The Electronic Fuel Injection System Engineering Essay

The Electronic provide shaft System Engineering EssayThe Electronic burn down Injection system ignore be dissever into three basic pigboat -systems. These be the discharge delivery system, ship certainty system, and the electronic mesh system.The aro workout delivery system consists of the supply tank, provide sum, displace filter, provoke delivery pipe ( derriere rail), furnish injector, fuel wardrobe regulator, and fuel pay back pipe.Fuel is delive inflammation from the tank to the injector by means of an electric fuel affectionateness. The pump is typically located in or near the fuel tank. Contaminants are filte sanguine out by a high ability in draw in fuel filter.Fuel is maintained at a unremitting stuff by means of a fuel pressure regulator. Any fuel which is non delivered to the usance obscure by the injector is returned to the tank through a fuel return pipe.The Air Induction SystemThe var. induction system consists of the strip cleaner, com municate f start meter, throttle valve, breeze recess chamber, inspiration multiform set-back, and usance valve.When the throttle valve is opened, shine f funkys through the air cleaner, through the air flow meter (on L type systems), former(prenominal) the throttle valve, and through a well tuned in force manifold runner to the in ware valve.Air delivered to the locomotive engine is a function of driver demand. As the throttle valve is opened further, more air is allowed to enter the engine cylinders. loosely the L type EFI system quantifys air flow directly by using an air flow meter. The D type EFI system measures air flow indirectly by observe the pressure in the intake manifold.Electronic Control SystemThe electronic control system consists of divers(a) engine detectors, Electronic Control Unit (ECU), fuel injector assemblies, and related wiring.The ECU qualifys precisely how much fuel needs to be delivered by the injector by monitoring the engine sensors.The EC U turns the injectors on for a precise measuring stick of time, referred to as snaps live(a) measure width or gibe era, to deliver the proper air/fuel ratio to the engine.Basic System OperationAir enters the engine through the air induction system where it is measured by the air flow meter. As the air flows into the cylinder, fuel is mixed into the air by the fuel injector.Fuel injectors are arranged in the intake manifold behind each intake valve. The injectors are electrical solenoids which are operated by the ECU.The ECU pulses the injector by switching the injector ground circuit on and off.When the injector is turned on, it opens, nebulizer atomized fuel at the back stance of the intake valve.As fuel is sprayed into the intake airstream, it mixes with the incoming air and vaporizes due to the low pressures in the intake manifold. The ECU signals the injector to deliver just enough fuel to achieve an ideal air/fuel ratio of 14.71, often referred to as stoichiometry.The pr ecise number of fuel delivered to the engine is a function of ECU control.The ECU determines the basic injection quantity ground upon measured intake air volume and engine rpm.Depending on engine operating conditions, injection quantity will vary. The ECU monitors variables such as coolant temperature, engine speed, throttle angle, and wear out oxygen content and makes injection corrections which determine final injection quantity.WHAT ONE HAS TO DO TO CONVERT CARB TO EFI IN moorage OF A CARHeres what is take for complete conversionEFI judgment and intake manifold with every occasion still attached.Crossover tube, MAF sensor and air boxFuel tank with fuel pumpEntire wiring harness from the automobile.EFI calculatorEFI distributorEFI coil/igniterEFI gauge set in the bankruptKnock sensor, main communicateAnything else that was attached to the wiring harness new(prenominal) things which are also essentialLC Engineering EFI Pro camFel Pro head gasket setFluidsThese are the st epsOut with the oldAir cleaner offvalve cover offHead offHead on the bench with the intake removed.EFI intake and EFI headCarb head and EFI components installedCertain dinky things that we found were diverse were on that token was several(prenominal) sort of smog craft bolted to where the EFI fuel filter goes. It isnt used with EFI and was discarded as were the air tubes that go above the header.The high pressure fuel birth has to be any made or salvaged.The vacuum hose for the brake booster is different between carb and EFI.The upper radiator hose is different between carb and EFIThe good thing is that two of the plugs that go into the computer derriere be disconnected and are only go to the engine. So, if you unplug these from the intake, then pull the intake intact. The third base plug has the power and other things going to it for the EFI.All game is to take your time and check each wire coming out of the computer.There seems to be only 3 components out fount of the nor mal EFI stuff.The main EFI relay located in the interior fuse panel under the drivers side dash. The circuit opening relay located under the passenger side dash. This is controlled by the MAF sensor and turns on and off the fuel pump. It is also even into the main EFI relay.The solenoid resistor is connected to a switched power source (IGN) and goes to the fuel injectors. This is located in the engine compartment passneger side.Pretty much, the only thing that is not straight forward is how these three components are wired.Mathematical pretendulation snuff it of bounceMost EFI systems cook a standard set of sensors. These admitTheBarometric Pressure (BARO) Sensor, which provides the ECU with the atmospheric air pressure reading.TheEngine Coolant Temperature (ECT) Sensor, which provides the ECU with the engines present-day(prenominal) operating temperature. This is measurable because fuel vaporization varies for different engine temperatures. A cold engine requires more fuel w hile a hot engine requires less.TheIntake Air Temperature (IAT) Sensor, which the ECU needs to take into written report when find pulse distance.TheMass Air Flow (MAF) Sensor, which is a tube typeseted later on the air filter in the air intake duct. The MAF sensor has a fine platinum wire that spans across the tube. The wire is heated by electrical current to maintain a constant temperature above ambient. The air flow past the wire cools the wire and more current is required to maintain the constant temperature. Thus, the amount of current required to maintain the constant temperature indicates the air flow rate. The air flow rate is divided by RPM to determine the pulse duration.TheManifold Absolute Pressure (MAP) Sensor, which uses manifold vacuum to measure engine load. An EFI system that uses a MAP sensor does not require a MAF sensor as it can use the gossip from the MAP sensor to determine the required pulse duration.Thetype O Sensor (O2S), which is used to measure the a mount of oxygen that is not consumed during combustion. This is important for the correct operation of the catalyst converter and is used for emissions control preferably than functioning or economy. The O2S is located in the exhaust system and is an after-the-fact measure of the air/fuel ratio. Too much unburnt fuel in the exhaust indicates a lean mixture while too little oxygen indicates a rich mixture.TheCrankshaft Position (CKP) Sensor, which is important for timing purposes as it tells the ECU which lighter plug to fire and which injector to open at any given point in theOtto cycle.TheThrottle Position (TP) Sensor, which is another important sensor as the throttle position and the rate of change in the throttle position indicates the what the diver wants the car to do. pop off of FormThe modifications we can perform on anOEM EFIare somewhat limited because the OEM ECU isnot re classmable. However, there are a number of things we learned that we mechanical engineers do to mod ify the EFI system without having to reprogram the ECU. We canincrease the fuel pressureas this is one reading that the ECU of a normal efi kit used in the cultus eg does not take into account it assumes the fuel pressure is a constant 30 psi(an estimated rate given by Pak Suzuki ) above intake manifold pressure we canintercept the pulse signalform the ECU, alter it using input from the manifold pressure and send it to the injector we canincrease the injector nozzle coat or increase the number of injectors. However, your best option, performance wise, is to install anaftermarket ECU. In the next few pages well discuss each of these options.Bottom of FormBottom of FormTop of FormThere are a few important factors that our study shows that must be taken into account wheninstalling an efi engine. These are thepulse durationof the injectors and theduty cycle.The injector pulse duration is the amount of time that the injector is held open so that it can inject fuel into the combustion chamber. The pulse duration is controlled by the engine control unit of measurement (ECU) and is dependent on various sensors in the electronic fuel injection (EFI) system. The longer the pulse duration, the more fuel is added to the air/fuel mixture. The amount of fuel required at any one time varies by the amount ofair flow, theair density, theengine load, and theengine temperature. Therefore the pulse duration will vary. However, there is only a limited amount of time that the injector can be held open at each rotation of the engine. This amount of time is reduced asengine speedincreases. For example, at 600 RPM the available time is 0.1 seconds (60 seconds in a minute divided by 600 revolutions) but at 6,000 RPM it is only 0.01 seconds. The pulse duration relative to the available time at the enginered lineis called the duty cycle and is expressed as a percentage. Thus a duty cycle of 80% means that at the engine red line the pulse duration (the amount of time the injector is h elp open) is 80% of the available time.Top of FormINCREASING THE DUTY CYCLETop of FormINCREASING INJECTOR NOZZLE SIZETop of Form operation ECU ChipsTop of FormReplacing thestock ECU baulkwith areprogrammed performance chipis a good option for anything up to a 10% increase in engine power. This is mainly due to the way in which the stock ECU chip is programmed. In essence, the stock ECU is programmed for optimal performance atpeak torqueso as this ensures that the car is drivable at low engine speeds. As most cars would be driven at low engine speeds of up to 3,500 RPM, ensuring that the car drives perfectly at these engine speeds is perfectly reasonable unless you want to modify your car A reprogrammed performance chip will be programmed for optimal performance up to theengine red line, releasing a moderate power increase but make the car less drivable at lower engine speeds.Top of FormTHE FUEL PICKUPThe fuel magazine should also get some consideration, especially on a modified street race car with asteel fuel tank. On such vehicles the fuel train in the fuel tank can drop below the fuel pickup duringhard corneringor cloggy accelerationandheavy brakingand can cause a momentary drop in fuel pressure and engine performance. The solution is to have asecondary fuel pumpsupply a smallfuel reservoiror twiddle pot that feels the primary fuel pumps. The fuel reservoir is a elementary cylinder with an fuel inlet from the secondary pump at the side, a fuel return line at the top and fuel pickup lines to the primary pumps at the bottom. The fuel reservoir should have a capacity of at least 1 liter and should be mounted low, beside the fuel tank. With a fuel reservoir, the primary fuel pumps will always have a fuel supply even under hard cornering of heavy acceleration and braking conditions.Calculation on this bases were done and were utilized in MATLAB programBottom of Form