A typical four-stroke petrol engine has two valves per cylinder: one intake valve and one exhaust valve. Some engines may have more than two valves per cylinder, such as three or four valves per cylinder. These engines are often called "multi-valve" engines.
The number of valves in an engine affects the efficiency and performance of the engine. More valves allow for better airflow into and out of the cylinder, which can improve combustion and increase power output. However, more valves also add complexity and cost to the engine.
Here is a table summarizing the number of valves in different types of petrol engines:
| Engine Type | Number of Valves per Cylinder |
|---|---|
| Four-stroke petrol engine | 2 |
| Multi-valve petrol engine | 3 or 4 |
