No, I can't display MG1 RPM yet, but I am working on it. I have access to optical tach transducers, but I can't figure out how to "see" it without drilling the casting and I am not willing to do that on a new, under warranty vehicle. It is not on the CanBus either, so for now I have a "virtual" MG1 Guage based on the formula you previously posed. As stated before, I don't use a scan guage, but have access to small 1.75 inch instruments that can accept either analog inputs from DC transducers or CanBus inputs (through a programmable "happy box").

So far, besides the normal insturmentation I have ICE RPM, Axle RPM and Fuel Flow (Expressed for now as gallons/100 per mile as a concession to my "American" mind.) I still would like to do manifold pressure and manifold intake temperature as well as MG1 if I can figure it out.

Yes, I was referring to the reversal of MG1. I surmise that there is a steady state regime, dependent on speed, grade and temperature where MG1 turns slowly, either forward, reverse or static locked in an effort to maintain a near constant ICE RPM. This is that operating area where the car gives one a perception of going "dead quiet" that so many posters have described. I know the computer is using some kind of torque comparision or RPM sensing to do this, but if I didn't know better, I would think it has an inclinometer input as well because the sensing is so good it seems to "anticipate" small grade changes.

 

FastMover — I think it might indeed have a built-in inclinometer! Either that, or else they use some other method to prevent the car from rolling backward on inclines. There was some mention of this in some of their literature. [That said, I find my TCH does roll backward on more than moderate slopes. Is this other owners' experience too?]

The ICE's rpm is constantly changing as one drives, even on roads of seemingly constant slope, in my experience monitoring ScanGauge. Yes, at moderate speeds (say 100 km/h = 63 mph) MG1 is spinning relatively slowly, as is the ICE. The quiet is nice!

Stan

 

When cruising along at 50 mph, I noticed the ice would be on at a .6 to .7 gph. Although I don't recall ever seeing the battery charging arrow. I can look at the battery and see the charge gradually come up to full. (even with the plus sign)

I do see the battery arrow, indicating it's charging anytime I let up on the accelerator. I'm now learning to coast a good ways anytime I see a red light up ahead. Also i'm learning to use the foot-brake gradually to help keep the battery charged.

 

[quote=rburt07;137872]When cruising along at 50 mph, I noticed the ice would be on at a .6 to .7 gph. Although I don't recall ever seeing the battery charging arrow. ... quote]

The condition I am talking about is the other way around -- a fuel flow of around .4 to .6 GPH AND the arrow indicating electrical activity from the battery to the "wheels" (MG2). This occurs at speeds around 50 MPH at very low throttle demand and when the power transfer ratio is very high (MG1 either static locked or turning very slowly). The car is very quiet under this condition, and the MPG will take a noticable "dip" (towards better MPG) when the electrical activity display starts provided you do not change the throttle demand (don't move the pedal). This can be confirmed by a reduction in the ICE RPM, and since the axle speed (and therefore MG2 speed) have not changed, it implies that MG1 RPM did in fact either slow down, stop or go negative at the point that all this happened. I can't prove it yet, but I am working on it. (If MG1 RPM was already negative, then it would have needed to go more negative to cause the ICE RPM to drop, but I don't think that is the case here.)

 

Who wants to buy one of these and settle this once and for all?

 

I'm looking for something similar, but interfaced to laptop. Should be less expensive and easier to update or program. There is nothing about this device working with TCH, may need some reprogramming, I also think Prius has different battery than TCH , so trying to follow the steps with adding extra battery may not work.

 

rburt07 — Your fuel consumption numbers of 0.6-0.7 gal/h seem about right, and everything is now in good agreement!

FastMover — I think I also notice the effect you're talking about. It feels like an automatic transmission's torque converter locking up. The car surges ahead very slightly, the ICE's rpm drops, the fuel consumption drops, and there's a "battery discharging" arrow displayed. I haven't had the arrow stay for very long, however, but this might be related to local road conditions. I believe that the car has switched to "heretical" mode, although in this case (possibly because of the relatively low speed involved) MG1 isn't powered solely by electricity from MG2, but is being supplemented by some power from the NiMH battery as well. As long as MG1 is spinning backwards while the ICE is delivering power, MG1 must be acting as a motor, and so I think that this must be heretical mode.

Stan

 

I hadn't considered that, but it would explain things. The other possibility is that the same sort of "battery supplement" is being used to hold MG1 in lock, but given the high ICE/axle ratio, I tend to agree that it is probably very low speed HM.

I will know for certain when I get my MG1 "virtural tach" working. I have the first two needles on the triple tach working now for axle (corrected to show MG2 RPM) and the ICE. I am still calibrating them by fine tuning the equations. Then I need to get the programming done for the virtual gauge.

 

You guys have convinced me, thats got to be the Heretical Mode. Their is a area of highway we pull out on thats about 1/4 mile toward town. I get it up to 45 or 50 starting there then it happens. That slight surge forward, the rpm comes down, the gph drops down to about .5. It's so amazing to see a engine like this almost at idle pulling the car along at a constant speed.

 

I really don't understand this statement. My understanding of motor/generators is that the direction of spin isn't the determining factor as to whether or not it's acting as a motor or a generator. The subject of MG1/MG2 spin as well as the direction power flow on the display while in the heretical mode has been discussed in a fair amount of detail at least 3 years ago at Priusonline.com. I don't recall ever reading that as long as MG1 is spinning backwards it must be acting as a motor.

-Ed