A80 BT Intelligent Diagnosis System
49
(optional). The sensor has a temperature-dependent resistance, the
temperature coefficient of the resistor is negative, and the high-sensitivity
NTC (negative temperature coefficient thermistor) resistance increases
with temperature. It is a part of voltage divider circuit powered by 5V
support. The voltage connected to the resistor is read by an
analog-to-digital converter, which is a measure of temperature. There is a
characteristic curve in the microprocessor of the ECU that gives the
corresponding temperature for any voltage.
（
4
）
Air flow sensor
In order to achieve the statutory emission limits, especially in the
case of dynamic engine operation, the air-fuel ratio must be maintained.
For this purpose, sensors that accurately determine the actual intake air
mass flow are used. Changes in intake pulsation, back-flow, exhaust gas
return and camshaft control, and changes in intake air temperature must
not affect the accuracy of the load cell measurement. To achieve the
above objectives, in a hot film air mass flow meter, heat is extracted
from a heated sensing element by heat transfer to the air mass flow. The
micromechanical measurement system works in conjunction with a
hybrid circuit to measure air mass flow, including flow direction. When
the air mass flow is strongly pulsating, back-flow can be identified. The
micromechanical sensing element is disposed in the plug sensor flow
Содержание A80
Страница 4: ...A80 BT Intelligent Diagnosis System 4 1 1 Front view 1 2 Back view ...
Страница 29: ...A80 BT Intelligent Diagnosis System 29 Self test Check the VCI box yourself to see if there is a malfunction ...
Страница 34: ...A80 BT Intelligent Diagnosis System 34 the staff to complete the operation ...