Diesel vs. Hybrid Car Battle Heats Up

As automakers continue to introduce new models debuting within the next couple years, it’s apparent that improved fuel economy is being targeted by two completely different technologies – diesel engines and hybrid electric systems. Comparatively speaking, these two couldn’t be any more different in terms of age, operation or public perception, but both manage to yield some of the best fuel economy numbers currently on the market. As of late, European automakers have begun offering an increasing number of diesel-powered vehicles to the North American market, while the Japanese and American automakers are focusing primarily on hybrid electric drivertrains. We took a look at both technologies in an effort to break down the pros and cons of both fuel-efficient technologies.

Hybrid Vehicle Technology

As one of the fastest growing technologies in the automotive industry, hybrid electric vehicles are now being offered (or are planned to be offered) by almost every major automaker around the world. The only things holding hybrids back from becoming a truly mainstream vehicle are the cost premium associated with the advanced technology and its battery limitations. Like its name suggests, hybrid systems blend the technologies of an electric vehicle seamlessly into a conventional vehicle with an internal combustion engine. The electrical systems allows the engine to work less or to not have to work at all in some conditions which helps increase a vehicle’s range on the same amount of gasoline. Most hybrids currently use nickel metal hydride batteries to reduce costs, but more powerful lithium ion batteries are becoming more affordable for use in such applications.

The Toyota Prius (pictured) has become the face of hybrid electric vehicles, but the market is quickly getting crowded. Everything from small hatchbacks (2010 Honda Insight) and family sedans (2010 Ford Fusion) up to full-size pickup trucks (2009 Chevrolet Silverado) and sport utility vehicles (2009 GMC Yukon) are now available with hybrid power. As stronger battery systems become more readily available, the speed at which these cars can travel under electric power alone will greatly increase. As evident by the new Insight and Prius, the overall shape of the vehicle’s design is almost as important as the battery pack and electric motors. Even the GM hybrid SUVs offer revised styling that improves aerodynamics and vehicle weight.

Other versions of hybrid powertrains include extended-range electric vehicles such as the Chevrolet Volt. Unlike conventional hybrid systems, E-REVs are never powered directly by their internal combustion engines, but instead use them solely as generators to help recharge the batteries. Future E-REVs include the Cadillac Converj and the Fisker Karma.

Diesel Vehicle Technology

Outside the United States, diesel engines are commonplace in everything from sports cars to family sedans, but here diesels are relegated to towing duty in full-size pickup trucks and work vans. As the technology has advanced and diesels are now running cleaner and even more efficient, these engines are beginning to trickle back under the hoods of passenger cars. Besides the obvious gain in fuel economy, diesel engines also offer better reliability and stump-pulling torque compared to gasoline engines, but they still must overcome their reputation for emitting sooty, foul-smelling exhaust. Thankfully, automakers such as Volkswagen, BMW and Mercedes-Benz are leading the charge to offer exciting diesel-powered vehicles that are offer quieter engines and clean exhaust emissions that are now becoming available in all 50 states. Making diesel cars even more attractive now, diesel fuel prices have dropped on average to around the same price as mid-grade gasoline.

Cars like the Volkswagen Jetta TDI and Jeep Grand Cherokee (pictured) are examples of basic diesel vehicles that offer improved fuel economy, but now diesel-powered vehicles are showcasing performance such as the BMW 335d as well as luxury like the Mercedes-Benz E320 BlueTEC. Diesel-powered vehicles are usually turbocharged to offer improved acceleration from the grunty, low-end torque, but they also allow for fuel economy numbers that are vast improvements over their gasoline-powered counterparts. The all-new BMW 335d should be one of the most exciting cars of the bunch offering twin-turbochargers, 425 lb-ft of torque and an impressive 23 miles per gallon in the city and 36 mpg on the highway (the 335i gets 17 mpg in the city and 26 mpg on the highway).

A new take on alternative fuel for internal combustion is the use of pressurized liquid hydrogen fuel. Unlike hydrogen fuel cell vehicles, the pressurized hydrogen is burned in the engine like any gasoline or diesel, but it burns more efficiently and much cleaner. To date, almost all of the major automakers have offered concepts or prototypes of hydrogen-fueled vehicles but none have been brought to the market as of yet other than small fleets used by private companies more for the purpose of real world testing more than anything else.

The best thing to choosing between one or the either of course, is to offer a vehicle with both a diesel engine and a hybrid electric system. One such vehicle that is expected to use both technologies for optimal fuel economy is the upcoming Volkswagen Golf diesel hybrid. It’s not clear as to when Volkswagen would be able to offer such a vehicle in the U.S., but with a diesel-powered Golf expected to debut in 2010 and a hybrid version of the Touareg 2 on the way, VW has the technology in place to offer a diesel-powered hybrid. A hybrid electric version of the upcoming Golf GTD could easily outperform any current hybrid vehicle in terms of fuel economy and driving excitement.