With diamonds, bigger is not always better. Often it is about color, clarity, and cut. Similarly with engines, bigger doesn't necessarily mean better. While most people think that big-sized engines are always better, it is not necessarily correct. Recently we have seen smaller modern engines with low fuel consumption and advanced technology that are just as powerful as the larger engines.
What the Numbers Mean
You must have noticed items such as 1.8L, cc or engine displacement when looking through the engine specifications. Well, all these terms are useful in describing engine size, which you determine by the total volume of its cylinders. The number of cylinders in an engine usually varies from 3 to 12 for most cars. However, there are other unconventional cars in the market with as many as 16 cylinders or as few as 2.
Generally, supercars are the ones that pack many cylinders in the engine.
But what does engine displacement mean? Many questions surround the engine's displacement, including how it relates to fuel economy, how it affects the car’s performance, and why it matters.
We will clarify these things so that next time you buy a car, you will know what you’re getting.
Setting the trend today are small engines with smaller cylinders for fuel-efficiency. These engines are then coupled with a turbocharger to compensate for their small size. Generally, small engines that have a turbocharger generate more power compared to the large non-turbocharged types.
Turbochargers
Turbochargers are devices attached to engines, especially small engines, to boost the power they generate. They also contribute to fuel efficiency since these smaller engines use up less fuel but produce as much power as larger engines.
You can quickly identify a turbocharged engine by the letter "T" alongside the displacement specification. For instance ‘1.8T’ denotes a 1.8L engine with a turbocharger.
What Is Engine Displacement?
Engine terminologies can sometimes be confusing and boring. While not everyone is a car aficionado or wired towards the mechanic side of automobiles, people who are looking to own or drive a car must know the basics of an engine.
Engine displacement is the combined swept (or displaced) volume of air resulting from the up-and-down movement of pistons in the cylinders. In this repeating vertical motion, the pistons get to the highest point (Top Dead Centre) to the lowest (Bottom Dead Centre) and then back. Regardless of the number of cylinders your engine packs, calculating displacement follows the same procedure.
Aside from the number of cylinders, you also need to consider the bore and stroke. The bore of a cylinder refers to its diameter. The stroke refers to the distance the piston covers as it moves up and down.
Engine displacement is expressed in units of litres. For instance, most modern cars run on a 2.0-litre four-cylinder engine, which means that each cylinder has a capacity of a one-half litre or 500cc. Cool, right?
So, what does this mean?
The abbreviation 'cc' stands for cubic centimetres, also written as 'cm3'. It is a unit of measurement representing the engine's capacity.
In simple terms, 1cm3 refers to the volume of a cube with measurements of 1cm×1cm×1cm.
The terms engine capacity and engine displacement are interchangeable, which explains why the engine capacity sometimes comes in units of litres or the corresponding cc.
An engine with a displacement of 1000cc has a capacity of 1000cc or 1 litre, so that:
1000cc = 1000 cm³ = 1 Litre = 1.0L
How to Calculate Engine Capacity
You can find out the engine capacity of any car engine by the mathematical formula below:
Capacity = π/4 x (D) ² x h x N
Where D = Diameter of the cylinder or the Bore
h = Stroke
N = Number of cylinders in an engine
As you can see, the individual capacities of all cylinders are combined to obtain the engine capacity.
If your car has four cylinders and its engine capacity is 1.0L, then the 1.0L refers to the combined capacity of the four cylinders. It implies that all the four engines can accommodate a maximum volume of air/fuel of 1.0L.
Hypothetically, if the same car had a single-cylinder, then it would mean that the cylinder has a capacity of 1.0L. It is interesting to know that the Mercedes Benz MotorWagen had one cylinder in its 1.0L engine (954cc to be precise)
Before the 1980s, the standard unit for measuring engine capacity was cubic inches. One litre is equivalent to 61 cubic inches.
How Engine Capacity Affects a Car's Performance
In case you have not figured it out yet, the engine capacity plays a crucial role in determining the power, torque, as well as the mileage of your car. Power (expressed in HP or kW) and torque (expressed in Nm) are the frequently used measurement of the forces developed by an engine.
These two measurements are sometimes misunderstood. Torque refers to the rotational force that represents pulling power. You can think of power as a function of torque and engine speed which represents the maximum power an engine can develop.
Cars with high-power and low-torque engines start slowly but gain the pace as the engine starts spinning faster. On the other hand, vehicles with high-torque and low-power engines start very strongly but slowly fade as the engine speeds up.
If the engine specification states that it is 100HP rated, it means that when the engine is running, it generates 100 horsepower.
Back to the engine size, a car with a large engine will be able to produce more power because it is capable of burning more fuel than a smaller engine. As aforementioned, due to the introduction of smart technology, nowadays a smaller engine with a turbocharger can generate just as much power as a larger engine.
How Engine Size Affects Fuel Economy
Since a large engine burns more fuel, it logically consumes more fuel than a smaller engine in the same number of revolutions.
Hopefully, you now understand why engine size is a crucial factor when it comes to making the choice of car you want.
For more useful tips and guides about cars and engines, visit our blog section at Carpart.
Author
Sam O.