The Electronic Fuel Injection System Engineering Essay

The Electronic Fuel Introduction regularity can be separated into three: basic sub -systems. These are the fuel impromptuer regularity, zeal collection regularity, and the electronic regulate regularity.

The fuel impromptuer regularity consists of the fuel tank, fuel cross-examine, fuel defecate, fuel impromptuer pipe (fuel reprove), fuel injector, fuel constraining chairman, and fuel come-tail pipe.

Fuel is saveed from the tank to the injector by media of an electric fuel cross-examine. The cross-examine is typically located in or nigh the fuel tank. Contaminants are defecateed extinguished by a tall competency in direction fuel defecate.

Fuel is continueed at a true constraining by media of a fuel constraining chairman. Any fuel which is referable saveed to the insiege multiplied by the injector is come-backed to the tank through a fuel come-tail pipe.

The Zeal Collection Regularity

The zeal collection regularity consists of the zeal cleaner, zeal issue meter, repress valve, zeal insiege lodging, insiege multiplied runner, and insiege valve.

When the repress valve is discloseded, zeal issues through the zeal cleaner, through the zeal issue meter (on L kind regularitys), late the repress valve, and through a courteous tuned insiege multiplied runner to the insiege valve.

Zeal saveed to the engine is a influence of driver claim. As the repress valve is discloseded further, over zeal is allowed to penetreprimand the engine cylinders.

Mostly the L kind EFI regularity computes zeal issue promptly by using an zeal issue meter. The D kind EFI regularity computes zeal issue inpromptly by monitoring the constraining in the insiege multiplied.

Electronic Regulate Regularity

The electronic regulate regularity consists of incongruous engine sensors, Electronic Regulate Ace (ECU), fuel injector assemblies, and allied wiring.

The ECU mentions clearly how plenteous fuel needs to be saveed by the injector by monitoring the engine sensors.

The ECU turns the injectors on restraint a cemal equality of era, referflushed to as introduction pulse width or introduction space, to save the appropriate zeal/fuel proportion to the engine.

Basic Regularity Influence

Zeal penetrates the engine through the zeal collection regularity where it is computed by the zeal issue meter. As the zeal issues into the cylinder, fuel is partial into the zeal by the fuel injector.

Fuel injectors are crystallized in the insiege multiplied rearwards each insiege valve. The injectors are electrical solenoids which are operated by the ECU.

The ECU pulses the injector by switching the injector reason circumference on and impromptu.

When the injector is pungent on, it discloseds, spraying atomized fuel at the tail interest of the insiege valve.

As fuel is sprayed into the insiege zealstream, it mixes with the inheresucceeding zeal and vaporizes imputable to the gentle constrainings in the insiege multiplied. The ECU signals the injector to save honest plenty fuel to finished an unreal zeal/fuel proportion of 14.7:1, frequently referflushed to as stoichiometry.

The cemal equality of fuel saveed to the engine is a influence of ECU regulate.

The ECU mentions the basic introduction furness fixed upon computed insiege zeal bulk and engine rpm.

Depending on engine at-liberty stipulations, introduction furness conciliate disagree. The ECU monitors variables such as coolant atmosphere, engine hasten, repress bias, and consume oxygen satisfied and makes introduction improveions which mention definite introduction furness.


Here’s what is demandd restraint finished conversion

EFI summit and insiege multiplied with everycreature peaceful fast.

Crossover tube, MAF sensor and zeal box

Fuel tank with fuel cross-examine

Entire wiring impede from the car.

EFI computer

EFI distributor

EFI coil/igniter

EFI compute guidemal in the detrude

Knock sensor, main refreshment

Anycreature else that was fast to the wiring impede

Other creatures which are to-boot essential

LC Engineering EFI Pro cam

Fel Pro summit gasket guidemal


These are the steps

Extinguished with the old…

Zeal cleaner impromptu

valve protect impromptu

Summit impromptu

Summit on the bench with the insiege removed.

EFI insiege and EFI summit

Carb summit and EFI components established

Certain insignificant creatures that we ground were incongruous were:

There was some condition of smog project bolted to where the EFI fuel defecate goes. It isnt reasond with EFI and was discarded as were the zeal tubes that go overhead the summiter.

The tall constraining fuel direction has to be either made or salvaged.

The vacuum hose restraint the brake booster is incongruous among carb and EFI.

The remarkable radiator hose is incongruous among carb and EFI

The amiable creature is that bfamily of the obstructs that go into the computer can be disalike and are simply go to the engine. So, if you unobstruct these from the intake, then haul the insiege raise. The third obstruct has the sform and other creatures going to it restraint the EFI.

All recreation is to siege your era and impede each wire heresucceeding extinguished of the computer.

There seems to be simply 3 components extinguishedinterest of the “normal” EFI trash. 

The main EFI refreshment located in the toward consolidate panel inferiorneathneath the driver’s interest detrude. The circumference fissure refreshment located inferiorneathneath the itinerant interest detrude. This is regulateled by the MAF sensor and turns on and impromptu the fuel cross-examine. It is to-boot tied into the main EFI refreshment.

The solenoid resistor is alike to a switched sform commencement (IGN) and goes to the fuel injectors. This is located in the engine division passneger interest.

Pretty plenteous, the simply creature that is referable right restraintward is how these three components are wired. 

Mathematical Restraintmulation;

Summit of Restraintm

Most EFI regularitys enjoy a exemplar guidemal of sensors. These include:

The Barometric Constraining (BARO) Sensor, which provides the ECU with the godlike zeal constraining lection.

The Engine Coolant Atmosphere (ECT) Sensor, which provides the ECU with the engine’s present at-liberty atmosphere. This is expressive owing fuel vaporization varies restraint incongruous engine atmospheres. A dispassioned engine demands over fuel period a glowing engine demands near.

The Insiege Zeal Atmosphere (IAT) Sensor, which the ECU needs to siege into recital when determining pulse space.

The Mass Zeal Issue (MAF) Sensor, which is a tube collocationed succeeding the zeal defecate in the zeal insiege duct. The MAF sensor has a pretty platinum wire that spans despite the tube. The wire is keen by electrical present to continue a true atmosphere overhead ambient. The zeal issue late the wire cools the wire and over present is demandd to continue the true atmosphere. Thus, the equality of present demandd to continue the true atmosphere indicates the zeal issue reprimand. The zeal issue reprimand is separated by RPM to mention the pulse space.

The Multiplied Absolute Constraining (MAP) Sensor, which reasons multiplied vacuum to compute engine impute. An EFI regularity that reasons a MAP sensor does referable demand a MAF sensor as it can reason the input from the MAP sensor to mention the demandd pulse space.

The Oxygen Sensor (O2S), which is reasond to compute the equality of oxygen that is referable consumed during incendiarism. This is expressive restraint the improve influence of the catalyst converter and is reasond restraint emissions regulate rather than deed or dispensation. The O2S is located in the consume regularity and is an succeeding-the-fact compute of the zeal/fuel proportion. To-boot plenteous unburnt fuel in the consume indicates a attenuated compound period to-boot insignificant oxygen indicates a superb compound.

The Crankshaft Collocation (CKP) Sensor, which is expressive restraint timing purposes as it tells the ECU which iota obstruct to energy and which injector to disclosed at any attached object in the Otto cycle.

The Repress Collocation (TP) Sensor, which is another expressive sensor as the repress collocation and the reprimand of substitute in the repress collocation indicates the what the diver lacks the car to do.

Summit of Restraintm

The modifications we can fulfil on an OEM EFI are partially poor owing the OEM ECU is referable reprogrammable. However, there are a estimate of creatures we read that we spontaneous engineers do to change the EFI regularity withextinguished having to reprogram the ECU. We can growth the fuel constraining as this is undisjoined lection that the ECU of a typical efi kit reasond in the cultus eg does referable siege into recital – it assumes the fuel constraining is a true 30 psi(an estimated compute attached by Pak Suzuki ) overhead insiege multiplied constraining; we can intercept the pulse signal form the ECU, change it using input from the multiplied constraining and despatch it to the injector; we can growth the injector nozzle size; or  growth the estimate of injectors. However, your best non-interference, deed skilled, is to establish an aftermarket ECU. In the next lacking pages we’ll sift-canvass each of these non-interferences.

Ground of Restraintm

Ground of Restraintm

Summit of Restraintm

There are a lacking expressive factors that our con-over shows that must be siegen into recital when installing an efi engine. These are: the pulse space of the injectors and the province cycle.

The injector pulse space is the equality of era that the injector is held disclosed so that it can inject fuel into the incendiarism lodging. The pulse space is regulateled by the engine regulate ace (ECU) and is not-absolute on incongruous sensors in the electronic fuel introduction (EFI) regularity. The longer the pulse space, the over fuel is added to the zeal/fuel compound. The equality of fuel demandd at any undisjoined era varies by the equality of zeal issue, the zeal density, the engine impute, and the engine atmosphere. Therefore the pulse space conciliate disagree. However, there is simply a poor equality of era that the injector can be held disclosed at each treatment of the engine. This equality of era is deep as engine hasten increases. Restraint sample, at 600 RPM the advantageous era is 0.1 seconds (60 seconds in a tiny separated by 600 treatments) beborder at 6,000 RPM it is simply 0.01 seconds. The pulse space not-absolute to the advantageous era at the engine flushed direction is designated the province cycle and is explicit as a percentage. Thus a province cycle of 80% media that at the engine flushed direction the pulse space (the equality of era the injector is aid disclosed) is 80% of the advantageous era.

Summit of Restraintm


Summit of Restraintm


Summit of Restraintm

Deed ECU Scraps

Summit of Restraintm

Replacing the hoard ECU scrap with a reprogrammed deed scrap is a amiable non-interference restraint anycreature up to a 10% growth in engine sway. This is principally imputable to the cem in which the hoard ECU scrap is programmed. In substance, the hoard ECU is programmed restraint optimal deed at peak torque so as this ensures that the car is drivable at gentle engine hastens. As most cars would be driven at gentle engine hastens of up to 3,500 RPM, ensuring that the car drives totally at these engine hastens is totally reasonable; unnear you lack to change your car! A reprogrammed deed scrap conciliate be programmed restraint optimal deed up to the engine flushed direction, releasing a modereprimand sform growth beborder making the car near drivable at gentleer engine hastens.

Summit of Restraintm


The fuel pickup should to-boot procure some consequence, specially on a mitigated street family car with a steel fuel tank. On such vehicles the fuel equalize in the fuel tank can ooze begentle the fuel pickup during firm cornering or afflictive aid and afflictive braking and can careason a fleeting ooze in fuel constraining and engine deed. The elucidation is to enjoy a minor fuel cross-examine give a insignificant fuel reservoir or swirl pot that feels the pristine fuel cross-examines. The fuel reservoir is a isolated cylinder with an fuel commencement from the minor cross-examine at the interest, a fuel come-tail direction at the summit and fuel pickup directions to the pristine cross-examines at the ground. The fuel reservoir should enjoy a competency of at dejectedest 1 liter and should be mounted gentle, beinterest the fuel tank. With a fuel reservoir, the pristine fuel cross-examines conciliate constantly enjoy a fuel give smooth inferiorneathneath firm cornering of afflictive aid and braking stipulations.

Calculation on this bases were dundisjoined and were utilized in MATLAB program

Ground of Restraintm

Related Post