Prins VSI T2 sensor

[C3H8]

In another post Storm was curious about the pressure sensor specifications on the Prins VSI filter. This is a 4 wire sensor that measures both gas temperature and fuel rail pressure. It's operating range is 0 to 4 bar. It works on the standard we see for many automotive systems today which is a 5 volt reference signal signal. On this sensor the pin out is as follows.
Pin 1 Ground. Grounded through the map on a VSI but is shown as optional.
Pin 2 Temperature sensor signal
Pin 3 5 volt input
Pin 4 Pressure sensor signal.

Depending on what type of table might be required the pressure variations could be calculated quite fine depending on the sensor accuracy.

Is this what you wanted?

[storm]

Hi C3H8
Thanks for this information, just to clarify the sensor is on the regulator not the filter.
From this information my understanding is that it is just a sensor and does not have any other function in the system, is this correct?
If this is the case I can safely assume that the sensor itself does not need to be connected if it is not being run by a Prins ECU?
Take a close, you'll have to magnify it, look at this picture from the Profire website. I can't see any wiring connected to this sensor.

[C3H8]

That's the T1 sensor. It is actually a temperature sensor. The Prins ECU monitors it to determine if the regulator has reached 39 degrees C. Once it does the ECU signals the LPG injectors they can turn on. This sensor does not monitor pressure.

[storm]

Ah ok, I've never seen a picture of a filter with a sensor on it so I was unaware of the T2 sensor.
I can see no reason, apart from pressure, to not use another filter assembly as long as it can safely hold the pressure and has the same micron rating.

Let me elaborate my thoughts to explain things a bit better. My Toyota has a Holden 5.7 litre V8. The V8 is currently dual fuel (petrol injection and Gas Research throttle body). The ECU is a modified Delco 808 (similar to a Delco 1227165 from North America) that I can tune in real time using Kalmaker software (I can give a link if needed) on my laptop. The normal ECU loom would be modified to run either group of injectors at the flick of a switch by running an extra injector only loom and using the LPG switch to turn either injector loom on or off, the injection and timing tables in the ECU would change at the same time to run the tables setup for the selected fuel. Doing this keeps the vehicle dual fuel. On a very cold day (-10 overnight) I could use petrol and when the engine got to a certain temp (I can turn fans on and off so I'm assuming I can use the same function to turn fuel on and off) the ECU would switch over if the dash switch was set to LPG.

I have calculated the Injector rates required by Kalmaker for the various colour Prins Injectors and, as already mentioned, the last sticking point was the extra sensor(s). I do have 1 last question, it is something I was asked a couple of years ago but didn't know, what's the impedence of the Prins injectors? If they are low impedence injectors I'll have to get a driver box for them, if they are high impedence the Delco 808 should be able to run them no problem.

The car in its current setup has a range of over a 1000km. On Petrol I can get approx 400-450km (90 litres) and on LPG 550->600km (125 litres) with LPG injection I should be able to increase the fuel economy of LPG. The vehicle weighs about 3000 kilos so its no lightweight and is shaped like a brick. My tanks are nearly due, if not overdue, for their 10 year inspection. When funds permit (I have no money now because I just purchased AU-$1200 worth of Innovate Motorsport equipment) I would like to do this setup, there is no rush the vehicle is out of rego but it was my main tow vehicle for the horses and I will need it again later this year.

[C3H8]

The actual Prins site ( http://www.prinsautogas.com/en/products ... ctors.html ) specifies the injectors are low-resistance rated at 1.25 ohms. I also found this data on a site from a couple of years ago where another guy wants to use them but his petrol injectors were also high impedance. This is the link. http://www.msextra.com/forums/viewtopic ... 94&t=38789

This is the specification of Keihin LPG injectors listed on that link:
Operating voltage 6.3V tot 16V.
Current, Normal operation 4.0A peak, 1.5A hold, 6.0A limit.
Current, Cold start one shot og 8.0A peak.
Coil Resistance 1.25 ± 0.06? @ 20?C
Coil Inductance 3.5 mH @ 20?C

[C3H8]

One additional item. Keep in mind that the T2 temperature had an additional function. If the gas temperature suddenly dropped in the filter between the regulator and the fuel rail that meant the propane was starting to get past the regulator as a liquid. Prins has the T2 sensor in the filter and BRC has it in one of the fuel rails. The regulator has a limit as to how much fuel it can vapourize. On larger engines it was possible to exceed that limit on long uphill climbs especially towing heavy loads or if the regulator primary seat failed. The T2 temperature sensor was to protect the engine if the regulator failed and liquid propane got to the injectors. Usually the minimum temp allowed in the rail is -10C and then the ECU would switch it back to petrol.

[storm]

Thanks C3H8 you are a legend.