Diesels are trying hard to make a comeback in the US, but it’s clearly a bit of an uphill battle. Hybrids are already well established and more are on the way, and conventional gas engines are improving their efficiency. But diesel’s market share in the US is growing; will it continue to? Will you be one to see that it does?
In Western Europe, where diesel is taxed lower than gas, and fuel prices are overall much higher, diesel’s market share has bounced around the 50% for years. That varies, depending on the taxation in specific countries, as well as the economy (smaller and cheaper cars are more likely to be bought in gas versions there than bigger ones).
In the US, the situation is more difficult, given that diesel typically sells for about 6-15% more than gas, and diesels typically cost more. Diesel’s market share of the passenger car market has been increasing, to around 3%, thanks to aggressive pushes mostly by the Germans, most of all VW. But even they are introducing new gas hybrid models too, hedging their bets. And some models have been eliminated (BMW 335d). Others have been talked about, but yet to appear (Mazda). And GM is getting back into the game with their German-engined Cruze.
Undoubtedly, many diesel fans buy diesels because…they are diesel fans; similar to hybrid fans, although the exact reasons might be different. Obviously, diesel fans tend to place a higher priority on the driving experience, and modern diesels, with their high-torque characteristics, offer plenty. The economics of diesels are more complicated. They typically cost more, unless the purchase price has been subsidized by the manufacturer to help with CAFE numbers. Maintenance typically is more expensive than a simple gas engine. Modern diesels rely on numerous high-tech systems (read: expensive) to comply with current emission regs. That part does scare me a fair amount.
Of course, there’s the fuel efficiency improvement over a gas engine. But it’s often not enough to offset other costs. The 2013 Jetta diesel’s combined EPA rating (34) is 21% higher than the 2.0 gas engine, and 30% better than the 2.5. But those are pretty old-school; VW will be bringing substantially more efficient down-sized turbo gas engines for the Golf in 2014. The difference will than narrow substantially.
In fact, that’s exactly why the BMW 335d is gone; the turbocharged 2.0 gas 328i’s EPA numbers were too close, and the 335d engine was much more expensive to build. It reflects another reality: diesel engines have been struggling to maintain their efficiency levels due to their emission systems, which have a negative effect on efficiency. Meanwhile, gas engines have been making very substantial improvements in their efficiency over the past some years. The gap between the two is getting narrower.
Of course, in larger vehicles, that plays out differently than in smaller ones. The Mercedes E350 Bluetec diesel has a paltry 9% EPA combined improvement over the gas version.
In the much larger GL, the situation is more dramatic: the GL 350 Bluetec has a 38% better EPA Combined number than the GL450. Of course, that’s over a larger V8 gas engine, but apples-to-apples comparisons are not easy to come by. In Europe, the larger the vehicle, the more likely it will be a diesel, as the savings become more marked.
VW does offer three versions of the Touareg in the US: gas, hybrid and diesel. Their respective EPA combined numbers are 19, 21 and 23. But the VW hybrid system isn’t as much of a “full hybrid” as say the Toyota RX 300/Highlander.
In fact, the Toyota hybrid SUVs trump any of the German diesel ones by a substantial margin. The Lexus has a superb 32/28 and 30 Combined EPA rating, and attains similar number in the real world. The rather chauvinistic German magazine auto, motor und sport did an extensive comparison between a Lexus 400h and comparable German diesel SUV a few years back and found that the Lexus was fully their equal in overall efficiency, substantially trumping them in city mileage. Of course, if serous towing is on the agenda, the diesels have an obvious advantage.
The Prius and Jetta TDI are about as comparable as it gets, in terms of a hybrid-diesel comparison, although many will argue otherwise. Rather than use EPA numbers, in which the Prius crushes the VW 50 (combined) to 34, a better comparison are the real world results by users, which the EPA also compiles. There’s a range, depending on year and transmission, but the Jetta averages range from 37-43, and the Prius 45-49.
I didn’t intend this to be a hybrid-diesel comparison as much as simply an evaluation of the diesel’s own pros and cons, and its chance in the marketplace. So what say you?