SAE J2601 Appendix L Optional Integrity Check Method 22

APPENDIX L - Optional Integrity Check Method

L.1 Introduction

This appendix describes a non-normative method which may be implemented as a means to check and confirm the integrity of some key parameters which are utilized in the SAE J2601 standard fueling protocols. This method may only be implemented during communications fueling, as it relies upon the measured temperature MT. This method can potentially detect errors in the following parameters: CHSS volume, measured temperature MT, and the mass flow measurement utilized in the calculation of mass average fuel delivery temperature.

Figure L1 demonstrates the potential errors or faults which the integrity check method can detect, and which may not be otherwise detectable. An error in the tank volume TV may be the result of one or more tank valves being closed in a multi-tank CHSS. The measured temperature error MT may be the result of a faulty temperature sensor or the vehicle otherwise transmitting an incorrect value for the measured CHSS gas temperature MT to the station. The mass flow meter error may be due to an otherwise undetectable malfunction of the mass flow meter (note that even if the mass flow is incorrectly calculated, because the error is reflected in both the numerator and denominator of the mass average calculation, the error in the calculated mass average fuel delivery temperature is bounded, but it may still be desirable to detect such an error).