Internal combustion engines convert fuel into mechanical energy through combustion within a contained space. Vehicles today are equipped either with a two-stroke or four-stroke engine. Each engine type will have fuel requirements, essential maintenance, and other requirements. Understanding the difference will help you take better care of your engine and boost your vehicle’s performance.

 

How Your Car’s Engine Works

When it comes to your car’s engine, a stroke refers to the movement of its piston from the top to the bottom of the cylinder. During this movement, the engine pulls air and gas inside the chamber during the combustion cycle and burns the fuel. The explosion pushes the piston upward toward the top of the cylinder, which triggers a valve to open and expel the exhaust. Depending on its design, your car’s engine has several necessary parts working together to produce a stroke. Some combustion engines are designed to have four stages or four strokes, while others only have two phases.

A car’s engine will have the following essential parts to produce combustion:

Cylinder: This is a contained section of the engine and is the primary combustion component. The air and fuel mixture is drawn inside the cylinder and is ignited here.

Piston: This is a metallic moving disc enclosed in a cylinder that moves up and down the engine block. It converts the energy produced by the combustion of the fuel/air mix into mechanical energy.

Camshaft: This shaft controls the opening and closing of the engine valves to allow the air/fuel mix to enter and exit the cylinder.

Crankshaft: This shaft converts the piston’s reciprocating motion into rotational motion.

 

Two-Stroke vs. Four-Stroke Engines

The mechanics and design of two-stroke vs. four-stroke engines vary depending on the number of stages during their operation. A four-stroke engine operates on four stages or strokes:

– Intake

– Compression

– Combustion

– Exhaust

The piston moves down to take in air and fuel and contains it within the cylinder. The piston then moves up to increase compression, increasing the pressure and temperature. Following that is the combustion phase. A spark ignites the air and fuel mixture, creating an explosion that drives the piston upward. As the piston returns to its starting position, the fumes produced by the explosion are expelled, and the piston is ready to begin the initial phase all over again.

Two-stroke engines, on the other hand, only operate using two stages or strokes. It’s essential to make this distinction when differentiating two-stroke vs. four-stroke engines. It has the following stages:

– Compression/ignition

– Exhaust/intake

During the first stroke, the piston moves upward to compress the air and fuel mixture, thereby igniting it. The combustion drives the piston downward, entering its exhaust/intake phase. The spent air/fuel mixture is expelled during this second stroke, and a new mixture is drawn into the cylinder.

As you can see, the number of strokes differs between two-stroke engines and their four-stroke variants. Due to the difference in design, a two-stroke engine tends to be lighter and simpler.

However, even though a four-stroke engine will have more moving parts, it is designed to be more fuel efficient. In contrast, because of the design and mechanics of a two-stroke engine, it tends to produce more emissions, which you should pay attention to during maintenance.

 

Four-Stroke Engine Mechanics

The piston completes two strokes during a single revolution in a four-stroke engine. It performs a compression stroke and one exhaust stage, completing one piston revolution. This stage is followed by a return stroke, which cycles the whole process.

It is important to note that the engine’s spark plugs only ignite once for every other piston revolution. The engine generates power only after completing four strokes or the four stages of the piston’s movement. Four-stroke engines do not require any pre-mixture of gasoline and oil, unlike the case of diesel engines. These engines already have a separate compartment where the oil is stored, making them more efficient and producing fewer emissions.

Pros

– Yields higher torque levels.

– These engines don’t require extra oil.

– It only consumes fuel once every four strokes (more fuel efficient).

– These engines produce less noise.

– Since it requires no lubricant mixed into the fuel, it gives off fewer fumes.

– Four-stroke engines don’t vibrate as much as diesel engines.

– They are durable and can withstand plenty of wear and tear.

 

Cons

– These engines require regular maintenance, therefore, increasing your monthly costs.

– The gear and chain mechanisms of this engine can complicate the maintenance process.

– Because of the way it is designed, it produces less power compared to two-stroke variants.

– These engines have more moving parts, translating to higher maintenance costs.

 

Mechanics of Two-Stroke Engines

Two-stroke engines complete a combustion cycle using only one revolution of the piston. It first performs a compression stroke (upward stroke) followed by a return stroke (downward stroke). The spark plugs fire up the air/fuel mix for every single revolution or every two strokes. Two-stroke or diesel engines require the oil and fuel to be premixed before combustion.

Pros

– This engine type is smaller and lighter, requiring less space under the hood.

– It is equipped with inlet and exhaust ports.

– This engine type can operate better under hotter or colder weather than a four-stroke engine.

– It features a higher power-to-weight ratio.

– It has increased mechanical efficiency due to reduced friction in its engine parts.

– It has a simple design, making maintenance easier.

 

Cons

– It doesn’t burn fuel cleanly, producing more smoke and fumes.

– It tends to become unstable during the idling phase.

– This type of engine has a narrow speed range.

– It vibrates more and is noisier compared to four-stroke engines.

– These engines tend to consume more fuel.

 

Caring for Your Four-Stroke and Two-Stroke Engines

Knowing the differences between these two engine types will become helpful for maintenance. A four-stroke engine will require regular oil changes, filter replacement, valve clearance adjustments, and spark plug replacement. A two-stroke engine will also require the same replacement and maintenance, along with a regular oil and fuel mix check. It also needs more frequent checkups.

At Berryman Products, we offer effective engine maintenance solutions that will help prolong the service life of your vehicle. We have proudly supplied vehicle owners with high-quality vehicle maintenance products for over a century. Contact us today to learn more about the products that will be best suited for your two-stroke or four-stroke engines.