1. Background

2. Parallel vs. Series Hybrids

3. Hydraulic vs. Electric Hybrids

4. Applications
    Concept Vehicles  Shuttle Bus  Refuse 

5. References

Hydraulic Launch Assist (HLA) is a hydraulic hybrid regenerative braking system produced by the Eaton Corporation.

It also is referred to as the HLA (reg.) system.^[1]

Background

The HLA system recycles energy by converting kinetic energy into potential energy during deceleration via hydraulics, storing the energy at high pressure in an accumulator filled with nitrogen gas. The energy is then returned to the vehicle during subsequent acceleration thereby reducing the amount of work done by the internal combustion engine. This system provides considerable increase in vehicle productivity while reducing fuel consumption in stop-and-go use profiles like refuse vehicles and other heavy duty vehicles.^[2]

Parallel vs. Series Hybrids

The HLA system is a so-called parallel hydraulic hybrid. In parallel systems the original vehicle drive-line remains, allowing the vehicle to operate normally when the HLA system is disengaged. When the HLA is engaged, energy is captured and released during deceleration and acceleration respectively. This is in contrast to so-called series hydraulic hybrid systems which replaces the entire traditional drive-line to provide power transmission in addition to regenerative braking functions.

Hydraulic vs. Electric Hybrids

Hydraulic hybrids are said to be power dense, while electric hybrids are energy dense. This implies that electric hybrids, while able to deliver large amounts of energy over long periods of time are limited by the rate at which the chemical energy in the batteries is converted to mechanical energy and {{linktext|vice versa}}. This is largely governed by reaction rates in the battery and current ratings of associated components. Hydraulic hybrids on the other hand are capable of transferring energy at a much higher rate, but are then limited by the amount of energy that is stored. For this reason, hydraulic hybrids lend themselves well to stop-and-go applications or applications with high vehicle weights.

Applications

Concept Vehicles

Shuttle Bus

Refuse

References

• Liberal Party (Honduras)
• Liberal Party Hong Kong
• Liberal Party (Japan, 1945)
• Liberal Party (Japan) (disambiguation)
• Liberal Party (Labrador)
• Liberal Party leadership convention, 1990
• Liberal Party leadership convention, 2003
• Liberal Party leadership convention, 2006
• Liberal Party leadership convention, 2009
• Liberal Party (Manitoba)
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• Liberal Party (Newfoundland and Labrador)
• Liberal party of australia
• Liberal Party of Canada leadership convention, 1948
• Liberal Party of Canada leadership convention, 1958
• Liberal Party of Canada leadership convention, 1968
• Liberal Party of Canada leadership convention, 1984
• Liberal Party of Canada leadership convention, 1990
• Liberal Party of Canada leadership convention, 2003
• Liberal Party of Canada leadership convention, 2006
• Liberal Party of Canada leadership convention, 2009
• Liberal Party of Canada leadership conventions
• Liberal party of Honduras
• Liberal Party of Jura