Draft – Do not cite 

§1065.510 Engine mapping. 

Modify the existing paragraph 1065.510(b)(5)(i) to better specify the setpoint speeds as follows:

(b) Mapping variable-speed engines. 

(5) Perform one of the following:

(i) For any engine subject only to steady-state duty cycles (i.e., discrete-mode or ramped-modal), you 

may perform an engine map by using discrete speeds. Select map setpoint speeds based on the 

manufacturer declared maximum test speed as follows. From 95 % of warm idle speed to 90 % of the 

manufacturer declared maximum test speed, select at least 13 equally spaced setpoint speeds (i.e. a 

minimum of 12 equal speed intervals). From 90 % to 110 % of manufacturer declared maximum test 

speed select setpoint speeds in equal 2% increments (i.e. 92, 94, 96, ..., and 110 % of manufacturer 

declared maximum test speed). From 110 % of manufacturer declared maximum test speed to the 

highest speed above maximum power at which 50 % of maximum power occurs select setpoint

speeds that are equal to the speed intervals determined for the portion of the map from 95 % warm 

idle speed to 90 % of manufacturer declared maximum test speed. We refer to this 50 % speed as the 

check point speed as described in paragraph (b)(5)(iii) of this section. If the manufacturer did not 

declared a maximum test speed, estimate the maximum test speed based on other manufacturer 

specifications; run the map using the setpoint speeds as described above; and verify that the 

measured maximum test speed falls on one of the discrete speeds from 92 to 108 % of the estimated 

maximum test speed. If the measured maximum test speed does not fall on one of these discrete 

speeds, rerun the map based on another estimate. At each setpoint, stabilize speed and allow torque to 

stabilize. Record the mean speed and torque at each setpoint. We recommend that you stabilize an 

engine for at least 15 seconds at each setpoint and record the mean feedback speed and torque of the 

last (4 to 6) seconds. Use linear interpolation to determine intermediate speeds and torques. Use this 

series of speeds and torques to generate the power map as described in paragraph (e) of this section.

(ii) ...

(iii) The check point speed of the map is the highest speed above maximum power at which 50 % of 

maximum power occurs. If this speed is unsafe or unachievable (e.g., for ungoverned engines or 

engines that do not operate at that point), use good engineering judgment to map up to the maximum 

safe speed or maximum achievable speed. For continuous mapping, if the engine cannot be mapped 

to the check point speed, verify that the sweep time from 95 % of warm idle to the maximum mapped 

speed is (4 to 6) min.

Insert a new paragraph 1065.510(g) for the special case of electric hybrid engines.

(g) Mapping variable speed engines with an electric hybrid systems. Map variable speed engines that 

include electric hybrid systems as described in this paragraph (g). Do not use this procedure for 

engines used in hybrid vehicles where the hybrid system is certified as part of the vehicle rather than 

the engine. You may ask to apply these provisions to other types of hybrid engines, consistent with 

good engineering judgment. Follow the steps for mapping a variable-speed engine as given in 

paragraph (b) of this section with the exceptions noted in this paragraph (g). Note that you are 

generally required to generate two separate engine maps: one with the hybrid system active, and one 

with it inactive. The map with the system inactive is used to generate steady-state duty cycles and 

transient cycles that specifies no negative torques (i.e. no engine motoring). This map is also used in 

generating the map with the system active. The map with the system active is used to generate 

transient duty cycles that specify negative torques (i.e. engine motoring). If your engine is subject to 
a reference duty cycle that specifies negative normalized torques (i.e. engine motoring), you may 

skip the generation of a motoring map as described in paragraph (c) of this section and exclude 

motoring points from the cycle regression. Apply the provisions of paragraph (b) of this section with 

the following exceptions: 

(1) This paragraph (g)(1) specifies exceptions when generating a map with the hybrid 

system inactive. 

Operate the engine as specified in paragraph (b)(4) of this section, but remain at this 

condition until the renewable energy storage system (RESS) is depleted. Once the RESS 

is depleted, perform an engine map as specified in paragraph (b)(5) of this section. 

Ensure that instantaneous power from the RESS remains less than 2 % of the 

instantaneous measured power from the system at all system speeds. 

(2) This paragraph (g)(2) specifies exceptions when generatinga map with the hybrid system 

active. You may use a nominally continuous method or a discrete method. You may use 

either of the following methods to generate a map with the hybrid system active: 

(i) You may perform an engine map by using a series of continuous sweeps of 

narrow speed ranges. Note that the purpose of this mapping approach is to 

determine the maximum torque available at each speed such as might occur 

during transient operation with a fully charged RESS. Begin by fully charging the 

RESS. Perform the sweep as specified in paragraph (b)(5)(ii) of this section, but 

stop the ramp to charge the RESS when the power measured from the RESS 

drops below maximum expected RESS power by more than 2% of total system 

power (including engine and RESS power). Unless good engineering judgment 

indicates otherwise, use a linear fit for RESS power during the first 3 seconds of

each sweep to predict the maximum expected RESS power during the remainder 

of that sweep Calculate total system power as a 3 second moving average of the 

as-measured instantaneous total system power. For example, if the 3 second 

moving average of total engine-RESS power is 200 kW and the power from the 

RESS at the beginning of the ramp is 50 kW, once the power from the RESS 

reaches 46 kW, stop the ramp to charge the RESS. After each charging event, 

stabilize the engine for 15 seconds at the speed at which you ended the previous 

segment with operator demand set to maximum before continuing the ramp from 

that speed. Repeat the cycle of charging, mapping, and recharging until you have 

completed the engine map. You may shutdown the system or include other 

operation between segments to be consistent with the intent of this 

paragraph(g)(2)(i). For example, for systems in which continuous charging and 

discharging can overheat batteries to an extent that affects performance, you may 

operate the engine at zero power from the RESS for enough time after the system 

is recharged to allow the batteries to cool. Use good engineering judgment to 

smooth the torque curve to eliminate discontinuities between map intervals. (For 

example, for each sweep interval, smooth torque data using a speed-scaled 

method)

(ii) You may perform an engine map by using discrete speeds. Select map setpoint

speeds as described in paragraph (b)(5)(i) of this section. At each setpoint speed, 

stabilize speed and target torque at about 70 % of peak torque of the non-hybrid 

assisted engine. Make sure the engine is fully warmed up and the RESS state of 

charge is within the normal operating range. Snap the throttle to maximum and 
record at 1 Hz or higher the 3-second moving average values of the continuous

feedback speed and torque signals. Continue to record for 30 s or until the 3-

second moving average torque peaks and begins to fall. From data recorded 

during this snap throttle maneuver, identify the maximum 3-second average 

torque. Use this torque value and the corresponding 3-second moving average 

speed (i.e. the 3-second average speed recorded at the same time where the 3-

second average torque was at its maximum) as the speed and torque for the map 

at this discrete speed point. Repeat this maneuver for each discrete speed.