Diesel vs. Hybrid Electric Powertrains:
Assessing Dependability
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Perceptions Favor
Diesel
Diesel engines have a reputation for durability.
Among owners of diesel vehicles, 81% say they expect the future clean
diesel engines to be more reliable and dependable than conventional gasoline
engines, according to the J.D. Power and Associates 2004 Consumer
Acceptance of Alternative Powertrains Study.SM
In contrast, among owners of hybrid gasoline/electric vehicles, only 47%
expect future hybrid gasoline/electric powertrains to be more reliable
and dependable than conventional gasoline engines. Among owners of conventional
gasoline-powered vehicles, 32% expect future clean-diesel engines to outperform
gasoline engines in reliability and dependability, compared to only 9%
who expect hybrid powertrains to do so.
Diesels Better
in IQS
Owners of hybrid vehicles report more than twice as many engine problems
as do owners of comparable gasoline-powered vehicles (Fig. 1), according
to the J.D. Power and Associates 2004 Vehicle Dependability StudySM
(VDS). Among seven 2001 models with a diesel option, owners of the diesel
version report fewer engine problems than do owners of the gasoline version
in two models (Ram, Sierra) and more problems than gasoline – but
at a smaller differential – than hybrids in four models (Silverado,
Beetle, Golf, Jetta).
Diesels Better in Durability
For all seven 2001 models with a diesel option, owners of the diesel rate
the overall engine quality (at three years of age) higher than do owners
of the gasoline model (Fig. 2), according to VDS. Owners of hybrid vehicles
also rate their engines higher than owners of comparable gasoline-powered
vehicles, but at a smaller differential.
Diesel vs. Hybrid Electric (continued)
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Diesel, Hybrids Better on Costs...
While diesel and hybrid gasoline/electric engines
may entail higher initial costs at purchase, the total costs of ownership
is lower for these vehicles than it is for their conventional gasoline
counterparts, with the exception of the F-Series (Fig. 3).
…Even with More Mileage
Given the superiority of diesel-powered and hybrid
vehicles in total cost of ownership, it is well to note that all of the
alternative vehicles considered in this analysis were driven more miles
in three years than their conventional counterparts (Fig. 4). It would
appear that buyers of alternative powertrains either bought vehicles that
would have lower costs because they planned to drive many miles, or they
were encouraged to drive more miles since it was relatively cheap to do
so. Diesel-powered vehicles, in general, are driven many more miles than
hybrid electric vehicles are driven.
So Diesel is Better?
While diesel engines have an advantage over hybrid-electric powertrains
in durability, the current evidence is not the final word. In 2001, diesel
was already a mature technology but hybrid gasoline/electric technology
was nascent. As more companies develop, produce and sell hybrid vehicles,
the technology is likely to improve. However, diesel and gasoline technologies
are also likely to improve, so the standard will continue to rise. Manufacturers
will face an increasingly competitive environment, and it is difficult
to predict which technology and companies that will succeed. However,
it is clear that consumers will benefit from an expanding range of ever-improving
powertrains.
Copyright © 2004 by J.D. Power and Associates. All rights reserved.