How Do Diesel Motors Work?
- Much like a conventional gasoline engine, a diesel motor is an internal combustion engine that converts fuel to mechanical energy that can move pistons up and down inside the engine. The pistons are connected to a crankshaft that turns the linear motion of the pistons into a rotation that propels the vehicles wheels. Both types of engines require small explosions (combustion) from the mixture of fuel and outside oxygen to release the energy required to propel a car forward.
- The primary difference between the two types of engines is the process through which this internal combustion occurs. Conventional engines require spark plugs as a means of igniting the fuel. Diesel engines use higher temperatures to create higher air compression that causes the fuel to combust on its own without the help of spark plugs.
- Gas heats up when it is compressed, and this is the principle the diesel engine relies on in its use of energy. In the first step of the process, the diesel engine brings air into the cylinder as the piston moves away to clear space for it. When the piston comes back towards the intake valve, it compresses the air that was just brought in and heats it at the same time. Fuel is then injected under high pressure as well as the piston reaches the end of its compression. The high temperature of the air ignites the fuel, which causes the gases in the chamber to rapidly expand and force the piston back down. As it comes back up, it pushes used gases out of the cylinder and intakes another breath of fresh air to repeat the process all over again.
- Diesel engines can be much more powerful than conventional gasoline engines, which is why diesel engines are used for larger vehicles such as semi-trucks. Diesel engines can be very fuel efficient when running properly, up to 15% more efficient than regular gasoline engines. Diesel fuel can start to freeze in the engine in colder weather and lead to a condition called "waxing" where it starts to form crystals in the engine and fuel lines. Because diesel engines rely heavily on heat and compression to generate their power, they can be hard to start in colder weather. Heaters have been built into them in recent years to help solve this problem, and fuel additives can help prevent waxing. One of the biggest strikes against the use of diesel engines remains the larger amount of emissions it creates during operation, especially nitrogen oxide and unburned hydrocarbon emissions.