Last Updated Sep 22, 2010 11:13 AM EDT
Combined with direct injection, which squirts gasoline into the engine in high-pressure, computer-controlled bursts, turbocharging can produce more horsepower with lower fuel consumption. A turbocharger forces more air into the combustion process. The net effect of the two technologies is to get more power out of a given amount of fuel, and with no increase in emissions.
BMW, (BAMXY.PK) Ford (F), General Motors and others are all rolling out turbo engines with direct injection. BMW, for instance, recently announced that several of its 2011 models will get a new generation of engines featuring turbos and direct injection, including the BMW 535i Gran Turismo (pictured).
Ford calls the combination of turbocharging and direct injection EcoBoost. When I first heard the term, I thought it was more than a little ironic, because us Baby Boomers associate turbos with high performance, and not with better gas mileage -- in other words, not exactly what you would call eco-friendly. If anything, the same size engine with turbocharging alone is likely to get worse gas mileage.
However, direct injection more than makes up for the potential loss of fuel efficiency, so the combination of a turbo plus direct injection really does allow an automaker to substitute a smaller and therefore more fuel efficient engine for a bigger and less fuel-efficient one, like a four-cylinder engine for a six-cylinder, or a 6-cylinder for a V-8.
Honeywell (HON), a major supplier of turbos for the global car companies, recently said that in the United States, the company expects turbos to grow from around 1 million units annually today, or about 5 percent of the market, to more than 4 million, or more than 20 percent of the market.
Worldwide, the supplier expects turbo sales to double in the next five years to 35 million. That includes a doubling of turbo share in China, from about 10 percent today to 20 percent by 2015.