GPRP Shift System

[Matteo Tagliaferri]

Hello, i'm trying to optimize Upshift process on my Power-Unit (Hybrid).

I have set up the Gear Shift Timing Table for Upshift Power-On, but analyzing the telemetry registered on the straight trying to upshift, i've figured out that the effective engagement of forward gear is reached out in the rearm phase. Reading MoTeC GPRP manual i've understood that the effective shift has to occur in the "Shift" phase, so i'm thinking that i'll have to edit the Gear Shift Actuator Table. A little tip from the community may be helpful. Thank you in advance!

I'll post the log file.

https://drive.google.com/file/d/13OOjcL ... sp=sharing

[Stephen Dean]

Hi Matteo,

Your Gear Estimate is not aligning with your Gear channel, Gear Estimate is used for a number of shift related calculations, so if this isn't showing the correct information, then the shifting will not be as optimised as possible.

[Matteo Tagliaferri]

Hi Stephen, thank you for replying me. Have i to calculate the gear estimate as MoTeC GPRP manual presents? So should i have to recalculate correctly the value "Gear Estimate Tolerance" in the M1 Tune? If not, could you suggest me a way to correct this "Estimate" please?

If you are referring to the "Gear Estimate Tolerance" it was set at 0,500 , but performing the difference between the two closest gear ratio and dividing this by two i have obtained a value of 0,120. I've set up this value and tomorrow will be check if things get better and i'll let you know!

[Stephen Dean]

Hi Matteo,

The Gear Estimate is calculated by the relationship between Engine Speed and Vehicle Speed. It uses the Gear Ratio and Final drive ratios in the calculation so if these are not correct then the calculation will be out.

[Matteo Tagliaferri]

Hi Stephen,

I have been on track doing some tests for the Hybrid Strategy, so i did not manage to test the gearbox. I'll go and test the gearbox the next week so i'll try to correct the ratios of the transmission line and let you know.
I just would like to ask you another thing that unfortunately is not told in the MoTeC manual: with "Your Gear Estimate is not aligning with your Gear channel" do you mean that in each istant Gear should be equal to Gear Estimate to let the ECU properly perform its calculations?

Should also Gear Estimate Ratio and Gear Ratio have to be aligned (always equal)?

I've noticed that generally the ECU uses the Gear Position Sensor as source to have the info related to which gear is engaged in the gearbox, but in some moments the source becomes the Gear Estimate, that obviously is wrongly calculated so the Gear channel passes for the second while in a third-fourth Upshift. What may be the cause for which the source from the Gear Position Sensor becomes Gear Estimate?

Thank you for the availability and for the previous answers,

Matteo.

[David Ferguson]

When the gear position sensor is not within the tolerance for any gear (ie. it's between gear, disconnected or broken), then the gear source falls back to gear estimate. That is why it's critical to have this calculated correctly It's not very difficult to get right, you can compare "gear ratio" with "gear estimate ratio", and adjust wheel speeds, and gear ratio until it's the same.

Before doing all of that make sure you wheelspeeds are accurate (i usually calibrate by comparing to GPS speed near the end of a straight.

[Matteo Tagliaferri]

Hi David,

Do you mean that I have to adjust the gear ratio (not the gear estimate ratio) to match the average gear estimate ratio for each gear, even if the value will not be equals to the effective ones?

[David Ferguson]

No, I mean fix the problem. Probably by adjusting the tire circumference to be correct. But you need the Gear Ratio, and Final Drive Ratios to be correct as well.

[Matteo Tagliaferri]

As you said i plotted the difference between the Vehicle Speed and the GPS speed.

I'll post the plot :

https://drive.google.com/file/d/1aCCdF0 ... sp=sharing

I think that they generally match. The average difference is of 3 km/h.

I was reading another post by AlanB and he suggested a guy to insert as gear ratio the effective gear ratio multiplied by the Primary Gear Ratio of Gearbox.
Now i have insert that data in the channel "Gear Input Drive Ratio".
Which of the two ways is the correct one?

Also i read another post in which you said to do the average of the Gear Estimate Ratio for each gear and go and set that value in the Tune. Is this the solution to my problem as well if other parameters like (tire circumference, final drive and gear input ratio) are set up correctly?

[David Ferguson]

10 minutes of data is not the way to look at this data, please zoom in to 10 seconds abound where you are getting a large gear difference. For calibrating wheel speed, zoom in to the last few seconds on the straight.

If that image is from your data posted earlier, I will look at that file so I can see whatever you've logged.