Posted From: 184.108.40.206
|Posted on Friday, 30 May, 2014 - 05:34: |
Normally the compressor and the power turbine are on the same shaft
If the compressor is driven by an electric motor and the power turbine drives a generator then how much and when the boost happens can be controlled independently of the exhaust
Thus more efficiency
This idea is not new and big ships have electric blowers for starting
Ironically developments in electric cars have made this possible for road engines.
It also makes 2 stokes that don't burn oil possible for cars
I found out about this while talking to the manic with
the golf cart he is very sharp
I think the future of cars lies with electric drive but we need a
stop gap and a 4 cylinder decoupled turbocharged 1500cc 2 stroke could easily work most cars
(Message approved by david_gore)
Post Number: 47
|Posted on Friday, 30 May, 2014 - 16:34: |
2 stroke? I thought these are gone for good for cars since the end of East Germany's (DDR) Trabbi...
Post Number: 550
|Posted on Friday, 30 May, 2014 - 22:40: |
The death knell for 2-stroke cars was first sounded when the emissions laws ('smog' laws in the US) started to be introduced. Even the very first 'visible smoke' only ones made it difficult for them to pass the MOT. IIRC the first to go in the UK was the otherwise (apart from a tendency to dissolve in the rain) excellent little Wartburg estate car. With the advent of the exhaust gas analyzers the writing was definitely on the wall.
Only the ingenuity of the Japanese with 2-stroke mopeds and small motorcycles has managed to keep the genre viable to date.
However I like the sound of the electric 'blower' to add a small boost (2-3psi) to the 'static' pre-combustion cylinder pressure. Taking some of the power required from the exhaust with a small elecricity generator sounds like some kind of 'left field' thinker has been earning his/her pay for the year!
A couple of decades ago a friend suggested the addition of a similar electric blower to boost the inlet pressure on his relatively tiny 2.5 litre Triumph until I worked out just how much air it needed to shift just to keep up with the unpressurised flow. 44 CU Ft per 1,000 rpm per minute is going to be difficult to achieve over 5K! Adding a boost that's consistent with the needs of the engine on a second-by-second basis is going to be difficult (but far from impossible) to achieve - especially by a tinkerer. However I wouldn't want to be in the same county when BobUK's friend tries out something along these lines!
Posted From: 220.127.116.11
|Posted on Saturday, 31 May, 2014 - 05:55: |
2 strokes normally use the crankcase to suck in fuel oil mix then as piston goes down it pushes the mixture via a transfer port to above the piston
If a compressor is fitted then the air goes straight into the cylinder
And the crankcase can hold oil for lubrication as in a 4 stroke engine
The rush of air into the cylinder blows out the exhaust gases when the piston has covered the ports the fuel is injected
This way no fuel ends up in the exhaust
To run the compressor would require 4 hp[1500cc]
Brushless DC would be best due to 50000 rpm
Ricardo engineering has been sniffing around the idea
(Message approved by david_gore)