Volvo Construction Equipment’s EC300E Hybrid captures free energy created by the boom down motion to reduce fuel consumption
For Volvo Construction Equipment’s first hydraulic hybrid excavator, the EC300E, the company took a different approach to capturing energy for the system.
Unlike other hybrid models that capture the swing energy of an excavator’s superstructure to electrically assist the engine, Volvo’s novel hydraulic hybrid takes free energy generated by the boom down motion and uses it to reduce fuel consumption.
The powerful and regular boom down motion charges 20 litre hydraulic accumulators, which then deliver energy to drive hydraulic assist motors that help power the hydraulic pump. This also helps lower the torque requirement on the engine.
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“Other systems typically use the swing motion and capture energy that way. So, with the EC300E Hybrid excavator, our customers are able to capture the energy of a typical loading cycle, which is really where we’re optimizing the system to work,” said Sung Sook Kim, excavator product manager for Volvo Construction Equipment.
Volvo introduced its first hybrid machine, the L220F Hybrid wheel loader, in 2008 at ConExpo. The company began development of the EC300E hydraulic hybrid excavator in 2018, and the latest hybrid is now available throughout North America.
“It’s part of our commitment to bring innovative products to the market, particularly those that promote environmental sustainability,” Kim said. “Hybrid technology has been around for decades in the auto industry, but is just recently taking hold in the construction industry. … We pride ourselves on being at the forefront of conceptualizing and designing new construction equipment that pushes the boundaries of efficiency while maintaining impressive power and productivity.”
The new EC300E Hybrid features an operating weight of 29,780 to 31,790 kg, a lifting capacity of 11,400 kg, a maximum digging reach of 10.7 metres and a maximum digging depth of 7.3 metres.
The excavator is powered by a 240 hp turbocharged, four-stroke diesel engine with water cooling, direct injection and charged air cooler.
The new electro-hydraulic system and new MCV (main control valve) use intelligent technology to control on-demand flow for high-productivity, high-digging capacity and excellent fuel consumption.
The system also includes numerous functions to optimize performance, including:
- Summation system: Combines the flow of both hydraulic pumps to ensure quick cycle times and high productivity.
- Boom priority: Gives priority to the boom operation for faster raising when loading or performing deep excavations.
- Arm priority: Gives priority to the arm operation for faster cycle times in levelling and for increased bucket filling when digging.
- Swing priority: Gives priority to swing functions for faster simultaneous operations.
- Regeneration system: Prevents cavitation and provides flow to other movements during simultaneous operations for maximum productivity.
- Power boost: All digging and lifting forces are increased.
- Holding valves: Boom and arm holding valves prevent the digging equipment from creeping.
Kim explained the EC300E Hybrid performs just as well as comparably sized excavators.
“In fact, if you compared it to our conventional EC300E excavator, their horsepower, maximum digging reach and depth, width and tail-swing radius are identical,” Kim said. “And their lifting capacity, breakout force and tear out force are nearly the same.”
The most noticeable difference is the hybrid excavator reduces fuel consumption by up to 15 per cent, and reduces carbon dioxide emissions by about 12 per cent, when compared to the conventional machine.
“When used in high production dig and dump applications — especially those within a 90-degree swing — the fuel saving payback is approximately two years,” Kim said.
While the hybrid system does introduce additional components, they do not make a significant difference in terms of machine maintenance.
“The system is essentially a combination of hydraulic flow and valves that function automatically,” Kim said. “Also, unlike other hybrid machines on the market, our hybrid technology does not have electrical components or batteries.”
The EC300E is a popular model in medium range for production sites, especially in truck loading, making it the ideal machine for Volvo’s first hydraulic hybrid excavator. As well, many of the hybrid components developed for the machine can be used for other models.
While the hybrid system is not currently available as an aftermarket installation, Volvo is working to expand the availability of the technology.
“We are working on expanding this hydraulic hybrid technology into future excavator models in the coming years,” Kim said.