HOW TO USE LABVIEW TO EXERT PRESSURE

[jamran]

HI guys. im new to the site and labview so please excuse my ignorance. we are currently working on a diesel engine and want to convert it to run on a common rail fuel injector.

now we got hold of a common-rail fuel pump and injector from a factory a few years back. Now ive been working on it to get it to run. the problem ive found out is that like all modern enigines everything is controlled by the ECU(engine control unit). As siemens ECU's cannot be tweaked and an after market ECU is out of our budget, I am thinking to use labview to control the fuel injector and pump. at the momment im just concentrating on the pump. it has 3 control valves/electrical componnents. 1 is a pressure control valve, the other a volume control valve and 3rd one is the component on the common rail itself. NOw what we think happens is the pump generates pressure and when the software tells it to open or switch on it does so and the volume control valve opens when the ecu/labview tells it to and then when the fuel flows through pressure the common rail also opens and closes when the fuel needs tro get to the fuel injector.

so basically, what i need to do is control when the volume and pressure via labview. Any ideas? ive seen labview record pressure etc but how can this be done??

im SORRY IF IVE BEEN A BIT CONFUSING.

Message Edited by jamran on 12-15-2008 04:58 AM

[AdnanZ]

How exactly will you be communicating with the pump from the computer? Are you using a communication protocol or using some signals?

[jamran]

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Adnan Z wrote:
How exactly will you be communicating with the pump from the computer? Are you using a communication protocol or using some signals?

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the electrical components on the pump are 12v power supplys which have to be connected to the ecu. i think the ecu only gives it a power supply as and when it needs to open. if you want to answer between the 2 u have given me its gonna be signals.

 thanks

[Broken_Arrow]

jamran,

Your question is very high-level, and likely the responses to it will be as well. Pressure is measured with LabVIEW via a signal or a TE protocol or some communication with a device. Hence the first answer to the post was spot-on - we need to know what the interface is. So we know it's a signal. An anlaog signal is read with a DAQ or some type of board that has an analog input. The board connects to LabVIEW via serial, GPIB, PXI, SCXI, etc etc.

It might help to understand that LabVIEW doesn't measure anything. It's a programming language. Circuit boards (instruments) measure things.

[jamran]

thanks guys.

Ive got some more info of what im trying to do.

Firstly from the engine there is 2 types of data/.signals that are being transmitted to the DAQ. Firslty, the shaft encoder signal. This is connected to the crankshaft and in a full revolution it sends 5000 signals to the DAQ. This tells us where exactly the piston is in the engine. The second is the Top Dead Centre Indicator. As its name it lets us no when the piston is in the top. Now what we have to do is get the injector to inject at a certain time. or the injector to open at acertain time and close a certain time. That is before the piston reaches top dead centre and using the shaft enconder sig nal will know where the pistin is and just before it reaches the centre at a certain degree tell it to open and after a certain dgree past the TDC close.

Now it terms of the program, I want it to take the info from the DAQ and using both these signals the user can put in a certain degree it should open and close ( so thats 2 boxes to stick a number in on the front panel- 1 for what degree to open and the other when to close) and the Labview should send a signal to the DAQ telling it exaclty when to open and when to close. Then at that time the power isgiven to the Fuel pump, it generates the presurre and then transfers the fuel to the injector.

I hope i havent confused you guys burt this is basicaly what im trying to do.

please can anyone help me out???

many thanks

[RavensFan]

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