View source for ZWGRU 23.110 (Fundamental Ignition Angle)

See the ''funktionsrahmen'' for the following diagrams:

zwgru-zwgru

zwgru-zw-nws Sub-function ZW_NWS: Provision for binary or
continously variable camshaft control

zwgru-dzw-nws Sub-function DZW_NWS: Provision for binary or
continously variable camshaft control (delta-ignition angle)

<u>ZWGRU 23.110 Function Description</u>

  
The fundamental ignition angle is provided by the map KFZW. The sub-function ZW_NWS
describes the provision for any necessary camshaft timing (NWS). For binary
camshaft control, the factor fnwue switches seamlessly between the maps KFZW
and KFZW2. In the case of continuously variable camshaft control which depends
on the camshaft overlap angle wnwue, an ignition angle correction DZWNWSUE
added to KFZW. The currently valid camshaft control version is defined by the
system constant SY_NWS in the software generation:

  
SY_NWS
= 0: no camshaft control

SY_NWS
= 1: binary camshaft control

SY_NWS
= 2: continuously variable NWS

SY_NWS
&gt; 2: not
defined.

  
The
software is translated conditionally, i.e. only one variant is available in the
EPROM. SY_NWS is not in the EPROM and cannot be applied. The same additive
ignition angle correction is performed as when calculating the optimum ignition
angle (see %MDBAS), i.e. exhaust gas recirculation and lambda dependence are
considered. The temperature dependence is considered in a separate function (%ZWWL).
The result is the ignition angle for cylinder bank 1 (zwref) which is also the
reference for cylinder bank 2. For cylinder bank 2, the ignition angle offset
dzwb2 is added to the ignition angle.

  
<u>ZWGRU 23.110 Application Notes</u>

  
The
maps KFZW and KFZW2 are applied when the
engine is warm for the respective camshaft control position, exhaust gas
recirculation is inactive and lambda = 1. If the engine does not knock, the
optimal ignition angle is input. For engine knock, the knock limit is input.

                                                                                                                                                                
{| border="1"
|-
| 
Parameter

 
| 
Description

 
|-
| 
CNOKT

 
| 
Codeword for lower octane fuel

 
|-
| 
CWZWBANK

 
| 
Codeword for enabling cylinder-specific ignition
angle offsets

 
|-
| 
DZWNWSUE

 
| 
Delta ignition angle depending on camshaft overlap
angle

 
|-
| 
KFDWSZ

 
| 
Delta ignition angle for cylinder bank 1-specific
ignition advance; through camshaft control

 
|-
| 
KFDWSZ2

 
| 
Delta ignition angle for cylinder bank 2-specific
ignition advance; through camshaft control

 
|-
| 
KFDZK

 
| 
Delta ignition angle during knock

 
|-
| 
KFDZWKG

 
| 
Ignition angle correction by moving the knock limit

 
|-
| 
KFSWKFZK

 
| 
Ignition angle retardation threshold for switching
between ignition angle maps

 
|-
| 
KFZW

 
| 
Ignition angle map

 
|-
| 
KFZW2

 
| 
Ignition angle map, variant 2

 
|-
| 
TMZIZWV

 
| 
Engine temperature threshold for enabling
cylinder-specific ignition angle adjustment

 
|-
| 
TSWKR

 
| 
Time lag for summing ignition angle retardation
queries

 
|-
| 
VZIZWV

 
| 
Vehicle speed threshold for disabling
cylinder-specific ignition angle adjustment

 
|-
| 
Variable

 
| 
Description

 
|-
| 
B_KFZK

 
| 
Condition flag for anti-knock map

 
|-
| 
B_KRDWS

 
| 
Condition flag for knock control safety retardation

 
|-
| 
B_NOZWE

 
| 
Condition flag for no ignition angle intervention on
the engine torque structure

 
|-
| 
C_INI

 
| 
Condition flag for intialising ECU

 
|-
| 
DZWB2

 
| 
Ignition angle offset for cylinder bank 2

 
|-
| 
DZWBANK

 
| 
Cylinder-bank specific ignition angle offset

 
|-
| 
DZWKG

 
| 
Delta ignition angle for moving the knock limit

 
|-
| 
DZWOAG

 
| 
Exhaust gas recirculation rate-dependent ignition
angle correction of the optimum ignition angle

 
|-
| 
DZWOL

 
| 
Lambda-dependent ignition angle correction of the
optimum ignition angle

 
|-
| 
DZWZK

 
| 
Delta ignition angle during knock

 
|-
| 
FNWUE

 
| 
Weighting factor for ignition angle overlap (inlet)

 
|-
| 
LAMBAS

 
| 
Basic lambda

 
|-
| 
NMOT

 
| 
Engine speed

 
|-
| 
NMOT W

 
| 
Engine speed (Word)

 
|-
| 
RL_W

 
| 
Relative cylinder charge (Word)

 
|-
| 
SY_NWS

 
| 
System constant for camshaft control: none, binary
(on/off) or continuously variable

 
|-
| 
SY_ZIZWV

 
| 
''Text must be provided by Mrs
Sauer''

 
|-
| 
TMOT

 
| 
Engine temperature

 
|-
| 
VFZG

 
| 
Vehicle speed

 
|-
| 
WKRMA

 
| 
Average of the ignition angle retardation during
knock control, general (in limp mode with safety)

 
|-
| 
WNWUE

 
| 
Camshaft overlap angle

 
|-
| 
ZWGRU

 
| 
Fundamental ignition angle

 
|-
| 
ZWNWS

 
| 
Fundamental ignition angle taking camshaft control
into consideration

 
|-
| 
ZZYLZUE

 
| 
ECU cylinder counter for ignition calculation

 
|}