Cars.com Hybrid Mileage Challenge: Part 2

Yesterday, we introduced the four fuel-sippers — a Chevrolet Tahoe Hybrid, Ford Escape Hybrid, Honda Civic Hybrid and Toyota Prius — we schlepped through Chicago traffic early this month. We took pains to drive as we normally would: No nursing the gas pedal to stay in electric mode or purposely coasting to regenerate more braking energy. Just ordinary stop-and-go driving. Faced with some wonky fill-up numbers at a gas pump on the fritz, we took our results from each vehicle’s onboard mileage readout, which we reset at the beginning of each new leg. Read below for the numbers, along with some postgame analysis.

Thanks to their electric-only modes, the Escape Hybrid and Prius achieve their highest mileage ratings in city driving, and both handily outperformed EPA estimates. The Chevy Tahoe Hybrid stayed right on the money. The Civic Hybrid has more traditional mileage estimates — like most cars, it does best on the highway — but our mileage came up a bit short of the car’s 40-mpg city estimate. (We rotated drivers for each leg, so driving style can’t be to blame.)

How did the Civic do so poorly? Perhaps our A/C usage (see Part 1) had something to do with it, though the latest EPA mileage estimates purportedly account for some A/C usage. Honda spokesman Jon Fitzsimmons said using the Civic Hybrid’s high-efficiency A/C can lower mileage. He didn’t specify how much, but the University of West Virginia’s James Smith said most conventional A/C systems hurt fuel efficiency by two or three mpg. Smith teaches mechanical and aerospace engineering, and he’s also the 2009 president-elect for the Society of Automotive Engineers.

It’s hard to judge the effect of the remaining variables. Carrying a passenger — necessary for photography — had limited effects: The Escape and Civic hybrids managed their best mileage with the extra weight, while the Tahoe Hybrid and Prius yielded middling results. The day’s heaviest traffic took a toll on all but the Escape Hybrid, which generally thrived in congestion. Expectedly, the Civic Hybrid did better on the faster sections in the evening, while the Prius was the reigning fuel-sipper all morning. The Tahoe Hybrid proved unflappable — no matter the traffic, temperature or passenger load, its MPG readout stayed right around its EPA-estimated 20 mpg.

In the end, the day’s top honors went to the Prius. In stark contrast to our 34 mpg results a year and a half ago, this one posted 17% better city mileage than its revised EPA ratings. In fact, our results come within spitting distance of the Prius’ pre-2008 60 mpg city rating. The Escape Hybrid proved similarly impressive, with 13% better mileage than its 34 mpg city rating. The Tahoe Hybrid didn’t wow us with efficiency, but its consistency deserves merit. The Civic Hybrid was comparatively unimpressive, though we suspect that had the A/C stayed off, the results might have been a couple mpg better.

Stay tuned for some impressions of how each hybrid drove and conveyed mileage information, as well as some insight on how in-car mpg readouts work.

Comments

[Bob Wilson]

The Prius results are impressive especially when compared to the Oct 2006 numbers. Could you compare and contrast the weather between the two sets of tests?

BTW, your Prius numbers are higher than a lot of the folks in GreenHybrid report. I suspect a big part of it comes from: (1) keeping the car warm, and (2) modest speeds.

Check the second line of the Prius column. I think you meant "mph" but typed "mpg." I've taken the habit of using "mph" and "MPG" so the capitalization provides an extra 'opps' test.

For more details about warm-up, you might consider (if you do this again), taking MPG readings say every 2-5 minutes during the warm-up of each vehicle. We know the Prius is especially sensitive and suspect the others are somewhat sensitive too.

Nice results.

Bob Wilson

Why did GM put a hybrid with such a big engine? It would have got 30mpg if they just used a 4.8 or a 5.3 engine instead of the big gun.

[Tom Hilbun]

The 6.0 L engine has to do with GM's smart fuel management. This system drops from a V8 to V4 whenever there is a light load. By putting the big engine in, it drops down to V4 very easily, resulting in over all better economy, while still having the full power available for acceleration and towing.

I have read that early tests with the smaller engines had lower overall fuel economy because it remained in V8 mode for much longer.

[Red]

I recently purchased a 2008 Silverado extended cab pickup with the 5.3 V8 and active cylinder management. This is the best kept secret in the truck world. Because it drops into V4 mode based on your driving style, and because you can monitor it in real time on the dashboard, it's easy to average 25 mpg on the highway all day long (2 wheel drive and 55 mph). We are averaging 20 mpg in a combination of city and highway driving - not bad for a 300+ hp V8.(Mike Levine, have you tested one of these?) Back to the comparison above, this is the best piece of work done by Cars.com for some time. It points out the superiority of Toyota's Hybrid Synergy Drive and once again underscores the fact that "we don't need no stinkin diesel cars" when you can get a clean burning hybrid like the Prius or Escape.

[J]

You guys called the Tahoe Hybrid a fuel sipper?
Who are we kidding now?

[Mark]

Frankly, I might just be more impressed by the Tahoe than the Prius. 20 mpg in that big, heavy, thing? Not bad and a step in the right direction, I say. Still kinda shocked by the Civic's low numbers.

[Zerf]

Great article. Impressive on all but the Civic. When we were looking into a Hybrid we quickly ruled out the Civic over the Prius. The Prius offered better gas mileage, what seemed to have been a better hybrid system (confirmed here) and a hatchback's functionality. Would have like to have looked at the Escape but it got pricey and was hard to find at the time.

[Dave T.]

well remember with the Civic you get better highway mileage. so if you're a highway driver versus a city driver it is a good choice. but we wanted to focus on city driving for this contest.

[Oblio_A]

As a stop-gap technology until Honda's clean-diesels arrive to the USA, these Toyota hybrid numbers are impressive. However, a decade after use, all these hybrid batteries are going to need to be disposed of - causing a negative environmental impact that few care to admit or even think about. Honda diesels will be incredibly clean and efficient, will deliver quite impressive mileage on the highway, and will likely go over 200K miles. http://www.honda.co.uk/change/

[Shin K.]

Few comments:

The discussion regarding A/C usage on Honda is little bit confusing. Way the article reads, it makes it sound like A/C was on Honda Civic, but not on the other vehicles. That does not seem to make sense.

The table seem to indicate the MPG figures are based on what is displayed on screen. These figures should be compared with one calculated from the odometer reading and fill up information. The MPG reading on some vehicle models are closer to truth than the others.

EOL battery disposal is a big question. I believe Honda has the smallest battery pack at 0.87 kWh, while Toyota Prius has 1.31 kWh and Ford Escape has 1.81 kWh. I assume Chevy Tahoe has a larger battery pack.

Idaho National Lab has extensive information on Hybrid Vehicles (http://avt.inel.gov/). Their test results do not seem to indicate large difference in fuel economy between Honda Civic Hybrid (39.9 w/AC 55.7 w/o AX) vs. Toyota Prius (41.3 w/AC 52.7 w/o AC). Another information available from the web site is battery pack life. I believe this is an important factor one should consider, if the objective of driving hybrid is to save the environment.