Currently, there are two main contenders in the internal combustion engine arena: gasoline and diesel performance engines. This has largely remained the same since the 1980s, but winds of change are beginning to alter the landscape.
The increasing popularity of hybrid and electric performance vehicles (such as the Tesla Roadster,) as well as rising emissions taxes, are taking their toll on the classic internal combustion technology that has kept the Interstate busy since its construction. In this article, we will take a look at the science behind these power plants and what new developments are going to radically change the way we look at transportation.
What Are The Differences?
One key difference between gasoline and diesel-powered engines (other than the fuel itself), is the way they achieve combustion. Internal combustion engines typically have four cycles: intake, compression, combustion (power delivery) and exhaust. Power is only generated during the combustion cycle and it’s critical for the fuel to ignite at the right moment to provide the necessary downward force on the piston to keep the engine running.
Gasoline and Combustion Engines
Gasoline performance engines require spark plugs to ignite the compressed mixture of fuel and air, while combustion in diesel engines is achieved by the high pressure of the fuel and air mixture in conjunction with the cylinder temperature as the piston reaches the top of its compression stroke. These high pressures make diesel engines more expensive to construct and also cause them to have higher torque coupled to lower revolution characteristics.
Combustion engines are basically huge air pumps. The more air they can move, the better their performance. By pressurizing the intake air supply the engine can produce more power for the same cylinder capacity. This is called turbocharging (exhaust gas-driven compressor) or supercharging (electrical or belt-driven compressor) and is becoming increasingly popular across the range of combustion engine vehicles in a bid to get more out of smaller engine displacements.
In the performance engine arena, diesel and gasoline are very different beasts. It would be foolish to outright recommend one type of engine over another since they have very different use characteristics. Let’s take an example:
If you’re a track or street racing enthusiast who likes rev-happy motors that sound gorgeous and frequently push the red line, without too much care for the economy then a performance gasoline engine is what you’d be looking for in your ride. Gas revs higher, is super responsive, and ideally suit a track-orientated driver.
If you burn miles traveling between states but still like to occasionally ‘floor it’ and feel those extra g-forces brought on by hard acceleration, then a diesel is ideally suited to your use. Porsche’s latest Cayenne S-Class diesel engines are very refined, powerful, and extremely economical engines.
There are clear advantages to owning a gas-powered or diesel-powered vehicle depending on what you intend using it for. With the advent of extremely competitive hybrid or fully electric vehicles (like Tesla), should that not be your future choice for a performance car? Perhaps not, according to Mazda. They are working on a new internal combustion engine design that uses the spark-less high compression diesel system except, it runs on normal gas. With this design, they claim that they can improve emissions and engine efficiency by 30%. Seeing will be believing, but anyone up for an extremely potent Miata?