Kia Sensor and Actuator Training
Kia Sensor and Actuator Training
Kia Sensor and Actuator Training
Sensor
Sensors and
Troubleshooting
This is the cut pages sample. Download all 69 page(s) at: ManualPlace.com
Sensor
Sensor
1. General
Fig. 1 is outline of engine control system. Engine's basic input is air and fuel, output is mechanical driving force
and emission of exhaust gas.
Sensors measure physical variables generated by engine, and the measurements are sent to controllers, ECM as
electric signals after processed by signal processors. Controllers decide various controlling variables and driving
condition required for engine operation, and then generate electric output signal for operating actuators.
Typically engine control requires measuring variables, such as air flow rate, intake manifold and barometric
pressure, coolant and intake air temperature, crank and cam angle, rotational speed, oxygen density in exhaust
gas, throttle angle, presence of Knocking, etc. <Table 1> shows sensors typically used for engine control and
their operating principle.
Therrmistor
-40~120°C
(general purpose) -50~130°C Coolant temp., Air temp., Room temp.
(coolant temp.)
(MnCoNi type)
Resistance variation by temp.
Thermistor
-40~900°C
Temp (high temp.) 600~1000°C Catalyzer temp.
(catalyzer temp.)
(Al203, rO2 type)
Resistance-temp.’s polar ON, OFF at any Coolant temp., Coolant level, Chock
PTC
characteristic temp. between -40~900°C burner
Pressure Semiconductor type Piezo resistance effect 100~780 Torr -40~120°C Intake air pressure, Atmospheric
(intake air pressure) pressure
Capacity variation by diaphragm 500~780 Torr (idle mileage control,
Static capacity type
position change (atmospheric ignition timing control, etc)
Electronic generation pressure) engine oil pressure,
Magnet projection+Pick-up coil brake oil pressure
type
Magnetic resistance Two way feature of magnetic
Crank angle, Throttle angle
type resistance type effect
(ignition timing control, EGR
Rotation 0~360°C -40~120°C
Hall element type Semiconductor’s Hall effect control, etc),
Engine rpm, Car speed
Wiegand type Wiegand effect
Slit+Light emitint, receiving
Optical type
element
Vane Type Fluid pressure and Vane rotation
Intake air rate
Air flow Karman Vortex’s occurance 3
Karman Vortex 0.1~10 m /min -40~120°C (idle mileage control, ignition timing
rate frequency
control, etc)
Hot Wire Type Quenching effect by fluid
2. Pressure Sensor
<Table 2> shows input variables used for engine control. Initially they were usually used for intake manifold
pressure, engine oil pressure, etc.
That is, intake manifold pressure is used for indirectly calculating intake air rate for idle mileage control. Earlier
ignition systems used vacuum pressure around throttle valve to measure ignition timing angle. However
requirement for improved engine emission control, fuel mileage and output performance has measured various
input variables used for engine control, and consequently various input sensors are developed and being used.
Fig. 2 is outline of intake system simply. Intake manifold is the route through that air and air/fuel mixture are
inhaled to cylinder. At that time engine works as a pump that draws air into intake manifold.
When engine is not operating, air will not flow, and then intake manifold pressure will be same as atmospheric
pressure. When engine operates, throttle valve located in intake manifold will partly interrupt air flow. Then
pressure in intake manifold will decrease getting lower than atmospheric pressure to generate partly vacuum in
intake manifold. If engine were a perfect air pump and throttle valve is close, then intake manifold pressure will be
absolute zero pressure, say perfect vacuum. However an actual engine cannot be a perfect pump, and perfect
vacuum is not available, intake manifold's absolute pressure is a little above zero. On the contrary when throttle
valve is wide open, intake manifold pressure will be approx. atmospheric pressure. As described above, intake
manifold's absolute pressure will vary from relatively low value to just a little lower value than atmospheric pressure
during engine operation.
Sensor
Let's observe pressure variation in intake manifold when throttle valve position is constant. Intake manifold pressure
fluctuates rapidly by consecutive suction of air by cylinders. Each cylinder sucks air when intake valves open and piston
drops from TDC, and the intake manifold pressure will decrease. Air intake of this cylinder will be ended upon closure of
intake valve, and intake manifold pressure will continue to rise until next cylinder begins to take air in. This process will be
repeated to fluctuate intake manifold pressure between each cylinder's cycle, and pumping will be done from one
cylinder to another. Each cylinder's air intake action will occur once per two revolution of crank axis. When N cylinders
rotate, intake manifold's pressure fluctuation frequency may be expressed in fig. 3:
N × RPM
fp = .........(1)
120
Actual engine control system requires average pressure in intake manifold, and torque generated at constant
engine rpm will be approximately proportional to average value of intake manifold pressure. To say instantly
changing pressure in intake manifold is not used for engine control, and then average value after filtering
fluctuation components will be used. Engine control system has MAP sensor that measures absolute pressure in
intake manifold.
This is the cut pages sample. Download all 69 page(s) at: ManualPlace.com