6 Stroke Engine: Working Principle, Firing Order, Pros and Cons
Let’s discuss six stroke engines, their working principle and firing order, its advantages and disadvantages. Later on, we’ll also compare it with 2-stroke and 4-stroke engines. Shall we start?
Six Stroke Engine Working Principle and Firing Order
The 6-stroke engine operates on an extended cycle of the traditional 4-stroke engine, incorporating two additional strokes - water injection and steam exhaust.
Intake Stroke: The first stroke involves drawing an air and fuel mixture into the cylinder.
Compression Stroke: During the second stroke, the air-fuel mixture is compressed.
Combustion Stroke: The compressed mixture is then ignited, forcing the piston down.
Exhaust Stroke: The fourth stroke expels the burnt gases.
Water Injection Stroke: This is the first additional stroke unique to the 6-stroke engine, where water is injected into the hot cylinder.
Steam Exhaust Stroke: Finally, the injected water turns into steam due to the residual heat in the cylinder, forcing the piston down again, and the steam is then expelled.
The firing order of the 6-stroke engine depends on the number of cylinders and the configuration of the engine, much like the 4-stroke engine.
However, with the additional two strokes, each cylinder will complete a cycle in three revolutions of the crankshaft instead of two.
The specific firing order will vary depending on the design and application of the engine.
Benefits of the 6-Stroke Engine
Enhanced Efficiency: The added two strokes help extract more work from the same amount of fuel, thereby improving the engine's thermal efficiency.
Lower Emissions: The water injection stroke significantly reduces the temperature of the combustion chamber, minimizing the formation of nitrogen oxides (NOx), a harmful emission.
Internal Cooling: The water injection and steam exhaust strokes cool the engine internally, reducing the necessity for an extensive cooling system.
Better Fuel Economy: The extra power stroke contributes to getting more work done with the same amount of fuel, resulting in improved fuel economy.
Drawbacks of the 6-Stroke Engine
Increased Complexity: The inclusion of two more strokes adds to the complexity of the engine design and operation.
Water Injection System: The requirement of a water injection system increases the engine's weight and cost.
Comparison with 4-Stroke and 2-Stroke Engines
Efficiency: The 6-stroke engine surpasses both the 4-stroke and 2-stroke engines in efficiency by extracting more work from the same amount of fuel.
Emissions: The 6-stroke engine generates lower emissions compared to the 4-stroke and 2-stroke engines due to the water injection stroke.
Cooling: The 6-stroke engine demands less external cooling compared to the 4-stroke and 2-stroke engines as it is cooled internally by the water injection and steam exhaust strokes.
Complexity: The 6-stroke engine is more complex than the 4-stroke and 2-stroke engines due to the additional strokes and systems required.
Practical Applications of the 6-Stroke Engine
Although the 6-stroke engine is still under development, its potential applications are broad-ranging.
Automobiles: The 6-stroke engine, with its increased efficiency and lower emissions, could be a valuable option for powering automobiles.
Power Generation: The superior fuel economy of the 6-stroke engine makes it an appealing choice for power generation applications.
Marine Applications: The internal cooling feature of the 6-stroke engine makes it suitable for marine applications where cooling water is readily available.
The 6-stroke engine, with its advantages of enhanced efficiency, reduced emissions, and internal cooling, offers a promising alternative to conventional 4-stroke and 2-stroke engines.
However, challenges such as increased complexity and the need for a water injection system must be addressed for it to become a viable option for mainstream applications.
Despite these challenges, as the demand for cleaner and more efficient engines grows, the 6-stroke engine represents a step forward.
I really hope that this small guide helps you understand six stroke engines a bit in more detail. If you have questions, ask them below. I’ll try my best to answer.
