Hi NC,
The following link relates to a patent application by Yamaha for an innovative intake system that is rumoured to be employed on their 2007 R1 superbike, rather a lot of reading though by scrolling through you can get the idea. Primary and secondary injectors, upstream and downstream of the throttle butterfly, variable length inlet tracts, variable volume manifold etc.
v3.espacenet.com/origdoc?DB=EPODOC&IDX=EP1655464&F...4
Any thoughts? Perhaps on it's application in cars.
Regards.
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Thanks for posting the link - very intersting.
In some ways, I'm surprised we haven't seen more control over intake and exhaust configurations on cars - although, of course, there have been some examples.
The idea which was new to me was the use of an upstream injector to not only atomise the fuel earlier, but also to cool the air, thus affecting its acoustic properties, and hence affect the wave tuning in the inlet port.
Number_Cruncher
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Over the years there have been all manner of systems tried - but few stand the test of time. I guess it comes down to cost/benefit and reliability. The one that does seem to have gained acceptance on cars and bikes is variable length tracts.
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>>The idea which was new to me was the use of an upstream injector to not only atomise the fuel earlier, but also to cool the air, thus affecting its acoustic properties, and hence affect the wave tuning in the inlet port. >>
If atomising the fuel earlier cools the air it will enable a denser charge within the combustion chamber.
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Anyone remember water injection?
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Yes, that's right - the air will be cooled wherever the fuel is injected, upstream, or down. The new bit for me was that having two sets of injectors enabled you to tweak the wave tuning properties of the manifold further than simply varying its length.
So, for example, without changing anything other than which injector you use, upstream, or down, you will vary the volumetric efficiency, and hence the engine's output, purely via acoustic wave tuning effects, without throttling, and without substantially changing the temperature of the charge.
Whether there is enough of a benefit to warrant the extra set of injectors, I don't know.
Number_Cruncher
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Over the years there have been all manner of systems tried - but few stand the test of time. I guess it comes down to cost/benefit and reliability. The one that does seem to have gained acceptance on cars and bikes is variable length tracts.
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yes.as said cost for marginal benefit and reliability over many years can be a big problem.
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yes.as said cost for marginal benefit and reliability over many years can be a big problem.
Over the years multivalve heads, twin cams, variable valve timing, turbos etc have all been the exception and then the norm.
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Well of course. That's how new ideas come to market. CVT transmission is a very old idea going back to about 1904 (Rudge motorcycle used in the TT used leather-belt CVT). It had various problems and didn't catch on. The idea was revived in Germany in the 1930's. Again didn't really take off. Van Doorne had some success a few decades back - again didn't really take off. Then we have had more recent attempts that look a bit more promising - but the jury is still out. Usually its a case of good ideas waiting for more advanced materials and manufacturing processes to make them viable.
All-alloy multivalve engines with twin cams were built in Germany around the time of the start of the First World War, but it took very many decades before they became 'the norm'.
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