Chery A11. Manual — part 32
CAC Gasoline Engine Maintenance And Servicing Manual
83
IWM523 fuel injector applied in the system is of the shortened type of the first generation. It is entirely
made of stainless steel and superior in the function. The advantage may be embodied when the commercial
fuel containing corrosive material is applied. figure 138 shows fuel injector structure and some technical
parameters.
Technical parameters:
-winding resistance
R=1.8Ω+/-10%(20℃)
-power supply voltage
V=6-16V
-spraying shape
angle 30~90°
-operating temperature
-30~+110℃.
when fuel injector is not operating, it is sealed and doesn’t allow fuel drain. Fuel needed by engine, is
controlled by ECU(supplied electricity by relay (87))directly. And ECU decides the open time of each intake
order and fuel injection duration.
Fuel injection time is controlled by the following measures:
-synchronous(for normal operation) .injector opening corresponds with every TDC.
-not synchronous (for idling, cut-off, low speed, start operation).injector opening is completely
controlled by time and not related to TDC signal.
ECU has a basic current control circuit to control fuel injector. The circuit produces the maximal
current(signal) at the first control order speed up the opening of injector. Once maximum current is attained ,
the circuit will automatically change to and keep the current I=1A±0.3 A(Mean).
Injection duration is showed on the 2-dimension figure as a function of engine speed and intake manifold
absolute pressure . After engine warming up or speed turns to be stable, injection duration is 1~4mS.
Injection duration is increasing basically under special operation condition, such as accelerating, cold
starting, engine warming up. As accelerator pedal is released, fuel will be cut off.( ti=0mS). Running condition
and readjusting condition may be changed according to water/ intake air temperature or A/C condition.
——intake air temperature sensor “ATS05”
It is consisted of N.T.C.(Negative Temperature Coefficient) thermo resistance and 2-way junction box that
are installed in the plastic setting molding case. Sensor resistance will changed with intake air temperature.
Fig. 138 fuel injector
+12V relay
ECU 18 insert pin
CAC Gasoline Engine Maintenance And Servicing Manual
84
2.2 Lower body(air system)—description and function of accessories
Excepted that connecting throttle valve to accelerator pedal by a lever, the following parts should be
installed on the lower body.
·throttle valve position sensor
·stepper motor
·hot water loop near the throttle valve and idle air by-pass
·absolute pressure signal port in the lower throttle valve (necessary to be connected with pressure
sensor)
·PCV recirculation pipe
——throttle valve position sensor “PF2C”.
figure 140 shows the position sensor case structure ,also the relationship between output characteristic,
output signal and throttle valve opening ange.
·Sensor component is consisted of a potentiometer. The slipping ruler of potentiometer is driven directly
by accelerator pedal which is proportional with throttle valve opening.
·the potentiometer is inserted into plastic case with two baffles on the bracket. There are two
Fig.139 temperature sensor and principle
water
Air
Connecting chart
Fig. 140 throttle valve position sensor and operation chart
ground
Signal output
power
throttle valve opening(angle)
CAC Gasoline Engine Maintenance And Servicing Manual
85
holes in the bracket for installing the potentiometer on throttle valve.
· there is spline on the shaft. the spine provides data about throttle position. The data is used to confirm
idle operation condition(accelerator pedal released), full load(accelerator pedal depressed) and accelerating or
decelerating conditions.
· with absolute pressure sensor out of work, the position sensor will function when working condition
comes back.
·ECU supplies 5V voltage to the variable resistance terminal of throttle valve potentiometer . And
potentiometer output voltage varies with throttle valve position.
·sensor needs not adjustment(through assembling hole), for ECU program may self adjust to minimum
impedance(2°to 14°).
Warning——the following order should be taken during potentiometer replacement:
1. tighten mounting bolt on the new potentiometer.
2. turn ignition key to the MAR before connecting line to the potentiometer, and wait for several
minutes.
3. turn ignition key to Stop.
4. connect wire to the potentiometer’s insert hole.
5. insert CHECK-UP1 tester. Turn ignition key to CN and erase trouble display.
6. keep connection until throttle valve position displayed on the screen is 2°~14°. If the parameter is
above 14°, you should check throttle cable and make sure it’s correct (not very tight). Or it needs to
be adjusted again.
Notice: Don’t adjust the potentiometer bolt if it does not return to the specified value of throttle valve
opening angle. The potentiometer should be replaced because it fails.
——engine idle speed actuator(idle control stepper motor)
Idle control stepper motor is a position actuator of high precision and high distinguishability( +/-50r/min)
for controlling idle speed.
It is consisted of stepper motor and screw rod-type reduction gear. The reduction gear converts the valve
rotating into linear movement. Stepper motor receives the signal from ECU and makes valve shaft move by
screw rod changing air by-pass passage(see figure 8). Then engine air intake will change during idling. It will
vary with coolant water temperature whether air intake is increasing or decreasing, which keeps speed stable.
Engine minimum idle air intake is set by adjusting throttle valve opening when by-pass channel is closed
completely. Be sure not to touch mixture adjustment bolt. Engine maximum idle air intake is set by valve
returning position , i.e. about 200 steps (8mm travel). The operation steps is the function of engine
conditions(preheating cycle, electrical load, A/C working condition, engine running (hot)).
CAC Gasoline Engine Maintenance And Servicing Manual
86
If stepper motor needs to be replaced, remove the positive connector first and replace actuator. Then
turn ignition key to position 1(accessory position), ECU will readjust actuator position(to limit switch) and
adjust for steps according to engine water temperature so as to adjust idle speed with valve linear (axial
direction)movements(forward or backward).
Only CHECK-UP1 tester may be applied to check whether it’s running properly.
3.1MARWAL low pressure fuel pump“MSS070”
The fuel pump in this system is atmospheric
positive shift (see figure. 142). It is designed to work
with ethyl as its standard fuel and equipped with a
check valve and a pressure override valve (vibration
pressure is 2.6bar). It is installed inside the fuel tank and
equipped with a fuel filter.
Fuel pump supplies the fuel to fuel injectors and is
controlled directly by ECUD to ensure:
·The fuel pump will close when engine speed drops
under the minimum starting speed or engine stops.
· The fuel pump signal is timed. once ignition
switch is on and engine is not started , there will be a
fuel pump signal within 10 seconds.
· Under the engine running and starting conditions,
the fuel pump signal will not change.
Fig. 142 fuel pump
Fig. 141 Idle step motor and air by-pass valve
valve
idle actuator
by-pass channel
throttle
valve
throttle
valve
leak
by-pass
air control.
feature
parameter
electric connector
outlet
operation temperature
spiral resistance
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст