Two Stroke Engine How It's Work ?

An internal combustion engine that uses two strokes, or up and down movements of the piston, to complete a power cycle requires only one crankshaft revolution. This is not the case with a four-stroke engine, where a power cycle is completed by four piston strokes.

Compared to four-stroke engines, two-stroke engines are easier to use, lighter, and more compact. Given that they only fire once every revolution as opposed to four-stroke engines' twice-daily firing interval, they also have the potential to produce more power per unit of displacement.

But compared to four-stroke engines, two-stroke engines also have a number of drawbacks, including increased noise, reduced fuel efficiency, shorter engine life, and higher emissions. Due to these disadvantages, two-stroke engines are now less common in motorcycles, modern cars, and marine applications.

To address some of these issues and enhance the efficiency and environmental impact of two-stroke engines, several technological advancements and innovations have been made in recent years. Among these cutting-edge technologies are:

• Instead of combining fuel and air in the intake manifold, direct fuel injection injects fuel straight into the cylinder. As a result, there is less unburned fuel that escapes through the exhaust port, which lowers emissions and improves two-stroke engines' fuel efficiency.
• Variable valve timing: This system enables the intake and exhaust valves' opening and closing times to be modified in accordance with the load and engine speed. This lowers emissions and noise while increasing the two-stroke engine's power output and volumetric efficiency.
• Systems that use a compressor or a turbine to force more air into the cylinder in order to increase the pressure and density of the air-fuel mixture are known as supercharging and turbocharging. This makes two-stroke engines more powerful and torquey and makes up for the efficiency loss in scavenging at higher engine speeds.
• In place of a spark plug, a lean, homogeneous air-fuel mixture is compressed and ignited by the heat and pressure of the cylinder in a homogeneous charge compression ignition (HCCI) system. By lowering the combustion's peak temperature and pressure, this lowers the amount of nitrogen oxides (NOx) and particulate matter (PM) that two-stroke engines emit.

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The Development History of Two Stroke Engine

Two-stroke engines originated in the late 19th century as a result of various inventors experimenting with various designs and concepts. Among the prominent individuals in the annals of two-stroke engines are:

• Scottish engineer Dugald Clerk was the first to patent a two-stroke engine with cylinder compression for commercial use in 18811. Fresh air was pumped into the main cylinder of his engine through a separate charging cylinder.
• The crankcase-scavenged engine was created in 18911 by English engineer Joseph Day. His engine did away with the need for a separate cylinder by using the space beneath the piston as a charging pump. Most subsequent two-stroke engines were built using this design as a basis.
• German inventor Karl Benz invented the two-stroke gas engine in 1879, and in 1880 he received a German patent for it. His engine used a spark plug to ignite the air-fuel mixture, making it one of the first two-stroke engines with electrical spark ignition.
• In 19082, a Yorkshireman named Alfred Angas Scott started producing motorcycles with twin cylinders and water cooling. His motorcycles were the first two-stroke vehicles that were truly practical, featuring inventions like liquid cooling, rotary valves, and loop scavenging.

The 2 Stroke Engine Main Components are :

1. Engine Control Unit (ECU) : In a two-stroke engine, this device unifies and synchronizes the different electrical and engine control systems. It generates signals to regulate the fuel injection, valve timing, power valve, spark ignition, HCCI mode, and other engine parameters after receiving inputs from a variety of sensors, including oxygen level, crankshaft position, throttle position, knock detection, and engine temperature.
2. Homogeneous charge compression ignition (HCCI) : This system replaces spark plugs with a lean, homogenous air-fuel mixture that is compressed and ignited by the cylinder's heat and pressure. As a result, there are less emissions of nitrogen oxides (NOx) and particulate matter (PM) from two-stroke engines. This is due to a reduction in the peak temperature and pressure of combustion.
3. Two-stroke power valve system : This system adjusts the effective exhaust port area and length based on engine speed using a two-blade exhaust valve. This improves the torque and power delivery while optimizing the scavenging and expansion processes in a two-stroke engine. A tiny computer that tracks engine RPM and uses an electric servo to modify the power valve's position is in charge of it.