Interpretation ID: nht91-6.12
DATE: September 30, 1991
FROM: W.R. Kittle -- Director, Automotive Safety Planning and Compliance, Product Strategy and Regulatory Affairs Office, Chrysler Corporation
TO: Jerry R. Curry -- Administrator, NHTSA
TITLE: Re: Petition for Temporary Exemption; Low Emission Motor Vehicle; 49 CFR 555
ATTACHMT: Attached to letter dated 3/30/92 from Paul J. Rice to D.E. Dawkins (A39; Part 555)
TEXT:
Chrysler Corporation, a Delaware corporation, with offices at 12000 Chrysler Drive, Highland Park, Michigan 48288-1919, hereby petitions the NHTSA for a temporary exemption from certain requirements of Federal Motor Vehicle Safety Standards for the Chrysler TEVan, an electrically driven version of the Dodge Caravan/Plymouth Voyager multipurpose passenger vehicle. The exemption is sought for a one year period.
The Chrysler TEVan has been developed in cooperation with the Electric Power Research Institute, Southern California Edison Company, the South Coast Air Quality Management District, and the United States Department of Energy. The acronym, TEVan, is derived from the expression, "T-115 Electric Van", where T-115 is the engineering model code for the Caravan/Voyager vehicles. TEVan is pronounced as if it were two words, "Tee Van".
The basis for this petition is the facilitation of the development of low-emission engine features. The TEVan is a low-emission motor vehicle as defined by section 123(g) of the National Traffic and Motor Vehicle Safety Act of 1966. The TEVan does not have an internal combustion engine. Instead, it has an electric motor propulsion system powered by nickel-iron batteries. As a result, it will emit air pollutants in amounts significantly below new motor vehicle standards applicable under Section 202 of the Clean Air Act (42 U.S.C. 1857 f-1) at the time of its manufacture, and with respect to all other pollutants, it will meet the new motor vehicle standards applicable to it under Section 202 of the Clean Air Act at the time of its manufacture.
The TEVan is a Dodge Caravan in which the internal combustion engine, transmission, coolant system, manifold-vacuum-assisted power brakes, gasoline fuel system, and engine-driven hydraulically-assisted power steering system have been replaced by an electric drive motor, a nickel-iron battery pack, a micro-processor based battery management system, a controller-convertor-charger unit, a two-speed manual or three-speed automatic transmission, and electric-motor-driven pumps for the vacuum power brakes and the hydraulically-assisted power steering. In addition, the original hot water heater/defroster unit has been replaced by a diesel fuel-burning unit. Since their manufacture, those that were equipped with the automatic transmission have been refitted with the manual transmission.
Based on certification testing of the Caravan, and the anticipated effect of the modifications above upon the vehicle, the TEVan complies with all Federal Motor Vehicle Safety Standards with the considerations or exceptions indicated below.
FMVSS 102 - Transmission Shift Lever Sequence, Starter Interlock, and Transmission Braking Effect.
S3.1.2; TRANSMISSION BRAKING EFFECT. The requirement for transmission braking effect is met by regenerative braking, in which the electric motor becomes a generator, recharging the batteries and dissipating energy in the process. Regenerative braking can be switched off at the option of the driver to restore steering control on slippery surfaces.
FMVSS 105 - Hydraulic Brake Systems
S5.1; SYSTEM BRAKE SYSTEMS. The performance of the service brake system is predicated on the use of the regenerative characteristic of the drive motor to augment the power-assisted hydraulic wheel brakes. The motor, driven through the transmission by the mass of the coasting vehicle, functions as a generator to dissipate energy through charging the drive batteries. In the performance tests of S5.1.1 - Stopping Distance, however, the transmission must be in neutral, and in the TEVan, that would preclude the contribution of regenerative braking. No tests have been conducted with the TEVan, however, it is our opinion that with regenerative braking, the stopping distance requirements would be met.
Further, in the test for evaluation of S5.1.4 - Fade and Recovery, the distance between the starting points of successive brake applications at 60 mph is 0.4 miles. The TEVan will not accelerate from 5 to 60 mph in that distance, so the test cannot be conducted as prescribed. Then too, the TEVan is considerably heavier than the parent vehicle. Nonetheless, we believe that if the test could be conducted as prescribed, and with regenerative braking, the fade and recovery requirements would be met or nearly met.
FMVSS 207 - Seating Systems
S4.2(a)-(c); GENERAL PERFORMANCE REQUIREMENTS. The right end floor pan anchor sockets for the removable two-passenger second seat have been reduced in height below the floor pan to provide space for a portion of the battery pack. While the modified sockets are believed to be equivalent in strength to the original, compliance tests have not been performed.
FMVSS 210 - Seat Belt Assembly Anchorages S4.2; STRENGTH. The modified right end floor pan anchor sockets discussed in FMVSS 207 - Seating Systems, above, must also transmit seat belt forces to the vehicle structure through seat-mounted anchorages.
Again, while the modified sockets are believed to be equivalent in strength to the original, compliance tests have not been performed.
FMVSS 212 - Windshield Mounting, and
FMVSS 219 - Windshield Zone Intrusion
S5; REQUIREMENT. Windshield mounting and zone intrusion performance are ultimately determined by vehicle front structure crush characteristics.
The front structure of the base Caravan/Voyager, modified to support the
electric drivetrain components, is believed to be materially equivalent in strength to the original, however, a 30 mph barrier impact test has not been conducted to confirm compliance.
FMVSS 301 - Fuel System Integrity
S5.5 - FUEL SPILLAGE: BARRIER CRASH, and S5.6 - FUEL SPILLAGE: ROLLOVER. A 1.6 gallon tank has been provided just behind the rear axle for the fuel used in the diesel fuel-burning heater/defroster. The integrity of the diesel fuel system has not been evaluated with fixed and moving barrier impact tests, however, it is believed that the system would comply with the spillage requirements if the vehicle were so tested.
If exempted, the TEVan would differ from the 1989 model Year Dodge Caravan vehicle from which it was derived in that the internal combustion engine, drivetrain, and engine-driven vehicle subsystems have been replaced by an electric traction motor, a complement of nickel-iron batteries, an electric controller, and certain electrically-driven vehicle subsystems. Changes have also been made in structural elements to accommodate the latter components. To assist in the review of this petition, a brochure describing the TEVan in greater detail has been provided as Attachment 1. The probable effect on the performance of the modified vehicle with respect to the Federal Motor Vehicle Safety Standards is described above.
Chrysler is not presently manufacturing the TEVan, but is manufacturing an improved version of the Dodge Caravan upon which it is based. The latter vehicle meets all applicable Federal Safety Standards.
Chrysler is not aware of any tests conducted with the TEVan in which it failed to meet a Safety Standard. Since only four vehicles have been or will be modified for field evaluation of this initial design, no testing for compliance is planned or anticipated.
While destructive compliance testing has not been conducted on any of these vehicles, Chrysler believes that their safety performance will be very like that of the Caravan/Voyager vehicle from which they were derived. While vehicle weight is much greater because of the batteries for the drive system, hydraulic brake system performance is augmented by regenerative braking. The internal combustion engine is no longer in place to share or transfer front impact forces, however, the electric motor and its controller take the place of the engine, at least in part. Similarly, the potential for fuel-fed fire is greatly reduced, first because of the nearly tenfold reduction in the size of the fuel tank, and secondly because less volatile diesel fuel is used instead of gasoline.
The exemption of these vehicles from the requirement to confirm performance with respect to the braking, crashworthiness, and post-crash standards will facilitate the development of the electric motor, controller, and battery for the next generation of the TEVan. That vehicle will be designed to comply with all Federal safety standards, to the extent that an electrically-powered vehicle can so comply.
The four vehicles that are the subject of this petition will not be brought into compliance with the Federal standards applicable to them in the 1989 model year by Chrysler. Provided an exemption is granted, one or more of the vehicles will be titled and sold for ongoing endurance evaluation.
Not more than 2,500 exempted, first generation TEVans will be sold in any 12-month period for which an exemption may be granted. In fact, only four such vehicles were manufactured for test and evaluation.
The grant of the requested exemption would be in the public interest because it would:
o facilitate the field evaluation of a low emission motor vehicle without unreasonably degrading the safety of that vehicle;-
o facilitate the development of a vehicle which could be very fuel-efficient in terms of its use of fossil fuels;
o accelerate the development of electrically-driven vehicles and related technology which could help to reduce our dependency on foreign oil.
Please direct all questions regarding this petition to Howard Willson of my staff at 313-956-6037.