Aviation Training Tip: The 4 Stroke Cycle

0:00After watching this quick tip video, be sure to check out our website at Wi-Fi-CFI.com. Our online aviation courses include Study Courses for the private pilot, instrument rating, commercial pilot, CFI, CFWI, and multi-engine app on Study Courses. All of these include videos, podcasts, quizzes, flashcards, audiobooks, practice FAA exams, check-ride workbooks, and more. We also have courses for just the check-ride lesson plans. These are to teach on those flight instructor check-rides. We've got the CFI, the CFWI, and the MEI add-on lesson plans. They all come in PowerPoint, PDF, and dot formats, word formats. They're downloadable, customizable, printable. They've got animations, diagrams, images, included quizzes, and more. Additionally, we have teaching courses. If you're a flight instructor already and you want to teach your students, you can teach your private pilot, instrument rating, commercial pilot, CFI initial, and CFWI add-on students with flight syllabi, lesson plans, homework assignments,

1:07binders and tracking, quizzes, logbook audits, endorsements, and more. And you can try every single one of our courses for free for as long as you would like at Wi-Fi-CFI.com. Let's talk about the four stroke cycle. We talked to, we said we're going to get more into exactly how pissens and engines work and how they convert chemical energy to mechanical energy. This is how in the four stroke cycle, what we've got here is the four stages of what a piston goes through, over and over and over and over and over again, as it's creating power force. The first stage is called the intake stage. This is where this little plunger, whatever you would call it, the intake valve opens. So the intake valve comes open and fuel and air gets drawn into the cylinder. Here's our piston right here, and this would be where the piston is connecting to the crankshaft. So our intake valve opens and incomes fuel and air. That's our intake.

2:13Then we have our compression stroke where the intake valve closes and the piston comes up and compresses the fuel and air mixture together. Then we have the power stroke. The power stroke is where either the spark plug gives us a spark for the explosion, or just that compression explodes the fuel and air mixture. If it's just a compression engine and that doesn't have a spark plug. If it has a spark plug, this is where the spark plug would ignite, explode this fuel and air mixture and that is going to force the piston back down, and you can see how it's turning the crankshaft. Then as the piston goes down and around and comes starts to come back up, we've got our exhaust stroke and this is where the exhaust valve would open and it's going to push that old burned exhaust out of the cylinder. Then you just repeat the cycle. Then it opens, intake valve opens, incomes more fuel and air compresses, powers exhaust. Those are the four strokes of the four stroke cycle. Let's look at it a little

3:18bit more. Intake begins when piston starts its downward travel. We've talked about that. Intake valve opens, fuel air is drawn into the mixture. Compression begins when the intake valve closes and piston starts moving back towards the top. We saw that compresses the fuel and air mixture. Then we've got our power. That begins when the fuel air mixture is ignited and this pressure forces the piston back down. That turns the crankshaft and keeps the whole system going. Exhaust purges the cylinder of burn gases. Exhaust valve opens, piston moves toward the headed cylinder. This is just what I told you on the last slide in words, but we're just explaining. Each cylinder is going to operate on a different stroke and continuous rotation of the crankshaft is maintained by the precise timing of power strokes. Obviously all of these strokes of the four stroke cycle are happening very quickly and so you have to have extremely precise timing. If you start to have bad timing for any of these, you're going to start to damage your engine.

4:22It needs to be very smooth. All of these need to be timed perfectly so that the crankshaft is turning nice and smoothly. If any of them are off, even by like a tenth of a second, you're going to start to do damage to your crankshaft and you're going to start to do damage to your engine. They have to have B on different cycles and it has to be very, very precise.