Hydraulic Launch Assist
Encyclopedia
Hydraulic Launch Assist is a hydraulic hybrid
regenerative braking system produced by the Eaton Corporation
.
It also is referred to as the HLA (reg.) system.
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.
included the HLA system in their 2002 F-350 Tonka truck concept vehicle where it was reported to have reduced fuel consumption by 25%-35% in stop-and-go driving.[2]
Peterbilt Motors has designed a Model 320 chassis that incorporates the HLA system
, which was featured on the cover of the December 13, 2007 issue of Machine Design.
Hydraulic hybrid
Hydraulic Hybrid Vehicles or HHVs are vehicles that use pressurized fluid, instead of electric power, as an additional or alternative power source along with an engine.- Principle of Operation :...
regenerative braking system produced by the Eaton Corporation
Eaton Corporation
Eaton Corporation is a global diversified power management company with 2010 sales of $13.7 billion. The company is a leading provider of electrical components and systems for power quality, distribution and control; hydraulics components, systems and services for industrial and mobile equipment;...
.
It also is referred to as the HLA (reg.) system.
Background
The HLA system recycles energy by converting kinetic energyKinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
into potential energy
Potential energy
In physics, potential energy is the energy stored in a body or in a system due to its position in a force field or due to its configuration. The SI unit of measure for energy and work is the Joule...
during deceleration via hydraulics
Hydraulics
Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...
, 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.
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 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.Concept Vehicles
Ford Motor CompanyFord Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...
included the HLA system in their 2002 F-350 Tonka truck concept vehicle where it was reported to have reduced fuel consumption by 25%-35% in stop-and-go driving.[2]
Shuttle Bus
Eaton, Ford, the US Army, and IMACT Engineering built an E-450 shuttle bus as part of the Army’s HAMMER (Hydraulic Hybrid Advanced Materials Multifuel Engine Research) project.Refuse
Eaton has been awarded the Texas government’s New Technology Research and Development grant to build 12 refuse vehicles with HLA systems.Peterbilt Motors has designed a Model 320 chassis that incorporates the HLA system
, which was featured on the cover of the December 13, 2007 issue of Machine Design.