Bottom line up front: A gasoline engine runs on four distinct strokes that turn fuel into power.
Four-Stroke Engine Explained: How It Works
Image: Four-Stroke Engine Explained: How It Works – Performance Comparison and Specifications
Design & Looks
The four‑stroke cycle consists of intake, compression, power and exhaust. During the intake stroke the piston moves down, drawing in an air‑fuel mixture. The compression stroke pushes that mixture up, squeezing it to a high pressure. A spark plug ignites the mixture on the power stroke, forcing the piston down and creating torque. Finally, the exhaust stroke pushes burnt gases out of the cylinder.
Visually, you’ll see a single camshaft (or dual in some designs) that opens and closes valves at just the right moments. This timing gives the engine a smooth, rhythmic feel compared with a two‑stroke that fires every revolution.
Performance & Mileage
Because each cylinder fires only once every two revolutions, a four‑stroke engine usually delivers better fuel efficiency and lower emissions than a two‑stroke. The separate exhaust stroke lets the engine breathe more cleanly, which translates into higher mileage – often 25‑30 mpg for a small‑car gasoline engine.
- Higher torque at low RPMs
- Cleaner exhaust, meeting modern emissions standards
- Longer engine life due to reduced wear
Price & Rivals
Four‑stroke technology is the industry standard, so parts and service are widely available and competitively priced. Two‑stroke engines still appear in some motorcycles and outboard motors, where simplicity and power‑to‑weight matter more than fuel economy.
When you compare a typical 1.5 L four‑stroke engine with a similar two‑stroke unit, the four‑stroke often costs 10‑20 % more upfront but saves money on fuel and maintenance over the vehicle’s life.
Quick Comparison
| Engine | Mileage (mpg) | Price (USD) | Top Features |
|---|---|---|---|
| Four‑Stroke (1.5 L) | 27 | 3,500 |
|
| Two‑Stroke (0.5 L) | 18 | 2,800 |
|
FAQ
What are the four strokes of a gasoline engine?
The strokes are intake, compression, power (combustion) and exhaust.
Why do four‑stroke engines get better fuel mileage than two‑stroke engines?
Because they separate the exhaust process, allowing cleaner combustion and less fuel waste.
Is a four‑stroke engine worth the extra cost?
For most drivers, the improved efficiency, lower emissions, and longer durability outweigh the modest price premium.
Feel free to share your thoughts or ask questions in the comments below.
Source: Read Official News
