#GasPedalMysteries #CarQuestions #EngineMechanics
Have you ever stopped to think about what happens under the hood of your car when you press down on the gas pedal? ππ¨ I mean, sure, we all know it makes the car go faster, but how does it actually work?
I recently found myself pondering this question after learning the basics of how a 4-stroke engine operates. But the gas pedal’s role remained a mystery to me. π€ So, I set out on a quest to uncover the secrets behind this magical pedal that seems to have so much power over our driving experience.
What exactly does the gas pedal do to make our engines roar to life? π€― I’m looking for someone who can break it down for me in technical detail. π οΈ Share your knowledge and let’s unravel this mystery together!
Now, I don’t know about you, but I’m buzzing with curiosity and can’t wait to hear the insights and explanations from fellow car enthusiasts. Let’s dive deep into the world of engine mechanics and discover the wonders of the gas pedal! π‘β¨
Do you have any insights or experiences to share? Feel free to comment below and let’s explore this topic further! ππΌ #GasPedalRevelations #VroomVroomExplanation
It changes how much gasoline (if any) gets injected into the engine.
If it’s not pressed, there is no gasoline in the engine so nothing goes boom and makes the thingies go round.
If your press it down, gasoline starts to get squirted into the engine where it gets zapped and goes boom and makes things go round.
If your press it down harder, even moar gasoline get squirted into the engine, gets zapped and goes big-bada-boom and makes things go round faster.
The gas pedal is conntected to the throttle, which does all the work. The [wikipedia](https://en.wikipedia.org/wiki/Throttle#:~:text=When%20the%20driver%20presses%20on,communicates%20it%20to%20the%20ECU) article on it goes into great detail.
On modern cars, it tells the computer “more power!” The computer opens the throttle valve some more, and fuel will also be proportionately injected. It will monitor the system and fine tune on the fly. More fuel air = more pressure per piston stroke, so more power.
On older cars, the pedal was directly cabled to the throttle plate. Then the computer would sense the throttle position and react accordingly.
On really old cars, your pedal moved a plate, and the change in airflow would change pressure in a carburetor, which was designed to allow the pressure to change how much fuel was being metered through the carburetor jet.
On esoteric cars, you might have a control to manually control mixture too, but I don’t know of any. There’s also other designs too that I won’t go into. I think I kept this simple enough to answer the big question.
There are a slew of sensors that go into fine tuning the mixture that I skipped over, but if you want to look into them: mass air flow sensor, oxygen sensor, knock sensor.
Traditionally either let more air into the engine in a petrol engine or injected more fuel into the engine in a diesel engine.
Nowadays it basically tells the computer in your cars engine that you want more power which means it will do things like let more air in, inject more fuel, make the spark plug fire sooner and probably some others i’m missing.
I highly suggest watching Smart Every Day where he makes a transparent carburetor and films it in slow motion: https://www.youtube.com/watch?v=toVfvRhWbj8
While carburetors aren’t used in cars anymore, it will give you the basics of how more air + more fuel = more power.
Then watch his video on fuel injectors: https://www.youtube.com/watch?v=UkeGQotnsDU
Make car go vroom.
When you press the gas pedal in a car, you’re essentially controlling the engine’s power output. Hereβs how it works in a bit of technical detail:
1. Throttle Control: Pressing the gas pedal moves the throttle, which is a valve that controls how much air enters the engine.
– In older cars, this was done mechanically via a cable.
– In modern cars, it’s usually done electronically (drive-by-wire) with sensors sending signals to the engine control unit (ECU).
2. Air Intake: As the throttle opens, more air is allowed into the engine’s intake manifold.
3. Fuel Injection: The ECU senses the increased air flow and calculates the appropriate amount of fuel to inject into the combustion chamber to maintain the optimal air-fuel ratio.
4. Combustion: The mixture of air and fuel is then compressed and ignited in the cylinders, creating a controlled explosion that pushes the pistons down and generates power.
5. Power Output: This power is then transferred through the drivetrain to the wheels, increasing the carβs speed.
So, pressing the gas pedal ultimately adjusts the amount of air and fuel entering the engine, which changes the combustion process and results in increased power and speed.
It opens [this thing](https://haynes.com/en-us/sites/default/files/styles/unaltered_webp/public/What%20is%20it%20-%20Throttle%20Body.jpg?itok=SInFgHp7×tamp=1481295316)
https://haynes.com/en-us/tips-tutorials/what-is-car-throttle-body-and-what-does-it-do
>What is it?
>This is a component that varies the amount of air entering an engine, by using a flat valve (butterfly) that rotates inside a tube-shaped housing. In an electronically fuel-injected car, a throttle position sensor and air-flow sensor communicate with the main electronic control unit (ECU), which supplies the corresponding amount of fuel needed at the injectors.
> Where is it located?
> On older carbureted engines, the throttle body is built into the carburetor. It is opened and closed through a cable and linkage from the gas pedal and engine vacuum, more fuel is delivered as the valve opens.
>
> On a fuel-injected engine it is normally located between the air filter and the intake manifold, and is connected to the gas pedal mechanically with a cable, or electronically by wire. When the driver presses the pedal the butterfly in the throttle body pivots to let more air flow into the manifold.
>
> When that happens, the throttle position sensor reports to the ECU that you have stepped on the gas. And the airflow sensor detects more air and sends a message to the carβs computer to boost the amount of fuel being supplied by the injectors
You ever see people work on old cars and while under the hood with the engine running start turning something to get it to rev? That thing is connected to the throttle body and pedal.
make car go vroom
The irony is that it was an air pedal. It still is on most diesels, I think.
Now, the injection of gasoline and air is more careful and stoichiometric.
It pushes a little thing, thatβs hooked to a doodad under the hood. The doodad gets moved by the thing that got pushed. Doodad opens a little valve kind of thingy which allows fuel to be vaporized and then injected into the up/down thing. The more fuel, the faster car goes.
It unleashes the Kraken. In older cars it opened the carbs up flooding gasoline in to be burned by the engine to make car go vroom
Sounds like itβs time to rewatch the Magic Schoolbus engine episode, haha
On modern cars, it tells the ECU to open the throttle flap allowing for more airflow into the engine and apply more fuel through the injectors. On carbureted engines, it opens the throttle flap and ensuing vacuum from more air flowing past the throttle flap draws more fuel out of the fuel tank. If youβre driving a diesel older diesel engines donβt have a throttle flap, so it just applies more fuel through the injectors diesels have a throttle flap, but itβs not as crucial as gasoline engines also applies more fuel through the injectors.
U push it and it make car go zoom
Engines are essentially air pumps. The more air your engine can take in, the more fuel can mix with that air to make more power. The gas pedal more or less opens the air intake to allow more air in (either directly like on older cars or indirectly through the computer on newer ones.) That is why turbo chargers and super chargers increase the power output of an engine. They compress the air going into the engine so that you can cram more air into the same volume inside the cylinder. The more air you have, the more fuel you can mix with it, the more power your engine makes.
My old autoshop teacher taught us βSuck, Squeeze, bang, blowβ it sucks in air, the piston squeezes, the spark plug ignites, and it blows exhaust fumes out the exhaust.
Itβs called the accelerator pedal..Β
On an ECM controlled system there is a throttle position sensor attached to the pedal. As itβs pressed down a potentiometer relays data to the ECM, the ECM calculates the approximate percent of the throttle is being applied, which in turn the ECM relays another signal to the servo on the throttle body, where the servo clocks the throttle plate to open in a ratio to pedal position. This allows more air to enter the intake. The ECM also reads cam and crank rotation, using RPM as another data point to increase the pulse width of the injector causing it to change the fuel spray volume. Simultaneously it is also advancing or retarding the spark timing. Simultaneously it is also reading the MAF sensor and applying the data from it to also control fuel injector pulse width Β in relation to the density of air entering the intake. The aft O2 sensor is also reading the oxygen content post cat and that is also applied to the spark timing and pulse width. Concurrently, the wheel speed sensors are measuring the rotational speed of the tires and relaying this data to the TCM and antilock brake system to control transmission function and whether a kickdown should be applied downshifting the transmission to a suitable gear, or if the next higher gear should be applied, as well as applying brake pressure to reduce wheel spin.Β
While all this is taking place, the coolant temp data is being processed to determine approximate cylinder temps and reading knock sensors to alleviate a lean fuel condition requiring yet another parameter to control pulse width, and whether the EGR needs to open to allow exhaust has to enter the intake stream to cool the cylinders down. While all this is happening concurrently the various emission controls are reading data points and using engine vacuum to control their functions.
Opens the throttle