Synchronization Of The Injection And Ignition Order

Courtesy of NISSAN NORTH AMERICA, INC.

1	Top dead center of cylinder 1	2	Top dead center of cylinder 2	3	Top dead center of cylinder 3
4	Top dead center of cylinder 4
A	Crank angle	B	Multi-pulse wheel	C	Crankshaft position sensor signal
D	Cylinder 1 discriminate signal	E	Intake camshaft position sensor signal	F	Exhaust camshaft position sensor signal
G	Engine speed signal
a	Intake camshaft adjustment range	b	Intake camshaft position sensor (low signal)	c	Exhaust camshaft adjustment range
d	Exhaust camshaft position sensor (low signal)	e	Polarities at intervals of crank angle 18 deg.

Synchronization of The Injection and Ignition Order

ECM reads voltage signals of intake camshaft position sensor, exhaust camshaft position sensor, and crankshaft position sensor to synchronize the order of fuel injections with that of ignitions when starting the engine. ECM detects the top dead center of Cylinder 1 according to a signal of crankshaft position sensor.

Engine Speed Signal Control

Multi-pulse wheels with different polarities are installed to the crankshaft at intervals of crank angle 6 deg.. Since the crankshaft position sensor is installed opposed to the multi-pulse wheel, pulse signals of 5 V and 0 V are generated during the rotation of crankshaft. In addition, the multi-pulse wheels have polarities at intervals of crank angle 18 deg. to completely match the crank position.

ECM transmits a short-resistant engine speed signal via CAN communication based on a signal of crankshaft position sensor.

NOTE:

Detection of rotation direction: When the engine stops or temporarily rotates in the opposite direction immediately before stopping, a pulse signal of the crankshaft position sensor changes. Since ECM detects the change in rotation direction through the above mechanism, crankshaft angle position can be accurately detected any time. This information is required, in particular, when quickly starting the engine in the stop/start system.
When ECM cannot receive a crankshaft position sensor signal, ECM uses an intake camshaft position sensor signal or exhaust camshaft position sensor signal to enable the vehicle to be driven. When ECM cannot receive an intake camshaft position sensor signal, ECM uses an exhaust camshaft position sensor signal to detect the position of the top dead center of Cylinder 1. When both camshaft position sensor signals cannot be received, ECM performs ignition and injection to execute an emergency start after detecting crank angle 360 deg..