Why is it hard to start the car when it's cold?

[AnnaFitz]

When the weather gets cold, the main reasons for difficulty in starting the car are increased viscosity of lubricating oil, poor fuel volatility, and weakened battery performance. The higher viscosity and poorer fluidity of lubricating oil increase the rotational resistance of the engine crankshaft, reduce the starting speed, and slow down the gas flow rate in the intake pipe, leading to poor fuel atomization and difficulty in quick starting. In low temperatures, the battery's output power decreases due to increased electrolyte viscosity, reduced permeability, and higher resistance, making it hard for the starter to turn the engine and reach the minimum starting speed. Additionally, the low terminal voltage of the battery results in weak spark plug sparks, and the increased resistance between electrodes due to higher mixture density makes it difficult to ignite the mixture, further contributing to the difficulty in starting the engine.