Grease car heater controller project
dherde
Posts: 13
HI..
I thought I would post up the current project and see if anyone has a wheel that I won't have to recreate.
I am converting a 1995 Mercedes E300d to run on waste french fry grease. A single tank conversion.
To do this, I have installed an electric resistance heater wrap on the fuel injector tubes to final preheat the grease and put some thermistors in so I can monitor the temp of what is going into each injector. On the control side, I will be PWM controlling the current to the heater wrap so it will stay constant at oh.. 180 degrees. Thence to reduce current so the heater is not always sucking on the battery.
I have the thermistor circuits done. I am in need of a good circuit to safely control the15 amp heater current. I expect I will be PWM one or more Enhancement mode MOSFETs, but if there is a better way I would sure like to know about it.
I will also have a simple display and input module in the cabin.
I am real new to the propeller (and haven't worked with microcontrollers for a long time) and was wondering about the following:
Since I need two physical modules, one in the engine to read sensors and control the high current aspect of the heater, and one in the cabin to process info, receive driver input and send out heater control, is it better to use a microcontroller in each module that just talk or just have one controller (propeller) and use more wires between the modules?
I figure 4 wires to communicate to the ADC0838, one for the PWM signal to the heater power and a ground. is all I need. That is one cat5 cable with room to grow. Does this make more sense than running two uPs and just sharing data?
Is there a way to reduce the number of wires? (I expect I can if I use 2 micro controllers, but is it worth it?)
Should I design the circuit boards to accommodate both scenarios? Is this a lot more work for no particular reason? Would anyone be interested in the resultant board?
Is there an existing board out there that can communicate with a propeller quickstart and do the ADC and High current control?
Are there inexpensive pre-made (and maybe populated) propeller board that is cheaper than the quickstart?
On a different related subject, If I am powering the Quickstart from the battery of the car and plug in the USB connection, will I fry something (Like my laptop)?
Lots of things to chew on.
Thanks for any input.
I thought I would post up the current project and see if anyone has a wheel that I won't have to recreate.
I am converting a 1995 Mercedes E300d to run on waste french fry grease. A single tank conversion.
To do this, I have installed an electric resistance heater wrap on the fuel injector tubes to final preheat the grease and put some thermistors in so I can monitor the temp of what is going into each injector. On the control side, I will be PWM controlling the current to the heater wrap so it will stay constant at oh.. 180 degrees. Thence to reduce current so the heater is not always sucking on the battery.
I have the thermistor circuits done. I am in need of a good circuit to safely control the15 amp heater current. I expect I will be PWM one or more Enhancement mode MOSFETs, but if there is a better way I would sure like to know about it.
I will also have a simple display and input module in the cabin.
I am real new to the propeller (and haven't worked with microcontrollers for a long time) and was wondering about the following:
Since I need two physical modules, one in the engine to read sensors and control the high current aspect of the heater, and one in the cabin to process info, receive driver input and send out heater control, is it better to use a microcontroller in each module that just talk or just have one controller (propeller) and use more wires between the modules?
I figure 4 wires to communicate to the ADC0838, one for the PWM signal to the heater power and a ground. is all I need. That is one cat5 cable with room to grow. Does this make more sense than running two uPs and just sharing data?
Is there a way to reduce the number of wires? (I expect I can if I use 2 micro controllers, but is it worth it?)
Should I design the circuit boards to accommodate both scenarios? Is this a lot more work for no particular reason? Would anyone be interested in the resultant board?
Is there an existing board out there that can communicate with a propeller quickstart and do the ADC and High current control?
Are there inexpensive pre-made (and maybe populated) propeller board that is cheaper than the quickstart?
On a different related subject, If I am powering the Quickstart from the battery of the car and plug in the USB connection, will I fry something (Like my laptop)?
Lots of things to chew on.
Thanks for any input.
Comments
The heater control stuff is well known. I was exposed to this type of circuit on the Mendel Prusa 3D printer. There's a bit of toaster heating element wrapped around a nozzle, and 100k thermistor next to it. Look up RepRap Electronics, you might be able to copy a lot of that. It easily keeps the medium at 180c withing a couple degrees, and can go up to about 300c I think.
There are a bunch of guys that make boards. You might have luck if you look at two separate modules first, one for ADC and one for high current.
Nothing yet cheaper than the quickstart, BUT if you have a bread board and propchip and misc parts you can throw together your own on a bread board, that is the most flexible until you know exactly what you want solder together. Typically a design for an complex and specific application might change a couple time during development, take is slow and in steps.
The quickstart and the laptop SHOULD be ok if the grounds are connected I think, but I never tried it. Some other folks will chime in as they see this discussion.
Cool project, keep us posted, I want one on MY car!
You will need to regulate the car 12V down to 5V for the quickstart board. I would advise using one of the heftier regulator like the ones in a TO220 package. Same for the adc and heater control circuitry.
The only concern I have about running wires from the micro in the cabin to the adc/heater control in the engine compartment would be noise pickup. With no spark ignition system diesels will not be as noisy as a gas engine but there will still be some noise generated. For this reason the heater circuitry should be separate from the adc portion. Keep the pwm frequency low and take the adc readings between the pwm on/off transitions.
A little off topic, but how many miles do you have on the engine? I also have a '95 E300D (~230k miles); the few times I've has something wrong with the engine, the first anyone asks me is if I've been running grease in it. My original intention was to convert it, but I fell in love with that OM606 engine and can't bring myself to it. Are you expecting decent life out of it?
A - "You smellin' fries?"
I guess that'd be OK for a Kombi, you'd almost expect as much, but ignominy for a M-B (no offence) - unless it's salvage, of course.
I heard (couple years ago, lost the links) of a guy running a gas-turbine engine on discarded restaurant cooking grease, which turns a generator and powers an electric car. Everywhere he goes smells like fast food for blocks! That's gotta tick off the neighbors just the same whether its a Mini or a Cadillac. I must have one!
Can't see how a turbine can be efficient (can't be responsive enough without having /wasting a lot of power overhead), but It has a BIG wow factor. I have personally never actually smelled fries cooking in a fast food restaurant, but it surely has a distinctive smell out of the back of the car.
Have you replaced all your fuel hoses yet? I spoke with a fellow a couple days ago who converted his 300 to fry oil, and he's gradually having to phase in Viton hoses as the stock rubber hoses deteriorate.
-Phil