Engine: Description and Operation
Introduction M56 2.5L SULEV EngineThe 6-Cylinder M56 SULEV (Super Ultra Low Emission Vehicle) is available on a limited (by state) basis in the E46/2, E46/3 and E46/4.
SULEV models (E46 sedan, coupe and sportwagon all with automatic only) will be sold in
California, New York and Massachusetts as 2003 models and in Vermont starting in 2004
model year. In addition these vehicles are certified as PZEV (Partial Zero Emissions Vehicles).
PZEV regulations include:
- Vehicles must meet SULEV tailpipe emissions standard (approx. 1/5 of ULEV standards)
- Vehicles conform to Zero Evaporative Emissions
- Vehicles subject to extended OBD regulations.
- Emission relevant components warrantied for 15 years or 150,000 miles M56 Engine.
The following components are used to achieve SULEV and Zero Evaporative Emission
requirements:
- Pistons Revised to change spark travel path.
- Catalytic Converters Ceramic carriers with high cell density for better Warm Up Control.
- Oxygen Sensors Planar wide band O2 sensors in front of the cats
- Vanos Positioning changed during start up for improved start up and emissions
- Fuel Pump Control Revised with raised pressure and more accurate flow control
- Fuel Injectors New design for improved fuel flow and higher working pressure
- Fuel System All metal fuel system components made of stainless steel
- Air Intake System Revised to block HC escape
- Crankcase Ventilation Revised
- Secondary Air System Mass air flow sensor to monitor secondary air flow
- Cooling System Revised to reduce Ozone levels.
Catalytic Converters
The catalysts attached in direct proximity to the engine and are equipped with ceramic(s) carriers in high cell density technology. These converters reach operating temperature faster and offer quicker control of exhaust emissions.
Vehicles are also equipped with dual downstream converters.
Oxygen Sensors
The M56 engine uses four Oxygen sensors, two planar broadband sensors upstream of the converter and two sensors downstream.
The planar broadband sensor reach operating temperature very fast and are able to effect fuel mixtures in approximately 5 seconds.
Fuel Pump System
Fuel system operating pressure is increased to 5 Bar.
The fuel pump is controlled by the Fuel pump control unit, based on engine demand as received from the DME over the Lo-CAN. The fuel pump control unit additionally receives information over the K-Bus, specifically crash information from the MRS.
Fuel Injectors
Nozzle diameter of the fuel injectors has been reduced and the installation angle has been changed. The injectors were also adapted to perform at the higher system operating pressure. Injectors screw into the rail and a tap to test pressure readings is NOT provided.
Secondary Air
The secondary air pump has been revised to improve its response time in cold weather starting situations. A HFM (Hot Film Air Mass Meter) has been added to the secondary air system to monitor air volume pumped into the exhaust for more accurate control of the NOx emissions.
Fuel System Components
1. DMTL
2. Pressure Pipe
3. Charcoal canister
4. Breather Pipe
5. Evaporation Line
6. Fuel Fill Line
7. Fuel Tank
8. Fuel Tank Vent Line
In order to meet the Zero Evaporative Emission requirement, the fuel system was completely revised. The fuel tank, tank filler neck, charcoal canister, fuel rail and tank ventilation valve are all made of stainless steel. When perform repairs on the fuel system, it is imperative that all fitting's remain clean and that the proper tightening torques are observed. The fuel tank is manufactured of high grade steel and completely coated to meet the requirements of a minimum durability of 15 years.
The fuel tank can be exchanged only as a complete unit.
Cooling System
The radiator of the E46 SULEV looks similiar to the standard E46 radiator. The surface of the cooling fins are coated with a special "PremAir" coating. The coating consists of multiple porous layers of a catalytic surface. The task of the catalyst coating is to convert Ozone into Oxygen.
Transmission
New 6 speed manual transmissions will soon be available for all E46 models except the xi. The 6 speed will be available as the H-SMG as well. Refer to the E85 Training Manual for more information.
LIN Bus
April 5, 2000. . . BMW AG, several other car manufacturers, the communications specialist Volcano Communications Technologies AB, and the semiconductor manufacturer Motorola announced the formation of an industry consortium with the objective to define and implement an open standard for class-A serial buses in vehicle networks. The standard has been named Local Interconnect Network (LIN) and will be the enabling factor for the implementation of a hierarchical vehicle network in order to gain further quality enhancement and cost reduction of vehicles.
The standardization will reduce the manifold of existing low-end multiplex solutions and will cut the cost of development, production, service, and logistics in vehicle electronics.
Typical applications for the LIN bus are assembly units such as doors, steering wheel,
seats, climate regulation, lighting, rain sensor, or alternator.
In these units the cost sensitive nature of LIN enables the introduction of mechatronic elements such as smart sensors, actuators, or illumination. They can be easily connected to the car network and become accessible to all types of diagnostics and services. The commonly used analog coding of signals will be replaced by digital signals, leading to an optimized wiring harness.
The increasing software complexity of today's distributed electrical systems represents a major challenge for car manufacturers in terms of design, implementation and maintenance of these systems during the lifecycle of a car project. Provision for highly automated tools addressing the needs of this process are essential in order to ensure efficiency, high quality and short lead-times.
For this very reason - as an industry first - the LIN specification covers not only the protocol definition itself, but also the standardization of tool and application programming interfaces.
The introduction of LIN is accompanied by a holistic chain of tools supporting the car manufacturer in all phases of the development project.
The goal of LIN is to define a communication standard below the level of CAN - the major standard in vehicle networking. With respect to cost and performance, LIN is complementing CAN but not competing with it. LIN targets low end applications where the communication cost per node must be two to three times lower when compared to CAN and where the performance, bandwidth, and complexity of CAN is not required.
The communication protocol is based on the common serial ISO 9141 NRZ transmission. It is a single-master/multiple secondary protocol, transmitted via a single-wire bus powered by the 12V car battery. The concept of message identification allows a multi-cast data transmission between any network node controlled by the master. A particular feature of LIN is the incorporation of a synchronization mechanism for slave nodes so that - unlike CAN - a crystal resonator is not required.
This enables the application of true single-chip solutions for low cost mechatronics. The LIN standard includes the specification of the transmission protocol, the transmission medium, the interface between development tools, and the interfaces for software programming.
LIN guarantees the interoperability of network nodes from the viewpoint of hardware and software, and a predictable EMC behavior. It is not exclusively defined for automotive applications and is expected to be also successfully applied to industrial or whitegood electronics. A wide portfolio of semiconductor and software products is already available for first LIN implementations:
The LIN Bus is a standardized, serial single wire bus transferring data at a speed of 19.2 kBd. (Some LIN Busses may operate at slightly different speeds.)
The LIN Bus is very similiar to the M-Bus normally found on climate control systems.The LIN Bus (Busses) are diagnosible with the DISplus.
Vehicles may have more than one LIN Bus that are not interconnected (i.e. mirror system bus, AHL motor control bus, etc.).