New Anti Lag Turbo System
Discussion
Hi everyone, this is my first post. I'm 18 years old, studying mechanical engineering and recently had an interesting idea. That was to use a micro jet engine to provide the exhaust gasses to spool the turbo, thus lag is eliminated and boost pressure is constantly maintained at maximum pressure and controlled via the wastegate. Rather than keep it an idea I went ahead and have built a prototype. In principle it shouldn't destroy the turbo like a Rally car anti lag system, and provides higher airflow at much higher pressures than a conventional 2litre race engine. [url
|http://thumbsnap.com/sT0kE0fN[/url]
Looking forward to see what you think. Might be a pretty stupid idea that I wasted my time and money on but I had fun doing it.
|http://thumbsnap.com/sT0kE0fN[/url]Looking forward to see what you think. Might be a pretty stupid idea that I wasted my time and money on but I had fun doing it.
Why not look into ways of turning the turbo into the jet and then 'bleeding off' air for the engine?
Also someone has already tried to use a APU of a jet to feed an engine but they struggled to keep the turbine alight I think.
MaxTorque will love this and will be here shortly I'm sure .
Also someone has already tried to use a APU of a jet to feed an engine but they struggled to keep the turbine alight I think.
MaxTorque will love this and will be here shortly I'm sure .
Sometimes the World can seem a depressing place with all the problems. Work can be hard, life can be stressful and then......along comes someone with lovely enthusiasm, grit, determination, willing to put an idea on PH for peer group review (we all love engines I hope?) where many folk can take great delight in 'shooting things down', well done mate and good luck with your future whatever you do. Thank you for sharing.
Peter
Peter
Hi everyone, thanks for the replies.
Of course there will be challenges in reducing the back pressure to the turbine which could cause it to cut out, but this can be fixed with incremental changes to the angle and distance it is from the turbo exhaust inlet. The turbine requires about 2.5s from idle to full throttle, mainly due to its lightweight titanium core. It could be incorporated with the actual turbo exhaust manifold to add additional exhaust flow on braking and gear changes to keep the turbo spooled up continuously. Fuel consumption is 195g/min at full throttle and turbine weight with ancillaries is about 855g. Need to get a CNC machined turbine mount to properly bolt the it on without pressure leaks, but am a bit low on cash at the moment being a student.
Of course there will be challenges in reducing the back pressure to the turbine which could cause it to cut out, but this can be fixed with incremental changes to the angle and distance it is from the turbo exhaust inlet. The turbine requires about 2.5s from idle to full throttle, mainly due to its lightweight titanium core. It could be incorporated with the actual turbo exhaust manifold to add additional exhaust flow on braking and gear changes to keep the turbo spooled up continuously. Fuel consumption is 195g/min at full throttle and turbine weight with ancillaries is about 855g. Need to get a CNC machined turbine mount to properly bolt the it on without pressure leaks, but am a bit low on cash at the moment being a student.
The problem you have is that a aerojet engine is a low exit pressure high velocity device designed to make "Thrust" and an automotive turbocharger is a high pressure ratio low mass flow device. As such, to get any meaningful turbine work, you need several bar (usually around 4) of upstream pressure. I'm pretty sure you'll find the combustor in the jet engine will not even burn at that pressure, and even if it does, it will probably melt as there will be little post combustor expansion.
This has been done several times before, and most people use an reasonably large gas turbine and bleed air off it's compressor to precharger the ICE. Even then, most people keep an normal, but large, conventional turbocharger on the engine to provide the manifold pressure increase at high rpm/loads.
This has been done several times before, and most people use an reasonably large gas turbine and bleed air off it's compressor to precharger the ICE. Even then, most people keep an normal, but large, conventional turbocharger on the engine to provide the manifold pressure increase at high rpm/loads.
Thanks for reply, what you are saying was my fear aswell, as Bernoulli's equation dictates a loss in pressure due to high velocity, and back pressure would cause the turbine to overheat. Looks like i'm going have to find a different way to do this. A way in which the pressure is increased before it enters the turbo, this could be done by finding a way to decrease the turbines exhaust velocity. Then I'll need to find a way of cooling the combustor so it dosen't melt. Bit more work than I imagined, but this is a good engineering exercise for me in terms of thermo and flow dynamics.
Also a mechanical engineer here. One of the wonders I had one day was to increase the size of the turbo to the extend that you could take power off the turbo and not from the engine - thermally should be more efficient.
Just a thought (Don't mention the engineering challenges associated with getting the turbo to drive anything)
Just a thought (Don't mention the engineering challenges associated with getting the turbo to drive anything)
bearman68 said:
Also a mechanical engineer here. One of the wonders I had one day was to increase the size of the turbo to the extend that you could take power off the turbo and not from the engine - thermally should be more efficient.
Just a thought (Don't mention the engineering challenges associated with getting the turbo to drive anything)
Isn't that what the MGU-H in F1 does - and why the Mclaren is not competitive - their MGU-H unit is much smaller than the rest of them.Just a thought (Don't mention the engineering challenges associated with getting the turbo to drive anything)
S.
Ok going back to basics here. What are you actually trying to achieve? Is it higher manifold pressure than what a 'normal' turbo system can deliver or is it very fast response?
If you want higher manifold pressure then you can always compound conventional turbos to reduce the drive pressure but still having high intake pressure.
If you want higher manifold pressure then you can always compound conventional turbos to reduce the drive pressure but still having high intake pressure.
The problem with using compressor bleed air is that although the combustor runs stoichiometric behind the flame catcher, a large amount of additional air is used to cool that combustor, and is bypassed around the flame front and introduced down stream to dilute the exhaust gas to get it down to a temperature that the turbine can survive. With the relatively low expansion ratio the post combustor temps are sky high and need to be cooled. So, if you remove some of that bypass air by bleeding it off the compressor, you'll run into thermal issues due to the lack of cooling.
The Prodrive "rocket" ALS system uses a conventional turbine, and puts a combustor into the exhaust line upstream of the turbine. A controlled bypass valve shunts a large air mass flow around the engine, and into the combustor to bring the AFR back to stoichiometric (on average, AFR varies with location in the combustor, rich at the flame retainer, bled lean rewards for cooling).
The primary control arbitrator is turbo shaft speed, which effectively brings the system to a constant mass flow system (which it needs to be close to due to the (typical)design constraints with the combustor), and the position of the bypass valve sets how much goes through the engine, and how much just to drive the system.
Of you want to use this model jet, you'll need to find a massive turbine, and probably clip/trim the blades for min restriction. This will obviously seriously limit the total shaft power, but with a suitable (small) compressor will allow the system to provide a useful boost pressure at a low compressor mass flow.
The Prodrive "rocket" ALS system uses a conventional turbine, and puts a combustor into the exhaust line upstream of the turbine. A controlled bypass valve shunts a large air mass flow around the engine, and into the combustor to bring the AFR back to stoichiometric (on average, AFR varies with location in the combustor, rich at the flame retainer, bled lean rewards for cooling).
The primary control arbitrator is turbo shaft speed, which effectively brings the system to a constant mass flow system (which it needs to be close to due to the (typical)design constraints with the combustor), and the position of the bypass valve sets how much goes through the engine, and how much just to drive the system.
Of you want to use this model jet, you'll need to find a massive turbine, and probably clip/trim the blades for min restriction. This will obviously seriously limit the total shaft power, but with a suitable (small) compressor will allow the system to provide a useful boost pressure at a low compressor mass flow.
I'm not an engineer either but obviously have an interest.
My dumb question is;
If the object is to keep the turbo spooled up or to spool up quickly then wouldn't or be better;
a, Have a compressed air reservoir that could instantly spool the turbine up. Obvious limitations would be depleting the reservoir quickly if lots of gear changes are needed.
or
b, design some fancy pants diverter valve that would allow the turbo to be spooled up all the time, where boost is switched in and out via the diverter as needed. Obvious disadantage is that the compressor rotation would be quickly lost anyway which then gives rise the need to what you have designed or in a, above.
I'm sure it has all been tried before, just some dumb questions from a non engineer type .
My dumb question is;
If the object is to keep the turbo spooled up or to spool up quickly then wouldn't or be better;
a, Have a compressed air reservoir that could instantly spool the turbine up. Obvious limitations would be depleting the reservoir quickly if lots of gear changes are needed.
or
b, design some fancy pants diverter valve that would allow the turbo to be spooled up all the time, where boost is switched in and out via the diverter as needed. Obvious disadantage is that the compressor rotation would be quickly lost anyway which then gives rise the need to what you have designed or in a, above.
I'm sure it has all been tried before, just some dumb questions from a non engineer type .
The goal I was going for was to basically keep the turbo spooled at all engine RPM ranges. Meaning the engine would respond as though it was naturally aspirated. As MaxTorque highlights this will only be possible using a much larger turbine due to thermal and flow constraints. To re configure the micro turbine system will require a major budget and lots of time which I don't have. So I am going to have to think of a new way round the problem. Electric I think probably will be the way to go, I could get something like a YASA-400 electric motor with a 20:1 planetary gearbox, which kicks in through a clutch to keep the turbo spooled up when it drops in speed. It will work much like an MGU-H in F1.
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