Electronic fuel injection in modern cars works by requiring gasoline, oxygen-rich air, and an ignition source. The Piston creates a vacuum, pulling air into the engine.
How engine actually work:
The correct amount of fuel is added, starting with carburetors, which are archaic devices. Modern cars now use electronic fuel injection.
How carburetors work:
A six-cylinder V6 engine has a runner for each cylinder, where air and fuel are mixed and ready to go. Carburetors are single-source systems with a passage in the middle and a Venturi restriction. A pipe on the side of the passage has a fuel ball, and when air passes by, it creates a pressure differential between the air past the Venturi and the air on top of the fuel bowl. This creates a pressure differential, pushing fuel into the passage. When a car’s gas is pressed, a throttle plate opens, allowing more or less air to come in, corresponding to more or less fuel.
The revolution of electronic fuel injection began in the 1980s, when emission requirements became more stringent. Early versions of electronic fuel injection mimicked a carburetor with a single injector spraying fuel, controlled by a computer. This system sprays fuel and allows natural suction to occur
How multi-port fuel injection Work :
There is an injector for each Port there is an individual injector for every single cylinder now we have precise control how much fuel and where it’s going exactly not just kind of dumping into the mix and hoping for the best so here is the best part the fuel injector actually very simple device it is extremely simple the idea behind it so you have a basically a passage with a small plunger that is controlled by a small electronic solenoid you apply power to it that plunger gets pulled by the solenoid up opening a passage you shut it off it just comes down and it closes that’s it it’s a glorified faucet that’s basically what an injector is in essence but to get the fuel into that injector so it would spray it is it just going to dribble out this is where the magic is so in order for these injectors to actually spray fuel not dribble it out because we need a fine mist of fuel so it would vaporize and that’s actually what’s going to go inside CU
If you just dump raw liquid flu fuel into the cylinder you’re going to hydro lock it that’s the a problem so you want to atomize that fuel you want it to be in Vapor state so it needs to be a very missed here’s how they actually did that multi-port fuel injected cars they have an electronic fuel pump in the tank in the gas tank that takes that fuel sends it to the front at pressure then on the injectors themselves there is a rail basically a container that sits on top of the injectors connected to all of them and pressure start to build up in this rail so here’s what you have you have the pressure of this rail pushing on the injector waiting for it to open so when you now open the injector it’s going to come out with high pressure when you spray something at high pressure it’s going to tend to kind of fan out depending on the design of the tip of the of the injector it’s going to create that fine Mist because now it’s under high pressure pretty cool right so now that we have that pressure sitting it the rail the computer will very simply open that plunger it’ll spray fuel shut off the plunger we stop the plunger by the plunger I mean the injector and the way that it does that the computer is very simple you have power and you have ground you have two wires To every injector even in 2024 all modern cars will have two wires to every injector one of them is power and usually with car design they will have that power always there then you have a second wire which is ground
How the computer will operate:
It is going to be controlled by the computer, which will actually pulse the injector on the ground. It will do this so that we can spray fuel by opening the injector slightly and then shutting it off. It’s that easy. You have control over each injector separately; just open it and close it.
How does the computer actually know when to fire each cylinder :
Advancements in sensors and computers have significantly impacted the process of determining when to fire each cylinder in an engine. The computer uses the crankshaft position sensor and cam shaft position sensor to provide a 3D image of the engine’s state at any given point. The crankshaft position sensor determines the speed of the engine’s rotation and the start of the cycle. However, it doesn’t know when the piston comes down, either in the intake stroke or power stroke. Therefore, the computer sprays fuel around the intake stroke, not the entire engine.
Cam Shaft Position Sensor :
The cam shaft position sensor determines the engine’s intake or power stroke, enabling the computer to determine the speed of the engine rotation cycle and the cylinder’s stroke, ensuring optimal engine operation.
Hypothetical firing order 1 2 3 4 for Simplicity cylinder:
In a hypothetical firing order of 1, 2, 3, 4, Simplicity, cylinder number one is the intake stroke, followed by cylinders 2, 3, 4, and finally, the crank position sensor is reset.
Beginning of the Fuel cycle :
Camp position sensors are no longer necessary because the computer can recognize when a fuel cycle is starting. It is now able to determine when to send fuel to each cylinder. However, for gasoline to burn perfectly, the air-fuel ratio must be maintained. A stoichiometric ratio of 14.7 to 1 must be maintained by the computer, meaning that 14.7 grams of air are needed for every gram of fuel to ignite. Like a pump, the engine draws air naturally, and the computer uses two methods to evaluate air intake. The mass airflow sensor is one widely used technique.
Map sensor or manifold absolute pressure :
Mass air flow is the most common work star in engines, with multiple designs. It involves two hot wires that cool down air as it passes through them. A computer measures temperature drops and effort to maintain it, calculating air flow and air intake. A map sensor measures atmospheric pressure and intake manifold pressure, determining air intake. For example, a fuel spray can be calculated by spraying a specific amount of fuel. However, variables like temperature, air density, fuel wear, and filter issues can affect the calculations.
Computer test:
The computer tests if the engine maintains a 14.7 to 1 ratio, a balance between air and fuel. The oxygen sensor, also known as an air fuel ratio sensor, is used to detect the level of oxygen in the exhaust. A perfect mixture of 14.7 to 1 is achieved when all fuel is used, but a lean mixture with more than 14.7 Gams of air to every gram of fuel results in an excessive amount of oxygen. The oxygen sensor detects a lean or rich mixture, allowing the computer to make micro adjustments to maintain the ratio. However, variables such as air and fuel can vary as the engine operates.
Modifications :
The sensor used in electronic fuel injection makes adjustments based on air intake and fuel consumption. If the mixture is lean, the computer increases the injector pulse duration to increase fuel, while if it’s too rich, it decreases the duration. However, the sensor may not accurately monitor changes in air intake or fuel consumption due to factors like overdue spark plugs, dirty air filters, and changing temperatures. As technology advances, it’s crucial to ensure the computer accurately monitors variations or problems in the technology to ensure optimal performance.
