Electronic Fuel Injection System The Compose of EFI

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Electronic Fuel Injection System The Compose of EFI Powered By Docstoc
					Electronic Fuel Injection System
       The Compose of EFI
             Air inlet system - Air mass sup
             Fuel supply system - Fuel mass sup
             Control unit -Measure, calculate,…
             Ignition system - Ignition advance angle αz




                                  湖北汽车工业学院汽车工程系
                                  HuBei Automotive Industries Institute Dep. of Automobile
                     Injection Valve
                Multi Point Injection-MPI




1-fuel filter 2-connector plug
 3-electromagnetic solenoid
      4-spring 5-gag bit
6- nozzle assembly 7-needle
Φa =Air mass sup/ 14.7*Fuel mass sup
  Fuel mass sup= F(ti ,pi)
             The Functions and
             Control Parameters
1、Functions:
-at least the two basic functions ignition and fuel injection,
-additional subsystems as required for improved engine
control.
2、Control parameters:
 -the injection time ti (i.e. the quantity of injected fuel)
 -ignition advance angle αz and the dwell angle βs.
are calculated for instantaneous engine operating conditions.
       The Advantage of EFI

Precise and smart A/F ratio control
 Mixture uniformly to every cylinder
Smart accelerated performance
High charge efficiency
Easy start-up and break off fuel at
decelerate condition




                             湖北汽车工业学院汽车工程系
                             HuBei Automotive Industries Institute Dep. of Automobile
Engine Management System




                   湖北汽车工业学院汽车工程系
                   HuBei Automotive Industries Institute Dep. of Automobile
The Electronic Control Unit(ECU)
   (Hardwire Block Diagram)
  Engine speed
                                          Micro-




                                                    I/O (Output Porters)
 Crank position

                    I/O(Input Porters)
                                                                           Pump
    Air quantity                         Computer
Air temperature                           System
                                                                           Ignition
    Engine temp.                          (CPU)
    Throttle pos.                         (ROM)                               Fuel
Battery voltage                           (RAM)                             Injection
    Knock
  The Electronic Control Unit(ECU)
The ECU detects the instantaneous condition of the engine at very
short intervals via a number of sensors. An A/D converter then
transforms the signals output by the sensors to their digital
equivalents. This information is then processed by the
microcomputer, which generates the appropriate output signals. The
output stages amplify the low power level of microcomputer outputs
to the level required by the actuators. All programs and maps are
resident in a semiconductor memory. Digital accuracy is governed
by word length, quartz-clock frequency constancy and the
algorithms used for processing. Program configuration must allow
for the extreme real-time requirements of the engine: The interval
between two ignition pulses in a 6-cylinder engine is only about 3 ms
at maximum speed. All essential calculations must be performed
during this period. In addition to crankshaft-synchronous control
processing, the ECU also has to calculate time-synchronous events.
Both these functions have to wait if an interrupt occurs.