The engine control unit (ECU) might be the most critical component to the truck's power plant.
Leaning on datafeeds from a network of various sensors, the ECU manages everything from the mixture of air and fuel to idle speeds and valve control and timing, and it soon could be a key piece of regulatory compliance.
The Federal Motor Carrier Safety Administration’s (FMCSA) notice of intent to proceed with rulemaking to mandate speed limiters on most heavy-duty trucks published in the Federal Register Wednesday, May 4, restarting a process that had been dormant for six years. At the time the 2016 Notice of Proposed Rulemaking (NPRM) was published, NHTSA and FMCSA stated that all vehicles with ECUs are generally electronically speed governed to prevent engine or other damage to the vehicle. Since the ECU monitors an engine’s RPM – from which vehicle speed can be calculated – it also controls the supply of fuel to the engine.
[Related: Most fleets already use speed limiters]
"Based on this background, it is likely the required means of achieving compliance with a speed limiter requirement would be to use the ECU to govern the speed of the vehicle rather than installing a mechanical means of doing so," FMCSA wrote in its notice last week.
FMCSA said it intends to issue a supplemental notice of proposed rulemaking that would, if adopted, "impose speed limitations on certain CMVs subject to the FMCSRs. The rulemaking would propose that motor carriers operating certain commercial motor vehicles, as defined in 49 CFR 390.5, in interstate commerce that are equipped with an ECU capable of setting speed limits be required to limit the CMV to a speed to be determined by the rulemaking and to maintain that limit for the service life of the vehicle."
A poll conducted by CCJ earlier this week showed that a majority of responding motor carriers already have speed limiters deployed on their trucks.
