Volvo will feature its EC300E Hybrid excavator at CONEXPO-CON/AGG 2020. While this is not a new model, the one featured at the show will have a new product Volvo is bringing to market, said Ray Gallant, Vice President of Sales Support, North America at Volvo CE. The excavator Hydraulic Hybrid Assist System, a technology first introduced at bauma 2019, uses a 100% Volvo-engineered system which collects and reuses energy from the excavator boom. At CONEXPO it will be shown on an EC300 30-ton excavator.
Energy generated by the boom down motion is captured hydraulically and used to assist the boom up motion, which is where you need most of the pressure and power, said Gallant. Competitive machines typically use the swing motion to capture and reuse energy whereas Volvo is using the up and down movement.
Also unlike other hybrid excavators, the EC300E does not generate electricity or store any energy in batteries. “This is a very simple system that uses the hydraulic accumulator to give the upswing or the uplift more pressure, without having to rely on the pumps to do it all themselves,” said Gallant.
The system consists of a hydraulic accumulator mounted just behind the boom. As the boom goes down, the high-pressure oil being used to retard the boom dropping goes into the accumulator instead of being routed to an oil tank and charges the accumulator with a high-pressure charge. The high pressure is then routed through an assist motor and put back into the cylinders on the upswing. “So it’s all controlled automatically, the operator doesn’t have to do anything,” explained Gallant. Operators just feel the system working because the engine isn’t lugging when lifting the boom as would be the case in a traditional machine.
Maintenance of the system is simple, as well. There is a symbol on the dashboard in the operator cab which shows when the accumulator is charging and discharging. “It’s a very simple, robust system,” he said.
Inclusion of the hydraulic hybrid system provides about a 15% fuel savings in normal operating conditions, which can go up more if used in countries with higher fuel costs. It also helps reduce CO2 emissions by 12% because it is enabling more efficient fuel burn.
Volvo intends to bring the hybrid system to other excavator model lines in the future.