Diesel engine and Petrol engine ( Comparison ) - Essay Example

Despite their derivation from crude oil, the use of petrol or diesel engine varies according to the particular needs of the consumer who will drive the automobile such as fuel prices, fuel efficiency, fuel economy, running cost, taxes, etcetera (“Choosing between petrol and diesel”, 2013; “Buying A Car - Do I Choose Petrol Or Diesel?”, 2012; Foxall, 2012; Ottley, 2010; Work Truck Magazine, 2011). In terms of their chemical properties, diesel is denser than petrol and generates more energy upon combustion (Bloom, 2010).

By design, a petrol engine consists of connecting rods, brasses, strap, jibs, cotter and set screws (Narayana, Kannaiah and Reddy 2007, 359). The major difference between a diesel engine and a petrol engine, apart from the different fuels, comes from the way in which fuel is combusted inside the piston cylinder. Fuel in the petrol engine is mixed with air, compressed by the pistons and then ignited by the spark provided from the spark plugs. On the other hand, a diesel engine differs in terms of the stage when air is compressed.

As opposed to a petrol engine, air in a diesel engine is compressed first after which fuel is injected and ignited as the air heats up after being compressed (Brain, 2014). This essay will present an evaluative comparison of diesel and petrol engines in terms of their design and functioning. The engine’s compression ratio concerns to the amount to which the gasses can be squeezed into the engine’s cylinder. The higher the engine’s compression ratio the more preferable it is because compression generates high amounts of heat (“Difference between Diesel and Gasoline Engines”, 2012).

Compression involves blending and evaporating the fuel and air molecules, which mix with each other appropriately by being thrusted together into a smaller and tighter area. High compression ratio in an engine enables the generation of greater power by burning fuel and