Page 239 - Foton Workshop Manual - Aumark (BJ1099)

ENGINE CONTROL SYSTEM -AIR FLOW METER 11-13
AIR FLOW METER

1. Principle of Work
The system adopts mass flow measurement method to measure the air quantity
entering into the engine, and then control the injection pulse duration, so as to
accurately control the engine power take off.
2. Function and installation
Air flow meter is installed on the intake air duct between air filter and electronic
throttle valve to measure the air intake and intake temperature signal of the engine 11
in real time, and then feed back to ECU. ECU calculates fuel injection quantity per
cycle according to the intake air temperature, air intake and other parameters, so as
to precisely control air-fuel ratio, ensuring that the engine can meet the demand of
power performance and fuel economy under all working conditions.
3. Fault phenomenon and judgment method
(a). Fault phenomenon: poor acceleration, etc..
(b). General causes for faults:
•Poor-contact connector, short-circuit pin, accumulated dirt on the surface, etc..
•Vacuum unit is damaged in maintenance process.
(c). Precautions for maintenance:
Prevent falling and foreign matters from entering into the case of flow meter, so as
to ensure a good performance of air filter.

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