projectBuilder
Posts: 1
Joined: Sun Apr 14, 2019 9:46 am

engine fuel vacuum gauge

Sun Apr 14, 2019 10:02 am

Hi All,

I want to fit a vacuum pressure gauge to the fuel filter of a large marine diesel and monitor it via my rPi.

The purpose being to monitor the vacuum required to draw fuel from the tank and thru the filter. A high reading (very low pressure) will indicate blocked filter or fuel pickup (a recurrent problem :shock: )

If I can get a sensor reading to the rpi I should be able to make it available via OpenPlotter (https://docs.sailoog.com/openplotter-v1-x-x/) to my instruments.

My query is where should I look for an appropriate sensor? It needs to read 0 to minus 30 in Hg or 0 to -1 bar, fit securely to a vital fuel line, inured to diesel and obviously output in a form that can be readily converted to something the rpi can understand.

Grateful for any pointers.

L

User avatar
omegaman477
Posts: 148
Joined: Tue Feb 28, 2017 1:13 pm
Location: Sydney, Australia

Re: engine fuel vacuum gauge

Wed Apr 17, 2019 12:25 pm

projectBuilder wrote:
Sun Apr 14, 2019 10:02 am
Hi All,

I want to fit a vacuum pressure gauge to the fuel filter of a large marine diesel and monitor it via my rPi.

The purpose being to monitor the vacuum required to draw fuel from the tank and thru the filter. A high reading (very low pressure) will indicate blocked filter or fuel pickup (a recurrent problem :shock: )

If I can get a sensor reading to the rpi I should be able to make it available via OpenPlotter (https://docs.sailoog.com/openplotter-v1-x-x/) to my instruments.

My query is where should I look for an appropriate sensor? It needs to read 0 to minus 30 in Hg or 0 to -1 bar, fit securely to a vital fuel line, inured to diesel and obviously output in a form that can be readily converted to something the rpi can understand.

Grateful for any pointers.

L
It must be a purpose made pressure transducer, designed for long term diesel service.

Most of these car style engine pressure sensors return a variable resistance of 10-180 ohms, set up in a basic resistor divider, fed with say 5V you will get a voltage swing of say 2 volts min to max, according to the pressure. Feed this to a basic AD hat on the RPI and you will be good.

There are digital industrial sensors around that produce encoded TTL streams with the pressure value, some also send ASCII text data. Obviously more expensive.

Usually filter efficiency is measured by two pressure sensors, one either side of the filter, then calculate the differential in software. Two sensors give redundancy for the software to detect a sensor failure.
..the only thing worse than a stupid question is a question not asked.

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