40 CFR 1037.320 - Audit procedures for axles and transmissions.

View all text of Subpart D [§ 1037.301 - § 1037.320]

§ 1037.320 - Audit procedures for axles and transmissions.

Selective enforcement audit provisions apply for axles and transmissions relative to the efficiency demonstrations of §§ 1037.560 and 1037.565 as specified in this section. The following provisions apply instead of 40 CFR 1068.415 through 1068.445 for the selective enforcement audit.

(a) A selective enforcement audit for axles or transmissions would consist of performing measurements with a production axle or transmission to determine mean power loss values as declared for GEM simulations, and running GEM over one or more applicable duty cycles based on those measured values. The axle or transmission is considered passing for a given configuration if the new modeled emission result for every applicable duty cycle is at or below the modeled emission result corresponding to the declared GEM inputs.

(b) Run GEM with the define vehicles to determine whether the transmission or axle family passes the audit.

(1) For transmission audits, run GEM for each applicable vehicle configuration and GEM regulatory subcategory identified in 40 CFR 1036.540 and for each vehicle class as defined in § 1037.140(g) using the applicable default engine map in appendix C of 40 CFR part 1036, the cycle-average fuel map in Table 1 of this section, the torque curve in Table 2 of this section for both the engine full-load torque curve and parent engine full-load torque curve, the motoring torque curve in Table 3 of this section, the idle fuel map in Table 4 of this section. For transmission testing, use the test transmission's gear ratios in place of the gear ratios defined in 40 CFR 1036.540. Table 1 through Table 4 follow:

Table 1 to Paragraph (b)(1) of § 1037.320—Transient Cycle-Average Fuel Map by Vehicle Class

Light HDV and medium HDV—spark-ignition					Light HDV and medium HDV—compression-ignition					Heavy HDV					Engine cycle work (kW·hr)	N/V (r/min)	Fuel mass (g)	Idle speed (r/min)	Idle torque (N·m)	Engine cycle work (kW·hr)	N/V (r/min)	Fuel mass (g)	Idle speed (r/min)	Idle torque (N·m)	Engine cycle work (kW·hr)	N/V (r/min)	Fuel mass (g)	Idle speed (r/min)	Idle torque (N·m)	3.5404	2.8739	1109.31	600.5	37.997	3.3057	2.3317	919.01	750.3	36.347	11.4255	2.3972	2579.58	600.7	89.658	3.6574	3.0198	1153.35	600.4	37.951	3.3822	2.5075	982.53	750.2	36.461	11.6112	2.2432	2591.08	601.2	90.428	3.8119	3.0370	1188.66	600.2	37.956	3.4917	2.5320	998.64	750.2	36.608	12.5052	2.1620	2763.28	602.4	92.014	4.0121	3.1983	1250.76	600.1	38.153	3.6087	2.6181	1036.34	750.2	36.734	17.7747	2.5195	3835.77	602.2	91.780	5.5567	3.1325	1585.32	604.6	56.535	5.2397	2.5050	1354.33	753.0	51.992	18.4901	2.4155	3994.29	603.5	93.724	5.6814	3.2956	1639.08	604.0	56.549	5.3153	2.7289	1417.20	751.9	51.488	20.1904	2.3800	4374.06	605.1	96.340	5.8720	3.3255	1686.14	602.5	56.234	5.4112	2.6689	1416.75	751.3	51.280						6.1774	3.4848	1773.39	601.7	56.038	5.5590	2.7231	1450.67	751.0	51.254

Table 2 to Paragraph (b)(1) of § 1037.320—Full-Load Torque Curves by Vehicle Class

Light HDV and medium HDV— spark-ignition		Light HDV and medium HDV— compression-ignition		Heavy HDV		Engine speed (r/min)	Engine torque (N·m)	Engine speed (r/min)	Engine torque (N·m)	Engine speed (r/min)	Engine torque (N·m)	600	433	750	470	600	1200	700	436	907	579	750	1320	800	445	1055	721	850	1490	900	473	1208	850	950	1700	1000	492	1358	876	1050	1950	1100	515	1507	866	1100	2090	1200	526	1660	870	1200	2100	1300	541	1809	868	1250	2100	1400	542	1954	869	1300	2093	1500	542	2105	878	1400	2092	1600	542	2258	850	1500	2085	1700	547	2405	800	1520	2075	1800	550	2556	734	1600	2010	1900	551	2600	0	1700	1910	2000	554			1800	1801	2100	553			1900	1640	2200	558			2000	1350	2300	558			2100	910	2400	566			2250	0	2500	571					2600	572					2700	581					2800	586					2900	587					3000	590					3100	591					3200	589					3300	585					3400	584					3500	582					3600	573					3700	562					3800	555					3900	544					4000	534					4100	517					4200	473					4291	442					4500	150

Table 3 to Paragraph (b)(1) of § 1037.320—Motoring Torque Curves by Vehicle Class

Light HDV and medium HDV— spark-ignition		Light HDV and medium HDV— compression-ignition		Heavy HDV		Engine speed (r/min)	Engine torque (N·m)	Engine speed (r/min)	Engine torque (N·m)	Engine speed (r/min)	Engine torque (N·m)	700	−41	750	−129	600	−98	800	−42	907	−129	750	−121	900	−43	1055	−130	850	−138	1000	−45	1208	−132	950	−155	1100	−48	1358	−135	1050	−174	1200	−49	1507	−138	1100	−184	1300	−50	1660	−143	1200	−204	1411	−51	1809	−148	1250	−214	1511	−52	1954	−155	1300	−225	1611	−53	2105	−162	1400	−247	1711	−56	2258	−170	1500	−270	1811	−56	2405	−179	1520	−275	1911	−57	2556	−189	1600	−294	2011	−57			1700	−319	2111	−58			1800	−345	2211	−60			1900	−372	2311	−65			2000	−400	2411	−81			2100	−429	2511	−85					2611	−87					2711	−88					2811	−89					2911	−91					3011	−91					3111	−96					3211	−96					3311	−97					3411	−98					3511	−99					3611	−104					3711	−105					3811	−108					3911	−108					4011	−111					4111	−111					4211	−115					4291	−112

Table 4 to Paragraph (b)(1) of § 1037.320—Engine Idle Fuel Maps by Vehicle Class

Light HDV and medium HDV—spark-ignition			Light HDV and medium HDV—compression-ignition			Heavy HDV			Engine speed (r/min)	Engine torque (N·m)	Fuel mass rate (g/s)	Engine speed (r/min)	Engine torque (N·m)	Fuel mass rate (g/s)	Engine speed (r/min)	Engine torque (N·m)	Fuel mass rate (g/s)	600	0	0.4010	750	0	0.2595	600	0	0.3501	700	0	0.4725	850	0	0.2626	700	0	0.4745	600	100	0.6637	750	100	0.6931	600	100	0.6547	700	100	0.7524	850	100	0.7306	700	100	0.8304

(2) Follow the procedure in paragraph (b)(1) of this section for axle audits, but cover the range of tire sizes by using good engineering judgment to select three representative tire sizes for each axle ratio for each vehicle configuration instead of using the tire size determined in 40 CFR 1036.540.

(3) The GEM “Default FEL CO2 Emissions” result for each vehicle configuration counts as a separate test for determining whether the family passes the audit. For vocational vehicles, use the GEM “Default FEL CO2 Emissions” result for the Regional subcategory.

(c) If the initial axle or transmission passes, the family passes and no further testing is required. If the initial axle or transmission does not pass, select two additional production axles or transmissions, as applicable, to perform additional tests. Note that these could be different axle and transmission configurations within the family. These become official test results for the family. Use good engineering judgment to use the results of these tests to update the declared maps for the axle or transmission family. For example, if you fail the audit test for any of the axles or transmissions tested, the audit result becomes the declared map. This may also require revising any analytically derived maps.

[86 FR 34464, June 29, 2021, as amended at 88 FR 4639, Jan. 24, 2023]