When an internal combustion engine with variable valve liming (cam phasing) capability is started, it is normal practice to verify the position of the intake and exhaust camshafts relative to the crankshaft to ensure that the engine timing is within acceptable tolerance limits to avoid engine damage. This confirmation of engine timing is typically performed at a discrete position of the intake and exhaust cam phaser, also known as the park position for the variable valve timing mechanism(s) during which time the operation of the variable valve timing mechanism(s) is/are disabled. Limiting the operation of the variable valve timing mechanism(s) until the engine timing confirmation process is completed can result in sub-optimal engine startability and startup engine-out emissions, particularly under cold ambient operating conditions.
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