The Four Stroke Cycle

A key component of the turbo hybrid engine is the power unit, but how does it work? Within this article I will dive into the four stroke cycle which helps to produce power.

(Image credit to F1technical.net)

To start off with a key word which is necessary to know what a stroke is, within Formula 1 a stroke is known as when the piston moves from the top of the cylinder to the bottom.

One movement is when the cylinder moves down and up twice, which is two rotations of the crankshaft. Within one movement there are four key aspects known as the induction stroke, compression stroke, power stroke and the exhaust stroke. This may be more commonly known as suck, squeeze, bang and blow. This happens around 200 times in the space of one human blink and at temperatures of up to 2750℃ which is roughly half the temperature of the sun.

Induction Stroke

The process begins with the piston moving from the top of the cylinder to the bottom as the inlet valves open. This downward movement means the pressure inside the cylinder is slightly reduced as the gasoline direct injection (GDI)  engine and fuel gets injected directly into the cylinder while prepared air rushes in.

Compression Stroke

The next stage involves the closing of the inlet valves and the piston upwards, compressing the air fuel mixture. This is preparing for the high pressures and therefore meaning higher temperatures. A spark is then produced by the spark plug initiating the combustion process where the air fuel mixture ignites and burns rapidly, releasing energy. 

Power Stroke

The piston is driven back to the bottom of the stroke. Through connecting conrods and offset crankshafts, this generates torque applied to the crankshaft, which is the power.

Exhaust Stroke

The exhaust valve then opens allowing for the burnt air fuel mixture to leave the cylinder, whilst the piston moves back upwards to expel the exhaust gases.

Article written by Skyla Crook