What is the key difference between diesel high-pressure fuel systems and gasoline port-injection systems?

What is the key difference between diesel high-pressure fuel systems and gasoline port-injection systems?

• A. Diesel uses very high-pressure delivery with direct injection and no spark, while gasoline uses lower pressure with spark ignition and can be port or direct injection.
• B. Diesel uses low-pressure delivery with spark ignition, and gasoline uses high-pressure direct injection.
• C. Diesel uses turbocharging to create pressure, whereas gasoline relies on atmospheric pressure.
• D. Diesel and gasoline use identical fuel pressures and no spark differences.

Answer: (A)

The main difference is how and where the fuel is delivered and how the mixture is ignited. Diesel engines rely on compression ignition: air is compressed to a very high temperature, and fuel is injected directly into the combustion chamber at extremely high pressure, causing auto-ignition with no spark plug needed. In contrast, gasoline engines that use port injection spray fuel into the intake port at relatively low pressure, where it mixes with incoming air before entering the cylinder, and the mixture is ignited by a spark in the cylinder. This ignition method and the injection location set the two systems apart.

The main difference is how and where the fuel is delivered and how the mixture is ignited. Diesel engines rely on compression ignition: air is compressed to a very high temperature, and fuel is injected directly into the combustion chamber at extremely high pressure, causing auto-ignition with no spark plug needed. In contrast, gasoline engines that use port injection spray fuel into the intake port at relatively low pressure, where it mixes with incoming air before entering the cylinder, and the mixture is ignited by a spark in the cylinder. This ignition method and the injection location set the two systems apart.