The company says that this is achieved through the excavator’s boom-down motion which charges energy-storing accumulators that are used to power the engine system.
It adds that this differs from other systems that capture the swing energy of an excavator’s superstructure to electrically assist the engine. Instead Volvo’s hydraulic hybrid harvests ‘free’ energy generated by the down motion of the excavator’s boom and uses it to supercharge the engine system.
The powerful and regular boom-down motions charge 20 litre hydraulic accumulators, which then deliver energy to drive hydraulic assist motors that help power the engine system. Volvo CE says there are the same levels of controllability and performance as the standard EC300E, including the ability to work in ECO mode and hybrid mode simultaneously.
This process is claimed to help the engine deliver up to 20% higher fuel efficiency, and up to 17% less CO2 emissions with no loss of performance. When used in production ‘dig and dump’ applications (especially those within a 90o swing) Volvo CE claims the payback of this approach can be a little less than two years.
It adds that the system requires just a few add-on components that are simple to maintain.