Timing and Synchronization of the Event Data Recorded by the Electronic Control Modules of Commercial Motor Vehicles - DDEC V
It is well recognized that Heavy Vehicle Event Data Recorder (HVEDR) technology has been incorporated in the Electronic Control Modules (ECMs) on many on-highway commercial motor vehicles. The dynamic time-series data recorded by these HVEDRs typically include vehicle speed, engine speed, brake and clutch pedal status, and accelerator pedal position. With specific respect to Detroit Diesel ECMs, data are recorded surrounding certain events at a rate of 1.0 Hz. In this research, controlled testing was conducted to determine the time differences between the values being generated by the sourcing sensors and the interpreted data being broadcast on the vehicle's SAE J1939 controller area network (CAN). To accomplish this, raw sensor data as provided to the ECM was monitored, as were the subsequent J1939 CAN transmissions from the ECM.
Event Data Recorder (EDR) technology has been incorporated into the Electronic Control Modules (ECMs) of many on-highway heavy trucks. One benefit of this technology is its applicability to vehicle collision investigation and reconstruction ( Goebelbecker & Ferrone, 2000 ; van Nooten & Hrycay, 2005 ). However, collisions that cause extensive damage to the truck may cause a loss of electrical power to the ECM, which might interrupt the data storage process. This research is an attempt to determine the effects of power loss on heavy vehicle ECMs 1 , and the associated effects on data collected by the EDR function. Controlled testing was conducted with Detroit Diesel, Mercedes, Mack, Cummins, and Caterpillar engines, and power failures were created by artificially interrupting power between the vehicle's battery and ECM at predetermined intervals. EDR data from the test vehicles were extracted after each test, and the presence or absence of new data was examined.
Heavy trucks can have the capability to record vehicle status and performance data. In many applications, this capability is intrinsic to the powerplant’s electronic controls. However little information has been published regarding Heavy Vehicle Event Data Recorder (HVEDR) data obtained from Mack trucks equipped with the V-MAC vehicle electronic control units. This study is focused on data from Mack trucks and the influence of wheel slip on the HVEDR-reported vehicle speed. Additionally, the influence of variables such as initial speed and loaded condition are discussed. A late model Class 8 Mack was instrumented with a calibrated data acquisition package (DAQ) and put through a series of tests so that the HVEDR data could be compared to the data collected by the DAQ.