(a) If your engine system includes features that recover and store energy during engine motoring operation test the engine as described in paragraph (d) of this section. For purposes of this section, features that recover energy between the engine and transmission are considered related to engine motoring.
(b) If you produce a hybrid engine designed with power take-off capability and sell the engine coupled with a transmission, you may calculate a reduction in CO2 emissions resulting from the power take-off operation as described in 40 CFR 1037.525. Use good engineering judgment to use the vehicle-based procedures to quantify the CO2 reduction for your engines.
(c) The hardware that must be included in these tests is the engine, the hybrid electric motor, the rechargeable energy storage system (RESS) and the power electronics between the hybrid electric motor and the RESS. You may ask us to modify the provisions of this section to allow testing non-electric hybrid vehicles, consistent with good engineering judgment.
(d) Measure emissions using the same procedures that apply for testing non-hybrid engines under this part, except as specified otherwise in this part and/or 40 CFR part 1065. If you test hybrid engines using the SET, deactivate the hybrid features unless we have specified otherwise. The five differences that apply under this section are related to engine mapping, engine shutdown during the test cycle, calculating work, limits on braking energy, and state of charge constraints.
(1) Map the engine as specified in 40 CFR 1065.510. This requires separate torque maps for the engine with and without the hybrid features active. For transient testing, denormalize the test cycle using the map generated with the hybrid feature active. For steady-state testing, denormalize the test cycle using the map generated with the hybrid feature inactive.
(2) If the engine will be configured in actual use to shut down automatically during idle operation, you may let the engine shut down during the idle portions of the test cycle.
(3) Follow 40 CFR 1065.650(d) to calculate the work done over the cycle except as specified in this paragraph (d)(3). For the positive work over the cycle set negative power from hybrid to zero. For the negative work over the cycle set the positive power to zero and set the non-hybrid power to zero.
(4)(i) Calculate brake energy fraction, xb, as the integrated negative work over the cycle divided by the integrated positive work over the cycle according to Equation 1036.525-1. Calculate the brake energy limit for the engine, xbl, according to Equation 1036.525-2. If xb is less than xbl, use the integrated positive work for your emission calculations. If the xb is greater than xbl use Equation 1036.525-3 to calculate the positive work done over the cycle. Use Wcycle as the integrated positive work when calculating brake-specific emissions. To avoid the need to delete extra brake work from positive work you may set an instantaneous brake target that will prevent xb from being larger than xbl,[GRAPHIC] [TIFF OMITTED] TR15SE11.007
(i) Calculate brake energy fraction, xb, as the integrated negative work over the cycle divided by the integrated positive work over the cycle according to Equation 1036.525-1. Calculate the brake energy limit for the engine, xbl, according to Equation 1036.525-2. If xb is less than xbl, use the integrated positive work for your emission calculations. If the xb is greater than xbl use Equation 1036.525-3 to calculate the positive work done over the cycle. Use Wcycle as the integrated positive work when calculating brake-specific emissions. To avoid the need to delete extra brake work from positive work you may set an instantaneous brake target that will prevent xb from being larger than xbl,[GRAPHIC] [TIFF OMITTED] TR15SE11.007
(ii) The following definitions of terms apply for this paragraph (d)(4):
xb = the brake energy fraction.
Wneg = the negative work over the cycle.
Wpos = the positive work over the cycle.
xbl = the brake energy fraction limit.
Pmax = the maximum power of the engine with the hybrid system engaged (kW).
Wcycle = the work over the cycle when xb is greater than xbl.
(iii) Note that these calculations are specified with SI units (such as kW), consistent with 40 CFR part 1065. Emission results are converted to g/hp-hr at the end of the calculations.
(5) Correct for the net energy change of the energy storage device as described in 40 CFR 1066.501. [76 FR 57381, Sept. 15, 2011, as amended at 78 FR 36389, June 17, 2013]