Forklifts are classified as vehicles with small engines. Forklift engines all follow the principles of internal combustion, while the numerous models and makes of lift truck will have a different layout and design. Forklifts are made more toward generating high torque than for speed. They usually are geared to low speeds. The engine powers the forklift's drive wheels. The engine is also required to lift and lower the forks via a series of chain pulleys. Nearly all modern lift truck engines are fueled by propane as they would be utilized for indoor applications, where diesel and gasoline engines would be unsuitable due to the exhaust they make.
Normally, the lift truck is a four-cylinder engine-block. The engines of the forklift are like car engines because they contain pistons connecting to a camshaft. The head of each and every cylinder consists of a spark plug, an intake hatch and an exhaust hatch, each of them spring-loaded and one-way.
Propane passes through the opened throttle-plate in a fine spray, when the driver starts up the forklift engine. This fine spray mixes together with air that comes from the mass air intake before moving into the cylinder's head intake hatches. Every one of the four pistons is staggered to rise in an exact sequence, compressing the mixture of air and propane as every piston rises to the top of the head. With extremely precise timing, the engine's alternator and battery generate an electrical current which passes through the spark plug. The fuel ignites causing an explosion that drives the piston back down to the bottom of the cylinder, causing a continuous turning of the camshaft. In the cylinder, an air pressure imbalance causes the exhaust to be drawn out through the exhaust hatch when more fuel passes into the cylinder. Propane burns cleaner than diesel and gasoline and the exhaust is not as harmful.