1. Increased Friction: When the engine is cold, the metal components, such as pistons, piston rings, and cylinder walls, have not yet expanded to their optimal operating temperatures. This results in increased friction between these components, leading to higher mechanical losses and reduced efficiency.
2. Incomplete Fuel Combustion: The fuel-air mixture in a cold engine is denser due to the lower temperatures. This denser mixture can make it more challenging for the spark plug to create a proper ignition, resulting in incomplete combustion. Incomplete combustion leads to wasted fuel and reduced power output, affecting overall efficiency.
3. Richer Fuel Mixture: To compensate for the difficulties in starting and running a cold engine, the engine control unit (ECU) often enriches the fuel mixture by increasing the fuel injection duration. This richer mixture ensures a more reliable ignition, but it comes at the cost of increased fuel consumption and reduced efficiency.
4. Thicker Lubricating Oil: Engine oil becomes thicker when it's cold, which increases the resistance to the movement of engine components. This increased resistance leads to higher energy losses due to increased friction and reduced overall efficiency.
5. Reduced Catalytic Converter Efficiency: The catalytic converter, which helps clean the exhaust emissions, operates most effectively within a specific temperature range. When the engine is cold, the catalytic converter is not fully functional, resulting in reduced emissions control and potentially lower fuel efficiency.
6. Increased Warm-Up Time: A cold engine requires more time to reach its optimal operating temperature, resulting in a longer warm-up period. During this warm-up phase, the engine is operating at lower efficiency until it reaches its ideal temperature.
To mitigate these inefficiencies, modern vehicles incorporate various technologies such as electronic fuel injection, variable valve timing, and closed-loop feedback control systems. These systems help optimize engine performance and efficiency even during cold starts and operation. Additionally, using the correct viscosity oil for the specific climate and following the manufacturer's recommendations for engine warm-up can also help improve efficiency and reduce wear.
