$4.$ The role of the crankshaft in an internal combustion engine is to $\_\_\_.$ It converts $\_.$ This component is crucial for $\_\_\_.$

$-($convert the linear motion of the pistons into rotational motion, the energy generated during combustion, driving other engine components, ensuring smooth engine operation, maintaining engine timing$)$

$5.$ Brake mean effective pressure $($BMEP$)$ is a measure of $\_\_\_.$ It indicates $\_.$ High BMEP values generally correlate with $\_\_\_.$

$-($the average pressure exerted on the pistons during the power stroke, the engine$$s efficiency and power output, improved engine performance, higher fuel consumption, reduced mechanical losses$)$