Chapter 9: Fuel injection systems
Returnless fuel injection systems
do not use fuel return line between the engine and the tank
diesel fuel injection
similar to gasoline injection, but requires higher injection pressure
cold start valve
to add extra fuel to the intake manifold when starting a cold engine
intake air heaters
to aid in igniting the compressed air-fuel mix during cold starting
manifold vacuum sensor
engine load is transmitted to the computer by means of an intake
turbine wheel
connected to the compressor wheel by a shaft
supercharger
consists of a drive belt and driven gears, and a centrifugal compressor wheel
engine control computer
constructed using many different electronic circuits and components
Intake manifold
part of the air induction system
Throttle body
part of the air induction system
control rack
plunger is connected, by means of a flange, to the toothed control sleeve that meshes
waste gate
controls the engine exhaust gas flow
Air cleaner assembly
part of the air induction system
Sensors
various engine functions and feed this information to the computer
Mechanical fuel injection
were the first and many years the only type of fuel injection
auxiliary air regulator
admits additional air into the intake manifold to increase the idle speed
Stoichiometric
air-fuel mixture will burn very cleanly with a minimum of pollutants
glow plugs
an electrically operated device that protrudes into the pre- combustion chamber
prechamber
at the precise time the piston has completed the compression stroke diesel fuel is sprayed into the combustion chamber
Non-timed fuel injections
at the same time or on an alternating basis
cetane number
comparing the burning characteristics
Spring pressure
forces the needle closed
delivery advance mechanism
fuel automatic
Continuous fuel injection
fuel pressure is controlled by an electronic control device or by an airflow metering valve
outward opening injectors
injector nozzle
inward opening injectors
injector nozzle heavy spring
Fuel rail
installed in the intake manifold and connected to the fuel system
Electronic fuel injection
made possible by the introduction of compact, durable, and inexpensive electronic components and computers for automotive use
Cone shaped pattern
maximum distribution and atomization
barometric pressure
measures the pressure of the outside air
engine speed sensor
monitors engine RPM
Oxygen sensors
monitors the amount of oxygen in the engine's exhaust gases
diesel injection pump
must be capable of producing high pressures
Sealing pintle
needle
Timed fuel injection
opened for only several milliseconds and is carefully timed to each cylinder
boost pressure
pressure delivered to the intake manifold controlled by the waste gate
fuel distributor
provides a constant pressure drop through the fuel distributor metering slots, a pressure regulating valve
octane
rating of gasoline
Pulse width
refers to the amount of time during which the injector electronic solenoid is energized, causing the injector to open
Water trap
removes any water from the fuel
viscosity compensator valve
tends to keep the injector pump functioning the same with either light or heavy fuels
airflow sensor
the amount of air entering the engine
compressor wheel
the belt drives the gear
Filter
the fuel delivery system
Nozzle
the fuel moves down through the injector until stopped
Pulse fuel injection
the injector may be opened and closed by electrical signals
Fuel injection
the process of spraying fuel directly into the engine
Atomizes
the spraying action of the injectors
throttle position sensor
throttle position is relayed to the computer
distributor injection pump
two types single and double
Direct fuel injection
used in diesel engines and few older gasoline engines
Indirect fuel injection
used in modern gasoline injection systems
fuel shutoff
used on diesel engines to stop the engine
speed density
uses a combination of the other sensors to determine air flow
incline injection pump
uses a separate cylinder plunger-cam for each cylinder
Throttle body fuel injections
uses an assembly containing one or two fuel injectors
turbocharger
uses the exhaust gases to drive a turbine wheel
Solenoid winding
when the injector is energized by the computer
Multiport fuel injection
when the system uses one injector per cylinder, the individual injector nozzles are located inside the intake manifold or in the cylinder head, close to the intake valve
Pressure Regulator
where the injection system pressure is controlled by
Throttle valve
which is opened and closed by the driver to control the amount of air entering the intake manifold
water in fuel sensor
will alert drivers to the fact that water is present in the fuel