Fill in the Blanks 4-stroke engineOnline version The four-stroke internal combustion cycle by David Fernández 1 closed expand INTAKE spark COMPRESSION up downwards torsion ignited intake thousands downwards cam POWER up up downwards away explosion IGNITION burnt EXHAUST down The four - stroke internal combustion cycle BEFORE THE CYCLE BEGINS . The cycle begins at top dead centre ( TDC ) . Here the piston is furthest from the crankshaft . There are four strokes of the piston . STROKE . The crankshaft rotates . This makes the piston move the cylinder , away from the valves . At the same time , the above the intake valve rotates . This makes the valve move , which opens the intake port . As the piston moves down , fuel is sucked into the cylinder through this inlet . STROKE . As the crankshaft rotates , it makes the piston move the chamber towards the valves . Simultaneously , the cam above the valve rotates and allows it to close . Both valves are now . As the piston moves towards the valves , it compresses the fuel . . Now the piston is once again at TDC . The compressed fuel is by the plug , and there is a small at the top of the cylinder . STROKE . Immediately after this , the gases in the cylinder , which pushes the piston . This makes the crankshaft rotate and provides to drive the wheels of the vehicle . STROKE . As the crankshaft rotates , it pushes the piston the cylinder . At the same time , the cam above the exhaust valve pushes the valve . This opens the exhaust port , and the gases are pushed out . The cycle is repeated of times per minute .
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