USCAR, the United States Council for Automotive Research - a consortium of GM, Ford and Chrysler, has just issued a new standard for high voltage wiring and connectors in hybrid and electric cars. The existing standards only covered conventional systems up to 20V. The new standard covers systems operating up to 600V. The advantage of establishing industry standards is that suppliers can tool up common components that can be used by a variety of automakers and applications. This will help drive down the cost of these systems especially as production volumes for hybrids and EVs get ramped up over the next few years.
Until now, every automaker has specified unique connections for its high voltage wiring. This necessitates tooling and significant testing for each one of these designs. Because environmental sealing and safety from electrocution are critical, the ability to test once and have confidence is paramount. The press release is after the jump.
USCAR'S EWCAP ISSUES NEW SPECIFICATIONS THAT HELP HYBRIDS AND ELECTRIC VEHICLES 'CONNECT'
Detroit Three research group issues three new SAE/USCAR specifications
SOUTHFIELD, Mich., March 31 – The United States Council for Automotive Research LLC (USCAR) Electrical Wiring Component Application Partnership (EWCAP) recently released two new supplemental/revised SAE/USCAR specifications – one for high-voltage connectors, the other for cable-to-terminal electrical crimps – along with a third specification that defines ergonomic guidelines for assembly.
Since it was established in April 1994, EWCAP – whose members are Chrysler LLC, Ford Motor Company and General Motors Corporation – has been developing and releasing automotive wiring and connector specifications that typically become published for the U.S. auto industry by SAE International. The two new wiring specifications support the high-voltage requirements for a full range of new hybrid-electric and electric vehicles.
"Our previous SAE-USCAR 2, Performance Specification for Automatic Electrical Connector Systems, applied to wiring capacities of up to 20 volts. The new supplement, published in August 2008, addresses performance up to 600 volts," said EWCAP Technical Specialist Jim Roberts.
Similarly SAE/USCAR 21 Revision 2, Performance Specification for Cable-to-Terminal Electrical Crimps, published in October 2008, addresses larger crimps (the metal end-bands used to terminate wires or cables). The previous specification covered crimps for wires up to 8 mm2, while the revised specification sets crimp requirements for high-energy cables of up to 103 mm2.
Summarizing EWCAP's new specifications by name and brief description radically simplifies what is truly a complex and arduous process. Each specification actually comprises a multitude of requirements for measurements and other functional characteristics. Testing can take more than six-months to complete. Testing procedures, validation processes and acceptance criteria are captured in a bound document for each published specification. "For example, electrical tests in the crimp specification will include thermal shock, temperature, humidity and power current cycling," Roberts said.
The 46-page crimp specification revision defines basic test methods and requirements for solderless crimped connectors, with some sections applying to other wire/cable termination methods, such as sonic or resistance welding.
In addition to the two new wiring specifications, EWCAP technical specialists, Roberts and Harry Zaverzence, and the EWCAP team supported the revision of a third specification related to worker ergonomics.
SAE/USCAR 25 Revision 1 (released in September 2008), titled, Electrical Connector Assembly Ergonomic Design Criteria, sets specifications for the design, assembly force requirements and packaging of conventional hand-plug, mechanical-assist and twist-lock electrical connectors, as well as 'connector position assurance features' and other design guidelines that ensure good fit and function.
"The ergonomic update came through a committee of Chrysler, Ford and General Motors engineers, working to identify operator needs," Roberts said. "We looked at things like tactile issues and excessive connector mating forces in an effort to minimize the possibility of repetitive stress injury during the vehicle assembly process."
The resulting specification requires assembly forces to be "as low as possible" yet assures the connection will remain functional over the life of the vehicle. It also includes a "Hand Clearance Guidelines" section to ensure that potential negatives like obstructed access, awkward or unnatural postures and lateral body forces are minimized.
All three new specifications can be ordered online through SAE by visiting www.sae.org/technical/standards and entering "USCAR" under the "search by author" heading.
EWCAP's work continues to save the U.S. automakers time and money as testing redundancies are minimized and common connector and electrical wiring specs for all three streamline supplier parts design fulfillment. In addition, with an increased focus on vehicle electrification by all three U.S. automakers, EWCAP's work in setting universally accepted electrical wiring and connector specifications will continue to be front and center in increasingly 'wired' vehicles.
"While wireless aspects of vehicle communications and operations will continue to grow, there are key areas where hard-wiring is essential to ensuring uninterrupted performance and safety," Roberts said. "I think EWCAP will continue to be ahead of the curve in that regard, providing needed specifications for all types and combinations of conventional, as well as electric vehicles, ranging from battery-electric to hybrids, plug-ins and range-extended EVs."
Founded in 1992, USCAR is an advanced technology research collaboration of Chrysler LLC, Ford Motor Company and General Motors Corporation. The goal of USCAR is to further strengthen the technology base of the domestic auto industry through cooperative research and development. For more information, visit USCAR's Web site at www.uscar.org