443 replies to this topic

[alexb]

 

actually the memory was not so bad   http://www.ohizumi-m...chnote1.html#a7 7. Thermal time constant A thermal time constant γ is defined to be a constant indicating the degree of thermal responsiveness of a thermistor. No thermistor operation can be free of a time lag because the thermistors every operation is a thermal phenomenon. Thermal time constant γ is the period of time necessary for a thermistor temperature to change by 63.2% when wattage is applied to the thermistor and an abrupt change is made to it from a heat equilibrium state to a zero load state.

Can you translate that steve Thanks

 

 

The part that's missing in that definition is the temperature interval. The T63 response time is the time it takes for the sensor to reach 63.2% of the total temperature interval. I assume for this TMAP that's 170 degrees (-40 to +130 C). 63% Of that is about 107C. Going from -40 to +67C (or from 0 to 107C) will take 10 seconds. In the datasheet there is a note indicator at the 10 sec value. Too bad the note isn't there, as they might have used a different interval.

 

 

 

[siztenboots]

The note indicator *2 ,

 

2) In air with a flow rate of 6 m · s–1

 

 

[alexb]

That makes sense, as it influences the response time.

[Goosenka]

Sorry for side lining this but I never get the fact that noone can hack/gain access to it. What is area 51 grade security or something?

[slindborg]

the access is easy... its interpreting what comes out thats hard without any documentation.

 

e.g. for the Landrover Defender PCM that managed the integration of there is the HEX file that does all the hard work, but to understand that hex file with any tools you need a reference of memory location to a variable name/table etc. GM are very very good at keeping hold of their stuff, the Turbo bits are only sussed because the Bosch data is fairly easily available and useable from other cars. Delco information is thin on the ground, I even tried to get some info from friends there but its not worth yer job anymore.

Edited by slindborg, 25 June 2014 - 02:40 PM.

[CHILL Gone DUTCH]

Reply from peter[color=rgb(54,95,145);] [/color]

 

[color=rgb(54,95,145);]Regarding the voltage jump, this is normal. The temperature sensors have an exponential curve and the ECU bumps up the sensor voltage for more precision when the temperature sensor gets below a certain resistance at higher temps. This is common practice to get more precision over a wider temperature range using an NTC sensor.[/color]

[color=rgb(54,95,145);] [/color]

[color=rgb(54,95,145);]This is also the case for your coolant sensor voltage, if you have a log where you coolant temperature starts below 40C then you will see the same jump when the coolant is warming up.[/color]

[fezzasus]

So i'm right!

[CHILL Gone DUTCH]

So i'm right!

 

never doubted you tom

[The Batman]

So i'm right!

I'm a lefty

[CHILL Gone DUTCH]

I'm surprised a certain doubter didn't no this with all of the expertise

[leevx2.2]

Yes but to be honest Mr Scuffers does no his stuff and believe it or not is trying to help .

[CHILL Gone DUTCH]

Yes but to be honest Mr Scuffers does no his stuff and believe it or not is trying to help .

I'm in no doubt lee, he can clearly offer a lot of knowledge and experience to the forum

[The Batman]

Uh oh the balance of the earths ying yang is now out. You do realise that there is massive post coming explaining why he is write and definately not wrong.

[P11 COV]

Uh oh the balance of the earths ying yang is now out.

You do realise that there is massive post coming explaining why he is write and definately not wrong.

 

Well you're wrong not write right.

[Scuffers]

I'm surprised a certain doubter didn't no this with all of the expertise

You can take the p*ss if you want, but thus is the first time i have ever heard of an ecu or datalogger do this, and to be honest, i am still skeptical...

[CHILL Gone DUTCH]

I'm surprised a certain doubter didn't no this with all of the expertise

You can take the p*ss if you want, but thus is the first time i have ever heard of an ecu or datalogger do this, and to be honest, i am still skeptical...

I like the way you assume this was aimed at you

[The Batman]

Uh oh the balance of the earths ying yang is now out. You do realise that there is massive post coming explaining why he is write and definately not wrong.

  Well you're wrong not write right.

I blame my nap on that one

[fezzasus]

 

I'm surprised a certain doubter didn't no this with all of the expertise

You can take the p*ss if you want, but thus is the first time i have ever heard of an ecu or datalogger do this, and to be honest, i am still skeptical...

 

 

I get it actually,

 

The resistance will vary significantly with temperature (it's design to, after all) so by stepping the voltage the ECU gets greater resolution and reduces risk of burning out the resistor when it's cold.

[slindborg]

I'm surprised a certain doubter didn't no this with all of the expertise

You can take the p*ss if you want, but thus is the first time i have ever heard of an ecu or datalogger do this, and to be honest, i am still skeptical...

Agreed. I have never seen or implemented an a2d resolution shift on the raw reading of a sensor. There isn't really a way to shunt the voltage on the potential divider either... Well not a way that any self respecting tier 1 hardware engineer would do. I can see why some would like the step to be cause by a voltage or resolution shift, but sadly I don't think it will be the reason for this.

[oakmere]

TYPES OF COOLANT SENSORS Most coolant sensors are "thermistors" that change resistance as the temperature of the coolant changes. Most are the "NTC" (Negative Temperature Coefficient) type where resistance drops as the temperature goes up. With this type of sensor, resistance is high when the engine is cold. As the engine warms up, the internal resistance of the sensor drops until it reaches a minimum value when the engine is at normal operating temperature. . . A typical GM coolant sensor, for example, may have around 10,000 ohms resistance at 32 degrees F and drop to under 200 ohms when the engine is hot (200 degrees). A Ford coolant sensor, by comparison, may read 95,000 ohms at 32 degrees and drop to 2,300 ohms at 200 degrees. Resistance specifications will vary depending on the application, so any sensor that does not read within its specified range should be replaced. Coolant sensors have two wires (input and return). A 5-volt reference voltage signal is sent from the PCM to the sensor. The amount of resistance in the sensor reduces the voltage signal that then returns to the PCM. The PCM then calculates coolant temperature based on the voltage value of the return signal. This number can be displayed on a scan tool, and may also be used by the instrument panel cluster or driver information center to display the temperature reading of the coolant. On some applications, a "dual range" coolant temperature sensor may be used. When the coolant reaches a certain temperature, the PCM changes the reference voltage to the sensor so it can read the coolant temperature with higher accuracy (higher resolution).