SuperMID up and Running

Discussion in 'Fuel Economy' started by krousdb, Feb 24, 2006.

  1. krousdb

    krousdb Defiant NX-74205

    I just took a drive to see what the initial calibration was like. The trip odometer on the del sol says 6.0 miles. The SuperMid says 9.70 km or 6.01 miles. I expected it to be close because I am using the same size tires as a Prius.

    After the 6 mile trip the display showed 0.376 liters used, or 25.79 km/l, or 60.6 MPG. Hmmm the calibration seems a little off there, but not too much. The Del Sol uses 240cc injectors. Yoshi says his Prius calibration number shows 222cc. So there is probably an under registration of 10% which would bring me back down to 54 MPG. Sounds about right because I started on a warm engine. I'm gonna drive to work and back to get a better calibration on the odometer and see what the trip FE is. I will adjust the calibration down to make the trip 51MPG which is what I average. Then I will fill up the tank for a full tank calibration.

    So far so good with the BETA testing. I was even able to verify that the injectors shut off completely under colsed throttle. The PW shows 0.0. I have it hooked up so that I can shut off the engine and restart by either bump start or starter and the SuperMID keeps on recording distance.
    I found a convienient place to mount it. I didn't really need a case. you can't see it from the outside of the car because it is hidden by the safety and emmission stickers.

    [​IMG]
    Another interesting point is the % time the engine is running and FE while the engine is running(shown as 76% and 19.46 km/l). During the 6 mile test run, the injectors were only active for 76% of the trip time, either because the engine was off completely or the injectors were cutoff during closed throttle engine braking. Whil the engine is running, my FE is shown as 19.46 km/L or 46 MPG. Now some of the off time was due to stopping at a convinience store for a few minutes to pick up some stuff. Also I had the supermid runnning for several minutes during installation so the 27 minute and 21km/h ave speed are not truly indicative of the trip.

    More to come.
     
  2. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___IIRC, the Prius II’s injectors are fed with a positive displacement pump with a non-return fuel supply setup? I do not think most cars are setup like this as they more then likely have a return line (recirc) back to the tank and a back pressure regulator controlling the fuel pressure? I am pushing well beyond my knowledge but I believe the Prius II is kind of unique in the way it operates and I was surprised to hear how well the SuperMid worked with the del Sol given the technology is at least 2 and possibly 3 generations back! Gotta love Yoshi for that one :D

    ___Your analysis on fuel cut is excellent. Can you have Yoshi give us the SuperMid inner working details as to how it calc’s fuel economy in both ICE-On and Off conditions? He has programmed it to know when fuel cut is evoked while still tallying up distance traveled and very few of the OBD-II SW scanners do this properly. I have read the Can-View does it properly as well but who can afford that SW package let alone not being able to tie it into your del Sol due to the lack of a CAN bus!

    ___Thanks once again for your commentary and pic as it shows someone who pushes the envelope in ways most would never have even thought of!

    ___Good Luck

    ___Wayne
     
  3. krousdb

    krousdb Defiant NX-74205

    Wayne,
    It is true that the Hondas have a recirculating fuel system and the Prius does not recirculate. But what they both have in common is constant pressure at the injector. The SuperMID, the Prius MFD as well as the scangauge measure the pulse width (duration) of the signal that fires the injector. As long as you have constant pressure, calculating fuel used is as easy as adding the pulse widths and multiplying by a factor that is consistent with the fuel injector size. I don't understand why the scan gauge has a problem reading fuel cut off. Since there are no signals sent to the injectors duriong fuel cutoff, zero times some number is still zero. Pretty simple. Instead of blaming the scangauge, my first question would be, are you sure that your ECU is actually shutting off the fuel? On the Del Sol, it doesn't always cut off the fuel during closed throttle engine braking. According to the shop manual, all that is required is that the throttle position sensor sees a closed throttle and the RPMs are above 1100. But from what I have seen so far, there are other criteria, probably ECT. The injectors don't seem to shut off until the coolant temp is in the normal operating range.

    I'm no expert on this, just learning. Would you like me to invite Yoshi to Clean MPG?
     
  4. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___Thank you for the reply. I would love to have Yoshi join us as he is one surprising individual that really knows the insides and out of the Prius I and II … Do you think he could make a non-specific (adjustable) OBD-II based SuperMid for other manufacturers makes and models vs. the Prius II specific and ECU lead clamp-on SuperMid that you have? If he were to add an iFCD to the aFCD data and keep the rest of the info (English units however ;)), he could sell thousands and I would be the first in line :D Ask him what he thinks because I trust his judgment, his technical ability, and his engineering capabilities to supply the US hypermilers with something that truly works as it should. I do not know if you have read up on the Scangauge but it is still having issues with FAS’ing and some hybrid’s as far as accuracy. Yoshi has the accuracy issue licked given the miles and FE on the SuperMid vs. the Odometer and gallons/distance from your Prius II last August.

    ___Thanks in advance!

    ___Wayne
     
  5. krousdb

    krousdb Defiant NX-74205

    Just an update on the SuperMID and FAS. I was focused on watching the pulse width go to zero and the SuperMID staying powered up, which it does. What I just noticed though is that the distance stops accumulating while the key is off so it is not perfect during FAS. But you can't blame the SuperMID, it is still able to record distance, it's just that ignition off also cuts power to the speed sensor, so it is not able to send a pulse.
     
  6. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___You are rebooting the del Sol by taking the key to IG-II for IG-I, right? Most of today’s automobiles speed sensors are live in that condition but not with the Key in IG-I. This is very interesting to me because nobody ever posts real time data in older vehicles with OBD-I or prior sensors and communication.

    ___Good Luck

    ___Wayne
     
  7. krousdb

    krousdb Defiant NX-74205

    Well I don't know what the positions are called. I just back off on click and then back forward when I think the ICE has stopped. Sometimes I am too quick.

    I noticed the SuperMID distance counter stopped while I was coasting in the work parking lot. When I turned the ignition on, the couter started again. I will checlk my wiring diagrams to verify when the speed sensor has power.
     
  8. krousdb

    krousdb Defiant NX-74205

    According to my wiring diagram, the vehicle speed sensor has power only when the ignition switch is in the RUN position and not in the ACC position.

    On another note, I have just finished installing the 400W OEM engine block heater and a 192F thermostat. Based on the fuel map for the Del Sol, I can reduce the ECT multiplier by 2-3% by starting with warm coolant. By going from a 172F thermostat to a 192F, I can reduce the multiplier by another 2%. I already have the warm air intake mod which according to the AIT multiplier could be worth up to 6% in very cold weather. The goal here is to minimize the cold weather hit on FE.
     
  9. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___Great info! The Run position is IG-II. IG-III is to start her up so perform your FAS like most do. Key to IG-I to shut down the car and electronics, key back to IG-II to reboot the car’s computer and electronics but not start the ICE, coast to the lower target, and reignite with a momentary key to IG-III and release leaving the key back in IG-II (Run) while pulsing back up to your HS target.

    ___I may be confusing some future reader as ACC position can be called IG-I with IG-II being Off, IG-III being Run, and IG-IV being Start. Since we have to key back instead of forward to get the ACC, I don’t call it anything but ACC thus leaving IG-I as Off, IG-II as Run, and IG-III as start.

    ___A thermostatically controlled ICE block heater? That is fringe baby, fringe … and I love it :D

    ___Good Luck

    ___Wayne
     

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