One of the frequently asked questions to me from numerous people was "How diesel engine differs from a gasoline engine"
Both are internal combustion engine, both of them run on a 4-stroke cycle known as Otto-cycle, both convert chemical energy of fuel to mechanical energy by a series of small explosion in large number. So what's the basic difference, huh. The basic difference lies in the way fuel is induced in both the engine's cylinder. For better understanding of Diesel engine, do read our "How gasoline engine works" or 4-stroke engine works section and come back fast because now unfolding the biggest mystery of engineering that How Diesel Engine Work.
Technically, the difference between these engine lies in their Intake Stroke and Compression Stroke. In diesel only air is induced into the cylinder during Intake Stroke. Now piston moves up and compression stroke begins, this compresses the present air in the cylinder. The temperature of the air increases because on compressing or on reducing its volume the temperature of the air increases. Once the piston reaches the top or compresses the air fully, fuel is induced in the system. The temperature of the cylinder or system is high enough to ignite the fuel sprayed. An explosion occurs or Combustion Stroke begins this drives the piston back and after-that emission Stroke Occurs.
Diesel engine too have a 4-stroke cycle. These are:
- Intake stroke-Air is induced in the cylinder via intake port or pipe.
- Compression Stroke- Now the air present is compressed in order to increase the temperature of the air and also of the system.
- Combustion Stroke- Once the piston has completed the combustion stroke, fuel is introduced in which explodes due to high temperature of the system. This drives the piston back and hence combustion stroke comes into play.
- Emission Stroke-Now the piston comes back to remove the waste gases via exhaust port.
Everyone has its pros and cons. Let's talk about the advantages and disadvantages of a diesel engine.
- Highly fuel efficient engine. Have a greater mileage than that of gasoline engine
- Powerful boost. Diesel engine have less weight to compression ratio of cylinder and hence able to give much horsepower than a gasoline engine of its weight.
- Emit less CO2 and CO
- Produces sooty smoke, full of hydrocarbons leading to acid rain.
- It also generate nitrogenous compound which are very much harmful for the environment.
- These diesel engine has made their image like making clattering sound while moving. This is also posing a negative image on diesel engine while most of the gasoline engine don't produces much sound.