An automobile engine creates the power needed to propel your vehicle through hundreds of small explosions every minute, where fuel, air and pressure combine in one cylinder to force pistons upward and downward.
The pistons are connected to a crankshaft that’s turned by either a belt or chain, which then turns a camshaft with lobes along its length that briefly press against valve stems and close them off.
Combustion Chamber
Combustion chambers are where fuel and air in your engine come together to be ignited, transforming chemical energy into mechanical force which then moves pistons up and down with each revolution of your crankshaft.
The shape and size of a combustion chamber determine how much compression can be attained, which impacts power output from an engine. Air swirls play an integral part of its design by helping ensure air atomization with fuel as part of an engine’s power output.
The cylinder head sits above an engine’s cylinders and creates space at the top of its combustion chamber for intake and exhaust valves, as well as housing the spark plug, which supplies electrical current to start combustion process and fuel injectors. Furthermore, its connecting rod connects piston with crankshaft.
Cylinder Head
A cylinder head is at the heart of engine operation, providing mounting structures for intake and exhaust valves, camshafts and fuel injectors as well as cooling passages to keep things operating optimally. It sits atop of your cylinder block to form part of its combustion chamber while also covering it. Additionally, it serves to cover cooling passages.
There are various kinds of heads. One such option, known as the flathead, consists of a cast iron part which serves to protect the cylinder block. While they’re easy to keep clean and maintain, their design does not allow for proper airflow and therefore performs less efficiently.
Hemispherical and pent-roof types of engines are very popular. Their combustion chamber shapes allow for better burning of air/fuel mixture, leading to more complete and powerful burn. Furthermore, this results in more power from each size engine.
Intake Valve
On the power stroke, the intake valve opens to allow air/fuel mixture to enter, compress it and ignite it – thus turning chemical energy into mechanical energy that turns the crankshaft. After combustion has taken place, then exhaust valve closes, sending combustion gases out through exhaust system.
A camshaft regulates the opening and closing of valves. A timing chain or belt ensures that camshaft and crankshaft move at exactly the same rate for seamless power production and to minimize noise, vibration and emissions.
Valve components in an engine undergo hundreds of thousands of load cycles during its lifespan, fluctuating temperature variations and being subjected to fatigue failures; thermal fatigue being the most commonly identified mode, although other damage mechanisms include brittle cracking near seat face cracking and mechanical bending stresses may also present themselves as risks.
Exhaust Valve
Few engine components experience as much tribological wear and abrasion as an exhaust valve does, being continually hit by hot gases while being subject to enormous acceleration forces every time they open or close.
In order for any valve to function effectively, it must open at precisely the right moment allowing air and fuel to enter while exhaust leaves at once. A camshaft controls this by opening its valves when an intake or compression stroke takes place.
Exhaust valves are often the first indicators of engine trouble in cars. Unburnt byproducts from combustion create colorful buildsups on exhaust valve faces; when these fail to seat correctly, hot gases from combustion can scorch thin rims of these valves; often this results in an asymmetric pattern similar to overcooked pizza as evidence of failure.
Crankshaft
The crankshaft is an impressive piece of machinery, transforming the linear up and down motion of pistons into the rotating motion that drives your car’s wheels. Due to considerable rotational forces it must also withstand significant stress-reducing counterweights cast as part of its design in order to relieve stress on it. In addition, clearances between journal and bearing require proper lubrication in order to prevent excessive forces or metal-to-metal contact occurring within them.
Inside each cylinder are small cylindrical plugs known as pistons that resemble upside-down soup cans. When fuel ignites in the combustion chamber, it creates a powerful explosion which sends pistons tumbling and drives the crankshaft, powering your wheels of your car 50,000 times per minute! This process occurs repeatedly within Formula One engines.