What is the firing order of a 4-cylinder engine?

[DiRiley]

Four-cylinder engines typically have two firing order patterns: 1-2-4-3 or 1-3-4-2. The specific firing sequence depends on factors such as crankshaft configuration. Four-cylinder engine composition: The operating cycle of a four-stroke gasoline engine consists of four piston strokes: intake stroke, compression stroke, power stroke, and exhaust stroke. Modern engines universally adopt the four-stroke principle, where one complete cycle involves four piston movements (two upward and two downward) to complete intake, compression, power, and exhaust processes. Four-cylinder engine working principle: The crankshaft design positions cylinders 1 and 4 in the same phase, while cylinders 2 and 3 share another phase. "Same phase" indicates synchronized upward/downward movement but separated by two strokes in the cycle. During four-stroke operation: intake and power strokes correspond to downward piston movement, while compression and exhaust strokes involve upward movement. After the air-fuel mixture enters cylinder 1, the compression stroke actually occurs in cylinder 3. Essentially, each cylinder undergoes all four strokes, with the four cylinders never simultaneously performing the same stroke during operation.