running. You can drive something smaller. You can drive more moderately. You can accept lower performance. You can buy a hybrid. I see no reason to expect hybrid owners to also choose to drive more moderately.
 
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They're comparing totally different cars, not just hybrid versus diesel powertrains. It is true that hybridization only helps when you're sitting in traffic or using the brakes, but most drivers do plenty of both!
 
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The point of people saying that hybrids excel at city doesn't exclude them from doing well on the highway. I look at the figures you posted and conclude that, well, hybrids DO excel in the city. Look at what the Prius achieved compared to the Jetta on the back roads, about 6 mpg better. Compare the two in the city and the difference jumps to 17 mpg better. I would conclude that the Prius does better than the Jetta on the highway but it excels in the city...
 
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 Originally Posted By: CATERHAM
It entirely depends on how fast you drive.
Yep, and how you drive...
 
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 Originally Posted By: Pop_Rivit
I'm waiting for the Prius haters to start bashing and the VW lovers to start whining.
Both groups have been notably silent since the arrival of the new Gen-III Prius (really Gen-IV from a world-wide perspective), as this car clearly outperforms the new VW Jetta TDIs, while providing substantially more passenger and cargo room.
 
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The benifit a Hybrid has over a conventional car on the highway is taller gearing but mostly the Atkinson cylce engine (instead of the otto cycle we're all used to) which has a higher expansion ratio than compression ratio. So on the 2.4 for normal cars, 158hp and160 ft/lbs. In the atkinson version of that it's more like 140/135. So I guess my question would be, why can't/don't they make a Camry FE special with that engine? Does an Atkinson Cylcle engine just that terrible of a driving experience?
 
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For what it's worth, I rented a Prius for a couple of days while on a business trip about a year ago. During that time, I did two long highway stints of about 200 miles each time. Just for grins, I filled up before and after each run since Mrs. Familyguy has been Jonesing for a Prius. My observed mileage was a skosh over 50mpg. That was doing 65-ish on I-95 in the northeast in the winter. It was a nice little car. Would I give up my hemi for it? Nah. As for the Jetta TDI, that's a nice little car too. If/when refiners in the US get around to making enough Diesel so that there isn't obvious price gouging making it substantially more expensive than gas, I wouldn't mind owning one. That little turbodiesel is a real stump puller.
 
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 Originally Posted By: rpn453
. . . It is true that hybridization only helps when you're sitting in traffic or using the brakes, but most drivers do plenty of both!
rpn, with all due respect, that's not correct. There are two reasons why the Toyota HSD cars are doing so well on the highway, and not just the city. First, and this is candidly not necessarily related to the hybrid system: their ICEs are all programmed, using the VVT system, to run in Atkinson-cycle mode when loafing on the highway. This gives them a huge advantage (and makes me wonder why the makers of conventional cars don't do the same thing). Second, even in what deceptively appears to be steady-state cruising on a flat Interstate highway, the hybrid system is still working its magic (though certainly not as noticeably as in urban driving). If you know what it's doing (and I have a Scan-Gauge-II added), you can see the system constantly shifting between what I call "gas dominant" and "electric dominant" modes, as the variables change. Once the charge state on the battery creeps up to a higher level, the ECU makes the motors do more of the work; once the TB SOC drops, it calls on the ICE, with excess power being converted my MG1 to electrical energy, and stored in the TB for later use. And in hilly terrain, the HSD system is great. Above 42 mph, because of the system's gearing, the ICE must turn (but not necessarily burn). On long downhills, I advance the throttle until the car shows about 50 mpg. This results in speed climbing above what I'd normally cruise at. Personally, depending upon traffic, and the absence of law enforcement, I let the speed build up to a bit above 90 mph. On the uphills, I typically don't start burning any gas at all until I'm halfway up, allowing the speed to decay to "normal". You can do essentially the same thing in a regular car, but the hybrid system allows you to maximize this technique. Bottom line: the hybrids do very well on the highway too, but certainly, the relative advantage is not as great as it is in urban driving.
 
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 Originally Posted By: ekpolk
rpn, with all due respect, that's not correct . . .
I don't disagree with anything you say beyond that first sentence, but I missed the part where the battery is charged without the system providing braking to the car! I didn't know it could switch in and out of Atkinson-cycle mode. It must sacrifice some peak engine power to function that way though, or they'd be putting out more than 98 hp from a 1.8L. I imagine we'll see more of that as the focus shifts from power to fuel economy in the future.
 
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The wonders of computers and engineering at work! I am tempted to look at the Hybrids when I get another used car. The Fusion looks like a good possibility.
 
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The Atkinson cycle doesn't turn on and off on these cars. The cylinder head is different. It is shown in the lessened max HP ratings. I can get 55-60 mpg pretty routinely on highway trips in an 07 Prius, and if the traffic gets heavy, all the better. It can do better. Short trips,frequent cold starts, headwinds, use of accesories all bring the mpg down pretty fast to the forties. Still I have never had a tank less than 48 in 19K miles, and usually it is 50-52, about 60/40 city highway mix. It is a roomy car with the hatchback, and contrary to belief, not slow at all. I drive less than 65 mph as I have in all my cars since I started driving in 1962.
 
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 Originally Posted By: Newtonville
The Atkinson cycle doesn't turn on and off on these cars. The cylinder head is different. It is shown in the lessened max HP ratings. I can get 55-60 mpg pretty routinely on highway trips in an 07 Prius, and if the traffic gets heavy, all the better. It can do better. Short trips,frequent cold starts, headwinds, use of accesories all bring the mpg down pretty fast to the forties. Still I have never had a tank less than 48 in 19K miles, and usually it is 50-52, about 60/40 city highway mix. It is a roomy car with the hatchback, and contrary to belief, not slow at all. I drive less than 65 mph as I have in all my cars since I started driving in 1962.
Yes, the AC operation does cycle on or off in these cars (but not in a strictly "binary" fashion, see the post I'm adding below). It is true that there are other differences between the non-hybrid and hybrid versions of the various engines (1NZ-FE vs 1NZ-FXE, Yaris and Prius; 2AZ-FE vs 2AZ-FXE Camry and Camry Hybrid). But that doesn't mean that the engines are locked in Atkinson cycle operation. They use the variable valve timing feature (which of course Toyota calls "VVT-i") to implement Atkinson-cycle operation. A-C is not determined by the shape of the chamber. It's determined by valve timing. When the car is in A-C operation, the intake valve remains open far longer normal. In fact, it stays open for a substantial portion of the compression stroke. This forces a portion of the intake charge back into the intake tract. The intake valve then closes, and the engine compresses for the remainder of the compression stroke. The effect in the HSD cars is that the power stroke is substantially longer than the compression stroke. Since the compression stroke in a four-stroke engine is the one stroke of the four that consumes substantial energy itself, this "shortening" of the compression stroke, particularly as compared to the "normal length" power stroke is a big part of the relative efficiency gained by using Atkinson-cycle operation. Once you learn the car (and especially if you add a Scan-Gauge as I have) you can feel, and see, the difference in the engine when it's in Atkinson-cycle, and when it's not. Floor it to pass, and the ECU tells the VVT that we're looking for performance now, and you get "normal" non-Atkinson valve timing. Drop back to loafing along at 75 mph on the interstate, and the ECU will put you back in full econo-Atkinson operation. Final comment: note the signature block, below. I've put 60k miles on a Prius, and almost 30k on a Camry hybrid.
 
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