EcoBoost is the trade name that the Ford Motor Company uses for its direct injection system. Chevrolet’s is called Ecotec, Mazda’s is called DISI, Volkswagen’s is GDI, etc., 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.)
Here is how it works. Direct injection utilizes precise control of both the volume and delivery timing of fuel. Precise amounts of fuel are sprayed under extremely high pressure directly into the combustion chamber. This differs from previous types of fuel injection systems where fuel is delivered “upstream” of the engine’s intake valve. Because, with direct infection, fuel is delivered directly into the combustion chamber, it can be delivered at various points in the combustion cycle, and it can 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, and the goal in all circumstances was to achieve an air/fuel ratio of 14.7-1. (This is known as the stoichiometric air fuel ratio which is by definition the correct ratio of air and fuel required to produce a chemically complete combustion event.)
A companion technology is variable valve timing. With variable valve timing, an engine’s intake and exhaust valves can be opened and closed at different points of the camshaft’s rotation. This differs from engines without variable valve timing where 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.
The downside of direct injection engines is that, because the fuel is injected directly into the combustion chamber, there is no fuel 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, which is a by-product of combustion. This can build up in the intake valves, on the intake valve stems, on top of the pistons, and on the cylinder walls. With older systems where fuel was introduced above the intake valves, the fuel would help 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, and 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 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.
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 the intake valves, and intake valve stems before entering the combustion chamber. Once the chemical has entered the combustion chamber, it cleans the cylinder walls and the top of the pistons, before being expelled out the exhaust valves which it cleans en route to the catalytic converter which can benefit from cleaning as well. This is one hard working chemical.
Introducing 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.