When engines are being described, the displacement volume of the engine is always noted. This displacement volume is always indicated in litres. For example, a 2.5-litre engine means that the engine has the displacement volume of 2.5litre or 2500 cubic centimetres(cc).
What this means is that the quantity of fuel the engine can burn at any particular time will be burnt in a 2500 cubic centimetres volume… You still don’t understand right? Let me explain this very well, shall we? In every engine, there’s a reciprocating part(forward and backward movement), called Piston.
When the piston reciprocates in the ‘cylinder’. It does so between two ends, Top dead centre (TDC) and bottoms dead centre (BDC) the volume covered when the piston reciprocating in the cylinder is called the “swept volume”.
If the engine is made up of more than one cylinder( maybe 4 or 6), the addition or all the swept volumes of the piston in the cylinders give you the displacement volume. For example, in a 1.2-litre four-cylinder engine, the total displacement volume for the four cylinders is 1.2 litre or 1200 cubic centimetres.
This means that the swept volume of each individual cylinder is equal to 1200 divided by 4, which is equal to 300cc or 0.3 litre. The displacement volume is therefore the total volume or space where fuel combustion occurs in an engine.
How do all these affect the performance?
The total performance of an engine that is the Horsepower, Torque, Acceleration and so on depends on the quantity of fuel it can burn when the Piston inside the cylinder reciprocates once.
One can only add a limited amount of fuel to the cylinders( only the quantity the displacement volume can contain) and to burn this fuel in the cylinder you also need a certain amount of air. If there’s no space for enough air in the cylinders, some or most of this fuel will be unburnt and will mess up the engine block with some coming out through the exhaust as thick greasy deposits which can lead to clogging.
Therefore for you to get more performance from your engine, you need to burn more fuel and to burn more fuel you need to suck in a lot of air into the cylinder. One way of achieving this is to have a larger capacity cylinder which will, in turn, have a higher capacity to hold air and so can burn more fuel producing better performance.
A bigger engine is therefore equal to a better performance from your car. However, it is important to note that having a bigger engine also comes with a price too. This comes in the form of lower the price of the car being higher, and the fuel efficiency is significantly lower. A bigger engine with a larger displacement volume means more fuel being consumed even at low speed when the improved performance is not needed.
So if you are tired of the low performance of your small engine and can afford the cost of purchasing and maintaining a bigger displacement engine, you are sure to get a better performance from it no doubt.