00:00:00.230 a car engine generates power from the 00:00:07.53900:00:07.549 expansion of compressed air in a 00:00:09.73000:00:09.740 contained cylinder with the help of fuel 00:00:11.82900:00:11.839 that is why it's called as an internal 00:00:15.10000:00:15.110 combustion engine before getting into 00:00:18.07000:00:18.080 the working let's see the main parts 00:00:20.49900:00:20.509 involved in the working of an engine 00:00:23.33900:00:23.349 first the crankshaft this is the part 00:00:27.13000:00:27.140 which converts the linear motion of the 00:00:29.07900:00:29.089 piston to a rotational force next the 00:00:33.13000:00:33.140 Pistons and the piston rods the Pistons 00:00:36.13000:00:36.140 will be pushed down by the expansion of 00:00:38.41000:00:38.420 compressed air and turns the crankshaft 00:00:40.66000:00:40.670 and the valves which controls the flow 00:00:44.92000:00:44.930 of air and fuel into the cylinders these 00:00:48.63900:00:48.649 vowels are driven by the intake camshaft 00:00:51.06900:00:51.079 and the exhaust camshaft and the 00:00:53.52900:00:53.539 camshafts are driven by the crank itself 00:00:56.47000:00:56.480 using a timing belt there will be idler 00:01:00.00900:01:00.019 pulleys and attention a pulley to hold 00:01:02.86000:01:02.870 the belt tight in place this here is the 00:01:06.82000:01:06.830 internal structure of a four-stroke 00:01:09.34000:01:09.350 inline 4-cylinder dohc engine which is 00:01:13.27000:01:13.280 commonly found in most hatchback and 00:01:15.40000:01:15.410 sedan cars the four-stroke engine should 00:01:19.03000:01:19.040 pass through four different strokes to 00:01:21.58000:01:21.590 complete one cycle to produce power 00:01:23.89000:01:23.900 they are intake compression power and 00:01:26.74000:01:26.750 exhaust stroke the crank two camshaft 00:01:30.64000:01:30.650 ratio is 2 is to 1 which means it will 00:01:34.06000:01:34.070 take to crank revolutions to complete 00:01:36.73000:01:36.740 one camshaft revolution and the 00:01:39.40000:01:39.410 camshafts are designed in a responsive 00:01:41.80000:01:41.810 manner to open or closed based on the 00:01:44.23000:01:44.240 corresponding strokes of each cylinder 00:01:47.16000:01:47.170 let's take a look at a single cylinder 00:01:49.93000:01:49.940 and see how a four-stroke engine works 00:01:52.63000:01:52.640 in detail in order to ignite the air 00:01:56.20000:01:56.210 fuel mixture a spark plug is used this 00:01:59.83000:01:59.840 will ignite the compressed air fuel 00:02:01.66000:02:01.670 mixture with the help of an electrical 00:02:03.88000:02:03.890 spark 00:02:05.60900:02:05.619 we will take it down by each stroke the 00:02:10.02900:02:10.039 intake stroke the inlet valve opens and 00:02:13.27000:02:13.280 the downward movement of the piston 00:02:15.07000:02:15.080 creates a suction this pulls the air 00:02:17.80000:02:17.810 fuel mixture into the cylinder once the 00:02:21.46000:02:21.470 air fuel mixture is in the cylinder 00:02:23.61900:02:23.629 compression stroke begins compressing 00:02:26.11000:02:26.120 the mixture at this time both Inlet and 00:02:28.83900:02:28.849 outlet valves stays closed at the end of 00:02:32.55900:02:32.569 compression stroke the air fuel mixture 00:02:34.60000:02:34.610 is ignited by the spark plug the 00:02:37.78000:02:37.790 explosion exerts pressure and pushes the 00:02:40.27000:02:40.280 piston down this is the power stroke 00:02:42.97000:02:42.980 which produces power to the crank at the 00:02:47.05000:02:47.060 exhaust stroke the outlet valves opens 00:02:50.11000:02:50.120 and the piston pushes out the burned gas 00:02:53.10000:02:53.110 the cycle starts again from intake 00:02:55.96000:02:55.970 stroke keeping the engine running and 00:02:58.18000:02:58.190 produces power for a carburetor engine 00:03:01.75000:03:01.760 the air and fuel are mixed inside the 00:03:04.18000:03:04.190 carburetor assembly and fed to the 00:03:06.49000:03:06.500 cylinders in the case of a fuel-injected 00:03:10.03000:03:10.040 engine the fuel is injected into the 00:03:12.55000:03:12.560 intake manifold or directly into the 00:03:15.22000:03:15.230 cylinders since only a power stroke 00:03:19.09000:03:19.100 produces power you may wonder how the 00:03:21.49000:03:21.500 engine turns continuously well the 00:03:25.03000:03:25.040 answer is in the crank itself the 00:03:27.61000:03:27.620 flywheel and the crank counterweights 00:03:29.71000:03:29.720 provides momentum which keeps the 00:03:32.05000:03:32.060 crankshaft from stopping immediately for 00:03:35.65000:03:35.660 a four-cylinder engine considering any 00:03:38.11000:03:38.120 time instance one cylinder is always in 00:03:41.02000:03:41.030 power stroke which produces more power 00:03:43.87000:03:43.880 and less vibrations comparing to a 00:03:46.15000:03:46.160 single cylinder engine and that is how a 00:03:49.47900:03:49.489 car engine produces power and simple 00:03:52.74000:03:52.750 thanks for watching and stay tuned for 00:03:55.78000:03:55.790 more presentations from Auto Tech labs
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