DPF Pressure sensor with single input
Discussion
Just a quickie really
Normally, a differential pressure sensor, used for pre/post DPF pressure and thus a way to measure DPF loading has 2 prongs on it. 2 prongs, for two pressure sample points.
But the car we have, just has a single pressure sample point and the sensor has a single input prong. yet it is still referred to as a DP sensor.
So
Either they compare this value to the barometric pressure from the ECU and its a DP sensor in software only.... OR.... It is actually a DP sensor, but the second input is a baro reference inside the unit itself.
But I can't confirm this. The part number is 227709604R
If anyone can shed some light on how that sensor works that would be amazing because I am coming up stuck and I can't find a datasheet or anything for that kind of sensor.
Normally, a differential pressure sensor, used for pre/post DPF pressure and thus a way to measure DPF loading has 2 prongs on it. 2 prongs, for two pressure sample points.
But the car we have, just has a single pressure sample point and the sensor has a single input prong. yet it is still referred to as a DP sensor.
So
Either they compare this value to the barometric pressure from the ECU and its a DP sensor in software only.... OR.... It is actually a DP sensor, but the second input is a baro reference inside the unit itself.
But I can't confirm this. The part number is 227709604R
If anyone can shed some light on how that sensor works that would be amazing because I am coming up stuck and I can't find a datasheet or anything for that kind of sensor.
When it's clear from googling that there is clearly a standard 3 pin terminal on it....why are you referring to a single prong ?
Or do you mean the hose barb ?
It most likely is just referencing to ambient ( via sensor elsewhere ) if there is only one sensor prior to the DPF....which is still a differential between before and after, which should be ambient/baro.
Or maybe there is an opening within the housing for the ambient reference.
No big deal either way....is the sensor working or not, or what is the actual problem ?
Or do you mean the hose barb ?
It most likely is just referencing to ambient ( via sensor elsewhere ) if there is only one sensor prior to the DPF....which is still a differential between before and after, which should be ambient/baro.
Or maybe there is an opening within the housing for the ambient reference.
No big deal either way....is the sensor working or not, or what is the actual problem ?
stevieturbo said:
When it's clear from googling that there is clearly a standard 3 pin terminal on it....why are you referring to a single prong ?
Or do you mean the hose barb ?
It most likely is just referencing to ambient ( via sensor elsewhere ) if there is only one sensor prior to the DPF....which is still a differential between before and after, which should be ambient/baro.
Or maybe there is an opening within the housing for the ambient reference.
No big deal either way....is the sensor working or not, or what is the actual problem ?
Yes, barb for connecting a hose. Sorry wrong choice of word.Or do you mean the hose barb ?
It most likely is just referencing to ambient ( via sensor elsewhere ) if there is only one sensor prior to the DPF....which is still a differential between before and after, which should be ambient/baro.
Or maybe there is an opening within the housing for the ambient reference.
No big deal either way....is the sensor working or not, or what is the actual problem ?
I know its only needs to have 3 pins on the plug (grnd, signal and supply)
But its referred to as a Delta Pressure sensor in the ECU and yet its only got 1 pressure sampling point. I have pulled it from the car and had a look. I cannot see an ambient reference on it anywhere. So I guess they are using the ECU baro sensor as the other side?
The problem, is a unique one to what we are doing. We have some equipment that can simulate altitude without having to use a barometric chamber. It involves hooking the air box and exhaust up to a machine that can then supply air at whatever pressure we like. We need to make sure certain bits of the air path are sealed and we have had to make sure the ECU is sealed as best we can as well as referencing the ECU to the machine so that it reads the pressure correctly.
Something, somewhere is not working right as the car flags a Low DPF pressure warning. My theory was that the sensor had an ambient reference in it and because this is still at room pressure, when we drop the pressure in the exhaust it confuses the ECU into thinking there is a hole in the DPF. ( i think I might need to draw a diagram out to think about that). Or, because of pressure fluctuations (ECU is referenced to the airbox) reaching the sensors at different times there is a temporary reversal of which pressure is lower/higher and this is causing the error.
Either way, we think the ECU has essentially lost track of how full the DPF actually is and now its become damaged as the PN emissions have risen considerably. Its a SiC filter, so it should be very hard to melt, but having read around it appears it is possible to inflict pin-hole melt damage at much lower temps than the melting point if the right ingredients are present inside.
Sorted it
Sensor has a single input for the DPF, but if you pop the top casing off of the sensor (very easy to do) you can see that there is a channel and some electronics encapsulated under a clear, gel-like membrane. It is clear that this is the ambient reference for the sensor.
So this should be referenced to our altitude kit as well, otherwise, its possible that exhaust pressure > ambient pressure at low load and at high load exhaust pressure is lower than it usually would have been under normal ambient conditions.
I can't divulge how the DPF loading is modelled, suffice to say it this has messed them up and its likely that a regen has happened with an overloaded filter and that has caused thermal damage.
Sensor has a single input for the DPF, but if you pop the top casing off of the sensor (very easy to do) you can see that there is a channel and some electronics encapsulated under a clear, gel-like membrane. It is clear that this is the ambient reference for the sensor.
So this should be referenced to our altitude kit as well, otherwise, its possible that exhaust pressure > ambient pressure at low load and at high load exhaust pressure is lower than it usually would have been under normal ambient conditions.
I can't divulge how the DPF loading is modelled, suffice to say it this has messed them up and its likely that a regen has happened with an overloaded filter and that has caused thermal damage.
Otispunkmeyer said:
Yes, barb for connecting a hose. Sorry wrong choice of word.
I know its only needs to have 3 pins on the plug (grnd, signal and supply)
But its referred to as a Delta Pressure sensor in the ECU and yet its only got 1 pressure sampling point. I have pulled it from the car and had a look. I cannot see an ambient reference on it anywhere. So I guess they are using the ECU baro sensor as the other side?
The problem, is a unique one to what we are doing. We have some equipment that can simulate altitude without having to use a barometric chamber. It involves hooking the air box and exhaust up to a machine that can then supply air at whatever pressure we like. We need to make sure certain bits of the air path are sealed and we have had to make sure the ECU is sealed as best we can as well as referencing the ECU to the machine so that it reads the pressure correctly.
Something, somewhere is not working right as the car flags a Low DPF pressure warning. My theory was that the sensor had an ambient reference in it and because this is still at room pressure, when we drop the pressure in the exhaust it confuses the ECU into thinking there is a hole in the DPF. ( i think I might need to draw a diagram out to think about that). Or, because of pressure fluctuations (ECU is referenced to the airbox) reaching the sensors at different times there is a temporary reversal of which pressure is lower/higher and this is causing the error.
Either way, we think the ECU has essentially lost track of how full the DPF actually is and now its become damaged as the PN emissions have risen considerably. Its a SiC filter, so it should be very hard to melt, but having read around it appears it is possible to inflict pin-hole melt damage at much lower temps than the melting point if the right ingredients are present inside.
So, for whatever reason you are reducing the intake side of the engine to below barometric pressure ?I know its only needs to have 3 pins on the plug (grnd, signal and supply)
But its referred to as a Delta Pressure sensor in the ECU and yet its only got 1 pressure sampling point. I have pulled it from the car and had a look. I cannot see an ambient reference on it anywhere. So I guess they are using the ECU baro sensor as the other side?
The problem, is a unique one to what we are doing. We have some equipment that can simulate altitude without having to use a barometric chamber. It involves hooking the air box and exhaust up to a machine that can then supply air at whatever pressure we like. We need to make sure certain bits of the air path are sealed and we have had to make sure the ECU is sealed as best we can as well as referencing the ECU to the machine so that it reads the pressure correctly.
Something, somewhere is not working right as the car flags a Low DPF pressure warning. My theory was that the sensor had an ambient reference in it and because this is still at room pressure, when we drop the pressure in the exhaust it confuses the ECU into thinking there is a hole in the DPF. ( i think I might need to draw a diagram out to think about that). Or, because of pressure fluctuations (ECU is referenced to the airbox) reaching the sensors at different times there is a temporary reversal of which pressure is lower/higher and this is causing the error.
Either way, we think the ECU has essentially lost track of how full the DPF actually is and now its become damaged as the PN emissions have risen considerably. Its a SiC filter, so it should be very hard to melt, but having read around it appears it is possible to inflict pin-hole melt damage at much lower temps than the melting point if the right ingredients are present inside.
But you are leaving the exhaust discharge at atmospheric ? That's bound to cause issues regardless ?
Can you also reduce the exhaust discharge point to the same pressure environment as the intake ?
I would imagine the exhaust gas is exposed to altitude conditions but the sensor body isn't
To crack/melt SiC you don't have to let the soot load get too much higher than the modelled value to be fair, and it could have been gaining soot load quickly at altitude conditions depending on the tuning and what testing you were doing
To crack/melt SiC you don't have to let the soot load get too much higher than the modelled value to be fair, and it could have been gaining soot load quickly at altitude conditions depending on the tuning and what testing you were doing
Benrad said:
I would imagine the exhaust gas is exposed to altitude conditions but the sensor body isn't
To crack/melt SiC you don't have to let the soot load get too much higher than the modelled value to be fair, and it could have been gaining soot load quickly at altitude conditions depending on the tuning and what testing you were doing
Yes, exhaust is also connected to the high altitude air source (I actually said so in my previous post and there would be no way for the DP sensor reading to be screwed up if the exhaust wasn’t connected). Essentially the machine is a box of turbos and it generates a stream or river of air at the desired conditions and then you attach the car intake and exhaust to it. The car then just takes what it needs from the flow and the machine is quick enough to compensate for the hard accelerations.To crack/melt SiC you don't have to let the soot load get too much higher than the modelled value to be fair, and it could have been gaining soot load quickly at altitude conditions depending on the tuning and what testing you were doing
We have the ecu and air box sealed, all soft pipe work reinforced. But hadn’t realised about the dpf sensor. It’s tucked away, Out of sight out of mind. So we need to sort out how to encapsulate it.
Yes, I had assumed we hadn’t melted the dpf because it was a SiC filter, but I found some papers that suggest it’s entirely possible to do so even at much lower temps of 800degC. Guy at work told me today they have damaged filters before with thermal runaway events and that they basically skyrocket so fast you can’t stop it, temps easily exceeding 1200.
Given the amount of time between regens, I think it’s safe to say it was probably quite overloaded.
Edited by Otispunkmeyer on Thursday 8th October 23:36
Edited by Otispunkmeyer on Thursday 8th October 23:39
Otispunkmeyer said:
Yes, exhaust is also connected to the high altitude air source (I actually said so in my previous post and there would be no way for the DP sensor reading to be screwed up if the exhaust wasn’t connected). Essentially the machine is a box of turbos and it generates a stream or river of air at the desired conditions and then you attach the car intake and exhaust to it. The car then just takes what it needs from the flow and the machine is quick enough to compensate for the hard accelerations.
We have the ecu and air box sealed, all soft pipe work reinforced. But hadn’t realised about the dpf sensor. It’s tucked away, Out of sight out of mind. So we need to sort out how to encapsulate it.
Yes, I had assumed we hadn’t melted the dpf because it was a SiC filter, but I found some papers that suggest it’s entirely possible to do so even at much lower temps of 800degC. Guy at work told me today they have damaged filters before with thermal runaway events and that they basically skyrocket so fast you can’t stop it, temps easily exceeding 1200.
Given the amount of time between regens, I think it’s safe to say it was probably quite overloaded.
Just relocate the DPF sensor inside the airbox ?We have the ecu and air box sealed, all soft pipe work reinforced. But hadn’t realised about the dpf sensor. It’s tucked away, Out of sight out of mind. So we need to sort out how to encapsulate it.
Yes, I had assumed we hadn’t melted the dpf because it was a SiC filter, but I found some papers that suggest it’s entirely possible to do so even at much lower temps of 800degC. Guy at work told me today they have damaged filters before with thermal runaway events and that they basically skyrocket so fast you can’t stop it, temps easily exceeding 1200.
Given the amount of time between regens, I think it’s safe to say it was probably quite overloaded.
Edited by Otispunkmeyer on Thursday 8th October 23:36
Edited by Otispunkmeyer on Thursday 8th October 23:39
stevieturbo said:
Otispunkmeyer said:
Yes, exhaust is also connected to the high altitude air source (I actually said so in my previous post and there would be no way for the DP sensor reading to be screwed up if the exhaust wasn’t connected). Essentially the machine is a box of turbos and it generates a stream or river of air at the desired conditions and then you attach the car intake and exhaust to it. The car then just takes what it needs from the flow and the machine is quick enough to compensate for the hard accelerations.
We have the ecu and air box sealed, all soft pipe work reinforced. But hadn’t realised about the dpf sensor. It’s tucked away, Out of sight out of mind. So we need to sort out how to encapsulate it.
Yes, I had assumed we hadn’t melted the dpf because it was a SiC filter, but I found some papers that suggest it’s entirely possible to do so even at much lower temps of 800degC. Guy at work told me today they have damaged filters before with thermal runaway events and that they basically skyrocket so fast you can’t stop it, temps easily exceeding 1200.
Given the amount of time between regens, I think it’s safe to say it was probably quite overloaded.
Just relocate the DPF sensor inside the airbox ?We have the ecu and air box sealed, all soft pipe work reinforced. But hadn’t realised about the dpf sensor. It’s tucked away, Out of sight out of mind. So we need to sort out how to encapsulate it.
Yes, I had assumed we hadn’t melted the dpf because it was a SiC filter, but I found some papers that suggest it’s entirely possible to do so even at much lower temps of 800degC. Guy at work told me today they have damaged filters before with thermal runaway events and that they basically skyrocket so fast you can’t stop it, temps easily exceeding 1200.
Given the amount of time between regens, I think it’s safe to say it was probably quite overloaded.
Edited by Otispunkmeyer on Thursday 8th October 23:36
Edited by Otispunkmeyer on Thursday 8th October 23:39
Otispunkmeyer said:
Yeah, one of the ideas. But we might just make a little tube for it to go in or use one of those little electronics boxes you can get from RS. Just get one with a waterproof gasket on the lid and use some grommets to pass stuff in/out and a lot of sealant!
Should be easy to seal it into the air filter box really, pre-filter ?One fitting is just a hose tail...dead easy. And making a wiring pass through or bulkhead connector is again easy.
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