Volvo Construction Equipment last week unveiled a pre-production prototype of its L220F Hybrid wheel loader at the ConExpo show in Las Vegas. The unit offers a 10-percent reduction in fuel consumption.
While much of the technology remains confidential, subject to patents pending, the heart of the hybrid system is an integrated starter generator. Fittted between the engine and the transmission, the ISG is coupled to a state-of-the-art battery that has many times the power capacity of a normal lead acid battery, Volvo says.
The ISG is valuable because 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.
The ISG can also overcome diesel engines’ traditional problem of low torque at low engine speeds, the company said, by automatically offering a massive electric torque boost, adding up to 50 kW of instant mechanical energy.
Added benefits include an electrically powered climate control system, rather than being powered directly by the engine.
Volvo chief executive Tony Helsham said at ConExpo that Volvo expects to begin delivering the unit in late 2009.