KE Jetronic

[Cauf61]

Hello

I am interested in your Lambda shield 2 set. I assume I can use it to convert a wide band lambda input signal to a narrow band signal for my KE Jetronic. I shall need to build a PWM RC filter/output buffer because I don’t know the current (impedance) a KE Jetronic draws.

But, would it be possible to adapt the output to a plus or minus 10% level ?
I have some arduino skills.

Grts
Patrick
Antwerp

[Christian_Bylund]

Hello Patrick,

I am interested in your Lambda shield 2 set. I assume I can use it to convert a wide band lambda input signal to a narrow band signal for my KE Jetronic. I shall need to build a PWM RC filter/output buffer because I don’t know the current (impedance) a KE Jetronic draws.

Unfortunately I have no knowledge of the lambda input of KE Jetronic. In this video we use a Lambda Shield and Arduino Uno to generate a narrowband signal for a lambda gauge. For Lambda Shield 2 it is recommended to use the Arduino Mega, see more here.

But, would it be possible to adapt the output to a plus or minus 10% level ? I have some arduino skills.

Yes, simply adjust the output conversion from wideband to narrowband in Lambda_Shield_2_Example.ino

Code: Select all

//Displays the AFR value on an external narrowband lambda gauge with an (RC-filtered) 0-1V PWM signal from ANALOG_OUTPUT_PIN. 0V = AFR 20.00. 1V = AFR 10.00.
void UpdateAnalogOutput() {

  //Local constants.
  const float AirFuelRatioOctane = 14.70;
  const int maximumOutput = 51; /* 1V */
  const int minimumOutput = 0;  /* 0V */

  //Local variables.
  int analogOutput = 0;
  float lambdaAFR = Lookup_Lambda(adcValue_UA) * AirFuelRatioOctane;

  //Convert lambda value to PWM output.
  analogOutput = map(lambdaAFR * 100, 2000, 1000, minimumOutput, maximumOutput);

  //Make sure we do not exceed maximum values.
  if (analogOutput > maximumOutput) analogOutput = maximumOutput;
  if (analogOutput < minimumOutput) analogOutput = minimumOutput;
  
  //Set PWM output.
  analogWrite(ANALOG_OUTPUT_PIN, analogOutput);
}

Hope it helps.

[Cauf61]

Thank you very much.
I will order a set (but with wifi)

Could you give as example a -10% conversion factor (so as result 10% leaner mixture) please ?

As said I will make a RCfilter/buffer capable of max 500mA narrowband signal out , so I think that will be more than enough for the KE Jetronic

Grts
Patrick

[Cauf61]

Hello Christian.

I am looking a bit deeper in to the matter. Am I wrong or is the shield giving out a linear 0-1V signal out in your AFR meter video ? This is not a narrow band simulation, no ? A narrow band signal goes from +- 0,1 to 1V with a very steep angle between 400 to 500 mV. (14,7 R)

Grts Patrick

[Christian_Bylund]

Hi Patrick,

As said I will make a RCfilter/buffer capable of max 500mA narrowband signal out , so I think that will be more than enough for the KE Jetronic

The maximum current you can draw from a nernst cell is in the μA range. But again, I do not know what kind of input the KE Jetronic use or if it is some amplified circuitry.

Could you give as example a -10% conversion factor (so as result 10% leaner mixture) please ?

I am looking a bit deeper in to the matter. Am I wrong or is the shield giving out a linear 0-1V signal out in your AFR meter video ? This is not a narrow band simulation, no ? A narrow band signal goes from +- 0,1 to 1V with a very steep angle between 400 to 500 mV. (14,7 R)

Do you want it to be ±10% lambda 1? You are correct, a narrowband signal is exponential. The example is a simplified linear output for lambda gauges.

[Cauf61]

Hello Christian

Do you want it to be ±10% lambda 1?

Yes, as example.

The example is a simplified linear output for lambda gauges

But the shield can reproduce a real narrow band signal from the WB 4,9 LSU ?

[Cauf61]

Hello Christian

Can the shield reproduce a real (exponential at +- 450mV ) narrow band signal from the WB 4,9 LSU ?

Grts
Patrick

[Cauf61]

So I guess not.

Ok.

[Christian_Bylund]

Can the shield reproduce a real (exponential at +- 450mV ) narrow band signal from the WB 4,9 LSU ?

The shield no, the Arduino yes. The lambda shield measures a wideband sensor that the Arduino can use for any purpose.

[Cauf61]

Dear Christian,

I assume you program the "exponential" NB curve in the arduino lookup table itself ?
The values, you calculate in excell or so ?

Like I said i would like to buy the "wifi" kit, but I have to be certain that I have the possibility to trick the ECU (now running on a NB) to run richer of leaner.
I know, leaner is very dangerous. :-)