I am new here and this is my first post.
Here is my problem,
I want to replace the AFC(aneroid fuel control) on a P-pump cummins engine.
I would like to take input from boost pressure and engine RPM to control either a stepper motor or some type of variable distance solenoid(21mm thrust) to control fuel flow rather than the boost actuated AFC.
I am reading and researching this but i would appreciate any insight or direction for research or personal input.
I am not sure how much speed you can get out of a linear actuator, but that might be something that would equal a variable length solenoid.
What do modern diesel engines use for fuel control?
The 6BT Cummins 12 valve engine used the P-7100 injection pump and is controlled by boost actuated diaphram to limit the overall fuel to the motor until the turbo can create pressure.
Many people also take a more modern 24 valve cummins and put the old style pump on them.
A linear actuator is what i was trying to think of and i am unsure as to what speed it will need to move. i do know it needs to be able to travel 21mm though.
It is going to be difficult to help you with finding a fuel control valve that meets your needs here at a electronics site. However, if you can find something that would work and you need help connecting to it's electronics you are likely in the correct place.
My suggestion is to do more research on methods used to control fuel, using a electronics. Modern semi-trucks must have something that is fully electronic that perhaps can lead you in the direction of a solution.
cyclegadget,
there are three electronic devices on this engine; alternator, starter and fuel shutoff solenoid. The fuel control is a boost actuated diaphram with a push rod. No matter how much throttle you give it there will only be so much fuel delivered to the engine based on how much boost you have from the charger.
I want to create an electronic control system for as cheap as possible to test out on an engine i am currently building up.
Ill lay out what i think i need and you guys help me see if it is possible to do this.
Input: Manifold pressure(< 100psi), RPM (from cam position sensor), EGT(from thermocoupler for a safety shutoff and data logging)
Output: Precision control from a linear actuator for fuel with a 21mm throw and possibly an LCD readout stating the fuel valve percentage of movement.
When i say precision control i am not looking for stepper motor precision by any means. I do need to be able to take into account the manifold pressure and rpm to know how much to move the actuator.
any help and info is much appreciated
All the things you list are can be done with Arduino, finding the actuator you need can be a challenge without your parts in hand.
I am interested in the idea, so I spent some time searching. Is there anything on this page helpful? http://www.drakecontrols.com/Woodward-Engines-Diesel-Actuators
With such a small throw would an RC servo with, say, a 100mm connecting rod provide enough linearity of control for the job?
i need lateral movement from an actuator with position control. rotary stepper motors and servos will not be easy enough to work with in my opinion.
this pq12 seems to be exactly what i have been looking for. I have some more research to do on the original manual control valve for modification. the only thing that worries me is the force capable and the force necessary.
http://www.firgelli.com/products.php
My next question is a cheap pressure sensor capable of up to 100 psi for less than or near $100. Do the exist? I have been thinking of raping a digital tire pressure gauge from an auto parts store to keep the cost down. the only problem is if it will be reliable and responsive enough to satisfy my needs.
I have used these and they work well.
SSI have a range with different outputs, thread sizes etc.
well it seems i have all the information i need for now except which arduino i should use to run this? any ideas???
and thanks a bunch lemming that was exactly what i was needing and at the right price too!!!
the Arduino Uno seems to be what would work for my needs.
Would i need anything to connect the linear actuator, pressure sensor, and pyrometer to the arduino?
If i am correct i just need to plug in the wires and program it to do what i need...unless i have missed something
The pressure sensor will not plug directly into the Arduino, it requires at least 8volts. You will need to use your 12volt supply and a transistor/switch to turn it off and on, and a 250ohm resistor to convert the 4-20ma to 1 - 5 volts.
The actuator will require some sort of motor driver, possibly an H-bridge style but, I haven't look over the datasheet yet.
Hey mrgrimm, great project.
My daily driver is a 1998 Dodge Ram 2500 4x4 with a 12 valve Cummins, I haven't made any major changes, so shes basically all stock expect for the exhaust. However, out of curiosity, will you be doing any other tuning to your p-pump? Are you planning on just replacing the AFC diaphragm setup and controlling the foot directly?
Good luck and can't wait to see your progress.
Here is the force rating of the actuator: Maximum Force: 9-35N That is Newtons of force, which is not very much. I think you need a lot more but, I can only guess.
the whole goal of this project is to make these mechanical pumps easily tuned by electronics. right now it takes a lot of driving and stopping to tune these pumps. if we can design this and it works we will not require much force to push or pull the rod in the AFC. this will replace the rear cover of the AFC housing, eliminating the diaphragm and pre boost screw that is on the back, and also the spring that is behind the diaphragm.
cyclegadget
I noted the force for the linear actuator and i believe that 35 newtons will be enough for what we are looking to do. The linear actuator is not actually pushing on anything but rather setting the place of a stopblock that a fuel lever rides against during operation.
dropdeaddick
we are going to be testing this on an 01 P-Pumped 24valve. To be short it is nothing close to stock. My brother is the diesel nut and im the mad scientist fabricator so this should be an enjoyable project.
The linear actuator is not actually pushing on anything but rather setting the place of a stopblock that a fuel lever rides against during operation.
That's a key question: Just how much force does it take to position the stopblock etc. that the diaphragm moves now??
With 21mm of throw, one of the more powerful servos like this http://goo.gl/BnnPg with 9Kg/cm torque should be plenty. Why avoid a rotary-to-linear mechanism when you will be calibrating all this in software anyway?
As I recall the injector pump control on some stationary diesels I worked on, there wasn't much force needed to move the control.
But I don't know your engine/pump ...
This is a very interesting project
I have a question about the 100 psi pressure transdusor
Is this xdusor to measure the turbo boost ?
On my Ford diesel the maximum boost is only about 25- 30 psi under max power
so why the 100 psi xdusor ? or is this (modified?) diesel getting really high boost presures ?
I hope you keep us posted on this project
terryking228
i am avoiding the complexity of a rotary to linear actuator for simplicity reasons. the less moving parts on this project the easier it will be for me to make it work effectively.
solarpanels
this will be going on a modified cummins. currently we are dealing with 60+ psi boost on a single charger with plans of compound twins. the end result will be a plug and play fuel control system that we can offer the 12 valve cummins community without breaking their bank.
MrGrimm, what kind of applications are these high-boost engines typically going into? Why is throttle response highly important?