EcoBoost is the trade name that the Ford Motor Company uses for its direct injection system. Chevrolet calls it Ecotec, Mazda calls it DISI, Volkswagen’s is GDI, etc. The goal of direct ignition engines is to increase power and fuel economy while reducing emissions. Increased fuel economy and decreased emissions are two sides of the same coin, but I digress.
How Direct Injection Works:
Here is how it works. Direct injection utilizes precise control of both the amount and delivery timing of fuel. It sprays precise amounts of fuel under extremely high pressure directly into the combustion chamber. Previous types of fuel injection systems delivers fuel “upstream” the engine’s intake valve. Direct injection delivers fuel directly into the combustion chamber. So, it can deliver fuel at various points in the combustion cycle. Fuel can also be delivered whether the intake valve is open or not.
With previous types of fuel injection, throttle body and multi-port for example, fuel was mixed with air before it entered the combustion chamber. The goal in all circumstances is to achieve an air/fuel ratio of 14.7-1. (This is the “stoichiometric air fuel ratio,” the correct ratio of air and fuel required to produce a chemically complete combustion event.)
For more on this and an interesting diagram, click here.
Variable Valve Timing:
A companion technology is variable valve timing. With variable valve timing, an engine’s intake and exhaust valves open and close at different points of the camshaft’s rotation. In engines without variable valve timing, valves always open and close at the same point in the crankshaft rotation. With variable valve timing, a vehicle’s electronic ignition control can operate in one of three different combustion modes: ultra lean burn, stoichiometric, or full power, depending on required load. Amazingly, some vehicles in the ultra-lean mode can utilize air/fuel ratios as high as 65:1 for brief periods.
Downside to Direct Injection:
Because direct injection engines inject fuel directly into the combustion chamber, there is no fuel going through to clean the intake valves. (EGR systems introduce exhaust gas into the intake manifold upstream of the combustion chamber.) Unfortunately, the re-circulated exhaust gas will contain some amount of soot, a by-product of combustion. This can build up in the intake valves, the intake valve stems, on top of the pistons, and on the cylinder walls. Older systems introduce fuel above the intake valves, which helped remove carbon deposits.
With direct injection, fuel no longer flows over the intake valves, and carbon buildup can result. Moreover, because precise amounts of fuel are delivered with direct injection system, there is not enough fuel to wash a vehicle’s cylinder walls. Carbon buildup can occur there and on top of the pistons as well. Carbon buildup will degrade performance, and, in severe cases, carbon deposits can break off and ruin catalytic converters.
“How do I prevent carbon buildup in my direct injection engine,” you ask? Thanks for asking. The best way to avoid carbon buildup in your engine is to maintain the proper oil change intervals and to change air filters and PCV valves as needed. Use high quality fuel with the octane rating suggested by your vehicle’s manufacturer, and be sure to use the correct viscosity motor oil. We feature Castrol products, and we recommend Castrol Edge.
Carbon Buildup Removal:
The best way to remove any carbon buildup in your fuel system is to have an induction service performed. Sant Automotive utilizes a three step system to perform this service:
- One chemical atomized and sprayed through the air intake, usually through the throttle body. This process cleans the throttle body, air intake, and in the intake valves, and on intake valve stems before entering the combustion chamber. Once the chemical has entered into the combustion chamber, it cleans the cylinder walls and the top of the pistons. Before being expelled out the exhaust valves, it cleans the catalytic converter, which can benefit from cleaning as well. This is one hard working chemical.
- We introduce a second chemical through the fuel system insures that the high pressure fuel pump, fuel rails, and fuel injectors are cleaned.
- The third chemical is a detergent that is added to your vehicle’s engine oil. Its purpose is to clean deposits off of the cylinder walls that were not removed by the other two chemicals. Additionally, it helps to remove carbon, dirt, and debris from all lubricated areas of the engine.
Direct injection is one of the technologies that hold the promise to increase fuel economy and help the environment. But, there are still some drawbacks to it. Enjoy the increased performance and fuel economy, but be aware of the maintenance needs.
If you have any questions, please call Sant Automotive at 314-849-2900.