EPA Strugges to Devise Plug-In Hybrid MPG Rating

Robert Farago
by Robert Farago

How the Hell do you calculate the official Environmental Protection Agency (EPA) mileage figures for plug-in or serial hybrids, vehicles that can/will operate in electric-only, charge-sustaining, gas-only and/or blended modes? In a phone interview with TTAC [below], EPA Senior Project Engineer Carl Paulina reveals that the Feds have been working on the problem with the Society of Automotive Engineers (SAE) for the last year-and-a-half. And… they're still working on it. In fact, Paulina reckons it'll be another year, easy, before the SAE committee figures out how to modify SAE standard J1711 to deal with the new technology (the equivalent fuel cell committee met for five years). Meanwhile, I asked Paulina how the EPA measures current [parallel] hybrid MPG stats. The result is a rivet counter's wet dream. Bottom line: your mileage may vary.

Robert Farago
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  • Stuntnun Stuntnun on Oct 11, 2007

    i copied this from mazda,is it fake?----japanes authorities approve leases with two companies in the energy sector HIROSHIMA, Japan— Mazda Motor Corporation received permission from Japan's Ministry of Land Infrastructure and Transport (MLIT) on February 10, 2006, to begin leasing the RX-8 Hydrogen RE to its first two corporate customers. These vehicles, equipped with a rotary engine, feature a dual-fuel system that allows the driver to select either hydrogen or gasoline with the flick of a switch. Mazda has started limited leasing of the vehicles and today concluded leases with two energy-related companies, marking the first lease contracts of a hydrogen-powered rotary engine equipped vehicle in the world. Delivery of the vehicles is scheduled to take place in late March 2006. Idemitsu Kosan Co. Ltd. and Iwatani International Corporation, both companies operating in the energy sector, have leased one vehicle each. By the end of 2006, Mazda plans to lease about 10 RX-8 Hydrogen RE cars to local government and energy companies. In 2003, Mazda exhibited a RX-8 hydrogen rotary vehicle at the Tokyo Motor Show and received permission from MLIT in October 2004 to conduct public road tests for ongoing development and practical application of this advanced technology. Mazda undertook 29 months of development from the time of announcing the concept model to achieving the breakthrough, real-world rotary hydrogen vehicle. Employing a dual-fuel system, the Mazda RX-8 Hydrogen RE can run on either high-pressure hydrogen gas or gasoline. This combination offers excellent convenience because it can be driven in remote areas where hydrogen fueling stations are not readily available, easing driver concerns about running out of fuel. In addition, this system boasts great environmental friendliness—zero emission of carbon dioxide (CO 2) gas and near zero nitrogen oxide (NOx) emission when fueled by hydrogen—together with the natural driving feel of an internal combustion engine. It uses engine parts and production facilities that already exist in Mazda's inventory, so this innovative engine can be built with a high degree of reliability at a relatively low cost. The standard monthly lease price is 420,000 yen with tax included (400,000 yen/month without tax) which is almost half the monthly lease price of a fuel cell vehicle already available in Japan. With the RX-8 Hydrogen RE, Mazda continues to advance the possibilities of the internal combustion engine and improve the performance of hydrogen-fueled rotary engine vehicles. It represents another Mazda contribution to a more environmentally friendly hydrogen energy society of the future. Specifications and lease price of Mazda RX-8 Hydrogen RE Vehicle Type Mazda LA-SE3P ‘Kai' (modified model) Overall length/width/height 4.435mm / 1.770mm / 1.340mm Wheelbase 2,700mm Curb weight 1,460kg Seating capacity 4 adults Engine Class RENESIS hydrogen rotary engine (Dual fuel system) Type 13B Displacement 0.654L x 2 Maximum output Hydrogen 80kW (109PS) Gasoline 154kW (210PS) Maximum torque Hydrogen 140Nm (14.3kgm) Gasoline 222Nm (22.6kgm) Fuel Type Hydrogen/gasoline switch Fuel tank Hydrogen 110L/35MPa ( 350 bar ) high pressure hydrogen tank Gasoline 61L Performance Cruising distance (10-15 mode) Hydrogen 100km Gasoline 549km * Standard lease price (Price without tax indicated in brackets.) 420,000 yen (400,000 yen) per month *Monthly lease payment for the 30-month lease period. Mazda's hydrogen vehicle development milestones 1991 Developed the first hydrogen rotary engine vehicle, HR-X 1992 Test drive of golf cart equipped with fuel cell 1993 Developed second hydrogen rotary engine vehicle, HR-X2 Developed test version of MX-5 equipped with hydrogen rotary engine 1995 Conducted Japan's first public road test with Capella Cargo equipped with hydrogen rotary engine 1997 Developed Demio (Mazda2) FC-EV 2001 Developed Premacy FC-EV and conducted first public road test in Japan (with methanol reformer fuel cell system) 2003 Announced Mazda RX-8 Hydrogen Rotary Engine vehicle development model 2004 Conducted the world's first public road tests of the RX-8 hydrogen rotary engine that can run on two types of fuel--hydrogen and gasoline heres a newer link says it gets 200 km on a tank now http://media.ford.com/mazda/article_display.cfm?article_id=17134&make_id=227

  • Carl Paulina Carl Paulina on Oct 11, 2007

    Engineer, Thanks for the units explaination, sorry your worried (yes your correct). When I'm measuring power instantaneously, it's kilowatts, if we integrate power with time, isn't it energy? (i.e. kWh, Joules, BTUs, Ft-lbs, calories) I apologize for mixing the references in these short responses, I should be more careful. And of course nothing is free.

  • Engineer Engineer on Oct 11, 2007

    stuntnun, Your rather lengthy post proves that one can burn hydrogen in an ICE. That was news to you? It also list some numbers relevant to hydrogen's (in)ability to penetrate the market: Maximum output Hydrogen 80kW (109PS) Gasoline 154kW (210PS) Note: ~ a 50% power penalty for using hydrogen. Cruising distance (10-15 mode) Hydrogen 100km Gasoline 549km Note: Hydrogen does not even have one fifth the range of gasoline. The conclusion seems obvious...

  • Stuntnun Stuntnun on Oct 11, 2007

    sorry it was long - its been updated to 200 km and the reason im sure that battery power is yesterdays news is because the largest refinery in the midwest (my dads been there over 30 years)just spent a lot of time and money adding hydrogen production to the plant .id rather be driving an rx8 over a prius any day ---and no this isnt news to me ive been following this closely for about 15 years,and hydrogen is almost here ,still think gas is just as clean as any of these technologies and the gov can tax it easier.