Validation of machine CAN bus J1939 fuel rate accuracy using Nebraska Tractor Test Laboratory fuel rate data

Abstract

A pilot study concluded that there was a difference (up to a 6.22% error) between data collected using the machine controller area network (CAN) bus Society of Automotive Engineers (SAE) J1939 standard fuel rate and data collected from a physical measurement system utilized by the Nebraska Tractor Test Laboratory (NTTL). This indicated a need to perform further studies on the accuracy of the CAN fuel rate message.The SAE J1939 standard fuel rate message utilized by the machine CAN bus has a theoretical value, however little work has been done to verify the accuracy of this value. Reported fuel flow rate values are rarely measured directly on field equipment using a flow meter, instead these values are estimated from other operating parameters (e.g., engine speed, number of cylinders, injector timing and pulsation, etc.). The goal of this study was to compare fuel rate values collected from the CAN bus to the physically measured fuel rate value from tractor performance tests conducted at the NTTL. The fuel rate values were collected simultaneously and then synchronized to confirm accuracy of results. The parameters for comparison in this study were comprised of the performance test points as described in the Organization for Economic Co-operation and Development (OECD) Code 2, Section 4.1.1. The NTTL has a certified fuel rate measuring system with an accuracy of ±0.5%.Results from this study indicated fuel rate as recorded from the CAN bus resulted in a ±5% error of actual physically measured fuel rates. Errors for higher fuel rates within the torque curve were closer to ±1%. This produced knowledge of machine fuel rate accuracy for in-field efficiency and/or spatial fuel usage for additional analysis, whether used for research or grower cost analysis with an accurate knowledge of actual fuel consumed during operation.