For anything you'd like to see added to Speeduino
User avatar
By gpineau
#47038
Secondary Throttle Plate position control.
Position the Secondary throttle plates based on RPM vs: TPS.

They are common in high performance carbs and I suspect they will become more common in newer vehicles.
Most new EFI motorcycles have them.

I am working on this myself but it will be a one-off implementation for my special needs.

https://www.freepatentsonline.com/6581567.pdf
By theonewithin
#47040
I would suspect it won't be something Josh would allow to come to Speeduino.

He doesn't want DBW in Speedy due to lawsuits/liabilities issues.


Just wire the secondary set open.

It's used for antiwheelie/traction control anyway which Speedy doesn't have either.
User avatar
By gpineau
#47041
It's not actually DBW. The main throttle (the one connected to TPS) is driven a cable controlled by the driver.
The secondaries can only add restriction to the airflow but they can not over ride the main throttle settings.

It is the secondary plates that restrict the air and change the air velocity ahead of the main throttle plates.
They do more than wheelie control.
They provide idle air control and fast idle during warm up.
And in my case I hope it can prevent the problem I am having of going too lean when quickly going to WOT by slowing the opening allowing RMP to catch up with the TPS.
By theonewithin
#47042
I know it's not DBW but it is close enough that it could be repurposed to do that functionality.

Hence I doubt it will be added.

May be better to use a different ECU if you need that functionality.or look at blended tables to help tuning control.

And remember that there were EFI bikes out there TT made big power with only the 1 set of throttle blades and they words fine ;)
User avatar
By PSIG
#47056
Secondary throttles may be useful for many effects, and it will be important to define exactly the effects you want to see form them. Because assumptions and reality (cause and effect) are often a cloudy relationship, you could cross-list perspectives, such as:
  • Intended effect(s)
  • Current issues
  • Alternative solutions
In these comparative lists, the point is to draw relationships between each. If an intended effect is torque control, then there should be a current issue of uncontrolled torque, and a known alternative solution for that issue that helps define the effects and potential solutions. This may (hopefully) define the real needs and root causes to be addressed, perhaps by secondary throttles as a superior solution (judgmental or actual) to other alternatives.

David

PS: This process may help explain why I commonly suggest solutions to issues that may seem hokey or primitive, as a way to define root issues and effects, and use that perspective to create better or other solutions.
User avatar
By Chris Wolfson
#47107
If the engine has a band of more than 10.000 rpm you can use for driving your vehicle, secondary butterflies make it behave well in the lower band. Lower band means anything from 2.500 to 8000 rpm. To produce 150 or 220 horsepower from 1 litre displacement, the inlet has to be tuned to resonate and forcefully charge the cylinders. This tune will do nothing good in the rpm band you use most of the time, as you operate even a race replica mostly at road speeds. Here these additional butterfly disturbs the optimum top end air flow, to make it drive able at maybe 2000-4000 rpm and every day traffic.
Now translate this to a "normal" engine, that does not even reach 8000 rpm. The effect of the inlet at top HP is much less a problem at low rpm. With such an engine, to improve torque, you need other measures, like switchable volumes, tumble flaps or variable length intake channels .
Basically the same problem, but, if seen necessary for a little extra low down torque by the engine builder, addressed with slightly different methods. Lower frequency resonance usually needs more volume.

What kind of legal problems some might see with such add on´s in the Speeduino makes no sense to me, as there are no valid patents any more, any where. All this stuff is more than 20 years old. For example, variable cam timing dates back to the early eighties and adjustable intakes are even older! These are things like sequential injection or wasted spark, anyone can use it, private or commercially.
So if someone wanted it, only a technical programming / switching problem with Speeduino. Even the option of a stepper motor driver is already there.
By JHolland
#47108
Chris Wolfson wrote: Wed Dec 16, 2020 10:02 am What kind of legal problems some might see with such add on´s in the Speeduino makes no sense to me, as there are no valid patents any more, any where.
Safety and liability is the problem with DBW. The Mega is not an automotive processor and also has no support for functional safety, the STM32 has some limited support for functional safety but Speeduino doesn't have even the most basic of safety functions like memory checks and a watchdog. Also Arduino is an inherently unsafe coding environment.
By JHolland
#47109
Chris Wolfson wrote: Wed Dec 16, 2020 10:02 am What kind of legal problems some might see with such add on´s in the Speeduino makes no sense to me, as there are no valid patents any more, any where.
Safety and liability is the problem with DBW. The Mega is not an automotive processor and also has no support for functional safety, the STM32 has some limited support for functional safety but Speeduino doesn't have even the most basic of safety functions like memory checks and a watchdog. Also Arduino is an inherently unsafe coding environment.
By JHolland
#47115
Chris Wolfson wrote: Wed Dec 16, 2020 2:58 pm So you say the whole Speeduino is a project gone wrong from the beginning?
Which programmable EFI has the safety features you demand?
Speeduino is a cheap, DIY EFI that is sold as not for road use. There are aftermarket DBW controls that have functional safety built in - DBWX2 for example uses dual processors.

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