Skip navigation
Hydraulic System Runs with Engine Shut Off

Hydraulic System Runs with Engine Shut Off

Altec won an award for its JEMS vehicle, which employs a hybrid hydraulic-electric system that saves on fuel consumption.

Improving efficiency in both on- and off-highway vehicles and equipment ultimately leads to reduced fuel consumption. Designing more efficient hydraulic systems also helps cut fuel consumption, but this is only part of the equation. Even if a hydraulic system is 100% efficient, it still requires a gasoline or diesel engine to burn fuel in order to power the hydraulic power unit.

Of course, we can’t have a perfectly efficient hydraulic system, but companies have been able to find an alternative source of power for driving the hydraulic pump: an electric motor instead of an internal-combustion engine. This solution would be impractical for many applications. However, aerial work platforms present an excellent opportunity because the hydraulic system usually operates only when the vehicle is stationary.

When a work crew parks a vehicle and operates the hydraulic system, they can shut off the vehicle’s motor but still operate the hydraulics. That’s because the pump in a hydraulic power unit is driven by an electric motor, which draws power from a bank of rechargeable batteries. Depending on the system, the batteries may supply full power for an hour or longer.

Although this is adequate for typical tasks, situations arise when more time is needed. In such cases, the system can be plugged into an external source of electrical power, or the vehicle’s engine can be started to provide power while also recharging the batteries.

Award-Winning Solution

This type of hybrid hydraulic-electric system is one reason why Altec Industries, Birmingham, Ala., won the 2016 Green Award for its JEMS (Jobsite Energy Management System) hybrid-electric vehicles at the most recent Work Truck Show. The Green Award recognizes the product at the show that best improves work-truck fuel utilization, as determined by a panel of trade media editors and truck fleet managers.

Altec Industries was presented the Green Award for its JEMS 4 Series Jobsite Energy Management System at the latest Work Truck Show. At left is William Callis, senior account manager for telecommunications at Altec, accepting the award from Steve Carey, executive director of NTEA. (Photo courtesy of NTEA)

Altec’s JEMS 4 Series is an updated energy-management system for utility work trucks. This integrated system uses stored electrical energy to power the aerial device, tools, accessories, exportable power, and engine-off cabin heating and cooling. It features lithium-ion energy and an on-demand electrified PTO (ePTO) for hydraulic power. This allows bucket units to operate quietly without the truck engine running, which is especially beneficial in urban areas.

The compact system is equipped with Altec’s Idle Mitigation System, which eliminates unnecessary idle time when the vehicle is parked, automatically transitioning from engine power to JEMS power. Mark Greer, market manager at Altec, says this reduces fuel consumption while minimizing emissions and engine maintenance. Ultimately, the integrated hybrid system reduces fuel consumption, cuts greenhouse gas emissions in half, and significantly reduces noise.

More Than Alternative Power

Eliminating or reducing fuel consumption to operate the hydraulic system is only one facet of Altec’s JEMS 4 Series vehicles. The hydraulic system itself uses BioPure hydraulic oil, which provides the highest ASTM rating and is non-toxic to plants and animals.

According to, BioPure is a biodegradable anti-wear hydraulic oil that meets or exceeds demands of both high- and low-pressure OEM hydraulic systems. It is intended as a replacement to mineral- and Canola-based hydraulic oils, where high performance, wide temperature range, high oxidation stability, low odor, and full biodegradability are required.

The JEMS 4 Series also takes advantage of lightweight materials, such as aluminum alloys. Altec's aluminum utility and service bodies are 45% lighter than steel, and about 15% lighter than fiberglass. As a result, the lower vehicle weight further contributes to fuel savings and reduces tire and suspension wear and brake maintenance.

Furthermore, Altec’s manufacturing plant in Dixon, Calif., employs a vacuum infusion fiberglass process that uses 30% less resin and reduces styrene emission by 60%. The plant also applies powder-coat paint that emits no volatile organic compounds, produces minimal waste, and is durable and non-toxic.

The Work Truck Show, one of the top 100 trade shows in the U.S., brings together more than 11,000 truck fleet managers, dealers, and equipment distributors every year in Indianapolis. It provides opportunities to network with other work-truck industry professionals on an exhibit floor covering more than 500,000 ft.2, and features a comprehensive educational conference. The 2017 Work Truck Show will be held at the Indiana Convention Center, Indianapolis, from March 15 to 17.

For more information on Altec’s JEMS hybrid technology and other Green Fleet Solutions, visit For information on the Work Truck Show, visit

Looking for parts? Go to SourceESB.

Download this article in .PDF format
This file type includes high-resolution graphics and schematics when applicable.
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.