What is the Relation of CC and Horsepower in Automobile Engine?
The ‘Cubic Capacity’ measured in Cubic Centimeters signifies the swept volume of the engine as a whole – all cylinders incorporated. It is commonly termed as the displacement of the motor measured in cubic centimeters. Whereas, horsepower is a unit of measurement of power (measured in kilowatts) and usually regarded as peak power. It indicates the maximum power that an engine can put out. But, what’s the relation between two? Is cc directly or indirectly related to horsepower? Let’s explore further how actually the cc and horsepower are correlated to one another.
Relation Between CC and Horsepower of Automobile Engine
CC (= cubic centimeter) is a generic measurement of displacement. For example, if a 3 cylinder engine has a rated capacity of 300 cc, it means that each cylinder of the engine can suck in 100 cc of fuel-air mixture to burn and compress. On the other hand, horsepower power output of the engine. So, if an engine possesses 100 HP, it means 100 horsepower of mechanical power is available when the engine is operating.
Cc and Horsepower are definitely not the same but there is a general correlation between the two. For example, a 1,800cc, oversquare, 4 valve, high compression ratio, fuel injected, titanium rods, with max 5,000 RPM Corolla can produce in excess of 125 HP. On the contrary, a less arresting engine, with a displacement of 2,000 cc will likely produce the same or even less HP. The explicit output of an engine depends on a huge number of design decisions.
Countless factors have an effect on an engine’s output. These factors include max RPM, number of valves, oversquare or undersquare, air/fuel ratio, compression ratio, air induction, efficiency etc. And not only that, they are all interrelated so altering one factor might change one or more factors. To attain complete information about all the factors, you may refer to the car industry knowledge by the professionals.
Brief Illustration about CC and Horsepower
Let’s suppose if we increase a cylinder’s diameter. It would seem simple but it’s not. Because increasing the cylinder’s bore diameter may just mean requiring a new cylinder sleeve or removing a bit of metal. A larger cylinder may have repercussion about the size of exhaust valves and intake valves: do they need to be larger to let out the extra combustion by-products or to supply extra intake charge? Do they require a different time (opened for longer, or opened sooner/later or closed sooner/later, etc.)?
A larger cylinder means a heavier piston, which will affect how fast the piston can go up and down. An engine either makes more power by burning more fuel and air per combustion cycle or does so by having more combustion cycles for a given period. And, all that is just taking into account only the cylinder and the piston. We are not considering about other things that affect output.
So, it’s true that there is a small correlation between cc and horsepower. Normally, a larger displacement engine will put out more horsepower than a smaller one, depending on many factors. We can say that more cc == more horsepower/more output.