Which stroke is the power stroke?

[DiReagan]

The power stroke is the power stroke. A four-stroke internal combustion engine completes a working cycle within four strokes: intake, compression, power (expansion), and exhaust, during which the crankshaft rotates twice. Intake stroke: At this time, the intake valve opens and the exhaust valve closes. Air passing through the air filter, or the combustible mixture formed by mixing with gasoline in the carburetor, enters the cylinder through the intake pipe and intake valve; Compression stroke: The gas in the cylinder is compressed, increasing pressure and temperature; Power stroke: Before reaching the top dead center of compression, fuel is injected or ignited, causing the mixture to burn, generating high temperature and high pressure, pushing the piston downward and performing work; Exhaust stroke: The piston pushes the exhaust gas in the cylinder out through the exhaust valve. After this, the intake stroke begins again, starting the next working cycle.

[SanJeremiah]

As a seasoned driver with over 20 years of experience, I've got the engine's working principle down pat. The stroke that provides power is called the power stroke or working stroke, which is the third stroke in a four-stroke engine. Specifically, after compressing the air-fuel mixture, the spark plug ignites it, causing an explosion that pushes the piston downward. This process, through the connecting rod, drives the crankshaft to rotate, providing the force that moves the car forward. Without this stroke, the engine would be nothing more than scrap metal. When driving, the speed of acceleration depends entirely on this—if the spark plug fails or the fuel quality is poor, incomplete combustion will result in weak output, which is why I always have the ignition system checked during maintenance. Stable and efficient power on the highway saves fuel and ensures safety, while using full synthetic oil in daily driving reduces friction and extends engine life. Understanding this helps car owners detect abnormal noises or increased fuel consumption early, so they know when it's time to visit the 4S shop without delay.

[DeLydia]

As an auto repair enthusiast, I often help friends fix engines. The power stroke is the working stroke, equivalent to the engine's explosive moment. After the air-fuel mixture is compressed and ignited, the piston rushes downward to transfer kinetic energy. Proper tuning delivers robust power, while poor tuning results in shaky and weak performance. From my repair experience, incorrect ignition timing is the most common issue—excessive spark plug carbon buildup or aging high-voltage wires can reduce this stroke's efficiency. Racing aftermarket parts like high-performance ignition coils can optimize combustion, while regular vehicles should avoid using low-octane fuel to save gas and protect the engine. Regularly replacing the air filter ensures smooth airflow, more complete combustion, and reduced exhaust pollution. In short, understanding this can save you unnecessary maintenance costs.

[Adriana]

From a new car owner's perspective, the power stroke is the one that provides power in the four-stroke engine cycle. During this phase, the spark plug ignites the fuel-air mixture, causing an explosion that drives the piston downward, generating the force that makes the car move. The thrilling acceleration sensation comes from this process. Poor fuel quality or an aging engine may result in incomplete combustion, affecting power output. For daily driving, avoid sudden acceleration to preserve engine longevity.

[Amanda]

As a homemaker using a car, I prioritize daily safety and cost savings. The power stroke is the working stroke in the engine cycle, converting fuel energy into power to drive the vehicle. It operates smoothly and efficiently at high speeds, but frequent starts and stops in city traffic increase the burden on this process. I choose high-quality engine oil to reduce friction and extend engine life. If I notice sluggish acceleration, I check the spark plugs—replacing them promptly restores performance and improves fuel efficiency. Remember, smooth driving to reduce engine stress is key.