1. Attachments are working again! Check out this thread for more details and to report any other bugs.

HEM Data Report

Discussion in 'Gen 3 Prius Fuel Economy' started by bwilson4web, Sep 11, 2014.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    27,068
    15,372
    0
    Location:
    Huntsville AL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Source: Fuel Economy Using OBD | HEM Data
    This is interesting for two points. First is the ability to run long-term, OBD studies of a Prius. There are Prius specific metrics that many COTS OBD interfaces and software are totally ignorant. For problem diagnosis and useful engineering studies, we need these Prius specific data.

    The other point is looking at their MAF vs injector timing study. What bothers me is on one hand, the injector timing matched the tank numbers, this is good. But they don't compare the the injector and MAF metrics directly but rather reference MAF with MPG. The problem is MPG is also a function of tire revolutions per mile.

    I'll be contacting them for details but wanted to share these data.

    Follow-up phone call points:
    • "OBD Minilogger" runs ~$2,400 but be sure to identify you want the Toyota version
    • It records at ~20 samples/second from any combination of data metrics (i.e., it is not limited to a specific ECU like the 'miniVCI')
    We had a nice technical discussion and I was impressed with the technical understanding. Of course he was kinda surprised by this 'strange character in Huntsville'. Still, it looks like we may do some business in January when I'll have some 'spending money'. <grins>

    Bob Wilson
     
    Feri likes this.