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The three VWs in question are the base 2013 Jetta GL powered by a conventional, naturally aspirated (as in no turbocharger) 2.5-litre in-line five-cylinder, the Jetta Turbo Hybrid, powered by a 1.4L turbocharged four-cylinder mated to a 27-hp electric motor, and the much ballyhooed Jetta TDI, with the company's evergreen 2.0L turbodiesel four-cylinder under its hood.
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In all our tests at steady-state highway cruising, the diesel trumped the Hybrid (and, naturally, the 2.5L gas engine). Please note that all three cars were driven at the same time, tail-to-front, their cruise controls set to identical speeds. Even at the lowest speeds, when we thought the Hybrid's turbocharged engine might be at its most frugal, the TDI always triumphed, though by a smaller margin.
Test Results
For the record, with a speedometer reading indicating 100 kilometres an hour the TDI sipped 4.2 L/100 km, while the Hybrid consumed a still-economical 4.8 L/100 km. The 2.5L GL, unsurprisingly, trailed at 5.9 L/100 km. Jacking things up to 115 km/h saw the gap widen, if only slightly. The three Jettas averaged 4.7, 5.4 and 6.4 L/100 km respectively. At our final speed of 125 km/h, the TDI's diesel extended its lead with a 5.4 L/100 km/h reading, while the Hybrid and GL recorded 6.1 and 7.0 L/100 km.
And the faster we went, the greater the diesel's advantage became (though the Hybrid hung in there better than other gas/electrics we've tested).
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In town, the results, as expected, reversed. The 2.5L was left even further behind during the stoplight circuit, averaging 10.8 L/100 km during our Port Hope, Ont., test run. The TDI, meanwhile, posted a still-credible 7.9 L/100 km, while the Hybrid's electrical assistance proved its worth by sipping just 5.9 L/100 km.
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Also, considering how thoroughly the Jetta Hybrid thumps the recently tested Ford C-Max Hybrid in highway consumption, it might be safe to posit that a small turbocharged engine (as in the Jetta's 1.4L turbo) is a better choice for hybridization than a naturally aspirated motor (the C-Max's Atkinson-cycle 2.0L). And, as Post Driving has long contended, perhaps the best combination would be a diesel/electric hybrid or, better yet, a plug-in diesel hybrid.
Whatever the case, this test should cement the thought that diesels offer superior fuel economy on the highway and hybrids rule in the city.
There's a lot to consider when looking at different fuels for your vehicle. Besides mpg/mpkW, there's the cost of the vehicle, the delta in mpg for actual savings, and most importantly, the type of driving.
The article you reference only covers highway cruising - hybrids will be weakest here because high-speed, sustained driving is where they lose their efficiency, and it is where diesel excels. This is exactly what the article shows and concludes - highway speeds essentially nullify the electric engine as it can barely if at all be used, and you end up with a comparison among a big diesel engine and two smaller gasoline engines. One intersting thing I did not see mentioned - the lead car will get worse mpg because it has to push the clean air, while the other two get to draft and see mpg benefits.
Change the test environment to urban stop and go, and you'd see very different results.
In the USA, diesel is more expensive but nets better mpg and it usually is a matter of the actual car costing more that negates any price advantage over gasoline. Hybrids are a good compromise, but not until cars with full EV capability (Like the Chevy Volt or Toyota RAV4 EV) are more common and priced lower will we see a really efficient alternative imo.
I drive a diesel but if I was buying a new car it would be a hybrid. The only interesting new diesels in the US are MB's 2.1L in the E class and Mazda's 2.2 in the 6. Volkswagen builds crap cars no matter what the fuel. I wouldn't drive one if they gave it to me for free.
I drive a diesel but if I was buying a new car it would be a hybrid. The only interesting new diesels in the US are MB's 2.1L in the E class and Mazda's 2.2 in the 6. Volkswagen builds crap cars no matter what the fuel. I wouldn't drive one if they gave it to me for free.
Audi A3 TDI is an amazing car, too bad it is no longer available in hatchback style for 2014.
Also too bad the BMW 335d has been discontinued, they'll come back in 2014 with a 4 cylinder 328d.
...The article you reference only covers highway cruising - hybrids will be weakest here because high-speed, sustained driving is where they lose their efficiency, and it is where diesel excels...
The article actually does mention both scenarios, and states that the hybrid beats the other two for city driving (much as expected). I wondered about the wind situation too. Ideally, the author should have discussed how far in trail the vehicles were from each other, and whether or not the vehicles stopped to switch positions and record new fuel economy figures. The other option would be for the vehicles to be driven abreast each other for the duration of the testing cycle, but that would have required the closing of highways, or finding a location suitable for the entire test.
Something I often notice on my drives are the timing of stop lights. I can't help but wonder how much more efficient driving would be if stop lights were better synchronized allowing the driver to proceed at a "recommended or synchronization speed" which would allow the driver to not be held up by traffic lights on the entire route. On relatively flat routes from home, when this happens, it's not uncommon for me to see 40-50 mpg in town commutes with my Jetta TDI...when I find myself sitting at red lights, and having to start/stop constantly, the number drops back down to the advertised 30 mpg figure.
If you really want to save money, you buy a cheap used beater and drive the wheels off it, not repairing anything minor ever. Buying any new car won't save you money over that.
Instead, in a new car look for a car that drives the way you want, fits your lifestyle needs, and only then is more economical than another new choice. That's what led me to the Volt, as a plug in hybrid that almost never uses fuel, unless I absolutely need it to.
The writer of that article, like many people, thing a diesel/hybrid might be the best overall choice. They thing diesel for great highway mileage and hybrid for city.
That is just not sensible. A diesel hybrid would be the most expensive package since both halves of the powertrain are expensive. Diesel engines ALWAYS cost more than comparable gasoline engines. Diesels also do not do well in start/stop modes which most hybrids need. A diesel hybrid might have better MPG overall, but would have the worst ROI.
Location: We_tside PNW (Columbia Gorge) / CO / SA TX / Thailand
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Today averaging 4.3 L/100km or 54.7mpg in my 97 VW Passat Diesel Wagon.
With 25 gal tank that will take me 1350 miles or 2175km
No need to spend extra for diesel. This car will burn about anything, from Jet A to Veggie oil. 50 mpg since 1976, no Dinosaurs or OPEC required
If I were a city dweller, I would probably consider or build a diesel hybrid, as is available in Europe. (~80 mpg)
For the average Joe, / non-mechanic / city dweller doing less than 10k / yr, tough to beat a Yaris or Focus ~ 38mpg on Gas (ick)... I am a farm kid, so I was weaned on Diesel.
I have several motorcycles that get close to 100 mpg on gas (ick), looking to make a diesel conversion.
Location: We_tside PNW (Columbia Gorge) / CO / SA TX / Thailand
34,690 posts, read 57,994,855 times
Reputation: 46171
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Originally Posted by Merc63
If you really want to save money, you buy a cheap used beater and drive the wheels off it, not repairing anything minor ever. ...
Works fine for my fleet. $35 VW Diesel Rabbits (I have 20+ of those). You can find them in Brier Patches (check your neighbor). I have found a few for free. Parts EZ to find and VERY cheap.
Will run on free waste cooking oil, bio diesel, used motor oil, waste Jet Fuel, heating oil, peanut oil...and hopefully soon... algae fuel.
For the record, with a speedometer reading indicating 100 kilometres an hour the TDI sipped 4.2 L/100 km, while the Hybrid consumed a still-economical 4.8 L/100 km. The 2.5L GL, unsurprisingly, trailed at 5.9 L/100 km. Jacking things up to 115 km/h saw the gap widen, if only slightly. The three Jettas averaged 4.7, 5.4 and 6.4 L/100 km respectively. At our final speed of 125 km/h, the TDI's diesel extended its lead with a 5.4 L/100 km/h reading, while the Hybrid and GL recorded 6.1 and 7.0 L/100 km.
And the faster we went, the greater the diesel's advantage became (though the Hybrid hung in there better than other gas/electrics we've tested).
In town, the results, as expected, reversed. The 2.5L was left even further behind during the stoplight circuit, averaging 10.8 L/100 km during our Port Hope, Ont., test run. The TDI, meanwhile, posted a still-credible 7.9 L/100 km, while the Hybrid's electrical assistance proved its worth by sipping just 5.9 L/100 km.
Highway: 125 km/h, eg what people drive and because I'm lazy.
Diesel 43.6 mpg, hybrid 38.6, gas 33
City: Diesel 29.8, hybrid 39.9, gas 21.8
Price: Diesel SE Convenience $23,000, Hybrid SE (+$1,300 price adjustment for Convenience) $28,000, Gas SE Convenience, $20,000
Hybrid might save you at the pump, but $8,000 buys a whole let of a lot of gas. Even the $3,000 extra on the diesel is going to take awhile to recoup.
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