Nissan E-throttle PID settings?

[Kieran]

Hi, can anyone recommend the PID settings for a Nissan E-throttle?  It's a 70mm Hitachi unit off a 2001 Primera P12 SR20VE, but I expect that similar vintage units off the VQ35 etc to be the same or similar.

I've set the E-throttle up with the recommended defaults provided in the PCLink help file, and tried some basic fine-tuning, but there is still a notable hum from the E-throttle when throttle position is 10% or less, and I don't want to risk burning out the motor.

[Phil Williams]

Hi,

Is the throttle position accurately tracking the target? If so then you have it setup correctly.

Most throttle bodies do make a hum when just sitting controlling the plate. The noise is often effected by the switching frequency, Have you heard the throttle body running on the OEM ECU?

Regards,

Phil

[Kieran]

Thanks Phil.

 

The throttle plate is tracking target pretty well, I just need to spend some more time tweaking the integral and derivative gains and it should be suitably accurate.  When the OEM ECU was connected, I couldn't hear any humming while the plate was being held stationary.

 

I've only gone as high as 2khz on the frequency, and that just raised the pitch of the hum.  I'll try some higher frequencies.

 

 

Cheers

Kieran

[Kieran]

OK I've got the PID settings to the stage now where the throttle plate is accurately and quickly tracking the target, with negligible overshoot.  The PID settings I'm using are:

P = 6

I = 0.047

D = 27

Max clamp = 60%

Min clamp = -60%

Deadband = 0.1%

 

I tried adjusting the frequency over the available range and it made negligible difference to the volume of the hum.  I've set it at 1kHz now as a 'safe middle ground'.  Interestingly, I translated the P12 FSM from Japanese, and its checks on the E-throttle drive circuits consist of checking for a DC voltage on the open / close terminals.  One example that was given was at warm idle with all loads turned off, there should be 0.1-015V on the 'open' terminal and 1-2.5V on the 'close' terminal.

I wonder if the factory ECU smooths the drive signal to the E-throttle, and if so would it be a wise idea to do the same with the Link?  I'm going to try and get hold of another P12 and scope the E-throttle drive signal wires.

[Phil Williams]

Hi Kieran,

I can't see how the factory ECU would smooth out the signal as this would be a super inefficient way to drive a DC motor. My guess is they will expect you to use a multimeter which has it's own internal filtering providing results as claimed in the FSM.

You're ear can hear anything upto about 20kHz, so the OEM must be controlling it at a frequency above that.

Unfortunately we don't have a solution for you, but I can tell you that running it at a lower frequency will not damage the throttle body.

Regards,

Phil

[David Lee]

One thing you could try to find the cause of the hum is to set the differentual gain (D) to 0. If you have significant noise in the tps signal this should eliminate the hum. The differential gain tends to amplify any noise and this can cause the controller to oscillate and hence the hum.  Note that I wouldn't recommend using 0 as the throttle response will be slow.

[Kieran]

Thanks, tried setting D to 0 but it made no difference to the hum of the motor.  I think I'm just over-reacting, as the hum is inaudible from within the car when the interior fan is on, let alone when the engine is running.

Having been driving around with the e-throttle for a couple of weeks now, I'm very pleased with the smoothness & linearity of throttle response that I've been able to gain by adjusting the E-throttle target table, while avoiding the inherent dullness of throttle response that is so prevalent in the donor car.