Best OBD?

BlueDriver

 

A hybrid assistant that will cost you nothing, i.e. absolutely free, for free.
Main screen.



Switchable screen for reading the speed and power of MG1 MG2 and engine.



And other functions for monitoring and reporting.

Hybrid Assistant

 

That's a nice screen, that seems to be newer than their user guide (that's the download link that worked for me after getting through all the Google Drive cruft, but I don't know if they make it session-specific so it might not work for you).

Have you seen documentation where they pin down the algebraic sign conventions they are using, or otherwise show their work with the math?

The kW they show at the wheels matches the sum of the kW they show for MG2, engine, and MG1. I can't quite make out whether the battery kW under the nomograph line should be −3.2, −8.2, or −9.2. Toyota uses minus on battery currents that are charging, so if these guys are using sign the same way as Toyota this would be a snapshot of the battery being charged, not at a heavy regen rate, but a pretty significant rate for cruising.

I don't know the gearbox specs of an Auris, but all Prius PSDs so far have split torque in carrier (engine) : sun (MG1) : ring ratios of 108:30:78.

5.5 kW / 1110 rpm for the engine is 47.3 Nm torque, and 5.5 kW / 2380 rpm for MG1 is 22.1 Nm, and that's not very close to a 108:30 ratio. (Also doesn't work out for engine : MG2 but many models have an MG2 reduction gear and I don't know that ratio for Auris so I'll let it slide.)

It's possible I'd agree with the app's math once I saw it written out and reconciled the picture to it, but I do hope they have it documented somewhere. Right at the moment I'm not 100% sure of it.

 

I don't have any mathematical formulas, I'm not the developer of this app. I'm just a regular user.

The Auris has the same engine as the Prius Gen 3 and Prius V. Do the gear ratios in the box match? I don't know.

I'll try to take a few screenshots from the power nomogram from my Prius V.

 

There is no refutation. Fuel supply and its consumption are also taken into account by this program based on information from sensors.
The program calculates instantaneous consumption, total fuel consumption in units of volume, fuel consumption per unit of distance.
When coasting, the value of instantaneous consumption is "zero".
On the phone screen there is an indicator for help in the form of a ball changing color - yellow, red, green and the point at which this ball gives maximum savings. Then fuel is not consumed and a balance is achieved between charging the battery and spending energy from the battery. Balancing on the tip of the blade. When you feel the car, you do not need to look at the ball, you reach it yourself.
"Avatar". Only not in flight, but on the road.

 

Any movement overcomes various forces that impede movement (friction, air resistance, etc.)
The practice of movement for hypermilling is built in such a way that in the coasting stage the car rolls as far as possible without the support of its power from the motors and at the same time does not take kinetic energy into the battery.

 

Yes, it's hard to figure out the first time. "Heretic" mode is what allows the Prius to move in a way that's contrary to normal concepts.

Heretical mode on third gen Prius, what do we know? | PriusChat

 

which it is ...

The drag is measurable and many with instruments (even, now, you) can measure it. Whether it does or does not "negate" other effects is then a simple matter of comparing numbers—a less error-prone approach than thinking about it from an armchair.

What are you thinking? That something can only be "freewheeling" if it isn't turning? Every freewheeling item has an RPM, whether one way or the other.

Right, you don't. The IGBTs in the inverter are all shut off. With no place for current to go, the capacitor on the boosted DC bus remains at a voltage equal to the higher of the two MGs' EMFs, and therefore no current flows.

In any case, the screenshot being discussed from post #3 was clearly taken under other conditions than Neutral.

 

Paul may have me on ignore again, but somebody else could come along and find this thread, and I doubt they'll find what I said nearly that hard to make sense of.

Where Paul said "Even if it were true that coasting in neutral were just the electric motor freewheeling" I said "which it is". 'Cause it is.

Where Paul asserted (because he's so sure of it) that "the drag from the high gear ration would negate any fuel savings", I suggested using instruments and finding out if it does or doesn't. Paul opened this thread for input on a good instrument to start with. That's a positive step.

Paul's claim that "the negative RPM is an indicator that it's not freewheeling" might have been my favorite. What made him think the fact that something is turning proves it isn't freewheeling?

For newcomers, that has to do with some longstanding stuff Paul thinks about Neutral, which he brought up here even though the screenshot in #3 clearly wasn't taken in Neutral or anything to do with Neutral.

I hope none of the above is too hard for most people to make sense of.

Sure, there was one part of my post that maybe won't make immediate sense to everyone, this part:

That's a description of what happens in the inverter electronics. It'll make sense to people who've looked at the schematics in the New Car Features manual and have some background in electronics, and might not make immediate sense to everyone else. Anyone whose curiosity might be piqued can find lots of ways to learn though.

 

For example, the engine and hybrid transmission diagram for the Prius V.
Speed 56 km/h (34.79 mph)

Screen_2025-03-30_16-09-00 by MAX2 posted Mar 31, 2025 at 12:05 PM

Speed 47 km/h (29.20 mph)

Screen_2025-03-29_10-08-36 by MAX2 posted Mar 31, 2025 at 12:04 PM

The gear ratios for the Prius V are different from the Prius Gen3 transmission gear ratios.

The Auris has the same hybrid transmission gearbox as the Prius Gen3.

 

On the contrary the fact that something isn't turning proves it isn't freewheeling - the engine isn't turning because it's much harder to move than MG1, which can freewheel.

Maybe Paul has never played with a LEGO Technic differential, so has no grasp of how power split devices work or feel.

The PSD is basically just a differential with asymmetric gearing and a different layout - it would feel the same as the LEGO differential.



If you imagine the Prius engine being attached in the middle as the LEGO motor, and MG1 and MG2 as the two wheels, then the PSD behaves basically like that differential does. If one input is locked in place, or has a fixed motion, the other two inputs have a fixed gearing relationship. If one input is left to freewheel, the other two are disconnected - a neutral relationship.

The contrast between pushing that contraption forwards on both wheels (it will fight you hard, because you can't easily turn the motor) compared to rolling it on one wheel (MG2) with the other (MG1) spinning backwards in the air is almost comical.

And that's exactly what's happening to let the Prius coast - MG1 freewheels backwards so MG2 can freely roll forwards with the car. They have to freewheel in opposite directions if the engine doesn't move.

And I think it is a hard thing to get an intuitive feel for without actually playing with one.

(And note that a typical post-2000s LEGO electric motor like the one shown here is hard to move, unlike MG1, because it has a significant gearbox built-in, giving it a top output speed under power of less than 400rpm. MG1 is ungeared to operate with an output speed of 10000rpm. You could strap an electrically-disconnected 1980s ungeared LEGO motor to the "MG1" wheel position and still be able to turn the "MG2" wheel reasonably easily with the central motor not moving).

 

I know the v and gen 3 liftback have different final-drive ratios.

I'm pretty sure they all have the same 108:78:30 PSD ratios.

What I don't have many notes on is the MG2 reduction ratio. It's 58:22 in the gen 3 liftback. 53:17 in gen 4 Prime, and those are about all I know.

 

Try to calculate it in a practical way using the data from the nomogram?
Although some error is possible. Scans were taken by briefly pressing the button. The speed at these moments changed, and the GPS values are used.