Starting in 1997, Caterpillar engines were built with the potential to record event data. There are two independant EDR functions in newer Caterpillar engines: The Quick Stop and the Snapshot Recorder.
The Quick Stop is the primary EDR function in a Caterpillar engine. However, unlike the EDR capability of other engines, the Caterpillar Quick Stop function is turned “off” when shipped to the purchaser. This applies to Caterpillar engines built prior to the Environmental Protection Agency's 2007 Standards. These EPA 07 engines are being shipped with the Quick Stop function turned "on." When enabled (or in other words, when set to a value other than zero miles per hour), the Quick Stop contains 45 seconds of data before the threshold is reached and 15 seconds of data after the threshold is reached.
The Quick Stop records:
Current research which is pending peer review as of 10/08 indicates that the sample rate of some Caterpillar engines may be substantially in error.
In addition to the Quick Stop, Caterpillar ECMs from as early as 1995 may contain a function called a “Snapshot Recorder. ” If the ECM senses a “critical fault,” the Snapshot Recorder automatically records approximately 13 seconds of data about the truck, including the wheel speed, engine load, throttle position, and all other monitored engine functions. Data are written for approximately 9.5 seconds before the onset of the fault and approximately 3.5 seconds after the onset of the fault, and these data are reported in 0.48-second increments.
Some examples of critical faults that can be created by crash damage are Low Oil Pressure, Low Oil Level, and Low Coolant Level. Although the data in snapshots created by critical faults are normally difficult to erase, these data will be overwritten if a module is downloaded when not connected to a truck (i.e., a desktop download).
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