Chikamu chezasi che cylinder block panoiswa crankshaft inonzi crankcase. Iyo crankcase yakakamurwa kuita yekumusoro crankcase uye yakaderera crankcase. Iyo yepamusoro crankcase uye cylinder block inokandwa semuviri mumwe. Iyo yepasi crankcase inoshandiswa kuchengeta mafuta ekuzora uye kuvhara yekumusoro crankcase, saka inodaidzwa zvakare kuti pani yemafuta. Pani yemafuta ine simba shoma uye kazhinji inodhindwa kubva kumarata matete. Chimiro chayo chinoenderana nekurongeka kwese kweinjini uye huwandu hwemafuta. Oiri inodzikamisa baffle inoiswa mupani yemafuta kudzivirira kuchinjika kwakanyanya muzinga reoiri kana mota ichifamba. Pazasi pepani yemafuta zvakare yakashongedzerwa neoiri yekudonhedza plug, kazhinji magineti echigarire anoiswa paoiri yekudhonza plug kuti itore simbi machipisi mumafuta ekuzora uye kuderedza kupera kweinjini. Gasket inoiswa pakati penzvimbo dzakabatana dzepamusoro nepamusoro crankcases kudzivirira kubuda kwemafuta.

Iyo crankcase ndiyo inonyanya kukosha chikamu cheinjini. Inotakura simba rinofambiswa kubva patambo yekubatanidza uye inoishandura kuita torque kuti ibudise kuburikidza ne crankshaft uye kutyaira zvimwe zvishongedzo painjini kuti ishande. Iyo crankshaft inoiswa pasi pekuita kwakasanganiswa kweiyo centrifugal simba rehuremu hunotenderera, iyo periodic gasi inertial simba uye inodzoreredza inertial simba, zvekuti iyo curved bearing inoiswa pasi pekukotama uye torsion mitoro. Naizvozvo, crankshaft inodiwa kuti ive nesimba rakakwana uye kusimba, uye pamusoro pejenari inofanirwa kusapfeka, kushanda zvakafanana, uye kuve nechiyero chakanaka.

Iyo crankcase ichasakara nzvimbo yekubatana pakati pekupedzisira kwetambo yekubatanidza nejenari nekuda kwemafuta asina kuchena uye simba risina kuenzana rejenari. Kana mafuta ane tsvina yakakura uye yakaoma, kunewo njodzi yekukwenya bhuku rejenari. Kana kupfeka kwakanyanya, zvinogona kukanganisa kureba kwepiston kumusoro uye pasi, kuderedza kupisa kwemoto, uye nemaitiro kuderedza kubuda kwesimba. Pamusoro pezvo, crankshaft inogonawo kukonzera kupisa pamusoro pejenari nekuda kwekusakwana kwekuzora kana mafuta akatetepa zvakanyanya, izvo zvinogona kukanganisa kudzoreredza kufamba kwepiston mumatambudziko akaomarara. Naizvozvo, mafuta ekuzora eakakodzera viscosity anofanirwa kushandiswa uye kuchena kwemafuta kunofanirwa kuve nechokwadi.