Large-volume engines place great demands on starters. At the top end of the power range, Bosch has a new addition to its 24-volt starter motor portfolio: the HEF109-L ‘large’ heavy-duty starter motor for commercial vehicles and off-highway applications.
The powerful starter motor generates 18 per cent more power than the tried and tested ‘M’ (medium) type starter motor on which it is based, and thus delivers a maximum output of 9.2 kilowatts. This is enough to reliably start engines with up to 28-litre displacement.
The design of the HEF109-L is especially compact, making it particularly suitable for applications where installation space in the engine compartment is limited. The high thermal robustness ensures reliable starting of large engines – even at very low ambient temperatures or in long-lasting starting sequences.
Due to the significantly greater service-life requirements associated with commercial vehicles, the engagement itself is designed as a two-stage process in order to limit the wear of the ring gear and pinion: In the first stage, the pinion shaft including the pinion is moved forward slowly, engaged, and turned slightly. In the second stage, the main current is released and the actual starting sequence takes place.
A mechanical relay integrated in the starter makes a connection to the engine control unit (ECU) easier. Unlike starts by ignition switch, the ECU can automatically control the starting sequence, which keeps emissions low.
The HEF109-L can also be upgraded. One example is the special dust protection, available up to IP57 protection class. An additional feature is the isolation of terminal 31. This separate connection to the battery’s minus pole is a feature of special applications such as railroad vehicles or watercraft, where increased safety and protection requirements against moisture and water apply. For maximum flexibility in diverse installation conditions, the starter motor can also be supplied with all common flange geometries, including a rotatable flange.
For applications utilising even larger displacement engines, Bosch offers parallel starting systems. By setting two or three starter motors of the 109-family in a parallel-system configuration, the output of each individual starter motor can be aggregated. The new HEF109-L also allows the total output of the parallel starter-motor systems to be increased significantly. With a maximum output of almost 28 kilowatts, diesel engines with displacements of up to 84 litres and gas powered engines with displacements of up to 168 litres can be started reliably under normal conditions. Engines of this size are very common in off-highway applications and watercraft. Stationary engines such as generator sets – also need to start quickly and reliably to stabilise the power supply net if there is a power cut. The HEF109-L is an ideal choice for these applications as well.