Transcription
Motor mechanics lesson one. Car engines work by internal combustion. Air and a drop of petrol enter the cylinder. The piston moves upward compressing the mixture. The spark plug ignites the fuel causing an explosion that drives the piston downward powering the engine.
Engine components are housed in what's called the engine block. It arrives at this plant partially made. Here, the cylinder bores, the holes in which the pistons move up and down, are finished off by machining. The tool carves a crisscross pattern on the cylinder bore walls. Lubricating oil will cling to the grooves in this pattern, enabling the pistons to move smoothly.
After machining, the engine block travels upside down to the engine assembly line. When it arrives, a scanner records the blocks traceability code, a barcode that enables the factory to track the block through every stage of production. As the engine block travels down the line, devices ensure that each component is installed properly. Elsewhere in the factory, the crankshaft is slowly taking shape. The crankshaft is a bar that's rotated by the up and down motion of the pistons.
As it turns, it transfers power to the transmission. The crankshaft starts out as a roughly shaped steel forging. Robotic arms pass it down the line from station to station until twenty tooling machines later it's fully formed. Next, a steel disc with teeth called the reluctor ring is installed. It's heated and pressed onto the crankshaft.
As it cools, it shrinks to a tight fit. This ring helps time the combustion cycle. As it spins, its teeth pass in front of a sensor which reads the crankshaft's position and tells the engine to fire the spark plug at precisely the right moment. Now workers balance the crankshaft. If it's off kilter, the engine will vibrate.
A computer analyzes the spin and determines whether they need to drill out metal at certain points to achieve equilibrium. Back on the engine assembly line, the engine blocks are still upside down. A robot lubricates the four bearings on which the crankshaft will turn, then it drops the crankshaft into position. The pistons come next. Six, because these are six cylinder engines.
The pistons are made of aluminium. Robots install them into the cylinder boards of the engine block. A steel connecting rod attaches each piston to the crankshaft. Now workers can close-up the back of the engine block. A robot applies sealant to the rear cover.
Workers bolt it on manually with a tool called a multi spindle torque gun. On another line, they assemble the two heads that will cover the top of the engine block. This robot applies sealant to spark plug tubes before inserting them into the heads. The heads cap off the cylinder bores. They provide each cylinder with a spark plug and four valves.
Two for allowing the fuel mixture in and two for releasing the exhaust. The black tubes running front to back are the camshafts. The components that open and close those valves. There are four per engine. A robot applies sealant and then bolts a cover onto the front of the engine block over a component called the timing chain.
This chain connects the crankshaft to the camshafts, so they rotate in unison. This ensures the valves open when the pistons are in the right position. All pretty complicated stuff. Now we can all look bemused next time we pop under the bonnet.