How does the Ford Fusion EcoBoost engine work?





Ford has the most advanced series called the “EcoBoost Engine” which began production in 2008. This engine was the successor to the now obsolete “TwinForce” series of engines.

So what exactly is unique about this engine that you will not find anywhere else? Ford describes a small part of this innovative technology as using “Direct Fuel Injection”.
Invented and used by Jonas Hesselman in 1925, it was refined and improved by the Ford Motor Company in the 1970s.

If I recall my basic O’ Level Physics, and helping my dad fix his car, a car engine that burns hydrocarbon fuel has four strokes called induction, compression, power, and exhaust. Induction is the only stage when a mixture of air and fuel enter the cylinder through the intake valve.

In a Direct Fuel Injection system, the fuel alone injects directly into the cylinder via a dedicated fuel rail line. Injected at a high pressure, the fuel may enter during any stage of the 4-stroke cycle. This method of directly introducing the fuel into the combustion chamber produces a bigger 'bang' during the power stroke.

An advantage of this method is that less fuel is used. This is commonly knows as ultra lean burn because the ratio of air to fuel can be as much as 65:1. This of course has the added advantage of lowering the waste emissions by 15 % and increasing fuel efficiency by around 20 %.

The Ford Engine Management System can vary the timing of the injection. For an ultra lean burn mode, it injects the fuel during the compression stroke.

Injected at pressure, the vapour settles at the centre of the cylinder close to the spark plug, whilst around it is an envelope of mostly air. During the power stroke - when the fuel ignites - the air that was surrounding the fuel behaves as a cushion and prevents the heat energy from escaping through the cylinder walls. This helps to keep the cylinder walls cooler and prevents the fuel from pre-igniting.

The Engine Management System typically determines the amount of fuel injected and its timing.

Turbocharger





The EcoBoost engine also has an integrated turbocharger. The exhaust gasses from the engine contain a lot of energy, in the form of gas molecules with a high kinetic energy. I knew my Physics would come to use one day…

All of these molecules with energy would normally go to waste through the exhaust; however, the turbocharger is able to make use of this energy. These gasses drive the turbine blades of the turbocharger. This makes the engine more efficient compared to conventional engines.

As shown in the diagram above, the shaft of the turbine blades connects to the compressor. The compressor section, shown in blue, sucks the air from outside and forces it back out at a great pressure. This highly pressurised air fed into the cylinders of the main engine produces a bigger bang.

Compressed air contains a larger amount of oxygen. When the fuel is ignited during the power stroke, there is a greater energy output - bigger bang - because the mixture contains more oxygen, which behaves as a catalyst. I knew my Chemistry would come to use one day…

By using a combination of both, direct fuel injection system, and pressurised air from the turbo charger, the EcoBoost engine is one of the most highly efficient engines ever produced for the automotive industry. This is a technology well worth having in a car.


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Author: Peter J. Vis