camshaft-less engine
Discussion
MG was working on a engine that does not have a camshaft.
www.autocarmagazine.com/News_Article.asp?NA_ID=214828
www.autocarmagazine.com/News_Article.asp?NA_ID=214828
Been used in F1 for a while now, BMW is also working on it, probably others as well.
Just in case you haven't heard M.G. - Rover most likely isn't working on anything at the moment as they filed for bankruptcy a couple of weeks ago.
>> Edited by Trooper2 on Thursday 5th May 07:42
>> Edited by Trooper2 on Thursday 5th May 07:43
Just in case you haven't heard M.G. - Rover most likely isn't working on anything at the moment as they filed for bankruptcy a couple of weeks ago.
>> Edited by Trooper2 on Thursday 5th May 07:42
>> Edited by Trooper2 on Thursday 5th May 07:43
They aren't the only ones. It will be intresting to see what comes out. With a ECU controlling the cam profile you could have various different settings at the same time. Cambelt failure would also be erradicated and wouldn't be stung for big bills every 70K miles.
We'll you probably would but they'd hide the reason in weaselese.
We'll you probably would but they'd hide the reason in weaselese.
liszt said:
They aren't the only ones. It will be intresting to see what comes out. With a ECU controlling the cam profile you could have various different settings at the same time. Cambelt failure would also be erradicated and wouldn't be stung for big bills every 70K miles.
We'll you probably would but they'd hide the reason in weaselese.
Weaselese
It will be short to ground, open or high resistance.
Hey wait a minute, I'm studying to be a weasel, err... a professional automotive technician.
Trooper2 said:
Been used in F1 for a while now, BMW is also working on it, probably others as well.
Just in case you haven't heard M.G. - Rover most likely isn't working on anything at the moment as they filed for bankruptcy a couple of weeks ago.
>> Edited by Trooper2 on Thursday 5th May 07:42
>> Edited by Trooper2 on Thursday 5th May 07:43
Its never been used in F1 sorry,all F1 engines use good old camshafts with finger followers,
electromagnetic operation was bench tested by renault and other teams,its to bulky,to heavy,and makes the top end of the motor to high,so camshafts still do
the job,
Dale.
kenmorton said:Could be but “Turboshaft” works as well without camshafts (Don’t even get me started on steam engines).
At the risk of being silly - arnt camshaftless engines generally called 2strokes ?
Lotus are working on an engine that uses solenoid valves, the only problem is that the solenoid’s are a little expensive.
speedy_thrills said:
At the risk of being silly - arnt camshaftless engines generally called 2strokes ?
Could be but “Turboshaft” works as well without camshafts (Don’t even get me started on steam engines).
Lotus are working on an engine that uses solenoid valves, the only problem is that the solenoid’s are a little expensive.
Turboshaft,do you mean gas turbine-jet engine.
Jet turbines are pretty useless for powering helicopters or cars, which need rotary motion not plain thrust, hence the turboshaft, which uses an extra turbine stage (called a free power turbine) which is geared down to provide rotary power.
If anyone is into model engineering, there is a Yahoo group (low traffic though) for people into playing around with electric engine valves.
http://groups.yahoo.com/group/EVIC-111/
It's certainly not a new idea, I was playing with them at Uni in the early 90s and I suspect they were around well before then. It seems to me that diesel engines would be a better testbed then petrol units, with their inherently slower speed.
Another technology that appeared around the same time was variable stroke control, which allowed the length of the piston's stroke to be varied as the load changes. So at idle or while cruising along, the engine may have a swept volume of 500cc, but under load it may increase to 3000cc, keeping the power of a big engine, with the potential economy of a small engine. Fuel companies tend not to like that sort of thing though.
Mike
If anyone is into model engineering, there is a Yahoo group (low traffic though) for people into playing around with electric engine valves.
http://groups.yahoo.com/group/EVIC-111/
It's certainly not a new idea, I was playing with them at Uni in the early 90s and I suspect they were around well before then. It seems to me that diesel engines would be a better testbed then petrol units, with their inherently slower speed.
Another technology that appeared around the same time was variable stroke control, which allowed the length of the piston's stroke to be varied as the load changes. So at idle or while cruising along, the engine may have a swept volume of 500cc, but under load it may increase to 3000cc, keeping the power of a big engine, with the potential economy of a small engine. Fuel companies tend not to like that sort of thing though.
Mike
Zad said:
Jet turbines are pretty useless for powering helicopters or cars, which need rotary motion not plain thrust, hence the turboshaft, which uses an extra turbine stage (called a free power turbine) which is geared down to provide rotary power.
If anyone is into model engineering, there is a Yahoo group (low traffic though) for people into playing around with electric engine valves.
http://groups.yahoo.com/group/EVIC-111/
It's certainly not a new idea, I was playing with them at Uni in the early 90s and I suspect they were around well before then. It seems to me that diesel engines would be a better testbed then petrol units, with their inherently slower speed.
Another technology that appeared around the same time was variable stroke control, which allowed the length of the piston's stroke to be varied as the load changes. So at idle or while cruising along, the engine may have a swept volume of 500cc, but under load it may increase to 3000cc, keeping the power of a big engine, with the potential economy of a small engine. Fuel companies tend not to like that sort of thing though.
Mike
Mike you say jet engines are usless for power'ing helicopters,so why are 90% of helicopters power'd by gas turbines.
A jet engine gives its output in the form of thrust: a gas turbine gives its output in the form of rotary motion.
The hot spinny bits are the same in both. It's how you get the output that's different.
Of course, gas turbines still produce some jet thrust. The Great Western gas turbine locomotives produced a powerful upward blast that dislodged the soot of ages from the roof of Paddington station onto the heads of journalists at the launch gathering.
Piston engines can also produce jet thrust: something like 10% of the thrust from a Merlin installation came from the rearward-pointing exhaust stubs.
The hot spinny bits are the same in both. It's how you get the output that's different.
Of course, gas turbines still produce some jet thrust. The Great Western gas turbine locomotives produced a powerful upward blast that dislodged the soot of ages from the roof of Paddington station onto the heads of journalists at the launch gathering.
Piston engines can also produce jet thrust: something like 10% of the thrust from a Merlin installation came from the rearward-pointing exhaust stubs.
thong said:
Jet turbines are pretty useless for powering helicopters or cars, which need rotary motion not plain thrust, hence the turboshaft, which uses an extra turbine stage (called a free power turbine) which is geared down to provide rotary power.
Mike you say jet engines are usless for power'ing helicopters,so why are 90% of helicopters power'd by gas turbines.
They aren't powered by jet engines as such, they are turboshafts. "Jet" engines provide thrust *directly* from the exhaust jet. Turboshafts derive their power from an additional turbine (placed in what would be the jet exhaust) which drives a shaft. There's a fairly good diagram of the Allison 250 (used on quite a few different models of Heli and propellor craft) here: www.helicopterflight.net/engine_fig_.htm
Similarly a turbo-prop derives it's thrust mainly from the propellor (driven by a turboshaft) and a turbo-fan derives it's thrust from the huge fan at the front of the engine rather than exhaust gasses. They do all use the same core "idea" just tweaked in different ways that's all.
As has been said, the exhaust gases do still provide some forward thrust, but then the R-R Merlin and Griffon engines gave a very useful increase in top speed when the engineers decided to point their exhausts backwards too!
Mike
Zad said:
Zad said:
Jet turbines are pretty useless for powering helicopters or cars, which need rotary motion not plain thrust, hence the turboshaft, which uses an extra turbine stage (called a free power turbine) which is geared down to provide rotary power.
Mike you say jet engines are usless for power'ing helicopters,so why are 90% of helicopters power'd by gas turbines.
They aren't powered by jet engines as such, they are turboshafts. "Jet" engines provide thrust *directly* from the exhaust jet. Turboshafts derive their power from an additional turbine (placed in what would be the jet exhaust) which drives a shaft. There's a fairly good diagram of the Allison 250 (used on quite a few different models of Heli and propellor craft) here: www.helicopterflight.net/engine_fig_.htm
Similarly a turbo-prop derives it's thrust mainly from the propellor (driven by a turboshaft) and a turbo-fan derives it's thrust from the huge fan at the front of the engine rather than exhaust gasses. They do all use the same core "idea" just tweaked in different ways that's all.
As has been said, the exhaust gases do still provide some forward thrust, but then the R-R Merlin and Griffon engines gave a very useful increase in top speed when the engineers decided to point their exhausts backwards too!
Mike
So we agree then that the main forword motion of gas turbines is created in the combustion cans or as used now anular can with a ring of burners.
i thought we were talking about camshafts.if you also use a pre-heated chamber[like the aero industry] you can run extremly weak mixtures like 50-1.this would give great economy.link this with no camshafts,you could have an 8 cylinder car run 1 cylinder,2,3 etc.also,the timing is so controllable by moving a switch,the engine could go from econ to race!! that would make a great engine.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff