In this article I'm comparing the diesel and the gas engine and discuss their differences. I'm specifically referring to their use in automobiles. Looking at them from a distance both the gas and the diesel engine work in about the same way. A fuel made from refined crude oil is burned inside a cylinder and the hot expanding gasses forces the piston to move. The movement of the piston is then transferred to the wheels through crankshaft, gearbox and transmission. It's when you look closer at the two engines that you start to see the differences. Difference in fuel economy, smell, vibration, expected age and price just to name a few. With a gas engine there is an ignition system that uses high voltage electricity with wiring and spark plugs. The diesel does not need this, it compresses the fuel/air mixture until it's so hot it ignites all by itself. In the gas engine it's the spark plug that ignites the fuel-air mixture through a high voltage spark at the right time. Also separating the diesel and gas engines is the fact that gas engines mix the fuel vapor with air in the intake manfold before it's entering the cylinder. The air/fuel mixture is then sucked into the cylinder and is burned the next time the piston passes the compression stage. On the other hand the diesel engine sucks fresh air into the cylinder and lets the piston compress it to maximum pressure. Fully compressed the air is hot enough to ignite disesel and at that point high pressure nozzles will start to spray fuel into the cylinder. The fuel ignites instantly due to the high temperature in the cylinder. The different fuel injection and combustion lets the diesel work more efficiently than a gasoline burner. That's why diesels have better fuel efficiency than it's gas burning relatives. This is not to say that a diesel is better. It's different, it has drawbacks too. A diesel engine is usually slow to start in cold, and especially in freezing weather. As you may remember it was the hot compressed air that ignited the fuel. When it's too cold outside the air will never become hot enough to ignite the fuel, and the engine won't run. That's why diesels have glow plugs that are used when starting a cold engine. Electrical power from the accumulator is used to preheat the glow plugs inside the cylinders before the engine is started. This way the hot glow plugs ignite the fuel when the air is not hot enough to do it. A couple of seconds after the engine has started it is usually hot enough to ignite the fuel without the help of the glow plugs and these are not used again until the next cold start. This is one of the things that might bother you when having a diesel engine in the car. Glowing can take from a couple of second to half a minute and can be quite a stress if in a hurry. You just have to wait until it's ready or the car won't start. On the other hand if the engine is well done the glowing does not take long and you soon get accustomed to it. Lets for a second look at the practical differences between the diesel and the gas engine. The diesel engine is large and loud and it produces clouds of black strinking smoke when accelerating. In addition it has a more robust construction because of the high compression is must handle and can usually go twice as many miles as the same size gas engine during it's life. The sturdier construction also makes it more expensive when first bought. Features of The Gas Engine
Features of The Diesel Engine
If I where to give you advice on selecting either a gas or a diesel powered car I would tell you this: Get a diesel if you drive long trips and can live with the small nuisances of more noise and poor acceleration. Get a gas powered car if you drive less than average or if you just want the comfort at any price.
Producer: Handy (Jam) Organization Audio/Visual: Sd, B&W Run time: 9:38
Diesel Story (1952)- Traces the development of the diesel from the Otto ‘SILENT’ gas engine of 1877, through Rudolph Diesel’s engine, to the machines that now drive…
