What are the two main categories of internal combustion engines?
2 Answers
Internal combustion engines are divided into two main categories: water-cooled and air-cooled. Below is a detailed classification of internal combustion engines: Classification by fuel type: Based on the type of fuel used, they can be categorized into gasoline engines, diesel engines, and gas fuel engines. An internal combustion engine that uses gasoline as fuel is called a gasoline engine, while one that uses diesel is called a diesel engine. Gas fuels mainly include natural gas, liquefied petroleum gas, and other similar fuels. Classification by stroke number: According to the number of strokes, they can be divided into four-stroke and two-stroke engines. A four-stroke engine completes one working cycle with the crankshaft rotating twice (720 degrees), during which the piston moves up and down four times in the cylinder. A two-stroke engine completes one working cycle with the crankshaft rotating once, and the piston moving up and down twice in the cylinder. Four-stroke internal combustion engines are widely used in automotive engines.
When it comes to internal combustion engines, having driven for over 30 years, I've mostly encountered two major types. One is the gasoline engine, also known as a spark-ignition engine, which relies on spark plugs to generate sparks for ignition—much like using a lighter to ignite a stove in the kitchen. It's direct, quick, and well-suited for cars and urban commuting. The other is the diesel engine, or compression-ignition engine, which works by compressing air to extremely high temperatures before injecting diesel fuel to ignite spontaneously. It's more efficient but noisier, making it more common in trucks and long-distance vehicles. This classification is classic—I've understood it since my younger days. Older diesel cars may start slower but are more fuel-efficient, while gasoline cars respond instantly when you hit the throttle. Overall, grasping this distinction helps us make better choices when selecting or maintaining vehicles.
