As far as locomotive engine functioning go , what comes out is just as significant as what goes in . exhaust fumes systemsaren’t added on merely to control where emissions go . At its gist , a honest exhaust system can avail an engine turn over apex functioning . elevator car makers want such an exhaust fumes organization , and this where the 4 - 2 - 1 exhaust arrive into play .
First of all , why does this particular system of rules go by " 4 - 2 - 1 " ? The number refer to the exhaust fumes pipe layout : Four tube get off the cylinder foreland ( or extra lintel ) , which turns into two pipes , and the scheme finally end with one pipe conduct to thecatalytic converterandmuffler .
The melodic theme behind any exhaust system system is to remove as much fumes flatulence as potential from the cylinders cursorily . The automotive term for this is " clean . " Effective scavenging of exhaust system gas increase an engine ’s overall efficiency .
Each clip a ability stroke pass off in the locomotive and an exhaust system valve opens , positive imperativeness is create in the exhaust fumes manifold . And in between these overconfident pressure , negative pressures also happen , especially at lower speeds . As cylinder make these pressures at different times , they can interfere with each other and slack the release of exhaust gas .
On a four - piston chamber engine , pipes 1 and 4 are bond into cylinders 1 and 4 . pipe 2 and 3 are tie into piston chamber 2 and 3 . The organ pipe distance are designed to bring the exhaust gases to the juncture of where the four pipes turn into two at a bias time . retrieve , cylinders 1 and 4 exhaust their gases at different time than 2 and 3 . These gas impulse are clock , through the pipe distance , to reach the juncture at a point where their passage helps each other along rather than interfering with each other . Once through , they head out through the unmarried pipage , go by through the catalytic convertor , and then leave the car by the muffler and out of the tail pipe .
4 - 2 - 1 scheme , while common , are mostly used in general drive program . Other car , such as race cars , use a 4 - 1 organization that boosts efficiency at higher rotation . Whichever system is used , the idea is to increase efficiency within a afford engine revolution range of a function .
For lots more information on fomite functioning , see the connexion on the next page .
