diesel engine remote starting circuit

Hi.

i'm new to this forum.

i have been searching for a circuit that will start and stop a diesel engine.

i've seen these for sale for several hundred dollars each.

i would like to have this circuit automaticaly start up a diesel generator from various diferent inputs.

i can do the circuts to generate the inputs, but starting this internal combustion engine is not a circuit i have seen before.

has anybody seen a circuit for starting these types of engines?

any halp would be appreciated.

thanks,

Mike.

mdj21 said:

Hi.

i have been searching for a circuit that will start and stop a diesel engine.
i've seen these for sale for several hundred dollars each.
i would like to have this circuit automaticaly start up a diesel generator from various diferent inputs.
i can do the circuts to generate the inputs, but starting this internal combustion engine is not a circuit i have seen before.
has anybody seen a circuit for starting these types of engines?
thanks,
Mike.

Click to expand...

Hi Mike,
On my 15 kva generator it has a NO/NC relay to turn it on and off but you haven't supplied enough detail on the motor. Some diesels have a pull cord to disengage the fuel pump where others use a solienoid. If you can provide a picture of the diesel then we might have a better understanding on where to go but with no information to go on where does one start????

Cheers Bryan

well, the generator is still down in Ft Lauterdale. i need to go pick it up so i cant really say much more about it.

i was looking for a circuit that would be similar to this gizmo......

https://www.xantrex.com/web/id/386/docserve.asp

it looks like it uses timed relays to activate the starter.

they don't give you a circuit diagram so i was looking on the web for a circuit that would do some of the things that this auto start gizmo does.

Are you wanting to start the generator from a remote location? Or do you just want to start it to make sure it's ok? Here in Tn all health care facilities must have an "exercise timer" that starts the generator automatically at least once a week to verify it's operation.
Typically all you need to do is parallel the ignition switch with other contacts, one set for crank (momentary), another for run (maintained).
A description of what you mean by
I would like to have this circuit automaticaly start up a diesel generator from various diferent inputs. Would be a big help..

ok,

well, automatically start up would mean that i want the generator to start up and run with out me doing anything.

various diferent inputs could mean several things. that generator exerciser function you mnetioned would be a good example. annother one could be a signal from an inverter that the bank of batteries is getting low and the generator needs to start up to charge them.

i was just looking for a circuit to operate the engines starter motor. it needs to be energized to start the engine, but how does the circuit know that the engine has started and it can stop cranking it over? that's the only part that i can't figure out. if it's a human doing it, he just lets go of the key when the engine starts. how does a circuit know when to let go of the key?

i was wanting to see a circuit where some one else has handeled this problem to get some ideas for my own circuit.

thanks,

Mike.

i was just looking for a circuit to operate the engines starter motor. it needs to be energized to start the engine, but how does the circuit know that the engine has started and it can stop cranking it over? that's the only part that i can't figure out. if it's a human doing it, he just lets go of the key when the engine starts. how does a circuit know when to let go of the key?

Click to expand...

The keyless entry/remote start thingy that I installed on my car just uses a timed output. I think I have it set to 0.8 seconds, so it will just run the starter for that long. Since it is fuel injected and whatnot it starts 99.9% of the time.
It can be programmed for a certain length. I started with the lowest time, 0.3 seconds and worked my way up.

mdj21 said:

i was just looking for a circuit to operate the engines starter motor. it needs to be energized to start the engine, but how does the circuit know that the engine has started and it can stop cranking it over? that's the only part that i can't figure out. if it's a human doing it, he just lets go of the key when the engine starts. how does a circuit know when to let go of the key?

Click to expand...

As it's starting a generator, how about detecting the output of the generator to confirm it's running?.

Presumably the generator won't produce full output until the engine is actually running?, although it may produce some output while it's turning over - measure the relative outputs, and switch the starter OFF when the output passes a suitable point.

well, a diesel is not going to start up so predictably every time. it could take a few cranks to get it up so i'm not so sure that a "timed" only circuit would be sufficient.

Nigel had a good idea though and i just found this link that has a breif discussion on this subject. it talks about two circuits that will disengage a starter motor when the engine has started. they key off of the alternator though. here is the link for anyone interested. the discussion is on page 20, "ADLO" circuits.

https://www.electro-tech-online.com/custompdfs/2005/10/CrankMots.pdf

there isn't very much spisific information on the circuit, but maybe i can figure something out from the information given.

thanks for the help and ideas.

Mike.

mdj21 said:

well, a diesel is not going to start up so predictably every time. it could take a few cranks to get it up so i'm not so sure that a "timed" only circuit would be sufficient.

Click to expand...

Very good point. The diesel starting circuit I know of would try a fixed number of cranks attempts, with time period in between for the battery to recover. If after the fixed number of crank attempts and the disel engine is still not running, then it will stop cranking attempts and gives an alarm.

I think this is the sort of circuits you are looking for. The circuit consists of several timer relays and voltage relays to detect the successful running of the diesel engine and then apply field excitation to the generator.

It is much simplier now to just use a microcontroller for all that.

Hi folks, this is one I have thought about alot in the past (more for car engines than anything else...) but what about two possible options.
1. Look at RPM of engine, get a micro to cut starter on sudden increase of RPM (as you would expect, surely the engine will idle much faster than the starter can turn the engine?!?!?)
2. Look at voltage drop across the supply lead to starter. On starting the drop will be much less due to reduced load and hence drop in current flow!

Don't forget if the engine has glow plugs there will have to be an inhibit which prevents starting before plugs have adequately heated!

Hope I have given some idea's???

yea, that's the kind of circuit i'm looking for. do you know where i can find one like that?

microcontrooler is an interesting idea.

One system that I've seen uses an oil pressure switch, same as the one that turns on the oil light. You typically don't have full oil pressure until the engine is running. The other systems used a fixed timer for cranking and monitored the generator output to see that it started..

Old topic I know, but is there a microprocessor or whatever that could detect sudden increase in RPM / voltage etc?

Many thanks

gerty said:

One system that I've seen uses an oil pressure switch, same as the one that turns on the oil light. You typically don't have full oil pressure until the engine is running. The other systems used a fixed timer for cranking and monitored the generator output to see that it started..

Click to expand...

Oil pressure switches are a nighmare. They deactivate the oil warning light much too early which cost me a new engine for a Ford Scorpio. According to the factory information the light extinguishes at an oil pressure of 0.8bar which is completely insufficient to supply two overhead camshafts with a nearly adequate amount of oil with the necessary pressure.

Boncuk

benneh said:

Old topic I know, but is there a microprocessor or whatever that could detect sudden increase in RPM / voltage etc?

Many thanks

Click to expand...

The best way to measure engine revs is to connect to an alternator coil before the rectifiers. Some rev counters already connect to that.

Even with an engine using an oil pressure gauge, I've seen the cranking of the engine under adverse conditions (it didn't want to start easily) bring the oil pressure up within the "safe" zone.

Your starter motor is only going to be able to spin the crank at some given maximum RPM. Detecting the RPM and checking for rotation that is well in excess of that should work. The Bendix of the starter should release from a slight overspeed I'd think.

Dean

Diver300 said:

The best way to measure engine revs is to connect to an alternator coil before the rectifiers. Some rev counters already connect to that.

Click to expand...

I'd rather not dismantle the alternator, is there no easy way of interfacing with injectors or something? I'm trying to make a push button engine start switch, but I need a way of detecting engine start/ engine revs to cut the starter solenoid.

You shouldn't have to dismantle the alternator. Slap a scope across the alternator output and you'll probably see some pretty severe AC you could refine and use for the sense input. The injector will work on a newer diesel if it's electronically controlled I suppose. All the diesels I've been associated with use mechanical injectors. The only electronics is for the starting and charging system.

Is there a speed sensor on the engine. For instance, the VW diesels have a sensor off the crankshaft that can be used to power the "upshift" dash indicator or for engine service.

Dean

how about using the voltage drop on the high side of the starter cable? The current should drop - and so the voltage - to almost zero if the engine is running and the alternator supplies charging current to the battery.

You can sense engine revs with the AC ripple on the alternator output (https://www.electro-tech-online.com/custompdfs/2008/10/H-SEN-KMT-RPM-D100-011US.pdf)

However, the signal is very small and it may not be present at cranking speeds. Alternators have a rotor winding, which is fed through the slip rings. That controls the alternator power and is used to regulate the voltage. The current for the rotor comes from the alternator itself, so it won't ever generate anything unless some other rotor current is provided. That comes from the ignition warning light.

When the alternator starts to work, it generates enough voltage to provide its own rotor current and the ignition light goes out. Until that happens, you won't be getting any conduction of the main diodes that feed the battery, so there won't be any ripple. That was why I suggested looking at the alternator voltage before the diodes, where there will be at least a volt of AC even at cranking speeds.

Watch the ignition warning light as you start the engine. On some cars, that doesn't turn off until the engine speed has gone a little over tickover, but I am fairly sure that it won't go out at cranking speeds.

If the ignition warning light does go out as the engine starts, you could use that but be careful. If the ignition warning light bulb fails, there is no rotor current so the alternator never generates. I would also suggest a timeout on how long you run the starter motor.

Alternators are not difficult to take apart enough to get to the diodes. The diodes are huge and on large heatsinks, and the wires are about 1mm in diameter so there is nothing little or delicate.