European Union regulation is responsible for much of the diesel’s popularity in Europe – and pending EU rules will cause a swing back to gasoline-powered cars after 2010, say two engine researchers.
Diesel engines are more expensive to produce than gasoline versions, but now manufacturers prefer diesels because they offer better fuel economy, which reduces CO2 emissions, says Rinaldo Rinolfi, director of the engine division of the Fiat Research Center near Turin.
“Diesels will be crucial to permit carmakers to meet the 140 grams per kilometer [of CO2 emissions] commitment they have set for 2008,” he says. “Diesels emit 20 percent less CO2 than a comparably performing gasoline engine.”
To meet a voluntary commitment to cut per-vehicle CO2 emissions in the EU to 140g/km by 2008 and a tentative second stage of 120g/km by 2012, European automakers are also designing more fuel-efficient gasoline engines.
A key part of the new engines is turbocharging, which lets smaller, lighter engines deliver the same power as larger engines.
“Turbocharging is expanding in all segments,” says Ken Watkin, vice president of engineering for Honeywell Turbo Technologies in Morges, Switzerland. “The driver is legislation, mainly CO2 reduction.”
But pending EU rules to cut emissions are changing the equation. Diesels that can meet expected limits for Euro 5 in 2010 and Euro 6 in 2015 will simply cost so much to make that Rinolfi expects demand for gasoline cars to rebound.