Against the backdrop of the VW emissions scandal, some manufacturers persist in offering diesel engines. You won’t find a lot of diesel cars, SUV’s and trucks about, but for some drivers diesel offers definite advantages.
Diesel Engine Strengths
Diesel engine pistons have a longer stroke than those in gasoline engines. That provides the compression necessary to ignite the fuel, but it has a very attractive side effect: bags of torque. Torque, measured in pound-feet, creates strong acceleration at low engine revs. It helps a car get off the line quickly, and provides plenty of grunt for overtaking.
To give an example, the 3.0 liter V6 diesel found in the Ram 1500 and Jeep Cherokee makes 420 lb-ft even though power is a relatively paltry 240hp.
The second thing diesels have going for them is efficiency. They get better mileage on the highway and around town than a gasoline equivalent. The Chevy Cruze diesel is rated at 46 mpg Highway while the BMW 328d achieves 45 mpg on the highway. And yes, you read that right, BMW builds diesels!
Diesel Engine Negatives
Everyone would drive a diesel, if it weren’t for these downsides:
- Diesel fuel is often more expensive, which counteracts the savings from better mileage.
- Emissions control needs urea injection. That’s another tank of fluid to top up.
- Noise. Modern diesels are well soundproofed but they still rattle more than gasoline.
When a Diesel Makes Sense
There are two situations when it’s worth considering a diesel-engined car or truck. First, if you drive a lot of miles, especially highway miles, the superior efficiency can lower your fuel bills. Second, if you carry heavy loads or do a lot of towing you’ll appreciate the low-down torque.
The Future for Diesel
Never highly regarded, diesel’s reputation took a knock when VW got caught rigging their EPA fuel efficiency tests. At the same time, economy-minded drivers now have hybrid vehicles to consider. Most hybrids get comparable mileage to a diesel, but without their negatives. (Plus, your neighbors will probably think better of a hybrid on your driveway than a diesel.)
To sum up, diesel engines have a place, but it’s probably under the hood of a truck that’s going to do a lot of towing. Meanwhile, diesel cars will probably get rarer than they already are.