Cylinder deactivation is well-known in spark-ignited (SI) engines and compression-ignited (CI) engines. The major reason why the efficiency of these engines is decreased at part load is due to flow restriction in the intake system caused by partially closing throttle valves, which causes increased pumping losses. In order to resolve this issue, the cylinder deactivation system can be implemented in SI engines with four cylinders by developing a suitable control system. Half of the engine's cylinders had their fuel injectors and valve trains turned off, enabling cylinder deactivation (CDA). Fuel consumption was reduced by reducing engine impelling work and decreasing heat transmission to the walls of the cylinder. CDA techniques are tested for their impact on in-cylinder pressure and pumping loss. This work reveals that all of these cylinder deactivation solutions minimize pumping losses and fuel consumption thereby enhancing the engine's thermal efficiency. These findings suggest that closing both intake and exhaust valves is the most effective way of triggering CDA, and lowering BSFC (Brake-specific fuel consumption).