Volvo Construction Equipment unveiled a pre-production prototype of its L220F Hybrid wheel loader. Offering more power, better performance and a 10 percent reduction in fuel consumption, the L220F Hybrid’s increased efficiency and cost saving potential will offer customers a much greater return on their investment over the life cycle of the machine, according to the manufacturer.
The Volvo L220F Hybrid’s parallel hybrid technology has been developed within the Volvo Group and uses as its platform the D12 engine. While much of the technology remains confidential, the heart of the hybrid system is an ISG — Integrated Starter Generator. Fitted between the engine and the transmission, the ISG is coupled to a battery that has many times the power capacity of a normal lead acid battery. The ISG works in a number of ways:
Power When You Need It — and Only When You Need It
Firstly, up to 40 percent of a wheel loader’s time can be spent with the engine idling. The ISG allows the diesel engine to be turned off when stationary — and then almost instantly restarted by rapidly spinning the engine up to optimum working speed using a burst of energy from the high power battery.
Secondly, the ISG also can overcome diesel engine’s traditional problem of low torque at low engine speeds by automatically offering a massive electric torque “boost” — as the ISG’s electric motor offers torque of up to 700 Nm from standstill. Put in engine power terms — the ISG adds up to 67.5 hp (50 kW) of instant mechanical energy.
The combination of these two attributes of the ISG mean that the diesel engine will remain off for long periods when it would otherwise be idling — and that the operator does not need to over-rev the engine in order to get sufficient torque to work, as peak torque will be offered at almost tick-over engine speeds. The battery is then replenished automatically without reducing productivity, with the ISG acting as a dynamo/alternator.
While the ISG is the heart of the system, there are other energy saving innovations in the L220F Hybrid, such as an electrically powered climate control system (rather than being powered directly by the engine). When coupled to the non-hybrid L220F’s already efficient V-ACT Volvo engine and hydraulic systems, the L220F Hybrid’s additions make for dramatic improvements in efficiency and economy without a reduction in reliability, according to the manufacturer.
The Best of Both Worlds
The Volvo L220F Hybrid will be Volvo’s first commercially available wheel loader when deliveries begin in late 2009.
For more information, visit www.volvo.com.
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