A New Crop of Clean Diesel Vehicles

By Rod McLaughlin —

I have a simple car question for you. What kind of car gets exceptional mileage, is good for the environment, is well built and can even earn you a tax credit? Well, if you said a hybrid, you’re close.

The type of vehicle that I’m referring to is clean diesel. That’s right, clean diesel vehicles are one of our best options for fuel efficient transportation. Hybrid vehicles such as the Toyota Prius are still the leaders when it comes to high mileage ratings, but clean diesels are a more than reasonable alternative. For comparison purposes, I’ll be using clean diesel cars from Volkswagen and Audi.

Fuel Economy

Clean diesel vehicles get higher fuel economy than their identical siblings that run on regular gasoline. For example, according to the US Department of Energy, the 2010 Volkswagen Jetta TDI (Turbo Diesel) and the 2010 Audi A3 TDI each achieve 30 mpg city and 42 mpg on the highway. The Jetta that runs on regular gasoline gets 23 mpg city and 30 mpg hwy while the gasoline-powered Audi A3 gets 22 mpg city and 28 mpg hwy. It’s clear to see that the clean diesel vehicles offer significantly higher miles per gallon.

But how do they compare against other high mileage competitors from other manufacturers? The Jetta and the A3 get significantly higher mileage that the Honda Civic, the Toyota Corolla, the Nissan Sentra, the Ford Focus and the Mini Cooper. But what’s really surprising is that the clean diesels get higher mileage than even the smallest vehicles the competitors produce, including the Toyota Yaris, Honda Fit and Nissan Versa. That’s right, an Audi A3 Diesel gets higher mileage than the Yaris, Fit and Versa.
Clean diesels get such high mileage that they even compare favorably against hybrids. For example, the highway mileage of the Honda Insight is 43 mpg, just one mpg higher than the Jetta and Audi A3. Not bad.

Performance

I must admit, as a car guy, one of my personal prejudices against hybrids is the lack of that roar created by a combustion engine. The quiet electric motor just leaves something lacking for me. But diesels have no such shortcoming. Not only is there an audible response, diesels have quite lively performance. This is due to the characteristics of diesel engines.

Most people are accustomed to hearing horsepower ratings as the measure of a vehicle’s performance capabilities. But vehicle engines are rated in horsepower and torque. Horsepower usually relates to the speed potential of a vehicle, whereas torque refers to pulling power. This is why race cars have high horsepower ratings while heavy trucks have a lot of torque for pulling power.

But interestingly enough, it is torque, not horsepower that determines acceleration. So while you may never drive 150 to 180 mph as some cars are capable of driving, you will definitely find yourself in situations where you will need acceleration such as freeway onramps or pulling away when that stoplight turns green. Diesel engines have significantly more torque than comparable vehicles with gasoline engines, often resulting in faster acceleration.

Emissions

Diesel engines emit different types and amounts of greenhouse gasses so direct comparisons are difficult. But Edmunds.com ran a recent comparison of CO2 emissions from high mileage vehicles. Their results are listed below.

The champ: 2010 Toyota Prius with 0.55 pound of CO2 per mile or 0.214 total tons

2nd Place: 2010 Honda Insight with 0.62 pound per mile or 0.241 total tons

3rd Place: 2010 Ford Fusion Hybrid with 0.70 pound per mile or 0.274 total tons

4th Place: 2009 Volkswagen Jetta TDI with 0.74 pound per mile or 0.289 total tons

5th Place: 2009 Mini Cooper with 0.75 pound per mile or 0.296 total tons

The results from Edmunds.com demonstrate that while the Jetta did have more CO2 emissions than the hybrids in the comparison test, the Jetta actually had fewer CO2 emissions than small gasoline vehicles such as the Mini Cooper.

Tax Credit

The new crop of diesel vehicles can be slightly more costly than comparable gasoline powered vehicles. Perhaps this is why the federal government offers federal income tax credits from $900 up to $1,800 to offset this price difference and encourage their purchase new energy tax credit for diesels. Manufacturers that make clean diesel vehicles eligible for the tax credit include Volkswagen (5 models), Mercedes (6 models), BMW (2 models) and Audi (2 models).

So the next time you’re in the market for a high mileage vehicle, give clean diesels a look. You might be surprised by how far they’ve evolved.