We know, we know. Diesels are loud, smoky and you can only buy the fuel at truck stops. Right? Ummm…ask us again next year when a new kind of diesel vehicle makes its way here, powered by cleaner fuel called Ultra-Low Sulfur Diesel (ULSD), and by quieter, more powerful and efficient engines that are clean enough to be legal in all 50 states.

Take that, you California tree huggers.
Up to now, five critical states, California, Maine, Massachusetts, New York and Vermont, pretty much do not allow the sale of diesel vehicles. That changes when the federal government makes everyone happy (except, perhaps, truckers) and establishes a uniform emissions standard for diesels. But wait a minute. All the fuss about diesel engines is because they are inherently different than gasoline-powered engines, in the way they work and what people get out of their use. Invented by Rudolph Diesel in 1892, the diesel was first demonstrated by using peanut oil – an interesting bit of irony for biodiesel fans. A diesel engine works without spark, unlike a gasoline engine, which is why it’s called a “compression ignition engine.” Where a gasoline engine uses a sparkplug, the diesel engine uses high temperature and compressed air to light the fuel. This makes the ratio of diesel compression higher than gasoline compression, which makes it more efficient, but heavier. When combined with richer fuel (more power per stroke) and turbochargers, this gives diesel cars more low-end torque for better off-the-line performance, but less horsepower than a similar gasoline engine. Mainstream diesel fuel results from the same oil refining process that gives us gasoline, but its place in that “spectrum” means that it contains more energy – thus better fuel-efficiency -- but also more sulfur – thus the putrid clouds of pollution, the evil eye from the California Air Resources Board (CARB), and the subsequent change to federal standards. As a result, expect to see current diesel vehicles go away, replaced by diesel vehicles with engines that meet the new emissions. This includes automakers that previously did not bother selling diesel versions of their vehicles in the US, such as Honda, which announced recently that they will begin selling a four-cylinder diesel vehicle in the US within three years, with a six-cylinder engine to follow. Someday soon, you can expect to see a Honda Odyssey diesel minivan, and a diesel Acura RDX SUV. Based on recent news, happy automakers selling diesels in the US – that would be Jeep, Mercedes-Benz and Volkswagen -- are planning to end production of existing models while making plans to introduce new models that meet the new requirements, and to watch demand for their new diesel vehicles skyrocket. A good example is Jeep: by killing the niche Jeep Liberty diesel and, at the same time, introducing the new 2007 Jeep Grand Cherokee diesel, Chrysler can usher in the Mercedes-Benz Bluetech diesel technology, confident that SUV buyers will appreciate the performance, efficiency and durability of a good diesel engine – one that reaches the average emissions requirements, from “California to the New York Island.”

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