Ryder

Ryder

Having a senior moment
I am thinking about tapping into the oil pressure switch. This is for obvioiusl reasons that most of you will know already.

My question is....

Are we talking about a switch.... ie something that is on or off (ie digital)

Or an analog measure... (ie a resistor that would change it's value according to the pressure)?

Does it vary between vehicles?

Obviously I am looking at options to expand my own operation and this one has been askedby a potential customer to whom I can not give a satisfactory response without the proper investigation
 
oil pressure switch is on /off for light in dash ,oil pressure sender is variable resistance for guage (not fitted as std)
 
Oil pressure switches are used on plant equipment for low oil alert so yes you could do what your planning.
You may want to consider a diode or two as well
 
James... I did not really follow your answer but I am slightly typsy and will revisit in the morning!

If I can use a variable resisitor reading then all the better. It would allow me to report back the actual pressure of the oil and whether there is a trend of dropping.

If it is digital then ok....

Fanny.... why the diodes? I would have thought that running the feed through a couple of resistors (effectively restricting the supplied voltage to between 5 and 12 volts) would suffice.

However... my electronciery understanding is not yet at genius... or even capable level!
 
diodes will allow you to stop back feeding if say you wanted an earth through oil pressure switch with engine off to trigger electronic input to earth, but didn't want 12v up the electronics.
 
oil pressure switch is just that a switch its normally closed i.e circuit made.

The bulb in the dash has a live to it and then from the bulb to the pressure switch when ign is on when there is no pressure the plunger is not operated but the switch is closed i.e no pressure and illuminated bulb. When the oil pressure is raised then the plunger is operated and the switch goes to open circuit breaking the earth and turning the warning light off.


You can get a manifold for the oil switch which is errrrr smallish bsp thread from ebay or whereever and get a sender which is usually a variable resistor or thermisotr which is tuned or matched to a particular guage. you will need to find out what the reading is to calibrate your electronics to the sender I would think.

Jai

slightly blurry in one eye!
 
jai_landrover said:
You can get a manifold for the oil switch which is errrrr smallish bsp thread from ebay or whereever and get a sender which is usually a variable resistor or thermisotr which is tuned or matched to a particular guage.
Click to expand...

how is pressure converted to a changing temperature ?
 
Yea Blonde moment I did write temperature then rewrote it forgetting to wipe out thermistor lol

I(ts late been in the pub and I'm half blind well thats my excuse anyway Ryder scrub thermistor from the above. You can also monitor temperature if you so wish but pressure is best using a suitable sender and matched guage
 
the only pressure sensor (that gives an analogue rather than on/off) output are bulb type that require a capillary to the gauge - within the fancy digital gauges there will be a pressure ADC - I am yet to find a automotive (threaded type) sensor with built in ADC for direct connection to some form of data logger/display etc
 
No reason you couldn't use the switch, or put a T in and install your own electrical pressure sensor as well. (Mine's a bit more old school and has a switch and mechanical pressure gague Teed together)

There might be data you could get from the OBD if the vehicle has a more modern ECU. Oil pressure in in the CAN-Bus spec as far as I can see (1 byte, 1/25th bar per bit), but if anyone actually fits analog oil pressure gauges for the benefit of the ECU these days, I've no idea.
 
Ok... loads of great info...

The purpose of this project (at the risk of hearing spam calls) is because I want to be able to monitor the oil pressure remotely by setting a sensor to return oil pressure values to a central server. My reasoning is that a hire company, or expedition base station, may benefit from having advanced information that there are oil preasure issues prior to the engine failing at a nasty location.

I can effect this monitoring by arranging for a voltage to be delivered to my analog input. The voltage can vary from 0-5 volts according to pressure... once I have calibrated the return value I can set the unit to text a number... or set an alert off on the server if the oil pressure drops below a preset level while the ignition is on... I would have to stipulate a minimum time period for this situation to be maintained prior to reporting it otherwise there would be texts being sent back and forth every time the ignition is switched off or on.

I think it was fanny who was talking about using the diodes... but having had a think about it I don't see any benefit to measuring the oil preasure while the engine is not running since one would expect the preasure to be zero anyway. Hence operating the sensor without firing up the entire 12 volt system is not necessary.

This is all giving me further ideas of course. Tapping into the engine temperature sensor would offer similar benefit.... hmmm
 
Don't Formula One teams do all of this already?
If you can find out who makes systems for them you might save yourself from re-inventing the wheel.
 
I used to be involved with a company that started to develop telemetry systems for racing, there are loads now. Might be worth (Ryder) your while to check out some of these systems, they already collect the data easily enough, you just then need to transpose it to a more useful signal for what you want.

GEMS - General Engine Management Systems Ltd - Performance Electronic Systems
AIM Technologies - UK AIM Data Acquisition Product Distributor: Mychron 3, Mychron 4, GPS Module, DaVid, MXL Pista etc... For Karts, Cars, Bikes, Dragsters, and More
 
dogsbody said:
Don't Formula One teams do all of this already?
If you can find out who makes systems for them you might save yourself from re-inventing the wheel.
Click to expand...
Doubt if they would even acknowledge the idea of a round thing with tyres?
 
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