Despite all the advancements and improvements in automobile and engine design, one thing hasn’t changed: the layout of two- and four-stroke engines. Even though you might know these kinds of engines, you might wonder how they differ. What you need to know about the effectiveness and operation of each engine type is provided below.
Difference Between A 2-Stroke And A 4-Stroke
Based on the number of times the piston swings up and down during each cycle, the speed at which this combustion cycle process takes place distinguishes a 2-stroke engine from a 4-stroke engine.
2-Stroke Engine in Bike
In a 2-stroke engine, the entire combustion cycle is finished in one piston stroke. This consists of the compression stroke and the compressed fuel explosion. The exhaust is released during the return stroke, and new fuel is injected into the cylinder. Power is generated per two piston strokes, and spark plugs ignite once per complete revolution. Additionally, the oil must be pre-mixed with the fuel for two-stroke engines.
The two-step method comprises:
- (IGNITION/COMPRESSION) UPSTROKE – The crankcase is filled with fuel and air as the piston rises. Compressed air and gasoline are combined, then ignited.
- EXHAUST/DOWNSTROKE POWER – After the fuel ignites, the piston is depressed, causing the exhaust to be released.
The best 2-stroke bikes available in India are TVS XL100, Yamaha RX100, and Bajaj CT 110.
4-Stroke Engine in Bike
In a 4-stroke engine, the piston completes two strokes—one exhaust stroke and one compression stroke—followed by a return stroke, one for each revolution. Power is generated per four piston strokes, and spark plugs only ignite every other revolution. Due to the oil being stored in a separate compartment, these engines also do not require fuel and oil pre-mixing. Four-stroke engines are both fuel-efficient and environmentally beneficial. They operate in four phases:
- INTAKE – Fuel is sucked in downward with the intake valve open.
- COMPRESSION – The fuel is compressed as the piston rises.
- POWER – Fuel is ignited after compression to provide engine power.
- EXHAUST – The exhaust valve opens, allowing exhaust gases to leave.
The best 4-stroke bikes available in India are Royal Enfield Himalayan, Bajaj Pulsar NS200, KTM 200 Duke.
Two-Stroke Engines Vs Four-Stroke Engines
| TWO-STROKE ENGINE | FOUR-STROKE ENGINE |
| Two-stroke engines are lighter. | The four-stroke engine is heavier in weight. |
| When compared to a four-stroke engine, a two-stroke engine is cheaper. | Four-stroke engines are expensive. |
| The two-stroke motor is found in many different types of two-wheelers and motorbikes. | Using a bus, truck, automobile, etc. As an example. |
| Moving causes extra wear and tear in this area. | But four-strokes wear and tear less. |
| Lubricating oil is used more frequently in two strokes. | Lubricating oil is used less often in four strokes. |
| Thermal efficiency is lower for two-stroke engines. | Compared to a two-stroke engine, it has higher thermal efficiency. |
| This engine is air-cooled, which means that as it heats up, air is used to cool it. | To cool an engine, water or air is pumped. |
| Because there is less friction between parts in a two-stroke engine, mechanical efficiency is enhanced. | Mechanical efficiency is lower because parts have more friction. |
| A crankshaft revolution only results in one power stroke. | Here, one power stroke requires two crankshaft revolutions. |
| The engine costs less than a four-stroke engine in comparison. | The engine is more expensive than a two-stroke engine. |
| Inlet and outlet ports make up the two-stroke engine’s two ports. | Four-stroke engines have inlet and exhaust valves. |
| A basic lubricating system is present. | The lubrication system is intricate. |
| Two-stroke engines require less room. | More room is needed for the four-stroke engine. |
| Two-stroke engines produce high torque. | But with a four-stroke engine, less torque is generated. |
| Two strokes produce more smoke. | Compared to a two-stroke engine, the four-stroke generates fewer fumes. |
| Due to oil burning alongside fuel, extra lubricating oil is needed. | Here, less lubricating oil is needed. |
| It has a higher power-to-weight ratio than a four-stroke engine. | The power-to-weight ratio, however, is poor in four-stroke engines. |
| Air and fuel mixtures, or charges, enter the cylinder after passing through the crankcase. | In four-stroke, fuel and air are directly infused into the cylinder. |
| The two-stroke engine scavenges. | No scavenging procedure. |
| Less output power is produced. | More output power is available. |
| Two-stroke engines cost less to maintain. | Because there are more components, maintenance costs are higher. |
| In contrast to a four-stroke engine, starting an engine is extremely simple. | It’s challenging to start an engine. |
Making the right decision and being proactive with maintenance throughout the life of your engine will be aided by your knowledge of the requirements for two-stroke and four-stroke engines and how they differ from one another.
