Fuel Delivery and Air Induction: Description and Operation

Fuel Tank Components:

Air Fuel Induction System:

DESCRIPTION
The air fuel induction system carries, filters, measures, and controls the flow of air into the throttle body. Fuel is metered and mixed with the air in the intake manifold. Air volume into the engine is regulated by the accelerator cable-controlled throttle plates mounted in the throttle body.

Fuel is delivered to the solenoid operation injectors through the fuel rail. Fuel pressure is controlled by a variable pressure regulator which -varies fuel pressure depending on the absolute manifold pressure acting on the regulator at the time.

OPERATION
An electrical pulse activates a solenoid in the fuel injector body. The duration of the pulse is determined by the ECM. The ECM varies the pulse duration based upon the amount of air passing through the mass air flow sensor and the engine speed which is determined by the crankshaft sensor.

A throttle position sensor attached to the throttle plate shaft signals the ECM of the throttle position and the rate of the throttle movement. These signals influence the injector pulse duration.

The ECM-controlled idle speed controller supplies extra air to maintain idle speed. Extra air is supplied to increase idle speed when the engine is cold. Idle speed is increased when the air conditioning compressor is engaged or when mechanical load affects idle speed.

Crankcase gases are vented to the intake manifold by the positive crankcase ventilation valve. The PCV valve is operated by the intake manifold vacuum. At idle the PCV valve opens slightly and allows some crankcase gases into the combustion chamber. As rpm increase, the PCV valve opening increases allowing a larger volume of gases into the intake manifold.

COMPONENTS
The fuel system for the Sportage consists of the following components:

^ Electronic fuel pump assembly
^ Fuel filters (2)
^ Fuel pipes (lines) and hoses
^ Fuel sender assembly
^ Fuel tank
^ Fuel rail
^ Fuel pressure regulator
^ Fuel injectors (4)
^ Fuel pump relay
^ Pulsation damper

ELECTRONIC FUEL PUMP ASSEMBLY
The electronic fuel pump assembly supplies filtered, pressurized fuel to each fuel injector through the fuel rail. The fuel pump assembly is mounted in the fuel tank to lower working noise. It is mounted with and connected to the fuel sending assembly. Both assemblies are removed from and installed into the fuel tank as a single unit.

The fuel pump is an electric pump controlled by the engine control module (ECM) through the pump relay. When the ECM commands the fuel pump relay to operate, the motor rotates an impeller within the pump assembly. This causes fuel within the fuel tank to be drawn into the fuel inlet port. Fuel is pumped out to the throttle body and fuel injector under pressure through the fuel feed pipe and hose. The fuel pressure is retained when the fuel pump is not running by means of a control valve located within the pump. Excess fuel is returned to the fuel tank by means of a fuel return pipe and hose.

FUEL FILTERS
A steel in-line fuel filter is used in the fuel feed pipe ahead of the fuel injector. The filter housing is constructed to withstand temperature changes and exposure. It has a paper filter element which traps particles that could damage the fuel injector system. A screen filter in the fuel pump assembly filters out particles in the fuel tank further protecting the fuel injector.

FUEL PIPES AND HOSES
Fuel feed and return pipes (lines) and hoses carry fuel from the fuel tank to the throttle body and back to the fuel tank. These pipes and hoses are attached to the underbody of the vehicle and must be inspected for kinks or dents which may restrict fuel flow.

Fuel vapor pipes and hoses carry fuel vapors from the fuel tank to the evaporative emissions canister located in the engine compartment. The fuel vapors are stored in the canister when the engine is not running. When the engine is running at normal operating temperature, and the accelerator pedal is depressed, the engine control module (ECM) will command the evaporative emission solenoid purge valve to open and allow the stored fuel vapors to be purged into the intake manifold and be absorbed into the combustion process.

FUEL SENDER ASSEMBLY
The fuel sending system consists of a float, float arm, and a variable resistor. Fuel level is measured by the position of the float in the fuel tank, and is indicated by a gauge in the instrument panel cluster assembly. When the fuel level changes, the float position changes. The change in float position increases or decreases the resistance of the variable resistor. The change in resistance causes the position of the fuel gauge readout to change.

FUEL TANK
The fuel tank is used to store fuel for the vehicle. It has a 15.8 gallon (60 liter) fuel capacity. The tank is molded from steel and is located directly in front of the rear wheels in back of and below the rear seat.

The fuel tank is held in place with five bolts. The tank is protected by a gravel shield to which it is mounted. The tank's shape allows for a constant supply of fuel around the fuel pump screen filter during low fuel conditions and during aggressive vehicle maneuvers. The fuel inlet port on the tank is equipped with an inlet valve. The fuel tank inlet valve prevents fuel from spewing into the fuel filler neck during abnormal vehicle driving conditions.

The fuel tank, along with its pipes and hoses, should be checked for road damage which could result in leakage. Also inspect the fuel filler cap for a correct seal and indications of physical damage.

FUEL PRESSURE REGULATOR VALVE
The fuel pressure is regulated by a fuel pressure regulator valve. The injectors are directly supplied with battery voltage through the main relay.

Fuel is metered and injected into the intake ports according to the signals received from the ECU.

When these injection signals are applied to the solenoid coil of the injector, the needle valve is pulled off its seat. Fuel is then injected into the intake port.

The amount of fuel supplied to the engine depends on the duration of time the injectors stay open.

Fuel is supplied to the fuel tank through the intake port covered by a protective control-opened panel on the right side of the vehicle.