Cleaner Diesel Engines Wooing Americans

Most Americans have a bad impression of diesel cars. We recall the days when diesel engines smelled terrible, were difficult to start and were known to be terrible polluters. But things are changing.

Today, diesel powertrains are on the map again, for both car manufacturers and efficiency-minded drivers. The technology could be here to stay as it is giving even hybrids a run for their money. As for the emissions problems, well, those are of the past also. Today’s new diesel engine is running smoother and cleaner. Having modified diesel fuel helps in this arena. In response to 2006 EPA mandates, oil refineries are now producing what’s called ultra-low-sulfur diesel (ULSD). By definition, this “clean diesel” has sulfur concentrations of no more than 15 parts per million (ppm). That’s 98.5 percent cleaner than diesel gas of the past. The cut in sulfur means that less sulfur dioxide goes into the atmosphere, where it can combine with water to produce sulfuric acid—and thus, acid rain.

In addition, sulfur clogs emission-control devices in diesel-powered cars the same way lead impeded catalytic converters in gasoline systems. Removing the lead from gasoline enabled engineers to develop a new generation of emission-control technologies that helped reduce noxious exhaust emissions by 98 to 99 percent.

With this, carmakers have already started building exhaust-scrubbing systems for engines that burn ULSD.

So to sum up what the new diesel engine will provide:

1. Advanced electronic engine control modules that regulate functions, from fuel injection to timing, more precisely than old mechanical control systems, further minimizing emissions and maximizing fuel economy.
2. Turbochargers that pump more air into the engines, helping to overcome diesel’s former sluggishness at higher rpm.
3. Improved engine isolation strategies, such as the incorporation of active mounts, has quieted the knocking noises typically associated with diesel-powered vehicles.
4. Running a vehicle on a fuel that contains more energy per unit volume than gasoline. Each time the mixture in a diesel engine’s cylinder ignites; the car gets a slightly bigger push than it would in a gasoline engine. That means it takes less fuel to move the car down the road. It also means that the engine generates a lot of power even when it isn’t cycling fast.

Will Americans be willing to trade in their regular cars for something that runs on diesel? Price and availability may determine that answer followed by those who are willing to give diesel another shot.