Iyunithi yokulinganisa amafutha eBosch (ivalve yokulinganisa ifuel) eveliswe yiYS yenye yezona nxalenye zibalulekileyo kwinkqubo yonikezelo lwamafutha enjini yedizili. Ilawula ubungakanani bamafutha angena kumzila kaloliwe wokuhlangabezana neemfuno zokumisela uxinzelelo lwenkqubo kaloliwe eqhelekileyo. zenza ulawulo oluvaliweyo loxinzelelo lukaloliwe kunye nenzwa yoxinzelelo kaloliwe.
Izishunqulelo zesiNgesi zevalve yemitha yemitha yeBosch eveliswe yiYS yi-ZME, MEUN, inkqubo yeDelphi ibizwa ngokuba yi-IMV valve, kwaye inkqubo yeDenso ibizwa ngokuba yi-SCV valve okanye i-PCV valve.