1 Steam Cars : Phorum
General Steam Car topics
Fuel Injection
Posted by: Peter Heid (IP Logged)
Date: February 15, 2002 05:59PM
<HTML>All,
I have been watching with great interest as the burner issue grows here at the forum. The low pressure or vaporizing burner seems to be a strong contender in the field and it appears much research has been completed, and maybe even lost, on this seemingly simple device. I have heard many pros and cons of pressure atomizing burners also and I am glad to see a 12v burner assembly available to the experimenting public. The discussion of on/off versus variable rate burners could also continue for ever, maybe with no clear winner. I think everyone is pretty much headed toward the same goals: clean burning, no residual fuel to smoke upon starting or stopping, adequate heat available to match the system needs through the entire range of operation, fuel efficiency, and low system power consumption as well as other factors such as noise levels and efficient operation in all climates. Another consideration to fuel system development is the SHED (sealed housing emission determination) test all new vehicles must be subjected to. What this does is measures the HC and VOC emissions from a non-running vehicle, and fuel injection, being a sealed system does not add to these emissions. This is a very sensitive and critical test and I have seen BMW motorcycles rejected because the vinyl seat covers were out gassing to much.
Before I proceed, a word of caution for those of us uninitiated in the safety of the system of which I speak.
1) Always wear eye protection when inspecting or working on pressurized fuel systems !
2) Bleed all pressurized fuel systems as per manufacturer instructions !
3) Never touch an automotive or other high amp battery terminal when wearing any metal !
Now back to the fun. The crazy thought I want to share today comes from my old world, the IC world. Imagine if you will, remember I am imagining this also, the use of a mechanical or electronic fuel injection system to control the fuel/air ratio feeding the burner. The bosch “K” mechanical injection system was my top contender in the field. The K system has been in use for over 30 years with few limitations and little refinement necessary on Volvos, VWs, Saabs and others. The system uses a throttle plate that measures air flow and varies the fuel rate directly by moving a metering needle in the fuel distributor. The metering needle uncovers laser cut slots, for exactly equal proportioning, that feed each injector. The throttle plate is dampened by piston/cylinder assembly fed by a pressure regulated control circuit the fuel distributor. The injectors in this system are opened by the fuel pressure, so if no air were flowing, the metering needle would block the flow to the injectors preventing them from operating. When off, there is no drip or leakage and when pressure is available to open the injector, the pressure is also adequate for the complete atomization of the fuel allowing start stop operation with very little unburnt fuel. The damping circuit has a warmup pressure regulator in the line to allow changes in the fuel air ratio during times of cold engine operation on the IC engine. The control pressure regulators on some autos includes an electric heater to speed the warmup of the regulator beyond the rate provided by the heat of exterior of the engine.
I see no reason why the original injectors as well as most of the Bosch system can’t be retained for use in the construction of a steam burner/boiler. The fuel flow rates can go from about 2MPG to above 30MPG on autos with IC engines which should be satisfactory for most steam applications. I have been quite set on the on/off type of burner for my use because it is hard to vary the fire box size to match the fuel burnt for maximum efficiency but this system could be used as a variable system as designed, an on/off system, or even operated in steps depending on the number of installed injectors (from a 4 or 6 cyl) that you feed with fuel. The warmup or control pressure regulator could easily be used to switch from one fuel to another by varying the temperature because this changes the control pressure which directly alters the air fuel ratio.
For very fine adjustments, the Bosch K system uses a feed back loop (lambda sonde I think it is called) in the control pressure circuit on versions produced from about 1979 on. The exhaust gas components are measured by an oxygen sensor that provides a tiny electrical potential to a computer which in turn regulates the control pressure by varying the duty cycle of a 12V solenoid valve in the control circuit. This is a super fine adjustment, if you were to unplug the oxygen sensor while a car is running and with one hand, touch the wire leading to the computer from the sensor, and with the other hand, touch the positive battery terminal, the fuel air ratio will go to richest point in the closed loop. Touch the negative terminal instead and it goes to the leanest point allowed by the loop and at an idle you can just hear the difference between the two points. If the closed loop was used, a failure of the that portion of the system such as the computer or frequency valve, would not impair or disable the vehicle except to increase the emissions.
This system does an excellent job of controlling air fuel ratios and is considered clean burning by today’s emission standards and the main causes of failure are dirt or water that remains in the fuel long enough to cause corrosion. The main reasons the K system are no longer specified on new cars involves the slight air flow restriction and slightly slow action of the throttle plate and the fact that the injectors are constantly firing into the manifold unlike the timed, cylinder injection of the newer electronic Bosch L system. Both issues don’t seem to be a concern when using the system to fire a burner but that doesn’t mean the newer electronic systems can not be used also.
The servicing of the K system involves few tools which include a pressure gauge to check injection & control pressure as well as leak down, a dwell meter to check the duty cycle of the frequency valve, a tiny allen wrench (2mm I think) to adjust the basic position of the metering needle in relation to the throttle plate, and a volt ohm meter completes the package of special tools needed. Several manuals are available on the various injection systems from companies like Haynes or Clymer and bosch produces their own work shop manuals also.
The fuel pump on most injected autos is in the fuel tank and it can be an expensive item to replace and since they use the fuel for lubrication and coolant, they don’t tolerate many dry runs or water corrosion. Of course the pumps are of electric in operation and although the power consumption is low, any device that adds to the overall power consumption of the vehicle can not be over looked. The volume and pressure required can be provided by an oil burner pump such as the sunstrand if the electric pump won’t fit the proposed design.
In conclusion (finally) I think this technology has the five abilities I most desperately desire in parts I choose for my system design, Availability, Affordability, Adaptability, Adjustability and Dependability.
Sorry I drag these things out so much
Peter Heid</HTML>
I have been watching with great interest as the burner issue grows here at the forum. The low pressure or vaporizing burner seems to be a strong contender in the field and it appears much research has been completed, and maybe even lost, on this seemingly simple device. I have heard many pros and cons of pressure atomizing burners also and I am glad to see a 12v burner assembly available to the experimenting public. The discussion of on/off versus variable rate burners could also continue for ever, maybe with no clear winner. I think everyone is pretty much headed toward the same goals: clean burning, no residual fuel to smoke upon starting or stopping, adequate heat available to match the system needs through the entire range of operation, fuel efficiency, and low system power consumption as well as other factors such as noise levels and efficient operation in all climates. Another consideration to fuel system development is the SHED (sealed housing emission determination) test all new vehicles must be subjected to. What this does is measures the HC and VOC emissions from a non-running vehicle, and fuel injection, being a sealed system does not add to these emissions. This is a very sensitive and critical test and I have seen BMW motorcycles rejected because the vinyl seat covers were out gassing to much.
Before I proceed, a word of caution for those of us uninitiated in the safety of the system of which I speak.
1) Always wear eye protection when inspecting or working on pressurized fuel systems !
2) Bleed all pressurized fuel systems as per manufacturer instructions !
3) Never touch an automotive or other high amp battery terminal when wearing any metal !
Now back to the fun. The crazy thought I want to share today comes from my old world, the IC world. Imagine if you will, remember I am imagining this also, the use of a mechanical or electronic fuel injection system to control the fuel/air ratio feeding the burner. The bosch “K” mechanical injection system was my top contender in the field. The K system has been in use for over 30 years with few limitations and little refinement necessary on Volvos, VWs, Saabs and others. The system uses a throttle plate that measures air flow and varies the fuel rate directly by moving a metering needle in the fuel distributor. The metering needle uncovers laser cut slots, for exactly equal proportioning, that feed each injector. The throttle plate is dampened by piston/cylinder assembly fed by a pressure regulated control circuit the fuel distributor. The injectors in this system are opened by the fuel pressure, so if no air were flowing, the metering needle would block the flow to the injectors preventing them from operating. When off, there is no drip or leakage and when pressure is available to open the injector, the pressure is also adequate for the complete atomization of the fuel allowing start stop operation with very little unburnt fuel. The damping circuit has a warmup pressure regulator in the line to allow changes in the fuel air ratio during times of cold engine operation on the IC engine. The control pressure regulators on some autos includes an electric heater to speed the warmup of the regulator beyond the rate provided by the heat of exterior of the engine.
I see no reason why the original injectors as well as most of the Bosch system can’t be retained for use in the construction of a steam burner/boiler. The fuel flow rates can go from about 2MPG to above 30MPG on autos with IC engines which should be satisfactory for most steam applications. I have been quite set on the on/off type of burner for my use because it is hard to vary the fire box size to match the fuel burnt for maximum efficiency but this system could be used as a variable system as designed, an on/off system, or even operated in steps depending on the number of installed injectors (from a 4 or 6 cyl) that you feed with fuel. The warmup or control pressure regulator could easily be used to switch from one fuel to another by varying the temperature because this changes the control pressure which directly alters the air fuel ratio.
For very fine adjustments, the Bosch K system uses a feed back loop (lambda sonde I think it is called) in the control pressure circuit on versions produced from about 1979 on. The exhaust gas components are measured by an oxygen sensor that provides a tiny electrical potential to a computer which in turn regulates the control pressure by varying the duty cycle of a 12V solenoid valve in the control circuit. This is a super fine adjustment, if you were to unplug the oxygen sensor while a car is running and with one hand, touch the wire leading to the computer from the sensor, and with the other hand, touch the positive battery terminal, the fuel air ratio will go to richest point in the closed loop. Touch the negative terminal instead and it goes to the leanest point allowed by the loop and at an idle you can just hear the difference between the two points. If the closed loop was used, a failure of the that portion of the system such as the computer or frequency valve, would not impair or disable the vehicle except to increase the emissions.
This system does an excellent job of controlling air fuel ratios and is considered clean burning by today’s emission standards and the main causes of failure are dirt or water that remains in the fuel long enough to cause corrosion. The main reasons the K system are no longer specified on new cars involves the slight air flow restriction and slightly slow action of the throttle plate and the fact that the injectors are constantly firing into the manifold unlike the timed, cylinder injection of the newer electronic Bosch L system. Both issues don’t seem to be a concern when using the system to fire a burner but that doesn’t mean the newer electronic systems can not be used also.
The servicing of the K system involves few tools which include a pressure gauge to check injection & control pressure as well as leak down, a dwell meter to check the duty cycle of the frequency valve, a tiny allen wrench (2mm I think) to adjust the basic position of the metering needle in relation to the throttle plate, and a volt ohm meter completes the package of special tools needed. Several manuals are available on the various injection systems from companies like Haynes or Clymer and bosch produces their own work shop manuals also.
The fuel pump on most injected autos is in the fuel tank and it can be an expensive item to replace and since they use the fuel for lubrication and coolant, they don’t tolerate many dry runs or water corrosion. Of course the pumps are of electric in operation and although the power consumption is low, any device that adds to the overall power consumption of the vehicle can not be over looked. The volume and pressure required can be provided by an oil burner pump such as the sunstrand if the electric pump won’t fit the proposed design.
In conclusion (finally) I think this technology has the five abilities I most desperately desire in parts I choose for my system design, Availability, Affordability, Adaptability, Adjustability and Dependability.
Sorry I drag these things out so much
Peter Heid</HTML>
Reply: Fuel Injection
Posted by: Jim Crank (IP Logged)
Date: February 16, 2002 01:44PM
<HTML>Hi Peter,
You make a good case for trying the Bosch K-Jetronic fuel injection system. Your points are relative to the steam car needs and it is worth the try, at least a good hard look.
There are hundreds of them in wrecking yards, look for injected VW's as they are plentiful.
Let me bring up a couple of items for consideration.
Taking the stand that one is going to use a post mix vaporizing burner, you need to first establish the form of the vaporizer. Hot plate, J tube, or whatever. Then determine just what kind of startup flow rate you want, quarter flow, half flow, or what. This greatly influences the type of fuel injection needed.
My questions would be:
1) Does one want to have a computer in his steam car? I sure don't after owning several cars that had the K system. Built as cheap as possible and until modified, very troublesome.
2) The need is for an injection system that can flow between 4 to 30 gallons of kerosene per hour. I question if the K can do this.
3) The systems that can be found are not capable of handling 600 cfm, which is probably the top need for a new steam car burner. One might need two or three of the intake/ throttle bodies. Remember these were for 2 liter engines.
4) Holly carburators can be had that are for racing purposes, and thus are stripped of any pollution gadgets. The go up to 1400 cfm.
A carburetor is a very good solution, especially if one uses a draft booster. Automatic air to fuel ratio no matter how much is being flowed. The servo interlock then being the throttle butterflys. The original idle jets then being enlarged to permit good firing when steaming up at a reduced rate.
The butterflys possibly interlocked with either throttle position or by burner air pressure. Complicated however when compared to a two step injection set of nozzles.
Both the Series E and the Series F Doble carburetors didn't have any throttle; but worked, and worked well, just by varying the incoming air flow rate, via the draft booster.
One possible way to go for a burner with variable draft, a modern racing carburetor stripped of all butterflys and accelerator pumps.
5) On the various race car equipment web sites there are many throttle body injection systems available that are quite simple. Look at the Holly and Edlebrock sites for data. There is a ton of good stuff out there that we could use.
6) Holly, and others, make electric fuel pumps that can go to 100 psi.
Just some items for consideration.
Jim</HTML>
You make a good case for trying the Bosch K-Jetronic fuel injection system. Your points are relative to the steam car needs and it is worth the try, at least a good hard look.
There are hundreds of them in wrecking yards, look for injected VW's as they are plentiful.
Let me bring up a couple of items for consideration.
Taking the stand that one is going to use a post mix vaporizing burner, you need to first establish the form of the vaporizer. Hot plate, J tube, or whatever. Then determine just what kind of startup flow rate you want, quarter flow, half flow, or what. This greatly influences the type of fuel injection needed.
My questions would be:
1) Does one want to have a computer in his steam car? I sure don't after owning several cars that had the K system. Built as cheap as possible and until modified, very troublesome.
2) The need is for an injection system that can flow between 4 to 30 gallons of kerosene per hour. I question if the K can do this.
3) The systems that can be found are not capable of handling 600 cfm, which is probably the top need for a new steam car burner. One might need two or three of the intake/ throttle bodies. Remember these were for 2 liter engines.
4) Holly carburators can be had that are for racing purposes, and thus are stripped of any pollution gadgets. The go up to 1400 cfm.
A carburetor is a very good solution, especially if one uses a draft booster. Automatic air to fuel ratio no matter how much is being flowed. The servo interlock then being the throttle butterflys. The original idle jets then being enlarged to permit good firing when steaming up at a reduced rate.
The butterflys possibly interlocked with either throttle position or by burner air pressure. Complicated however when compared to a two step injection set of nozzles.
Both the Series E and the Series F Doble carburetors didn't have any throttle; but worked, and worked well, just by varying the incoming air flow rate, via the draft booster.
One possible way to go for a burner with variable draft, a modern racing carburetor stripped of all butterflys and accelerator pumps.
5) On the various race car equipment web sites there are many throttle body injection systems available that are quite simple. Look at the Holly and Edlebrock sites for data. There is a ton of good stuff out there that we could use.
6) Holly, and others, make electric fuel pumps that can go to 100 psi.
Just some items for consideration.
Jim</HTML>
Re: Reply: Fuel Injection
Posted by: Peter Heid (IP Logged)
Date: February 16, 2002 03:50PM
<HTML>Jim,
Somehow I knew you would be the first to respond, probably since you seem to have spent a great deal of research on burners. I have the K injection system from my old V6 Volvo which I have considered for this purpose. I am a little more modest in my fuel rates, I am not looking for quite as much power for my first design as you seem to be after.
Your preference for keeping the computer from the steam vehicle is understandable but I was raised digital. I see a computer as being the answer to squeek the last bit of efficiency from most any system, just look at the world around you. Of coures it is easy to pick out the poor examples because they stick out so readily, but think of the thousands of hidden systems that out live the mechanics of the device. From the time of purchase to the recycle bin the electronic systems remain invisable to all but the most aware. Do you plan on using a modern stereo in your vehicle ? That would probably account for three or more computers (microcontrollers).
The carburetor is a nemesis of mine, I come from the IC world. All carburetors have multipule fuel supply circuits that makes them function in steps and these steps are much to wide. The carburetor usually functions most efficiently at very few points and to prevent this some very complicated carburetors were designed and built. The point was reached where the production of injected engines was cheaper to implement and produce than the carbureted version when trying to meet today's emission standards. Any fuel system that leaves the fuel exposed to the atmosphere can not meet the emission standards I wish to far exceed.
Your right the after market injection systems are deserving of a closer look if the budget allows.
I was wondering how to acheive reduced startup rates ? Of course a microcontroller can easily output pulse width modulation to controll the motor.
It looks like we are on oppsite sides of the coin on this one, and I look foward to further discussions on the subject.
Peter Heid</HTML>
Somehow I knew you would be the first to respond, probably since you seem to have spent a great deal of research on burners. I have the K injection system from my old V6 Volvo which I have considered for this purpose. I am a little more modest in my fuel rates, I am not looking for quite as much power for my first design as you seem to be after.
Your preference for keeping the computer from the steam vehicle is understandable but I was raised digital. I see a computer as being the answer to squeek the last bit of efficiency from most any system, just look at the world around you. Of coures it is easy to pick out the poor examples because they stick out so readily, but think of the thousands of hidden systems that out live the mechanics of the device. From the time of purchase to the recycle bin the electronic systems remain invisable to all but the most aware. Do you plan on using a modern stereo in your vehicle ? That would probably account for three or more computers (microcontrollers).
The carburetor is a nemesis of mine, I come from the IC world. All carburetors have multipule fuel supply circuits that makes them function in steps and these steps are much to wide. The carburetor usually functions most efficiently at very few points and to prevent this some very complicated carburetors were designed and built. The point was reached where the production of injected engines was cheaper to implement and produce than the carbureted version when trying to meet today's emission standards. Any fuel system that leaves the fuel exposed to the atmosphere can not meet the emission standards I wish to far exceed.
Your right the after market injection systems are deserving of a closer look if the budget allows.
I was wondering how to acheive reduced startup rates ? Of course a microcontroller can easily output pulse width modulation to controll the motor.
It looks like we are on oppsite sides of the coin on this one, and I look foward to further discussions on the subject.
Peter Heid</HTML>
Re: Reply: Fuel Injection
Posted by: Jim Crank (IP Logged)
Date: February 16, 2002 11:05PM
<HTML>Peter,
You are right, I am after a powerful system.
Nope, we are on the same side. I just want to eliminate any electronics if I can, because after all the years of using them in various contraptions for NASA and Lockheed, I have seen the real points of failure and they were almost always in the digital electronics.
If done properly, the electronics are reliable; but from what I see on cars now, the engine management computer has too many input sensors for my use. I want a simple system.
I keep thinking about those throttle body injectors that are used for racing. Need to really look into that.
There are carburetors and then there are carburetors. The Doble one is as simple as they get. nothing in there but a jet and the float. A late four barrel with all the extra circuits is, just as you say, a mess.
If a carburetor is used then one as simple as possible, like the SU or a racing version which is stripped of all pollution stuff.
We don't have the answer to this yet and I am still looking hard at all means of squirting fuel into the burner.
Reduced startup could be superbly done if you can get in and reprogram the K computer. I don't know how to do this. Then you could have a really stepless fuel rate just as you need it to match the draft.
Keep thinking about this, we need to find a really good and reliable way to do fuel injection into either the vaporizing or the atomizing burner.
Jim</HTML>
You are right, I am after a powerful system.
Nope, we are on the same side. I just want to eliminate any electronics if I can, because after all the years of using them in various contraptions for NASA and Lockheed, I have seen the real points of failure and they were almost always in the digital electronics.
If done properly, the electronics are reliable; but from what I see on cars now, the engine management computer has too many input sensors for my use. I want a simple system.
I keep thinking about those throttle body injectors that are used for racing. Need to really look into that.
There are carburetors and then there are carburetors. The Doble one is as simple as they get. nothing in there but a jet and the float. A late four barrel with all the extra circuits is, just as you say, a mess.
If a carburetor is used then one as simple as possible, like the SU or a racing version which is stripped of all pollution stuff.
We don't have the answer to this yet and I am still looking hard at all means of squirting fuel into the burner.
Reduced startup could be superbly done if you can get in and reprogram the K computer. I don't know how to do this. Then you could have a really stepless fuel rate just as you need it to match the draft.
Keep thinking about this, we need to find a really good and reliable way to do fuel injection into either the vaporizing or the atomizing burner.
Jim</HTML>
Re: Fuel Injection - 12v burner
Posted by: John Winter (IP Logged)
Date: February 17, 2002 03:50PM
<HTML>Hi Peter. You made mention of a 12volt gun burner being available. Could you post here or Email the source of these burners to me. Thanks, JOHN</HTML>
Re: Fuel Injection - 12v burner
Posted by: George K. Nutz (IP Logged)
Date: February 17, 2002 06:25PM
<HTML>John,
Think it may be something I mentioned a while back; Beckett now makes a 12 volt DC burner up to 6-8 gallons per hour. Think they may be at [www.beckett.com] but might be wrong on that website address. I believe it has a 4" diameter entrance housing, DC ignition and draws 15-20 amperes.
Best, George</HTML>
Think it may be something I mentioned a while back; Beckett now makes a 12 volt DC burner up to 6-8 gallons per hour. Think they may be at [www.beckett.com] but might be wrong on that website address. I believe it has a 4" diameter entrance housing, DC ignition and draws 15-20 amperes.
Best, George</HTML>
Re: Fuel Injection - 12v burner
Posted by: Rolly Evans (IP Logged)
Date: February 17, 2002 08:15PM
<HTML>Most oil burner supplys don't even know they make a 12V oil burner. You can get a Beckett from Spray Mart PO Box 6008 Springdale AR 72766-6008 Phone # 1-800-725-0177 The .75 to 3 Gal was $350.00 Model ADC
They also make a 1.75 to 5.5 Gal Model SDC Wayne also makes a 12V burner
Rolly</HTML>
They also make a 1.75 to 5.5 Gal Model SDC Wayne also makes a 12V burner
Rolly</HTML>
Re: Fuel Injection - 12v burner
Posted by: Ron Parola (IP Logged)
Date: February 18, 2002 12:45AM
<HTML>Actually the Kjetronic is a completely mechanical system with an overlay for very accurate fuel trim, no electronics needed. The O2 sensor (Lambda sond) was added later to keep up with tighter smog specs. Also the later Audi's and Mercedes cars use HIGH pressure fuel pumps,ie 250psi ( maybe higher if you force the issue) . I am using an Audi one ( actually they are all Bosch) as an aux. one in my car. It will pump 125psi gasoline with minimum draw, but pumping gas/diesel mix runs the current drain way up, I have it cut out around 95psi. Ron Parola</HTML>
Re: Reply: Fuel Injection
Posted by: Peter Heid (IP Logged)
Date: February 18, 2002 12:46AM
<HTML>Jim,
The K injection system really doesn't need a computer for the fuel regulation untill you need that last little bit of accurcy. The computer does control the warmup process, the lambda sonde feed back loop and the on off operation based on the function of the ignition system. My thought is to use a processor of my own choosing based on a PIC (programable interface controller). The output from an oxygen sensor can be determined from the manufacturers spec sheet, but it is in the few milivolt range and is easily amplified and handled by an ADC (analog to digital converter) built in to many PICs. The adjustment of the conversion (input signal to control signal) process is in software and instead of changing jets in a carburetor, you change values in the software. The computer on the K system is the part of it I know the least about but I do know, as shown in the manuals, what all the inputs values are supose to be and the outputs are also known values. For a few dollars the system can include another processor to monitor the operation of the system and alert you to any errors, system changes, or problems, providing actual information not going to the dealer and pluging it in.
The carburetor can function improperly at steep angles due to the float system and I am thinking of a steam snowmobile as my first project. Today's work well with a carburetor but better with a injection system. When I ran an automotive machine shop, I can remember a trade magazine running an article on the rebuilding of a Honda carburetor, it was continued thru 3 issues. The number of parts I could count in the picture series was well over 200 ! At that point I figured I could build an injection system easier than I could rebuild that carburetor.
Another thing, the fuel pumps like sundstrand used on household sized oil burners are rated for about 18 GPH max at 1750 RPM.
I think the Bosch LE Jetronic injection used on my BMW motorcycle might be able to provide the fuel flow rates you desire. If the NTC coolant sensor goes bad (always when sitting not running) and I try to start it, the system goes to full rich and a few turns with the starter make it a flame thrower. Keep cranking for a few seconds and the flames roar ten feet out the exhaust. What would happen if you controlled the NTC resistance value and the rpm sensor ? Seems like you could have an effective control. The LE system is the little brother of the L system which provides more fuel flow. The newer Motronic system is simpler and can be fooled into running as needed also. I do like the continueous injection, pressure controlled injectors of the K system versus the timed electronic injectors of the newer systems. The continueous have a wider range of fuel flow rates and electronic injectors come in various sizes to cover the range of various engine needs.
It seems an experimenter has a wide range of choices for a begining point when designing a burner.
Peter Heid</HTML>
The K injection system really doesn't need a computer for the fuel regulation untill you need that last little bit of accurcy. The computer does control the warmup process, the lambda sonde feed back loop and the on off operation based on the function of the ignition system. My thought is to use a processor of my own choosing based on a PIC (programable interface controller). The output from an oxygen sensor can be determined from the manufacturers spec sheet, but it is in the few milivolt range and is easily amplified and handled by an ADC (analog to digital converter) built in to many PICs. The adjustment of the conversion (input signal to control signal) process is in software and instead of changing jets in a carburetor, you change values in the software. The computer on the K system is the part of it I know the least about but I do know, as shown in the manuals, what all the inputs values are supose to be and the outputs are also known values. For a few dollars the system can include another processor to monitor the operation of the system and alert you to any errors, system changes, or problems, providing actual information not going to the dealer and pluging it in.
The carburetor can function improperly at steep angles due to the float system and I am thinking of a steam snowmobile as my first project. Today's work well with a carburetor but better with a injection system. When I ran an automotive machine shop, I can remember a trade magazine running an article on the rebuilding of a Honda carburetor, it was continued thru 3 issues. The number of parts I could count in the picture series was well over 200 ! At that point I figured I could build an injection system easier than I could rebuild that carburetor.
Another thing, the fuel pumps like sundstrand used on household sized oil burners are rated for about 18 GPH max at 1750 RPM.
I think the Bosch LE Jetronic injection used on my BMW motorcycle might be able to provide the fuel flow rates you desire. If the NTC coolant sensor goes bad (always when sitting not running) and I try to start it, the system goes to full rich and a few turns with the starter make it a flame thrower. Keep cranking for a few seconds and the flames roar ten feet out the exhaust. What would happen if you controlled the NTC resistance value and the rpm sensor ? Seems like you could have an effective control. The LE system is the little brother of the L system which provides more fuel flow. The newer Motronic system is simpler and can be fooled into running as needed also. I do like the continueous injection, pressure controlled injectors of the K system versus the timed electronic injectors of the newer systems. The continueous have a wider range of fuel flow rates and electronic injectors come in various sizes to cover the range of various engine needs.
It seems an experimenter has a wide range of choices for a begining point when designing a burner.
Peter Heid</HTML>
Re: Fuel Injection - 12v burner
Posted by: Peter Heid (IP Logged)
Date: February 18, 2002 03:21AM
<HTML>Ron,
I like the heating of the fuel for viscosity reasons and reduced energy of ignition, especially at low atmospheric temperatures.
Peter Heid</HTML>
I like the heating of the fuel for viscosity reasons and reduced energy of ignition, especially at low atmospheric temperatures.
Peter Heid</HTML>
Re: Reply: Fuel Injection
Posted by: Jim Crank (IP Logged)
Date: February 18, 2002 02:11PM
<HTML>Peter,
I agree about modern gas car carburetors, way too complex and too many parts, thanks to all the pollution requirements.
The F Doble carburetor, I am looking at one right now, has two moving parts, the float and the needle valve.
With variable draft, which I will use, I must have a good way to keep the air/fuel ratio constant, and right now, some carburator or throttle body injector is the simplest way to go. However, I am wide open for any better way to do it as long as it stays simple.
The line of Tuthill pumps, which is what was and is in the Doble, go up to 100 gph in the smaller versions.
Jim</HTML>
I agree about modern gas car carburetors, way too complex and too many parts, thanks to all the pollution requirements.
The F Doble carburetor, I am looking at one right now, has two moving parts, the float and the needle valve.
With variable draft, which I will use, I must have a good way to keep the air/fuel ratio constant, and right now, some carburator or throttle body injector is the simplest way to go. However, I am wide open for any better way to do it as long as it stays simple.
The line of Tuthill pumps, which is what was and is in the Doble, go up to 100 gph in the smaller versions.
Jim</HTML>
Re: Reply: Fuel Injection
Posted by: Peter Heid (IP Logged)
Date: February 22, 2002 01:00AM
<HTML>Jim,
I was thinking about the idea of using a O2 sensor in a burner system reguardless of the type. The sensor could feed a computer that could control a bypass air circuit to get the last bit of emission refinement. Failure of the computer would mean operating in regular mode untill serviced. It would be easier if the burner was of the on/off operation but could be adapted to that of a varying fuel rate also.
Peter Heid</HTML>
I was thinking about the idea of using a O2 sensor in a burner system reguardless of the type. The sensor could feed a computer that could control a bypass air circuit to get the last bit of emission refinement. Failure of the computer would mean operating in regular mode untill serviced. It would be easier if the burner was of the on/off operation but could be adapted to that of a varying fuel rate also.
Peter Heid</HTML>
Re: Reply: Fuel Injection
Posted by: Andy Patterson (IP Logged)
Date: April 16, 2004 05:12PM
<HTML>Jim and Peter
I have been looking at O2 sensor fuel injectors for some time. One might be able to make a pure electronic feed back control. I 555 timmer could be used to generate a variable width palse stream. It wouldn't be very hard to do teh job with a single board computer either.
After finding the combustion information I think it even more critical that the air fuel ratio be controled. Both for emmisions control and for best performance. The flame temperature is varied quite by the amount of excess air. I think that to get the best boiler efficiency we need to have some excess O2. But also the least that is required to to achieve emmision standards. We are looking for the hotest flame we can use.
It is not going to be easy to do a home built computer control. There are lot of problems that we are going to have to live with in a 1 UP project. We just can't aford the design effort of special hardware. We will coble pieces together to do whant we need. All these connections are potential problesm. Corosion, vibration, noise, dirt, cooling and others. I am not saying it's impossable. But Jim is right right for Jim. If you don't have the expertise to maintain the electronics don't do it. We spent $1,200,000 on the design of a industrial case for a single board data colection terminal. Keeping the electronics dry and clean is going to be a big problem. The programming is the simplest problem. But I am still going to use a computer control. I am going to use my own real time OS.
[www.greenhills.net]
Andy</HTML>
I have been looking at O2 sensor fuel injectors for some time. One might be able to make a pure electronic feed back control. I 555 timmer could be used to generate a variable width palse stream. It wouldn't be very hard to do teh job with a single board computer either.
After finding the combustion information I think it even more critical that the air fuel ratio be controled. Both for emmisions control and for best performance. The flame temperature is varied quite by the amount of excess air. I think that to get the best boiler efficiency we need to have some excess O2. But also the least that is required to to achieve emmision standards. We are looking for the hotest flame we can use.
It is not going to be easy to do a home built computer control. There are lot of problems that we are going to have to live with in a 1 UP project. We just can't aford the design effort of special hardware. We will coble pieces together to do whant we need. All these connections are potential problesm. Corosion, vibration, noise, dirt, cooling and others. I am not saying it's impossable. But Jim is right right for Jim. If you don't have the expertise to maintain the electronics don't do it. We spent $1,200,000 on the design of a industrial case for a single board data colection terminal. Keeping the electronics dry and clean is going to be a big problem. The programming is the simplest problem. But I am still going to use a computer control. I am going to use my own real time OS.
[www.greenhills.net]
Andy</HTML>
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