2003 BMW 745i catalytic converter

Downloaded from www.Manualslib.com manuals search engine Table of Contents
SubjectPage
N62B44 Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Objectives of the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Purpose of the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Engine Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Components
Fresh Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
- Air Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
- Throttle Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
- Intake Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
- Crankcase Venting System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Exhaust System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
- Exhaust Manifold with Catalytic Converter . . . . . . . . . . . . . . . . . . . . . . . 13
- Silencers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
- Secondary Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Ancillary Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
- Belt Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
- Alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
- Air Conditioning Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
- Starter Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
- Power Steering Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Cylinder Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
- Engine Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
- Valve Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
- Valvetronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
- Bi-VANOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
- Vacuum Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
- Chain Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Downloaded from www.Manualslib.com manuals search engine Exhaust System
The exhaust system is completely redesigned for the N62B44 engine. It has been opti-
mized in terms of cylinder filling, scavenging, sound level and rapid catalytic converter light-
off.
Exhaust Manifold with Catalytic Converter
Each cylinder bank is equipped with a four into two into one exhaust manifold. The mani-
fold and the catalytic converter housing together form one component. A ceramic-bed pre-
catalytic converter and a ceramic-bed main catalytic converter are arranged one behind the
other in the catalytic converter housing.
The mounting for the broadband planar oxygen sensors (Bosch LSU) and the secondary
oxygen sensors is located in front of and behind the catalytic converter.
13
N62 Engine
42-02-13 Exhaust System
1. Manifold with Integrated Catalytic Converter
2. Broadband Planar Oxygen Sensors
3. Secondary Oxygen Sensors
4. Exhaust Pipe with Front Silencer
5. Center Silencer
6. Exhaust Gas Flap
7. Rear Silencers

Downloaded from www.Manualslib.com manuals search engine Silencers
• A 1.8 liter capacity front silencer has been fitted for each cylinder bank.
• A single 5.8 liter center silencer is fitted downstream of the two front silencers.
• The resonator type rear silencers have capacities of 12.6 and 16.6 liters.
Exhaust Gas Flap
The 12.6 liter rear silencer is fitted with an exhaust gas flap to keep noise to a minimum at
engine idle speed and low rpm. The exhaust gas flap is opened allowing additional flow
when:
• The a transmission gear is engaged a an
nd
d
• The engine speed is above 1,500 rpm
A vacuum-controlled diaphragm (actuator mounted on the silencer) opens and closes the
exhaust gas flap. The exhaust gas flap is closed with vacuum, and is sprung open by the
actuator (when vacuum is not present). The procedure is carried out using a solenoid valve
which is electrically controlled by the ECM.
Secondary Air System
Blowing additional air (secondary air) into the cylinder head exhaust ducts during the warm-
up phase results in a thermal secondary combustion which results in a reduction of the
non-combusted hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas. The
energy generated during this process heats up the catalytic converter faster during the
warm-up phase, and increases it’s conversion rate.
14
N62 Engine
43-02-05
Secondary Air System
1. Air Intake Duct
2. Air Cleaner housing with Intake Air Silencer
3. Intake Pipe with HFM (Hot-Film Air-Mass
Sensor)
4. Non-return Valves
5. Secondary Air Pump