Speaking during a live chat, Tacoma and Tundra chief engineer Mike Sweers was unequivocal. “We will not be offering a diesel engine,” he said. “We’ve looked at diesels, and diesel is a difficult topic right now because of the new Tier 3 emission regulations.”
Those Tier 3 regulations, set in place by the Environmental Protection Agency, are set to take effect in 2017, further reducing tailpipe emissions and, as a result, making diesel-powered light vehicles harder to pass, not to mention more expensive to build.
Sweers is aware of the obvious advantages of a diesel engine. “Diesel, from a fuel economy standpoint, is about a 30 percent improvement right out of the box,” he said.
However, that’s not enough to offset the negative aspects of diesel engines.
“The downside to diesel is the emissions has to be certified at the same level as a gas engine,” said Sweers. “So the way to do that is you have to put on an after-treatment system.” That system, he claims, would add as much as $3,000 to the cost of a vehicle.
“So if we consider that cost, versus the fuel economy improvement, and the fact that diesel is $1 more per gallon more than gasoline, is there a return on the investment,” asks Sweers rhetorically.
Even if the answer is yes, Sweers wouldn’t bet on diesel tech for the future, pointing to further emissions regulations taking effect in 2019 that could then shelve certain engines. “Can you make that diesel survive? Is it a two-year engine? Is it a four-year engine? That’s the question,” said Sweers. “It’s very difficult to show a return on that investment.”