Unlike other consumer products, motor vehicle sales require approval—or certification—of each model year from the EPA, a process that applies to BEVs. With the continued penetration of BEVs into the market, the EPA has developed its regulatory interpretations and, with subject guidance, clarifies its regulations governing BEV MGPe certification and range. These regulations require vehicles to be operated in accordance with the manufacturer’s instructions, provided the instructions are representative of actual performance.1
This requirement is quite simple when the vehicle has a default, factory-set drive mode that engages whenever the engine is turned on. However, as BEVs become more sophisticated and manufacturers offer improved customizable options for user-controlled drive modes (such as “eco”, “range”, “sport”, “tow/haul or “track”), determining the default test mode settings becomes more difficult.
To determine this representative drive mode, the EPA will consider whether multiple drive modes can “lock,” meaning that the mode, when set, is saved and reactivated when the vehicle is restarted. If a vehicle defaults to the factory drive mode each time the key is turned on, there is only one default drive mode. However, if multiple modes lock, the guidelines require manufacturers to 1) test a vehicle in its best and worst lock modes (from an MPGe and range perspective) and average the results or 2) only test only in the worst case. lock mode. This guide replaces for BEV only previous shift and multimode transmission guidance provided in EPA guidance letters CISDE-09-19, CCD-02-10, CCD-01-025R, and CD-87-01 and apply testing of model year 2024 and later vehicles and may also apply to testing for model year 2023 if the vehicle requires new MPGe/range testing.
Key points to consider
Although determining the appropriate drive mode to use for certification testing should be made on a case-by-case basis based on the particulars of a given vehicle, the EPA has provided the following points of instruction applicable to many standard options. activated by the user:
- Generally, the EPA will consider the factory drive mode the vehicle was in when it was first delivered to be the default drive mode for certification testing unless there is “substantial evidence” that the vehicle will be driven in another mode. Such evidence may come from the owner’s manual or any publication from the manufacturer or the manufacturer’s agent instructing the operator to use a different mode.
- For vehicles with multiple key fobs, if each key fob can be programmed to start in a predefined drive mode for each user, the vehicle has multiple latching drive modes.
- If a vehicle is equipped with a manual drive selector (i.e. shifter or shifter) that can activate multiple drive modes, the vehicle will be considered to have one drive mode only if the manufacturer provides the end user with instructions on which mode to use for normal, everyday driving.
- The EPA will not consider modes that re-engage a user-selected mode through key cycles as an additional lock mode in limited circumstances. These “soft lock” modes include those activated by detection of a trailer or a timer set for less than 240 minutes (which would allow a short stop for recharging, but would default back to driving mode d). factory in case of overnight parking). Other soft lockout methods should be discussed with the EPA prior to certification.
- Drive modes not considered practical for on-road driving, including autonomous drive modes that limit vehicle speed and acceleration, need not be considered testable drive modes even if they lock.
- Generally, anything that affects the transmission shift map (i.e. shift points at a constant pedal position) or other characteristics that affect MGPe and range are characteristics affecting the mode of driving which must be taken into account.
- Neither the primary vehicle controls – such as throttle, brakes and steering – nor those unrelated to driving – such as headlight switches, climate control and audio controls – are functions affecting driving style.
- Tire pressure, even if set manually, is a function that affects the driving mode.
- Pursuant to an EPA preemption waiver, the California Air Resources Board (CARB) has an independent certification process for BEVs, which other states can join, provided certain requirements are met. CARB frequently follows EPA guidelines but does not necessarily adhere to EPA interpretations in all circumstances.
In issuing these guidelines, the EPA made it clear that manufacturers offering customers the ability to select multiple drive modes may be subject to enforcement action if the mode(s) used for certification testing are not representative. of typical on-road driving. Although BEVs may not have emissions per se, the EPA’s ban on neutralization devices – an auxiliary emission control device that reduces the effectiveness of the emission control system under reasonably foreseeable conditions during normal operation and use of the vehicle – still applies to both BEVs and internal combustion engine vehicles. Therefore, manufacturers should take special care to understand how it allows and requires users to change riding modes and work with their certification representatives to resolve any ambiguity. before certification tests are carried out.
1 See 40 CFR §§ 86.128-79, 1066.415.