Q & A: My New Car Has Gas Direct Injection

I just bought a new car with a GDI engine in it. I don’t really understand what that means. Can you please explain it?

 AutoPro in Worcester Answers:

GDI stands for Gasoline Direct Injection. Many newer engines in Worcester have this type of fuel injection system. There are two common types of fuel injection systems in most cars: Port Fuel Injection & Gasoline Direct Injection. Both systems introduce fuel into the combustion chamber but at different points.  Port injection delivers the fuel into the valve port and direct injection delivers it directly into the combustion chamber.

Now let’s get into a little more detail on how they each work to power the engine.

Port Fuel Injection:

• A bit of fuel is squirted in the port before the intake valve opens.
• When the valve opens, the air enters the port and mixes with the fuel. The air/fuel mix flows passed the valve and into the engine.
• The piston compresses this air/fuel mixture.
• Then the spark plug fires and ignites the air/gas. This combustion pushes against the piston and powers the engine.

Gasoline Direct Injection:
• The set up is different for GDI. There is not port outside the cylinder.
• The air gets pulled into the cylinder when the intake valve opens.

• The piston compresses the air.
• The emc (engine management computer) signals the fuel injector to spray the fuel directly into the cylinder.
• Then the spark plug fires and ignites the air/gas mixture. This combustion pushes against the piston and powers the engine.

So why have car manufacturers moved to GDI? There are a few good reasons for this change. With the fuel being injected directly into the engine, the ECM is able to time the injection more precisely. This combined with the cooling effects on the compressed air (read: better combustion), means more power and better fuel mileage around Worcester for any given size engine.  

Since both systems function differently, they also need maintenance in different ways. In the port injection system, the gas flows over the intake valves and acts as a natural cleaning agent. This in conjunction with periodically adding fuel system cleaner into the gas tank, helps keep the old style injection system clean.

Adding fuel system cleaner into a GDI system will not come close to keeping the system clean of carbon build up; the cleaner cannot reach the backside of the intake valves. When the intake valves become clogged with carbon, the vehicle will experience running issues. Call AutoPro to set up an appointment to professionally clean your GDI fuel system.

With more cars, trucks and SUVs around the Worcester area having gasoline direct injection, make sure your fuel system is cleaned as needed. Preventive maintenance is always cheaper than costly repairs.

Give us a call today!

AutoPro Import Repair
209 Stafford St