September 13, 2004 Vehicles with the potential for dramatic improvements in fuel efficiency, performance, and cost-effectiveness due to new advancements in hydraulic hybrid technology have been achieved through a strategic partnering between the Ford motor company and the U.S Environmental Protection Agency (EPA).
In late 2001 the EPA developed a hybrid, high efficiency vehicle using a hydraulic launch assist system (HLA).
Initial tests on the proof of concept chassis has since led to remarkable progress with the release earlier this year of a Ford F-550 commercial demonstration vehicle at the 2004 World Congress of the Society of Automotive Engineers in Detroit.
The hydraulic launch assist has a regenerative braking system that can reportedly improve fuel efficiency by 25 to 40 percent whilst also reducing emissions.
It works by recovering some of the energy wasted as heat by the vehicle's brakes when slowing. This energy is harnessed and used to propel the vehicle the next time it needs to accelerate.
The hydraulic system offers great advantages for vehicles operating in stop and go conditions because the system can capture large amounts of energy when the brakes are applied.
The original EPA hydraulic hybrid chassis successfully demonstrated that a typical diesel or petrol powered vehicle can be fitted with hydraulic components as a secondary energy storage system. The hydraulic components work in conjunction with the primary. Making up the main hydraulic components are two hydraulic accumulator vessels which store hydraulic fluid compressing inert nitrogen gas and one or more hydraulic pump/motor units.
Benefits of the hydraulic launch assist system not only include 25-45 percent improvement in fuel economy for city driving and reduction of emissions by 20 to 30 percent but also better acceleration, less braking maintenance and reduced operating costs. It can also provide high torque quickly, even at low speeds.
Because the HLA system offers greater advantages for vehicles operating in stop and go conditions the first production models will be urban delivery trucks and pickup trucks. Other attractive applications include school buses and waste disposal trucks.
Hydraulic hybrids also improve engine operation overall and vehicle acceleration by working in tandem with the primary engine.
The EPA's demonstration vehicle showed improved fuel economy by up to 55%, with a projected $600 increase in vehicle cost due to the hydraulic hybrid system.
According to their calculations, the initial cost of this system will be quickly recouped by the lower fuel and maintenance costs.
In its efforts to commercialise the technology EPA has also formed partnerships with Eaton Corporation, Parker Hannifin, SHEP technologies, the US Army, FEV Engine Technology, Michigan State University, Ricardo Inc., Southwest Research Institute and the University of Wisconsin.
All this will lead to a next generation of more efficient SUV's and pickup trucks. In America, SUVs are often the target of environmental lobbyists as they are labelled 'gas guzzling' vehicles which are not restricted to the same fuel economy regulations other vehicles on the road are subject to.
America's federal corporate average fuel economy (CAFE) standards set the fuel economy goals for new passenger cars at 27.5 miles per gallon (mpg).
SUVs, which are considered as light trucks not cars, only have to achieve an average of 20.7 mpg, but as the light truck economy goal is set as an average across the entire board of light trucks, some SUVs are known to achieve as little as 12 mpg.
In launching its new line of F-350's Ford recently teamed up with Tonka to develop a powerful and enormous concept truck that featured a HLA system incorporated in its powertrain.
More information on the HLA or the Tonka truck can be found at the EPA site http://www.epa.gov/otaq/technology/420f04024.pdf.