§ 1036.514 - Low Load Cycle.

§ 1036.514 Low Load Cycle.

Cross Reference

Link to an amendment published at 89 FR 29746, Apr. 22, 2024.

(a)

Measure emissions using the transient Low Load Cycle (LLC) as described in this section to determine whether engines meet the LLC emission standards in § 1036.104.

(b)

The LLC duty cycle is described in paragraph (d) of appendix B

of

to this part.

The following procedures

Procedures apply differently for testing certain kinds of engines and

hybrid

powertrains as follows:

(

1) For nonhybrid engine testing, the duty cycle is based on normalized

a) Test nonhybrid engines using the following procedures:

(1) Use the normalized speed and torque values for engine testing in the LLC duty cycle. Denormalize speed and torque values as described in 40 CFR 1065.512 and 1065.610 with the following additional requirements for testing at idle:

(i)

Denormalize speed

Apply the accessory load at idle in paragraph (c) of this section using declared idle power as described in 40 CFR 1065.

512. Denormalize torque as described in

510(f)(6). Declared idle torque must be zero.

(ii) Apply CITT in addition to accessory load as described in this paragraph (a)(1)(ii). Set reference speed and torque values as described in 40 CFR 1065.610(d)

.

(

ii) For idle segments more than 200 seconds, set reference torques to the torque needed to meet the accessory loads in Table 1 of this section instead of CITT. This is to represent shifting the transmission to park or neutral at the start

3)(vi) for all idle segments that are 200 s or shorter to represent the transmission operating in drive. For longer idle segments, set the reference speed and torque values to the warm-idle-in-drive values for the first three seconds and the last three seconds of the idle segment.

Change the reference torque to CITT no earlier than 5 seconds before the end of the idle segment. This is to represent shifting the transmission to drive.(2) Test hybrid engines and hybrid

For the points in between, set the reference speed and torque values to the warm-idle-in-neutral values to represent the transmission being manually shifted from drive to neutral shortly after the extended idle starts and back to drive shortly before it ends.

(2) Calculate and evaluate cycle-validation criteria as described in 40 CFR 1065.514, except as specified in paragraph (e) of this section.

(b) Test hybrid powertrains as described in § 1036.510(b)(2), with the following exceptions:

(

i

1) Replace P_contrated with P_rated, which is the peak rated power determined in § 1036.520.

(

ii

2) Keep the transmission in drive for all idle segments 200 seconds or less. For idle segments more than 200 seconds,

place

leave the transmission in

park or neutral at the start

drive for the first 3 seconds of the idle segment

and

, then immediately place the transmission in park or neutral, and shift the transmission into drive again

no earlier than 5

3 seconds before the end of the idle segment. The end of the idle segment occurs at the first nonzero vehicle speed setpoint.

(

iii

3) For hybrid engines,

select the transmission from Table 1 of § 1036.540, substituting “engine” for “vehicle”.(iv) For hybrid engines,

you may request to change the GEM-generated engine

-commanded

reference torque at idle to better represent curb idle transmission torque (CITT).

(

v) For plug-in hybrid engines and powertrains, determine criteria pollutant and greenhouse gas emissions

4) Adjust procedures in this section as described in § 1036.510(d) and (e) for plug-in hybrid powertrains to determine criteria pollutant and greenhouse gas emissions, replacing “SET” with “LLC”. Note that the LLC is therefore the preconditioning duty cycle for plug-in hybrid powertrains.

(

c) Set dynamometer torque demand such that vehicle power represents an accessory load for all idle operation as described in Table 1 of paragraph (c)(4) of this section for each primary intended service class. Additional provisions related to accessory load apply for the following special cases:(1) For engines with stop-start technology, account for

5) Calculate and evaluate cycle-validation criteria as specified in § 1036.545.

(c) Include vehicle accessory loading as follows:

(1) Apply a vehicle accessory load for each idle point in the cycle using the power values in the following table:

Table 1 to Paragraph (c)(1) of § 1036.514—Accessory Load at Idle

Primary intended service class	Power representing accessory load (kW)
Light HDE	1.5
Medium HDE	2.5
Heavy HDE	3.5

(2) For nonhybrid engine testing, apply vehicle accessory loads in addition to any applicable CITT.

(3) Additional provisions related to vehicle accessory load apply for engines with stop-start technology and hybrid powertrains where the accessory load is applied to the engine shaft. Account for the loss of mechanical work due to the lack of any idle accessory load during engine-off conditions by determining the total loss of mechanical work from idle accessory load during all engine-off

power demand

intervals over the entire test interval and distributing that

load

work over the engine-on

portions

portion of the entire test interval based on a calculated average power. You may determine the engine-off time by running practice cycles or through engineering analysis.

(

2) Apply accessory loads for hybrid powertrain testing that includes the transmission either as a mechanical or electrical load.

(3) You may apply the following deviations from specified torque settings for smoother idle (other than idle that includes motoring), or you may develop different procedures for adjusting accessory load at idle consistent with good engineering judgment:

(i) Set the reference torque to correspond to the applicable accessory load for all points with normalized speed at or below zero percent and reference torque from zero up to the torque corresponding to the accessory load.

(ii) Change the reference torques to correspond to the applicable accessory load for consecutive points with reference torques from zero up to the torque corresponding to the accessory load that immediately precedes or follows idle points.

(4) Table 1 follows:

Table 1 to Paragraph (c)(4) of § 1036.514—Accessory Load at Idle

Primary intended service class	Power representing accessory load (kW)
Light HDE	1.5
Medium HDE	2.5
Heavy HDE	3.5

(d) The d) Except as specified in paragraph (b)(4) of this section for plug-in hybrid powertrains, the test sequence consists of preconditioning the engine by running one or two FTPs with each FTP followed by (20 ±1± 1) minutes with no engine operation and a hot start run through the LLC. You may start any preconditioning FTP with a hot engine. Perform testing as described in 40 CFR 1065.530 for a test interval that includes engine starting. Calculate the total emission mass of each constituent, m, and the over the test interval as described in 40 CFR 1065.650. For nonhybrid engines, calculate the total work, W, over the test interval as described in 40 CFR 1065.650. Calculate total (d). For hybrid powertrains, calculate total positive work over the test interval for powertrain testing using system power, P_sys. Determine P_sys using § 1036.520(f). For powertrains with automatic transmissions, account for and include the work produced by the engine from the CITT load. For batch sampling, you may sample background periodically into the bag over the course of multiple test intervals.

(e) Calculate and evaluate cycle statistics as specified in 40 CFR 1065.514 for nonhybrid engines and 40 CFR 1037.550 for hybrid engines and hybrid powertrains. For For testing spark-ignition gaseous-fueled engine testing engines with fuel delivery at a single -point fuel injection systempoint in the intake manifold, you may apply all the statistical criteria in § 1036.540(d)(3) to validate the LLC.alternative cycle-validation criteria for the LLC in the following table:

Table 2 to Paragraph (e) of § 1036.514—Alternative LLC Cycle Validation Criteria for Spark-Ignition Gaseous-Fueled Engines ^a

Parameter	Speed	Torque	Power
Slope, a1		0.800 ≤ a1 ≤ 1.030	0.800 ≤ a1 ≤ 1.030.
Absolute value of intercept, |a0|
Standard error of the estimate, SEE			≤15% of maximum mapped power.
Coefficient of determination, r2		≥0.650	≥0.650.

^a Cycle-validation criteria apply as specified in 40 CFR 1065.514 unless otherwise specified.

[89 FR 29746, Apr. 22, 2024]