by Jack Rosebro
|Active standards work. Click to enlarge.|
During the SAE 2009 World Congress in Detroit, Gery Kissel of General Motors presented an update of hybrid, plug-in hybrid, and electric vehicle standards being revised or developed by the Society of Automotive Engineers (SAE) Hybrid Standards Committee.
Many of these are scheduled for completion this year. SAE standards are generally followed by manufacturers of vehicles destined for North America and other markets. Standards under development in these areas include:
J1711: Emissions and Fuel Economy Testing. J1711 (Recommended Practice For Measuring The Exhaust Emissions And Fuel Economy Of Hybrid Electric Vehicles) is designed to establish uniform chassis dynamometer test procedures for hybrid-electric vehicles that are designed to be driven on public roads. Such procedures will be used during exhaust emissions tests and fuel economy certification tests, and may be used for future “charge economy” certification tests. The committee has not yet decided whether or not the emissions certification component of J1711 will use the same procedure that determines fuel economy.
Fuel economy and electrical energy usage will not be combined under J1711 to make a composite efficiency metric for plug-in hybrids. Instead, fuel usage and watt-hours per mile will be stated separately, with the baseline charging assumption being one energy storage charge per day for each vehicle being tested.
However, J1711 will retain a “utility factor” component to determine the relative fuel economy of a plug-in hybrid (PHEV) vehicle in charge-depleting mode. The utility factor uses driving statistics from a 2001 DOT national household travel survey, and is itself defined by SAE standard J2841, which was released on 27 March.
J1711 was first approved in 1999, expiring in 2004, and had relatively little validation with plug-in hybrid vehicles. The revised Recommended Practice will focus on PHEVs and be coordinated with both California Air Resources Board (CARB) and International Standardization Organization (ISO) standards. Estimated completion for J1711 is summer 2009.
J1772: Conductive charging. J1772 (Electric Vehicle Conductive Charge Coupler) establishes physical, electrical, and performance requirements for EV (electric vehicle) and PHEV conductive charging system couplers in North America. The Japan Automobile Research Institute (JARI) is also in alignment with the J1772 work, Kissel said earlier. J1772 will cover the physical interface, control, and data signals for the coupler, including a control pilot signal, which will:
- Verify that the vehicle is present and connected
- Transmit supply equipment current rating to the vehicle
- Allow energizing and de-energizing of the charge current circuit
- Monitor equipment grounds
- Establish vehicle ventilation requirements (e.g. battery pack fans commanded on or off)
The standard will also provide for a proximity detector that will detect a plugged in coupler even if the charger is de-powered, to help prevent the vehicle operator from driving away with the coupler still engaged. Performance requirements include impact resistance and a life- span of 10,000 cycles.
Estimated completion of J1772 is summer 2009. A separate standard is being developed for the European market by a consortium of utility operators and vehicle manufacturers, independent of SAE efforts.
The different approaches, Kissel had noted before the session, are based on the different electric infrastructures in place (single phase in the US and Japan, 3-phase in Europe). Noting that while it was far from ideal to have two major approaches, Kissel said the global automotive industry would work around it.
J2464: Battery Pack and Capacitor Pack Safety. J2464 (Electric and Hybrid Electric Vehicle Rechargeable Energy Storage System (RESS) Safety And Abuse Testing), which is a comprehensive overhaul of a decade-old standard, is designed to “determine the response of batteries to conditions or events which are beyond their normal operating range”, according to Kissel. The standard, which is based on a similar document developed by the US Advanced Battery Consortium, has been under development for the past two years, involving around fifteen vehicle manufacturers as well as battery manufacturers, government agencies, and national research laboratories.
Test descriptions, procedures, and data analysis protocols have been improved as well as expanded to include new energy storage devices such as electrochemical capacitors.
While the number of abuse tests defined by J2464 will be unchanged at 17, with seven covering mechanical abuse, five covering thermal abuse, and five more covering electrical abuse, three previous tests (Elevated Temperature Storage, Compromise of Thermal Insulation and Extreme Cold Temperature Test) have been dropped, and three new tests (Pressure-induced Internal Short Circuit, Passive Propagation Resistance, and Separator Shutdown Integrity) have been added. Hazard severity levels have been also been defined to make the evaluation of abuse testing more quantitative.
J2836: Vehicle-to-Charger Communication. J2836 (sections 1, 2, and 3) (Use Cases for Communication between Plug-In Vehicles and the Utility Grid/EVSE/Power Flow) addresses modes of communication between plug-in electric vehicles and the electric power grid for the purpose of transferring energy between the vehicle and the grid.
Section 1 defines the fundamental communication for energy utility companies, while Section 2 covers DC energy transfer, replacing J2293, and Section 3 establishes a communication standard for reverse energy flow, e.g. vehicle-to-grid (V2G) or vehicle-to-home (V2H) systems.
J2836 establishes five categories of for utility programs: time of use, direct load/price control, active management, critical peak pricing, and optimized charging. Three Electric Vehicle Supply Equipment (EVSE) architectures are specified: 120V AC, 240V AC, and DC charging. Customer locations are defined into four subsets:
- Another home
- Public charging station
- Whether the vehicle is inside or outside the customer's utility territory.
Functions are also divided into four subsets:
- Charging the vehicle
- Discharging the vehicle
- Charging system diagnostics
- Manufacturer-specific functions
The committee will generate use cases to define scenarios that can be addressed by the SAE standard as well as standards establishes by ISO, International Electrotechncial Commission (IEC), and JARI. The standard is scheduled to be completed by the end of 2009.
J2894: Charging Power Quality. J2894 (Vehicle On-Board Charging Power Quality) will provide guidelines and standards for the quality of the charging voltage and current at the vehicle itself. Along with power factor—the relative synchronization between alternating current and the voltage that drives that current—J2894 will address:
- Power conversion efficiency
- Total harmonic distortion
- Harmonic distortion at different frequencies
- Input voltage range, swell, surge, and sag
- Variations in input frequencies
- Inrush currents
J2894 will also address automatic charger restarts after a sustained power outage, as well as the ability to ride through momentary outages. The standard is based on Electric Power Research Institute (EPRI) Recommended Practice TR-109023 (EV Charging Equipment Operational Recommendations For Power Quality), and is designed to enable vehicle manufacturers, charging equipment manufacturers, and electric utilities. The standard is scheduled to be completed by the end of 2009.
SAE Hybrid Standards Committee: Works In Progress