Bosch 2008 User Manual download pdf (Page 33)

Gasoline injection components | A31

2008 | 2009 Bosch Automotive Aftermarket

Air-mass meter

System:

LH-Jetronic, Motronic

Purpose:

The air-mass meter is installed between the air ﬁlter and the throttle valve and measures

the intake-air mass. Use is made in practice of hot-wire and hot-ﬁlm air-mass meters. Both

sensors operate on the same principle: An electrically heated thin platinum wire or platinum

ﬁlm resistor is positioned in the intake-air ﬂow together with a temperature sensor in the form

of a temperature-sensitive resistor. The electronic control unit is supplied with a voltage signal

proportional to the air mass ﬂow and uses this signal to calculate the quantity of fuel required.

Part number:

0 280 21. ...,

BX: 0 986 280 1.. (HLM), 0 986 280 2.. (HFM)

Auxiliary-air device

Systems:

D, L, K-Jetronic, Motronic (some)

Purpose:

The auxiliary-air device is installed in a bypass around the throttle valve. In the warm-up phase,

the engine is supplied with additional air/fuel mixture to ensure stable idling. The auxiliary-air

device is electrically heated and closes the bypass with increasing engine temperature. The

bypass is completely closed off when the engine reaches operating temperature.

Part number:

0 280 140 001 – 0 280 140 299

Camshaft speed sensor

Systems:

Motronic

Purpose:

The camshaft position indicates whether an engine piston moving towards top dead center is

in the compression or exhaust stroke. The speed sensor at the camshaft (also referred to as

phase sensor) passes this information to the electronic control unit. Such sensors are used

where high accuracy is required. Further advantages include a comparatively large air-gap range

and good temperature compensation.

Part number:

0 232 10. ...

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 ... 74 75

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Bosch 2008 User Manual Page 33