Lifan X60, Руководство по обслуживанию, Страница: 39 / 839

LIFAN X60 Service Manual
Knock control function is used to eliminate possible knock during combustion, so as to
optimize engine power and fuel economy. MT22.1 system will carry out independent
knock control on different engine cylinders.
1. Knock control working conditions
The knock control system will start when the following conditions are met:
(1) The vehicle is equipped with a knock sensor and will start knock control functions.
(2) The engine runs and the running time is more than 2s.
(3) The water temperature of engine is higher than 70°.
(4) The engine speed is higher than 600rpm.
2. Knock control mode
After knock or in the case of possible knock, the system will rapidly and properly delay
ignition advance angle. The system basic ignition advance angle is provided with normal
ignition advance angle parameter and safe ignition advance angle parameter table. The
adjustment of knock control will be carried out between the two tables.
The control program mainly include following modes:
(1) Steady knock control
During normal operation of engine, the ECM will collect and analyze the sound during
engine combustion through the knock sensor, after filtering, the knock will be detected. If
the knock intensity is over the permitted limit, the system will rapidly delay the ignition
advance angle of the cylinder suffering from knock. The knock will be eliminated during
subsequent combustion cycle and the ignition advance angle will gradually return to
normal.
(2) Transient knock control
Knock will happen easily during urgent acceleration or sharp change of engine speed.
When possible knock is detected, the system will automatically delay the ignition advance
angle to avoid overrun (strong) knock. When knock is detected, the system will rapidly
delay 3-5° of ignition advance angle in accordance with engine speed and then return to
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