Auto/throttle blip on downshift

[diy-efi]

There has been some chat on this on discord, this is a collection of the thoughts.

Jama — 10/24/2024 1:03 PM
I've had a customer asking about auto/throttle blip on downshift.

When I've got a fome running car here again I'll start to play in lua.

But a basic form should be pretty easy to implement.

Is this something that has been discussed before.

Inputs
Brake
Clutch/neutral switch

Configuration
On/off trigger
Blip amount (ETB add %).
Blip time (ms)
Activation delay (ms).

Rough logic.
If active.
If brake pressed.
After clutch press detected.
Wait (activation delay)
ETB add x%.
Wait (blip time).
ETB add 0%

In my mind.
With an activation switch.
When you are on the break and decelerating, when you push the clutch. After a while you'll get a blip. Which you can adjust to suit your pedal/ response time.

Simon@FPP — 10/24/2024 1:12 PM
Might make sense to use a clutch fully down switch as well as a clutch pressed one.
That way you can activate it only once the pedal begins to rise again.

Or maybe do it with a variable clutch pressure sensor, only trigger the blip when the clutch begins to lift

Jama — 10/24/2024 1:17 PM
Yup, I was thinking about that, even with a basic single on/off switch you could choose which switch phase the timer starts on.

Expansion beyond that is having a limit on the rpm blip, both overal rpm and added.
max overall rpm: 7000
max added rpm: 2000

There's a lot you can do with it.
Looking at haltech they even have tables for blip amount and duration with rpm against gear.

Simon@FPP — 10/24/2024 1:48 PM
Likely will be needed. How hard you have to blip is dependent on the rpm target for the shift
**Wider ratios want a bigger blip obviously

mck1117 | volvo hoarder — 10/24/2024 9:25 PM
I’d run an open loop table for throttle required to hold engine at some RPM
then a second table for throttle add/remove as a function of rpm and rpm error
or PID or something for the second part

Simon@FPP — 10/26/2024 8:24 PM
I'd think the major issue we would have with auto blip is we are back in the realms of taking authority away from the driver and having a system that can increase throttle without any driver input.

Which is heading close to the reasons there is no cruise control.

Jama — 10/26/2024 9:16 PM
Fair point.
There could be a hard cap in fw on the blip time.