eli5 What’s happening when an engine stalls from low RPM?
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Think of the engine as you, riding a bicycle. Let’s say you are riding your 10 speed bike in a “high” gear that is awesome for going really fast. Now you are similar to a car in say 5th or 6th gear. If you slow down, or go up a hill, problems start to come up if you don’t shift gears. In that gear on your bike your cadence (pedal speed) gets slower, and the resistance on the pedals gets higher as you slow down. There will be a point where you slow down enough that your legs are not strong enough to turn the pedals in that gear. You will stop/stall and have to put your feet down to keep from falling over if you don’w down shift. The concept is the same for the car.
As the car slows down, if the car is not in the right gear, the RPM gets really slow but the resistance is really high. Most engines (electrics being the exception) just cant put out huge power at slow rpms. They are not able to keep turning the wheels, and the engine will slow to a point where it can’t keep running, and it “stalls”. Just like you on the bike trying to go up hill in 10th gear, or trying to start from a stand still in a high gear.
Think of the engine as you, riding a bicycle. Let’s say you are riding your 10 speed bike in a “high” gear that is awesome for going really fast. Now you are similar to a car in say 5th or 6th gear. If you slow down, or go up a hill, problems start to come up if you don’t shift gears. In that gear on your bike your cadence (pedal speed) gets slower, and the resistance on the pedals gets higher as you slow down. There will be a point where you slow down enough that your legs are not strong enough to turn the pedals in that gear. You will stop/stall and have to put your feet down to keep from falling over if you don’w down shift. The concept is the same for the car.
As the car slows down, if the car is not in the right gear, the RPM gets really slow but the resistance is really high. Most engines (electrics being the exception) just cant put out huge power at slow rpms. They are not able to keep turning the wheels, and the engine will slow to a point where it can’t keep running, and it “stalls”. Just like you on the bike trying to go up hill in 10th gear, or trying to start from a stand still in a high gear.
After the spark fires, it has to produce enough momentum to return the piston for the exhaust stroke, then the intake stroke, and finally, and most difficultly, the compression stroke. At lower speeds it won’t have enough stored energy to complete the cycle.
Tiny motors in things like RC cars are nearly weightless, which is why they can’t run below 1500 rpm or so, as soon as they hit the compression stroke they lose all momentum.
After the spark fires, it has to produce enough momentum to return the piston for the exhaust stroke, then the intake stroke, and finally, and most difficultly, the compression stroke. At lower speeds it won’t have enough stored energy to complete the cycle.
Tiny motors in things like RC cars are nearly weightless, which is why they can’t run below 1500 rpm or so, as soon as they hit the compression stroke they lose all momentum.
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