Car Engines Automotive Appreciation Part 1

Car Engines Automotive Appreciation Part 1


hi welcome to automotive appreciation in this course we will learn about the operation of cars topics include engines transmission steering suspension brakes and electrics we start with a four-stroke engine in operation intake a mixture of fuel and air is drawn into the cylinder compression the piston compresses the mixture combustion compressed gas is ignited by a spark plug and exhaust burnt gases are expelled from the cylinder note the camshafts which operate the VARs only rotate at half the speed of the crankshaft this is achieved by using larger diameter pulleys on the camshafts the timing belt ensures that the valves open and close at the correct time relative to the position of the piston we take a look at the engine components at the top we have the camshaft which controls the inlet valve allowing fuel and air into the cylinder the block houses the main components of the engine and is cooled by the water jacket oil is stored in the sump and is used to lubricate the engine the crankshaft is supported by bearings at the bottom of the engine the cylinder liner provides a smooth surface for the piston to move inside while the con rod connects piston to the crankshaft thus converting leaks separating motion of the piston to rotational movement of the crankshaft at the top is the head gasket which provides the seal between the block and the cylinder head the exhaust valve is also controlled by a camshaft it allows the waste gas to exit from the cylinder finally at the tip of the spark plug the high voltage electricity jumps across the gap and ignites the fuel it’s important to change the timing belt at a recommended service intervals here we will see what happens if the timing belt breaks that’s an expensive repair we must remember a four-stroke engine only provides power on the combustion stroke the other three strokes actually take power from the engine to account for this intermittent supply of power it is normal to have a number of cylinders in the same engine in this case a four-cylinder engine all cylinders will have staggered combustion strokes for this engine the firing order is one three four to this firing sequence is used to reduce the engine vibration a flywheel is attached to the end of the crankshaft to reduce politicians and vibrations a pulley is attached to the other end of the crankshaft which can be used to drive ancillary equipment such as the alternator water pump or timing belt chapter 2 transmission to allow safe operation of the engine it is necessary to separate the drive from the driven wheels this is achieved with the clutch the clutch is attached to the flywheel and it allows connection and disconnection of the crankshaft output the driven plate is sandwiched between the flywheel and the pressure plate when the clutch is pressed the release bearing moves and the driven plate travels along the splint shaft away from the flywheel allowing the driven plate to rotate independently of the Flyway we see when the clutches press the driven player can move independently of the fly grain and pressure plate a gearbox is used to vary the shaft or depending on driving conditions high torque for accelerating low torque a cruising speeds here we show a basic for speed and reverse gearbox it consists of number of gears wheels which can be interest when required input shaft from gearbox at the bottom is the layer shaft which transmits power through the gears a small pinion for reverse and an output shaft connects to the driven wheels now we will move up through the gears using the selectors first gear starts with the smallest gear on the layers shaft second gear uses the bigger gear and again for third gear a bigger gear is used we see that fourth gear is straight through the crankshaft is connected directly to the output shaft some cars have an overdrive which means their output shaft is rotating faster than the crank shaft this is sometimes used for fifth and sixth gear for reverse an additional pinion is inserted to provide rotation in the opposite direction chapter three steering system the steering wheel is connected to the rack and pinion which converts steering wheel rotational movement to lateral movement the final connection to the wheels is made with the track rod and track arms we see that the inside wheel must turn in a smaller radius than the outside wheel also the outside wheel must travel a longer distance than the inside wheel on a back wheel drive car the differential in the back axle allows for the difference in speed here we can see the rack and pinion in operation chapter four suspension system the suspension on a modern car uses springs and dampers when a coiled spring is compressed and released it will return to its original length a damper or shock absorber is used to damp down the oscillations of a spring it consists of an oil filter and the flow of oil through the piston is restricted by a small orifice when the top rod moves down the gas below the bottom piston is compressed to allow for the extra rod volume a spring and damper are often combined in one unit cotton McPherson strut here we see the Macpherson’s dropped in operation it provides comfort for the occupants and maintains the wheel in contact with the road when a car is moving it is important to have a safe reliable means of sewing it down and stopping it in an emergency this is achieved with a hydraulic braking system the disc is attached to the wheel and the brake pads are accommodated in the calipers a reservoir provides a supply of oil to the master cylinder when the brake is pressed the piston pressurizes the oil and activates the wheel chambers tramping the wheel discs between the pads thus slowing down the wheel rotation chapter 6 electrics to start the car the battery provides power to the electric motor which starts the engine rotating via a connection to the flywheel when the engine is running the alternator are driven by the crankshaft ensures that the battery is maintained in a fully charged state power from the battery is used for various electrical systems fuses provided protection for each individual circuit and switches allow current to flow when we start the engine opinion on the starter moves forward and engages with the ring gear on the flywheel now the alternator supplies power to the battery and electrical circuits and switches allow current to flow we hope you learned from automotive appreciation


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