(1) Use one of the following approaches to define end-of-test criteria for vehicles whose maximum speed is less than the maximum speed specified in the driving schedule, where the vehicle's maximum speed is determined, to the nearest 0.1 mph, from observing the highest speed over the first duty cycle (FTP, HFET, etc.):

(2) Soak time between repeat duty cycles (four-bag FTP, HFET, etc.) may be up to 30 minutes. No recharging may occur during the soak time.

(3) Recharging the vehicle's battery must start within three hours after the end of testing.

(4) Do not apply the C coefficient adjustment specified in Section 4.4.2.

(5) We may approve alternate measurement procedures with respect to electric vehicles if they are necessary or appropriate for meeting the objectives of this part. For example, we may approve the use of an earlier version of SAE J1634 for carryover vehicles, or if you show that it is equivalent for your vehicle.

(6) All label values related to fuel economy, energy consumption, and range must be based on 5-cycle testing or on values adjusted to be equivalent to 5-cycle results.

(1) To determine CREE values to demonstrate compliance with GHG standards, calculate composite values representing combined operation during charge-depleting and charge-sustaining operation using the following utility factors except as specified in this paragraph (c):

(2) Determine fuel economy values to demonstrate compliance with CAFE standards as follows:

(ii) Except as described in paragraph (c)(2)(iii) of this section, determine fuel economy for dual fueled automobiles from the following equation, separately for city and highway driving:

Where:

MPG_gas = The miles per gallon measured while operating on gasoline during charge-sustaining operation as determined using the procedures of SAE J1711.

MPGe_elec = The miles per gallon equivalent measured while operating on electricity. Calculate this value by dividing the equivalent all-electric range determined from the equation in § 86.1866-12(b)(2)(ii) by the corresponding measured Watt-hours of energy consumed; apply the appropriate petroleum-equivalence factor from 10 CFR 474.3 to convert Watt-hours to gallons equivalent. Note that if vehicles use no gasoline during charge-depleting operation, MPGe_elec is the same as the charge-depleting fuel economy specified in SAE J1711.

(iii) For 2016 and later model year dual fueled automobiles, you may determine fuel economy based on the following equation, separately for city and highway driving:

Where:

UF = The appropriate utility factor for city or highway driving as described in paragraph (c)(1) of this section.

(3) To determine fuel economy and CO₂ emission values for labeling purposes, calculate composite values representing combined operation during charge-depleting and charge-sustaining operation using the following utility factors except as specified in this paragraph (c):

(4) You may calculate performance values under paragraphs (c)(1) through (3) of this section by combining phases during FTP testing. For example, you may treat the first 7.45 miles as a single phase by adding the individual utility factors for that portion of driving and assigning emission levels to the combined phase. Do this consistently throughout a test run.

(5) Instead of the utility factors specified in paragraphs (c)(1) through (3) of this section, calculate utility factors using the following equation for vehicles whose maximum speed is less than the maximum speed specified in the driving schedule, where the vehicle's maximum speed is determined, to the nearest 0.1 mph, from observing the highest speed over the first duty cycle (FTP, HFET, etc.):

(6) The End-of-Test criterion is based on a 1 percent Net Energy Change as specified in Section 3.8 of SAE J1711. We may approve alternate Net Energy Change tolerances as specified in Section 3.9.1 of SAE J1711 for charge-depleting tests or Appendix C of SAE J1711 for charge-sustaining tests if the 1 percent threshold is insufficient or inappropriate. For charge-sustaining tests, we may approve the use of alternate Net Energy Change tolerances as specified in Appendix C of SAE J1711 to correct final fuel economy values, CO₂ emissions, and carbon-related exhaust emissions. For charge-sustaining tests, do not use alternate Net Energy Change tolerances to correct emissions of criteria pollutants. Additionally, if we approve an alternate End-of-Test criterion or Net Energy Change tolerances for a specific vehicle, we may use the alternate criterion or tolerances for any testing we conduct on that vehicle.

(7) Use the vehicle's Actual Charge-Depleting Range, R_cda, as specified in Section 6.1.3 for evaluating the end-of-test criterion.

(8) Measure and record AC watt-hours throughout the recharging procedure. Position the measurement appropriately to account for any losses in the charging system.

(9) We may approve alternate measurement procedures with respect to plug-in hybrid electric vehicles if they are necessary or appropriate for meeting the objectives of this part.

(10) The utility factors described in this paragraph (c) are derived from equations in SAE J2841. You may alternatively calculate utility factors directly from the corresponding equations in SAE J2841.

(1) Calculate the theoretical maximum amount of energy that could be recovered by a hybrid electric vehicle over the FTP test cycle, where the test cycle time and velocity points are expressed at 10 Hz, and the velocity (miles/hour) is expressed to the nearest 0.01 miles/hour, as follows:

(i) For each time point in the 10 Hz test cycle (i.e., at each 0.1 seconds):

(A) Determine the road load power in kilowatts using the following equation:

Where:

P_roadload is the road load power in kilowatts, where road load is negative because it always represents a deceleration (i.e., resistive) force on the vehicle;

A, B, and C are the vehicle-specific dynamometer road load coefficients in lb-force, lb-force/mph, and lb-force/mph², respectively;

V_mph = velocity in miles/hour, expressed to the nearest 0.01 miles/hour;

0.44704 converts speed from miles/hour to meters/second;

4.448 converts pound force to Newtons; and

1,000 converts power from Watts to kilowatts.

(B) Determine the applied deceleration power at each sampling point in time, t, in kilowatts, using the following equation. Positive values indicate acceleration and negative values indicate deceleration.

Where:

ETW = the vehicle Equivalent Test Weight (lbs);

V_t = velocity in miles/hour, rounded to the nearest 0.01 miles/hour, at each sampling point;

V_t-1 = the velocity in miles/hour at the previous time point in the 10 Hz speed vs. time table, rounded to the nearest 0.01 miles/hour;

0.1 represents the time in seconds between each successive velocity data point;

0.44704 converts speed from miles/hour to meters/second;

2.205 converts weight from pounds to kilograms; and

1,000 converts power from Watts to kilowatts.

(C) Determine braking power in kilowatts using the following equation. Note that during braking events, P_brake, P_accel, and P_roadload will all be negative (i.e., resistive) forces on the vehicle.

P_brake = P_accel−P_roadload

Where:

P_accel = the value determined in paragraph (d)(1)(i)(B) of this section;

P_roadload = the value determined in paragraph (d)(1)(i)(A) of this section; and

P_brake = 0 if P_accel is greater than or equal to P_roadload.

(2) Calculate the actual amount of energy recovered (E_rec) by a hybrid electric vehicle when tested on the FTP according to the provisions of this part, as follows:

(ii) At each sampling point where current is flowing into the battery, calculate the energy flowing into the battery, in Watt-hours, as follows:

Where:

E_t = the energy flowing into the battery, in Watt-hours, at time t in the test;

I_t = the electrical current, in Amps, at time t in the test; and

V_nominal = the nominal voltage of the hybrid battery system determined according to paragraph (d)(4) of this section.

(3) The percent of braking energy recovered by a hybrid system relative to the total available energy is determined by the following equation, rounded to the nearest one percent:

(4)

(i) Determination nominal voltage (V_nominal) using the following equation:

Where:

V_S is the battery voltage measured at the start of the FTP test, where the measurement is made after the key-on event but not later than 10 seconds after the key-on event; and

V_F is the battery voltage measured at the conclusion of the FTP test, where the measurement is made before the key-off event but not earlier than 10 seconds prior to the key-off event.