Update on Eaton Medium-Duty Electric Hybrids
15 February 2008
|The core of the system: the Hybrid Drive Unit. Click to enlarge.|
In a presentation at the 2008 SAE Hybrid Vehicle Technology Symposium, Kevin Beaty, Eaton’s Business Unit Manager for Hybrid Power Systems, provided an update on the status of the medium-duty hybrid-electric systems the company currently has in the field. After several years of testing and putting prototypes into field trials with customers, Eaton began commercializing its medium-duty hybrid system in August 2007.
Eaton’s hybrid system for city delivery applications uses a parallel, pre-transmission design with Eaton’s Fuller UltraShift automated transmission. Primary components are the Hybrid Drive Unit (HDU), which combines a clutch, a 44 kW/420 Nm motor/generator and automatically controlled manual transmission; the motor inverter/controller; the DC/DC converter; and a 2 kWh li-ion battery pack from Hitachi. (Earlier post.)
The hybrid systems for utility companies feature a slightly more involved architecture, due to the addition of the ability to allow the truck booms to operate in electric-only mode.
Fedex. FedEx has 93 Eaton hybrid trucks operating at 20 stations in the US and Canada, and has ordered another 45 production trucks for delivery in the second quarter of 2008. The Eaton hybrids have accumulated a total of 1.96 million miles. The baseline engine for the FedEx delivery van is a 5.9L, 6-cylinder, 175 hp Cummins ISB. The hybrid version downsizes to a 4.3L, 4-cylinder, 170 hp MBE-904.
Eaton’s modeling and simulation projected a average 52% gain in fuel economy. Lab testing at Southwest Research Institute yielded a minimum 42% and a maximum 57% increase in fuel economy. FedEx has reported a wide spring in field operation from 10-80%.
UPS. UPS has 50 Eaton hybrids at 4 stations in the US, with an accumulated 501K miles. There are two models in service here, the P100 and the P70. Baseline engine for the P100 is an ITEC VT365 200 hp V8; the P100 hybrid engine is an ITEC VT275 V6 180 hp engine. The P70 baseline engine is a Cummins ISB 165 hp unit; the P70 hybrid engine is a MB904 170 hp unit.
Eaton’s modeling and simulation projected average fuel economy gains of 26% for the P100 and 52% for the P70. SwRI lab testing found average fuel economy gains of 32% for the P70 and 48% for the P100. Results in the field show gains in fuel economy ranging from 10% to 43% for the P100, and from 10% to 18% for the P70. The National Renewable Energy Lab is planning a controlled test of the fuel economy of these hybrid delivery trucks.
Coca-Cola. Easton has four trucks in service with Coke. Both baseline and hybrid engines are the same, a MaxxForce DT, 7.6L I6 225 hp engine.
Eaton modeling and simulation projected an average 30% gain in fuel economy, SwRI testing indicated an average 27% gain; and Coke field data shows an average 37% gain.
Frito-Lay. Frito-Lay has one Eaton hybrid, with 5,733 miles on it. The baseline engine is a GM 6.5L V8 160hp unit, and the hybrid engine is an ITEC VT275 4.5L V6 DI Turbo 180 hp unit.
Eaton’s modeling and simulation found average fuel economy gains of 34%. SwRI lab testing found average gains of 26%. Field results showed an average gain of 23%, with 14% minimum and 32% maximum.
Hybrid Truck Users Forum (HTUF). Eaton has 24 vehicles in 14 fleets in the hybrid utility truck program organized by HTUF. The trucks have accumulated 480K in-service miles. The baseline and the hybrid engines are the same: a 7.6L, 6-cylinder, 225 hp DT466 engine.
Eaton’s modeling and simulation projected a minimum fuel savings (as opposed to gain in fuel economy) of 29% and a maximum savings of 40%. SwRI testing found that the savings ranged from 38% to 60%, and field results indicate a range of 14% to 54%.
Foton Bus. There are 31 Foton buses in service in Guangzhou, China with the Eaton hybrid drive system. The baseline engines varied, but were typically a 6-cylinder, 220-260 hp, Euro 2-3 unit. The hybrid engines are ISB3 6-cylinder, 185-220 hp, Euro 3 units.
Eaton modeling and simulation projected average fuel economy gains of 28%. Track testing yielded a 27% gain with a manual transmission and a 59% gain with an automatic transmission. Field results showed a 37% gain in fuel economy, and a 110% gain compared to an LPG bus with a manual transmission.
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