Tractors are the workhorses of modern agriculture and for good reason: they are powerful, versatile and durable. The heart and soul of these legendary machines is of course the engine, and over time designers have replaced the unpredictable and dangerous steam engines with internal combustion engines that are much more powerful, efficient and reliable. But how do they work? Read on to find out!
Brief history of tractor engines
When tractors were first developed, they used huge steam engines that were notoriously unreliable and difficult to maintain. These were phased out in the early 20th century and replaced by internal combustion engines that were more compact yet powerful and ran on a variety of fuels, including kerosene, ethanol, and gasoline. In the 1960s, many of these engines were replaced by more efficient internal combustion engines running on diesel and now biodiesel.
How Tractor Engines Work
Diesel engines have become the predominant power behind modern tractors because they have the highest thermal efficiency of any internal or external combustion engine, thanks to their extremely high compression ratio. Unlike gasoline engines, tractor diesel engines use hot, highly compressed air to ignite the fuel instead of spark plugs.
Once air enters the combustion chamber, it is compressed to 580 pounds per square inch (PSI), which heats the air to a temperature of 1022 ËšF (550ËšC). At this point, the fuel is injected into the combustion chamber by an injector that disperses the small fuel droplets evenly throughout the chamber. These tiny droplets of diesel fuel then vaporize when in contact with hot compressed air, causing rapid expansion of combustion gases that drive the engine’s pistons downward, creating power that turns the tractor’s crankshaft.
where the power goes
Tractor engines generate an enormous amount of power, from 18 to 575 horsepower or more. But that power does much more than just turn the wheels of the tractor. One of the reasons why tractor sales continue to rise around the world is that these machines are so versatile, thanks to their ability to transfer power from their massive engines. This power can be harnessed to operate stationary equipment that uses PTO or PTO systems and can even be used to supply hydraulic fluid and electrical power to tractor attachments trailing behind or alongside the tractor, such as mowers, windrowers, balers and plows.