Building a compressor...

[Satashooter]

ahhh sorry I've got you, I was thinking at what speed the renault asembly was rotating not direction, miserable fail on my part haha

I've not had chance to look at one yet, but is that really all there is on them? The solenoid, glowplugs, starter circuit and cold start?

Dont get much easier than that! how is the cold start actually engineered and operated?

Really looking forward to getting one of these running on a bench, and experimenting... Thinking of having a play around with starting it on diesel, then switching over to pre heated used engine oil as well, could make for a crackingly cheap generator as well. If all goes well once I get stuck in, I'll be rebuilding two and taking full advantage

your dead right about not making anything more complecated than it needs to be as well, I'm really up on that basis. I've messed with tons of car restorations and engine conversions over the years, and I've allways ended up making them alot simpler than they were to begin with, just makes life so much easier!

 

[AndyStobbs]

ahhh sorry I've got you, I was thinking at what speed the renault asembly was rotating not direction, miserable fail on my part haha

I've not had chance to look at one yet, but is that really all there is on them? The solenoid, glowplugs, starter circuit and cold start?

Dont get much easier than that! how is the cold start actually engineered and operated?

Really looking forward to getting one of these running on a bench, and experimenting... Thinking of having a play around with starting it on diesel, then switching over to pre heated used engine oil as well, could make for a crackingly cheap generator as well. If all goes well once I get stuck in, I'll be rebuilding two and taking full advantage

your dead right about not making anything more complecated than it needs to be as well, I'm really up on that basis. I've messed with tons of car restorations and engine conversions over the years, and I've allways ended up making them alot simpler than they were to begin with, just makes life so much easier!

You might find a car engine difficult to keep on frequency, they don't have goveners in the pump, so additional loads on the genny will reduce speed and therefore frequency at the output.

 

[Satashooter]

I've got you... Could it be done with one on the throttle instead?

So when the revs drop it adjusts the throttle acordingly?

Do Petrol Honda GX generators work like this? Possible to pintch one off an old genny?

 

[the snooper]

Honda gx gennys have a governor that operates off the air from the flywheel via a linkage and light springs, it wont work on a car / van engine you can however buy various governors for the job, the problem is if you don't do it right what ever you have running from the genny will soon produce a puff of smoke lots of electronics don't have a big tolerance to varying frequency which is 50 Hz @ 3000 rpm on most small gennys so the speed needs to be constant and the governor very reactive to increasing and decreasing loads

 

[normspanners]

the best engine to use would be the transit york but fit the di head as the york has flat top pistons but the di has a flat top head then you would have the same as a normal compressor, use a di engine to drive it , fit the engines back to back take the spacer out from behind the front pulley then the oil pump would not drive but link the second engine/compressor from the drive engine oil pump by a hydraulic hose put a flat sump on the compressor engine like a dry sump with an interconnecting pipe so that the oil returns to the drive engine sump, use two transit type 9 bellhousings with no gearboxes so they would line up but just bolt then together, all you would need would be a flanged crank joiner or just use a short prop. Link up the cooling systems to one rad.
Fit soft valve springs as meantioned and take off inlet rockers off the shaft and push rods modify a cam pulley to use as the crank pulley so it is the same size as the camshaft all that would be required would be to thread each exhaust port bsp and link them to tank. I recon you would have at least a 100 cfm diesel compressor,at just over 1500rpm

 

[KemppiFrog]

You might find a car engine difficult to keep on frequency, they don't have goveners in the pump, so additional loads on the genny will reduce speed and therefore frequency at the output.

Are you sure about that? DPA pumps usually have a governor and if you keep the pedal at a fixed point, the revs stay constant even if the load changes. This may not be true of modern diesels but it seems to work on the pre. common rail types.
Quite a lot of Hondas have built in governors, rather than the air blown type. The two I have do, one a genset, the other a mower.

The cold start on the 1.8 TD used a water temp sensor that activates the cold start if the temp is less than ( I think)10C. For my use, a button and relay should be enough. Same for the heater plugs, I saved the big relay when I stripped the truck. Much the same as the system on the Renault. I know it is under 10C when it belches a bit of smoke on start up
KF

 

[normspanners]

dpa governors are more to stop the engine overreving than keeping a steady speed,but will work to certain degree. Industrial engines have a proper governor to keep the speed constant at a preset rpm.

 

[KemppiFrog]

Except that I used a Lister 35KVA genset that had what looked like a normal DPA pump and kept a steady 1500.

 

[normspanners]

I think that a variable speed dpa is different internally, for a compressor it would hardly make any difference, but for a genny it is obviously imperative to save the head from destroying itself. Some of the pumps I work on have dpa's and they are 1500 also, but again not critical it is just a more efficient speed

 

[normspanners]

quote from delphi re industrial dpa pumps for gennies
The G stand for Govered?

Fuel Injection Pumps
Delphi DPG Medium Duty Diesel Rotary Fuel Injection Pump
Delphi DPG Medium Duty Diesel Rotary Fuel Pump
Enlarge
The Delphi DPG Medium Duty Diesel Rotary Fuel Injection Pump is based on the Delphi DPA series of diesel fuel injection pumps and includes mechanical governor enhancements, providing durable governor performance to ISO 8528-5 Class G2 standards. The pump is easily adjusted to suit either 50 or 60 Hz operation, and offers easy in-service conversion to electronic operation using an integrated governor controller and actuator. The main components of the DPG pump include:
Fuel inlet
Transfer pump with pressure regulator
Distributor pumping system with two or four plungers
Internal cam ring
Driveshaft
Metering valve with droop control
Mechanical governor with low friction and wear features
Governor transient stabilizer
Electric shut-off
Options include:
Advance control (start retard or light load advance)
Clockwise or anti-clockwise drive
Engine transient overspeed limiting
Component package for low lubricity fuel
Benefits
Enhancements to the design of the governor improve wear performance of the governor components, and advanced knife edge pivots and governor weight design improve hysteresis performance between governor pull-off and pull-on.
Droop control sets droop (rate of governor pull-off) to a desired value and allows easy conversion from 50 Hz to 60 Hz generator operation within ISO 8528-5 Class G2 standards. This feature can also be used for in-service adjustments if required.
Hydraulic damper fitted to the governor helps keep the alternator stable and within ISO specified requirements.
A simple conversion to electronic governing with integrated governor controller and actuator allows in-service upgrades. No separate controller is needed, helping minimize wiring harness complexity. Digital control helps provide precise governing with multiple governing strategies such as isochronous load sharing, 50/60 Hz switching, auxiliary load sharing, etc. The actuator can be specified as original equipment by the engine manufacturer.
Typical Applications
The Delphi DPG Medium Duty Diesel Rotary Fuel Injection Pump is suitable for generator set and fixed speed applications within the following parameters:
Engine rated speeds up to 3,000 rpm
Engine ratings up to 24 kW per cylinder
Peak pumping pressures up to 550 bar (injection pressures up to 650 bar)
Three, four, or six cylinder engines
ISO 6519 standard 20 mm diameter drive taper
Gear or hub drive
12 V or 24 V electrical supply
Up to 8° advance travel

 

[normspanners]

I modded a water cooled lister from a stationary engine to a variable speed for a boat, the variable speed governor was not as large, but that had seperate pumping elements for each injector working on a rack system, not a dpa
the speed governor was too large/strong to be modded to be a largely variable version.

 

[Satashooter]

Would it be possible to achive the desired effect, by making use of the rev counter take off, then building a small PCB that looks at the engine revs (1500rpm) and if the revs drop, it controls a small servo or actuator, and adjusts the throttle back up or down to 1500rpm again?

I've got a friend I think might be able to build me something really simple.

Bare with me, but my knowledge on electronics is very limited. But where does frequency come into it, I know nothing about frequency. I just asumed it was a simple case of keeping the engines revs as steady as possible and the adjusments needed to be fast and fairly precise?

that seems fairly straight forward? Though theres afew things on there I havent a clue what they do... from letters G to P I dont understand...

 

[KemppiFrog]

The frequency bit is the 50 cycles that mains usually provides. The gensets I used had a frequency (hertz) meter to set the RPM. If it was 50 cycles then you had 1500rpm. and 230 volts. (though there were other ways to vary the volts)
KF

When I lived off grid. I bolted a spare 3KVA generator on the front of a little tractor. Then used a spare meter to set the RPM. The meters were quite simple, just a row of thin metal strips of slightly varying lengths. The middle on vibrated at 50 hz, the ones either side from 46 to 54. Harmonics

 

[normspanners]

If you dont understand frequency I think building a genny and compressor will be a little complicated .
No disrespect to you.
You could use DC which could be put through an inverter that then can use vairable speed and doesnt matter about frequency.
Frequency is the number of times the ac changes from either side of the zero volts line as it travels along on its sinusoidal wave, the actual voltage produced is about 280v peak to peak but when read on an AC meter only shows 240v this is the RMS (root mean square) of the voltage produced , this freq is in britain 50 hz in america 60hz , just for one example a motor is designed to run at a certain frequence and therefore speed, if that frequency alters the motor tries to follow the generators frequency, and can damage the motor because it ends up 'hunting',but when you get to transformers etc, it becomes even more complicated and very complicated for the generator head if not kept within a certain ( quite tight within a few hertz ) operating frequency, because it becomes if you like, overloaded with frequency, if not kept at its designed hz, it can damage/overload itself with hardly any actual load.
Where DC is what it says direct current and as long as it is regulated does not matter what speed it is generated at.

 

[normspanners]

I have in the design stage,an idea for a constant speed 5-7 kva 1500 generator head running off a variable speed lister engine, that will keep the generator constant even though the engine maybe at 1000 or up to 3000 rpm. but it uses an expensive magnetic flux drive unit.

 

[mike 109444]

I new I had heard of a flux drive " Back to the Future"
Not off somewhere/when are you Norm

 

[wookie]

When I lived off grid. I bolted a spare 3KVA generator on the front of a little tractor. Then used a spare meter to set the RPM. The meters were quite simple, just a row of thin metal strips of slightly varying lengths. The middle on vibrated at 50 hz, the ones either side from 46 to 54. Harmonics

Vibrating Reed Meter

Couple of ideas...

If you had a engine from a vehicle with cruise control could that not be used to govern the speed regardless of load ?

Also I know this would be a bit inefficient but with a generator setup could you not have a DC generator feeding a couple of batteries acting as a buffer with an inverter to get you back to AC ?

That would stop any problems with RPM affecting the frequency output.

 

[grandads_shed]

Vibrating Reed Meter

Couple of ideas...

If you had a engine from a vehicle with cruise control could that not be used to govern the speed regardless of load ?

Also I know this would be a bit inefficient but with a generator setup could you not have a DC generator feeding a couple of batteries acting as a buffer with an inverter to get you back to AC ?

That would stop any problems with RPM affecting the frequency output.

good idea and you can keep the revs low, wont bother the neighbors then

 

[normspanners]

Also I know this would be a bit inefficient but with a generator setup could you not have a DC generator feeding a couple of batteries acting as a buffer with an inverter to get you back to AC ?

You could use DC which could be put through an inverter that then can use vairable speed and doesnt matter about frequency.

pinchin my ideas? Ha

Heenan drive, variable magnetic flux drive
http://www.ebay.co.uk/itm/180891884133?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[normspanners]

I new I had heard of a flux drive " Back to the Future"
Not off somewhere/when are you Norm

Yep my Delorion is bust though I have to go everywhere on a skateboard now!