Definitions: Direct Injection
Pros: Direct injection improves both power and fuel economy by making the engine more efficient.
Cons: Costs more; engineers are still working out the kinks
Summary: If you're shopping for a car and you see the term "direct injection," it refers to a system that channels fuel into the engine more efficiently than conventional multiport fuel injection.
Direct fuel injection (DI) was invented more than a century ago, but it has only recently emerged as a trendy automotive technology. The reasons for its popularity are clear: It improves both acceleration and fuel efficiency. Sounds like a win-win situation, right?
Mostly, it is. DI engines are impressive already and getting better by the year, so there's no doubt that the technology is here to stay. And DI is available on cars of all pedigrees, so whether you're looking at a Kia Sorento or a high-end Lexus, DI will be in the mix.
However, there are some drawbacks worth mentioning.
First, there's no such thing as free horsepower and miles per gallon, so you won't be surprised to hear that DI engines cost more than comparable conventional engines.
And then there are the inevitable growing pains as engineers get comfortable with modern DI technology. Audi had some issues with carbon buildup in the engine valves, for example, and BMW was burning through a lot of fuel pumps for a while. It's still a hotly debated question whether DI engines are as dependable over the long haul as regular ones. The answer is probably "yes," but just keep in mind that it hasn't been perfectly smooth sailing for DI thus far.
You can buy DI with confidence, as the pros outweigh the cons. But make sure you follow the manufacturer recommendations for special treatments, fuel additives, scheduled maintenance and so forth.