Primer on Automobile Fuel Efficiency and Emissions - Pollution Probe

Table 3-2: Engine Technology and Fuel Savings continued
Technology
Fuel Consumption Reduction
Potential for Average North
American Vehicle
Gasoline Direct Injection (GDI) – In conventional engines, the air and fuel is mixed
prior to entering the combustion chamber. Using GDI technology, the air is drawn
into the chamber first and then the fuel is added directly into the cylinder with an
injector. This allows more precise control over the air-fuel mix ratio which results in
optimal combustion. It also helps reduce pre-ignition allowing for more fuel to be
injected, resulting in increased power output.
Up to 6 per cent
Homogeneous Charge Compression Ignition (HCCI) – In a conventional gasoline
engine, the ignition timing is controlled by a spark. In HCCI the fuel is ignited by the
air-fuel mixture heating during compression. In order to control the timing of ignition
in HCCI the air-fuel mixture must be tightly controlled and thoroughly mixed inside the
combustion chamber. Controlling the timing of ignition continues to be a challenge
for designers of HCCI engines.
Up to 20 per cent
High Speed Direct Injection Diesel (HSDI) – Electronically controlled high-speed
multi-pulse injectors in diesel powered vehicles improve air-fuel mixing through
multiple injections and injection pulse patterns. HSDI can significantly reduce engine
emissions allowing for the use of simpler, cheaper exhaust after-treatment systems.
HSDI has the potential to better control combustion and reduces vibration.
Up to 25 per cent
* NOTE: REDUCTION FACTORS ARE NOT ADDITIVE
<strong>Primer</strong> on Automobile Fuel Efficiency & Emissions
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