the “squish clearance”, and is what we will discuss in this article. The optimal surface of the squish crown ranges from 45% to 55% of the surface of the piston crown, the most "free" parameter is the height (minimum clearance, at TDC, between cylinder head and piston) of the squish crown, i.e. thinner inside than outside: not only would it not have the desired effect, but it would detonate the mixture inside the closed cavity created. The squish crown will rarely be parallel to the piston crown, more frequently inclined upwards by 1 degree or more than the same (clearly, in the case of domed pistons the inclination of the squish crown must be greater than in the case of flat top pistons).įor obvious reasons, a negative squish is never and in no case allowed, i.e. The part highlighted in red is the crown / band / ring of squish, the one in gray is the dome, and in the center in white we have the spark plug hole. In this image we see schematically the combustion chamber, seen from below: The "squish effect" (which takes its name from the hypothetical noise produced by the crushed mixture between piston and cylinder head) is what we are looking for: the piston, rising to TDC, will compress the fresh mixture against the squish crown, causing it to splash towards the center of the combustion chamber, where we normally find the spark plug. If you have arrived here you probably already know what squish is, but a brief introduction will do no harm: the "squish crown" or "squish band" or "squish ring" is the outer area of the combustion chamber and, unlike the actual "dome", is shaped so as to be at a short distance (in the order of a millimeter) from the piston to the top dead center. NOTE: the disclosure and dissemination of this article is welcome and expressly permitted, provided it is exclusively in the form of a direct link to this web page: any other use is strictly forbidden and will be prosecuted by law. Copyright © 2017 Fabio Bizzetti, all rights reserved.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |