"Embudo" is almost certainly a calque from the English here.

"Extending the Innovation Funnel
The ideas funnel has been with us a long time. We put our ideas into the funnel and then through a process of elimination out ‘pop’s’ finished products. Henry Chesbrough’s famous depiction of the Open Funnel has continued that concept, that ideas enter the more ‘open’ innovation process and go through a more ‘staged gate’ or equivalent process to emerge as the finished product or even spun-out"
http://bx.businessweek.com/open-innovation/extending-the-inn...

Yes, I don't see why you shouldn't just go with the literal translation here. Plenty of examples out there for both 'open' and 'closed funnel innovation models'.

A couple of examples:

http://www.nesta.org.uk/publications/guest_articles/assets/f...
'An open innovation model opens up the funnel that needs to be adapted to encompass flows of technology and ideas outside an organisation. The funnel can be compared to old-fashioned analogue technologies and COI to a digital regime with fewer 'bandwidth' constraints and more emphasis on connections. This analogy illustrates the fundamental shift in thinking that is required.'

http://www.openinnovate.co.uk/papers/dissertation.pdf (page 25):
'This process was illustrated using his famous version of the innovation funnel that had one primary point of differentiation compared with previous versions; a permeable membrane that allows the exchange of ideas and technologies with the exterior as it is shown in figure 5.'