Starter — general description (Nissan Murano Z50)

A starter is a DC electric motor that is capable of producing quite a lot of power for its size. The first thing that allows this engine to produce more power is that it has a high rotation speed. It turns the engine crankshaft via a small gear wheel included in the starter equipment, which turns a large gear wheel (flywheel) at a greatly reduced speed. Another factor that allows it to achieve greater power is that it operates in intermittent mode, i.e. only at startup. This means the starter has little need for air circulation and the windings can be placed in a small space. The starter used in this vehicle is equipped with a planetary gear.

Starter solenoid

The starter solenoid is a magnetic device that uses a small current supplied to the starter power circuit from the ignition switch. This magnet, when operating, moves a plunger that mechanically engages the starter and electrically closes a thick wire that connects the starter to the battery. The starter circuit consists of a starter switch located in the ignition switch and wires connecting them to the starter solenoid or relay.

The gear that serves to transmit rotation is mounted on a one-way clutch. This clutch is splined onto the starter armature shaft. When the ignition key is turned to the start position, the solenoid plunger drives the drive pinion (bendix) to the flywheel ring gear via a ring and spring. If the gear tooth and the flywheel tooth match exactly, the gear will immediately engage with the flywheel. If a tooth engages another, the spring will be compressed and will act on the teeth to keep them engaged as long as the starter is turning. As the solenoid reaches the end of its stroke, it closes the contact between the battery and the starter, and the engine is then turned by the starter.



Once the engine starts, the flywheel begins to spin faster than the pinion gear spins at its highest RPM. In this case, the drive pinion (bendix) begins to allow the pinion to rotate faster than the starter shaft, so the starter will not operate at high speed. When the ignition key is removed from the "start" position, the solenoid is de-energized and a spring inside the solenoid forces the pinion out of engagement, cutting off current to the starter.

There is a spring between the pinion and the drive lever from the starting relay, so that in the event of an imprecise alignment of the teeth, when the pinion is forced to engage the flywheel ring gear, the solenoid continues to operate and provides voltage. The gear will engage immediately as soon as the starter shaft begins to rotate.

The starter is secured with nuts to the clutch housing. The front support of the starter armature is located in the clutch housing.

Starter components

The material is based on data from the portal [Nissanbook.ru]