Hybrid Route Trucks Will Be Game Changers

Hybrid vehicles are generally defined as “having more than one source of power.” Those sources may be diesel, gasoline, natural gas or LPG in combination with electric or hydraulic power systems.

Eaton Corp., a longtime major commercial vehicle component manufacture and OEM supplier, is, by far, today’s leading commercial vehicle hybrid systems designer and OEM supplier of commercial vehicle hybrid drive systems.

Hybrids come in two “flavors” – series or parallel. A series configuration has no direct mechanical connection between the electrical power system and the wheels. As Light & Medium Truck magazine phrased it last spring, “Series motive power must be converted from chemical energy to mechanical energy to electrical energy and back again to mechanical energy to drive the wheels.” Parallel systems, the article continued, “feature direct hybrid power mechanical connections, with an electric motor to drive the wheels. Such systems allow the vehicle to use either the internal combustion engine, electric motor or both as needed to reduce power consumption or maximize acceleration.”

In my view, parallel electric hybrid systems are more likely to be the primary systems for at least the near future. In addition, L&MT says, “Series electric technology also requires larger and heavier batteries, makes greater demands on the engine for battery charging and is further burdened by the inefficient multiple energy conversions required.”

Energy consumption and emissions  are reduced 30% to 50%. Commercialization of parallel systems began with utility bucket trucks in 2006. In-service performance has been deemed to be excellent.

Eaton has designed and is continuing with the further refinement and OEM assembly line rollout of the Hybrid Electric, Eaton Hydraulic Launch Assist (HLA) system and Series Hybrid Hydraulic.

The parallel system connects the engine with an electric motor, generator and batteries. The system also uses regenerative braking to capture power normally lost during braking. When electric torque is blended with engine torque, the stored energy is used to improve fuel economy.

Eaton’s HLA system consists of regenerative braking and launch assist. This system supplements the conventional powertrain with a hybrid hydraulic system rather than electrical power. The braking system is said to capture about 70% of the kinetic energy produced during vehicle braking. Stored hydraulic pressure is transmitted to the drive shaft as additional torque.

The launch system has two operating modes. In economy mode, initial vehicle launch is done with stored hydraulic pressure; engine torque begins to accelerate as hydraulic energy is exhausted. Performance mode uses both power sources. Primary targets for best use of this system are heavy stop-and-go applications. Fuel economy improvements are in the 20% to 30% range. 

The third Eaton system is the Series Hybrid Hydraulic, the most revolutionary of the designs. Conventional transmission and drive line are replaced by the hydraulic powertrain and energy is transferred to the drive wheels through fluid power. The system is said to be suited to a broader number of applications than parallel hybrids, although the greatest benefits are in stop-and-go duty cycles.

In this system, the engine continuously operates at its fuel consumption “sweet spot,” thanks to the continuously variable transmission functionality of the series system and regenerative braking. Fuel economy improvements are between 50% and 70%.

I can see those kinds of numbers making the Series Hybrid Hydraulic the route delivery drive train of choice by 2015 or so.

In early 2009, UPS is putting its first group of Series Hybrid Hydraulics into service evaluation. These Eaton power trains will be in trucks built by Navistar International. UPS says it anticipates improvements of up to 50% in fuel economy and carbon dioxide emission reductions of up to 30%.

My friends, those kinds of numbers are route delivery game changers and will separate the haves and the have nots.

The parallel Eaton Hybrid Electric is currently available in medium-duty (commercial vehicle classes 6 and 7) route truck chassis and route delivery tractor configurations.

The potential for route truck hybrid refrigeration systems is also not to be overlooked. There are at least two large dairies experimenting with continuous cold-plate regeneration using new hybrid technology. 

HP Hood has partnered with Aura Systems to replace a diesel-powered route truck generator set with a truck engine belt-driven, miniaturized (6x12 inches), 8.5-kilowatt generator, developed by Aura Systems. Hood estimates a $300 monthly savings in fuel and maintenance, and net truck reduction of 550 pounds.

The second dairy is evaluating a new route truck design using the Eaton parallel system to also power a continuous recharge of their cold-plate systems. Aura Systems is also working with Eaton on its patented “AuraGen” in providing cold-plate recharge in combination with Eaton’s electric hybrid.

Critical to getting production of hybrids up to the point of reducing or eliminating the current 25% to 30% and greater purchase premiums is the use of and increase in local, state and federal vehicle purchaser financial incentives, rebates and credits.

In 2009, with a new administration desperate for ways to regenerate the economy, reduce air pollution and conserve energy, there will never be a better time to make that case.

And I must say that again I’m quite disappointed that dairy and ice cream industry leadership seems to be blind to the window of opportunity. I see no public sign that they appear to even be aware of what’s now possible in route delivery fuel consumption and emissions reductions.