gasoline electric hybrid air compressor - Page 2

oil pan 4 · 09-01-14, 09:11 PM

Chain drives really don't like operating at high speed like that unless there are pretty much in an oil bath.
There is so much dirt and dust that blows around here you can not believe it unless you have lived some where like this, or have been to Afghanistan or Iraq.
I just don't think a chain drive would do very well out side around here.

ICanHas · 09-01-14, 09:54 PM

It would need to be protected from dust, just like timing on cars.

I would consider hydrostatic drive so you can modify the compressor speed. It also makes it substantially easier to start by bypassing it hydraulically, then ramping up the ratio.

I think you can even make the adjustment automatic by using a pneumatic cylinder/spring combination to move the adjuster lever for hydrostatic transmission. Drive system from a small HS tractor should work well.

the efficiency loss is much greater than chain and it is unacceptable for a bicycle, but the versatility and smooth control makes it preferred for agricultural machinery of all sizes.

Depending on how you configure it, I think you can even start the engine using hydraulically with the electric motor running.

It is a very flexible setup, because you can have the hydraulic pump/motor anywhere only limited by hydraulic lines and bypassing is done entirely mechanically with valves.

If you can find a wound rotor slip ring motor that can be externally excited, you can do things like bypass the compressor, then back-drive the motor with the engine and use as a generator.

Personally, I think the efficiency gain while running on engine will offset the loss, because you can manipulate both the throttle and CVT to optimize engine for efficient RPM and load at all conditions.

NiHaoMike · 09-01-14, 10:36 PM

A car type alternator is always going to have power electronics inside. Usually Schottky diodes as they are simple to use, but even those are quite lossy at 12V. If you want 120V AC out, you could use a transformer to boost the voltage from the stator and then figure out what rotor current gives the desired voltage.

I don't think there's much point to the complexity of a CVT in this application when you could just change the engine RPM.

ICanHas · 09-02-14, 02:20 AM

Quote:

A car type alternator is always going to have power electronics inside.

Never said it would be a "car type" alternator.

which would do a HORRIBLE job in the primary role of motoring from a single phase supply.

oil pan 4 · 09-02-14, 02:00 PM

I cant use a hydrostatic drive. They are very expensive and are only 75% to 80% efficient.
The machines efficiency will come from running the engine as hard as possible, using a 6.5 horsepower engine to drive a "7 Horsepower compressor" at reduced speed and then shutting it off when not needed or running the little 110v powered air compressor when I have electrical power and only need a little air.

I was going to use a vehicle alternator on this "air compressor" to generate power for vehicle jump starting. I was going to attach an Anderson connector to a standard 3 wire ACdelco alternator and use my Anderson connector jumper cable set to connect the machine to a vehicle electrical system.

Throttling the engine will be accomplished by a standard gasoline air compressor unloader valve. The unloader valve will send air to the tank and throttle the engine up when air is needed and once the air hits a preset pressure it will trip the unloader valve throttling the engine down and venting compressor output to the atmosphere.

09-01-14, 09:54 PM	#12
ICanHas Banned Join Date: Aug 2014 Location: US Posts: 150 Thanks: 7 Thanked 5 Times in 5 Posts	It would need to be protected from dust, just like timing on cars. I would consider hydrostatic drive so you can modify the compressor speed. It also makes it substantially easier to start by bypassing it hydraulically, then ramping up the ratio. I think you can even make the adjustment automatic by using a pneumatic cylinder/spring combination to move the adjuster lever for hydrostatic transmission. Drive system from a small HS tractor should work well. the efficiency loss is much greater than chain and it is unacceptable for a bicycle, but the versatility and smooth control makes it preferred for agricultural machinery of all sizes. Depending on how you configure it, I think you can even start the engine using hydraulically with the electric motor running. It is a very flexible setup, because you can have the hydraulic pump/motor anywhere only limited by hydraulic lines and bypassing is done entirely mechanically with valves. If you can find a wound rotor slip ring motor that can be externally excited, you can do things like bypass the compressor, then back-drive the motor with the engine and use as a generator. Personally, I think the efficiency gain while running on engine will offset the loss, because you can manipulate both the throttle and CVT to optimize engine for efficient RPM and load at all conditions. Last edited by ICanHas; 09-01-14 at 09:56 PM..

09-01-14, 10:36 PM	#13
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	A car type alternator is always going to have power electronics inside. Usually Schottky diodes as they are simple to use, but even those are quite lossy at 12V. If you want 120V AC out, you could use a transformer to boost the voltage from the stator and then figure out what rotor current gives the desired voltage. I don't think there's much point to the complexity of a CVT in this application when you could just change the engine RPM. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

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09-01-14, 09:11 PM	#11
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Chain drives really don't like operating at high speed like that unless there are pretty much in an oil bath. There is so much dirt and dust that blows around here you can not believe it unless you have lived some where like this, or have been to Afghanistan or Iraq. I just don't think a chain drive would do very well out side around here.

09-02-14, 02:00 PM	#15
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	I cant use a hydrostatic drive. They are very expensive and are only 75% to 80% efficient. The machines efficiency will come from running the engine as hard as possible, using a 6.5 horsepower engine to drive a "7 Horsepower compressor" at reduced speed and then shutting it off when not needed or running the little 110v powered air compressor when I have electrical power and only need a little air. I was going to use a vehicle alternator on this "air compressor" to generate power for vehicle jump starting. I was going to attach an Anderson connector to a standard 3 wire ACdelco alternator and use my Anderson connector jumper cable set to connect the machine to a vehicle electrical system. Throttling the engine will be accomplished by a standard gasoline air compressor unloader valve. The unloader valve will send air to the tank and throttle the engine up when air is needed and once the air hits a preset pressure it will trip the unloader valve throttling the engine down and venting compressor output to the atmosphere.