Multi-Valve Technique

More valves per cylinder lead to more performance: by using more valves, larger inlet and outlet cross-sections can be attained. This way more fuel-air mixture reaches the combustion chamber. Nowadays, using this technique, priority is given to better exhaust emissions and reducing fuel consumption. Various design types are commonly used:

• three-valve engine:
  two inlet valves, one outlet valve per cylinder
• four-valve engine:
  two inlet and two outlet valves
• five-valve engine
  three inlet valves and two outlet valves