Fuel Delivery and Air Induction: Description and Operation

This system supplies the engine with the air/fuel mixture necessary for combustion. The air induction system and fuel injection system work in conjunction with an electronic engine control system which consists of various sensors, switches. and an ECM. All sensors and switches are connected to the ECM which interprets the data it receives and computes the timing and the duration so that the electrically operated injectors can he energized.

The basic fuel requirement of the engine is determined from the data supplied to the ECM by the mass air flow (MAF) sensor, which measures the amount of air being drawn into the engine. Other sensors and switches are used to measure:

^ Air temperature
^ Atmospheric pressure
^ Engine coolant temperature
^ Engine speed
^ Exhaust oxygen content

The various sensors and switches detect any changes in the operating conditions and send signals to the ECM. This permits the ECM to control the opening duration (pulse width) of the injectors and to maintain optimum exhaust emission control and engine performance for all operating conditions.

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

AIR FUEL INDUCTION SYSTEM

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.

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 air control valve 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.