Document ID: chunk:federal_register_of_legislation:F2005L03375:front:0:p6
Version: federal_register_of_legislation:F2005L03375
Segment Type: other
Provision Reference: 
Character Range: 13349–16220

below 2.8 oC above fan-off temperature. For modulated or variable-speed fans, fan-on temperature refers to the temperature at which the fan drive is fully engaged, or at which the fan is set to maximum speed; and fan-off refers to the point at which the fan drive begins to modulate off, or at which the fan is set to less than maximum speed. If the fan is not controlled directly by the engine control module, then set points for AECD activation and deactivation shall be referenced to fan-on and fan-off temperatures specified by the manufacturer, and subject to the above temperature difference limits and fan control state definitions.
3.1.3.5      The AECD described in paragraph 3.1.3.4 (correlated to coolant temperature and/or other engine operating parameter(s)) is the only timing strategy that may be employed for overheat protection. This strategy may only be employed where the manufacturer's specifications for cooling system, charge air cooler, and/or other requirements are such that the engine can operate without the need for such AECDs at both ambient temperatures below 38 oC and loads below 75 % maximum at that RPM. Such specifications shall be determined by establishing engine cooling and other system requirements based on testing at conditions at least as severe as 75 % load and 38 oC ambient air and representative operating conditions. This AECD shall be limited to the lowest practicable NOx level for the purposes of overheat protection.
3.1.3.6 Any altitude AECD may not be active at pressure above 82.5 kPa (below 1675m equivalent) and is limited to the lowest practicable NOx level after consideration of unburned hydrocarbons, black smoke and engine protection.
3.1.3.7      Any White Smoke AECD to control unburned hydrocarbons shall be limited to the lowest practicable NOx level after consideration of unburned hydrocarbon emissions, and engine misfire. In addition, the manufacturer must justify any White Smoke AECD that is active at conditions correlatable to an intake manifold temperature greater than 15 oC.
3.1.3.8      Any Idle AECD shall be limited to the lowest practicable NOx level after consideration of unburned hydrocarbon emissions, engine misfire, and engine protection and must be correlated with any relevant engine operating parameter.
Attachment A to Appendix B

Not To Exceed (NTE), Smoke or Alternate Opacity Requirements

      1. Requirements
    The Not To Exceed (NTE), Smoke or alternate Opacity limits stated in Table 2 of section 3 of Appendix B apply to engines when tested under conditions which can reasonably be expected to be encountered in normal vehicle operation and use.  The limits apply when new and in-use throughout the useful life of the engine.  In order to satisfy the NTE screening guidelines, the manufacturer must adhere to the requirements and protocols described in sections 2 and 3