Difference between revisions of "SLS 88.150 (Secondary Air Control)"

Latest revision as of 07:17, 28 December 2011

SLS88.150 Function Description

See the funktionsrahmen for the following diagrams:

sls-sls: Function overview

slson: Conditions for switching on secondary air

slsoff: Conditions for switching off secondary air

sls-slp: Conditions for setting the bits of SLP

sls-bmsl: Calculating the secondary air mass

sls-dichte: Calculating the air density correction factor for the secondary air mass

sls-bslpdyn: Description of the dynamic of the secondary air pump

sls-bslsoff: Description of the secondary air dynamic in the exhaust system

sls-bfmlssl: Calculation of enrichment due to secondary air

sls-bkt: Secondary air adaption/short journey

sls-e-slpe E_SLPE: error flag secondary air pump

sls-e-slve E_SLVE: error flag secondary air valve

sls-e-slpanst: Evaluation of the SLP-output stage

sls-slvanst: Evaluation of the SLV-output stage

sls-z-sls: Cycle flag: secondary air control (cylinder bank 1)

sls-z-sls2: Cycle flag: secondary air control (cylinder bank 2)

sls-init: Initialisation

sls-swoff: ECU delay

Function Description

Secondary air control is coordinated by the sub-function BBKHZ in overview module AK 1.10 and consists of the following sub-functions:

Switching Conditions:

The secondary air system is activated (i.e. B_SLS, B_SLV and B_SLP are all equal to 1) when B_kh = 1 and the imlpr-threshold IMLSLMN is crossed when the engine start temperature TMST lies in the window TMSSLU<tmst<TMSSLO and the intake air temperature tans is in the window TASLU<tans<TASLO. This allows the temperature range for switching on the secondary air system with respect to catalyst heating to be restricted, for example, secondary air pumps overheating or switching on to avoid a frozen secondary air system.

By setting bit 0 of the code word CWSLS, secondary air can already be enabled at start in the restricted temperature window TMSSLSTU<tmst<TMSSLST, for example in designs with thermal reactor, the self-ignition already ensured at engine start. However, the pre-condition is that this is voltage-slope compatible, i.e. the battery voltage is greater than UBSLSTMN.

Alternatively, by setting bit 1, the secondary air system can only be activated if the speed threshold VSLS is exceeded. This is common in secondary air designs in which the exothermic reaction is first ignited in the catalytic converter. Control of the secondary air pump relay is achieved by B_slp = 1 with the minimum holding time TSLPMN to prevent opening of the relay during pump starting current. Opening of the secondary air valve (B_slv = 1) can be delayed with respect to the pump by the time TVSLON. The secondary air valve is opened when B_sls = 1. For diagnostic purposes, the secondary air pump and the secondary air valve can be controlled additionally with the flags B_dspe, B_dslfa and B_dslp4.

In twin ECU designs, the secondary air valves or secondary air pumps are activated when it is detected by one of the two ECUs that conditions B_slp or B_slv are met. The two bits B_slp and B_sls are then fed to each ECU over the CAN bus to ensure that the desired effects are initiated on both sides of the same arrangement.

Switch-off/termination Conditions

The secondary air is terminated

· When the threshold IMLSLMX is crossed (B_slpoff = 1)

· Via a debounce time TSLABB after the end of start conditions (B_stend = 1)

· When the maximum air mass threshold MLSLMX is crossed

· When the pressure difference DPSLV is too low to keep the vacuum-actuated secondary air valve open

· When the battery voltage is too low (UBSLMN)

· When there are output stage errors E_slpe, E_slve, or

· When the catalyst-heating termination condition is met (B_khab = 1).

The secondary air is not activated in the first place if:

· the output stage error has already been switched on

· A high electrical system voltage is detected (as UBSLMX) from a boost-start, a twin battery system or battery emergency power.

After switching off the secondary air pump, the secondary air valve can be closed after the time delay TVSLOFF. This is possibly required for engine designs in which the secondary air effects an improvement in fuel atomization in the combustion chamber. Closing the secondary air valve later can dampen the load-diminishing effect due to run-down of the secondary air pump. Caution: For designs with a valve check function for the secondary air diagnosis, a delayed switch-off of the secondary air valve is not acceptable, since the pump must work against the closed secondary air valve. After the power is switched off, the function to reinitialize secondary-air (C_ini) is blocked.

Description of the Secondary Air Mass

The secondary air mass msl is dependent on the electrical system voltage which is predetermined by the characteristic MSLUB and is corrected depending on the operating point from the map KFFMSML and the ambient air density (characteristic FMSRHOL). When the engine is hot, especially during adaptations- additional diagnostic phase, the secondary air mass can still be corrected depending on tmot by the characteristic FMSTMOT. The pump will run up and down described by the dynamic factor fslpdyn.

In twin cylinder bank designs (SY_STERVK) as well as twin-ECU designs (SY_2SG) with an exhaust bank per ECU (not SY_STERVK) and a single SLP (SY_SLPANZ = 1) and one exhaust bank each, the secondary air system can be split in half and corrected on a bank-specific basis (FMSL, -2).

With bit 6 from the code word CWSLS (= B_slsadap), a secondary air adaptation factor fmsla(2) can be included as determined from the secondary air diagnosis. Finally, the secondary air dilution factor flamsl is calculated for the mixture control from the secondary air mass msl. After opening or closing the secondary air-valve, the dynamics of the secondary air flow into the exhaust are described by factor fmsldyn with the time constants ZKSLON and ZKSLOFF, after the air masses IMLSLSA, IMLSLSE were incorporated. The secondary air wash after closing the valve is indicated by B_slsoff.

Calculation of Enrichment due to Secondary Air

Bit 3 of the code word CWSLS determines whether there is lambda-engine set point during secondary air injection via map KFLMSKH from function LAKH (flmssl = 0) or whether there is lambda-exhaust set-point, including secondary air via map KFLASKH from function LAKH (flmssl = 1) from an automatic calculation of the required lambda-engine with consideration of the secondary air dilution factor flamsl. Designs with lambda-exhaust set point can also be dependent on bit 4 realized after leaving the debounced idle or inputting the driving phase (bit 5) of the transition to lambda-engine through a filter with time constants ZFLMSSL. Via bit 2 of the codeword CWSLS, one can select whether with transition from B_slsoff or B_sls flmssl from the PT1-filter output is switched hard to 0.

Secondary Air Adaption/Short Journey

The secondary air adaption via B_dslfa is requested from the secondary air diagnosis and switches on the secondary air for the time TDDSLA (B_sldsl4). It occurs in conjunction with the specification for lambda catalyst-heating then the secondary air mass adaptation or diagnosis in diagnostic phases 4, 5 (see also the description of the secondary air diagnosis in DSLSLR or DLSLRS).

The short journey is requested via B_fa and B_fasls when tmot > TMFASLMN and secondary air is activated for the time TDSLKT (B_slkt) when indicated by B_dslfa from module DSLSLR(S) via the diagnostics readiness. If catalyst heating is active, it remains so for the short test until the time TFALAMN and after that is disabled (since passive diagnostics are already running). Additionally, idle speed and torque reserve can be specified to set a diagnostics-capable engine operating point. This is especially necessary in conjunction with the diagnostic function DSLSLR for the two-point lambda control, by holding the engine under lambda = 1-control while the secondary air is not to operate at the rich limit.

It can be determined via CWFASL bit 2 whether the repeated incentives of short trips in a driving cycle is possible.

Application Notes

Suggested initial programming

Overview of the coding variants of code word CWSLS:

Bit 0 = 0: secondary air with B_kh	Bit 0 = 1: secondary air at start already in engine temperature window
Bit 1 = 0: secondary air with B_kh	Bit 1 = 1: no secondary air until vehicle speed >= VSLS threshold
Bit 2 = 0: select lambda-engine with B_sls TRUE.	Bit 2 = 1: select lambda-engine with B_slsoff TRUE
Bit 3 = 0: select lambda-engine	Bit 3 = 1: select lambda-exhaust (= secondary air enrichment)
Bit 4 = 0: lambda-set point the same as idle/part-load.	Bit 4 = 1: transition to lambda-engine in part load
Bit 5 = 0: lambda-set point the same as o/m drive.	Bit 5 = 1: transition to lambda-engine with driving phase
Bit 6 = 0. without secondary air adaptation	Bit 6 = 1: with secondary air adaptation
Bit 7 = 0: KFLASKH-set point with B_atmtpl (B_atmtpl enable secondary air enrichment)	Bit 7 = 1: KFLASKH-set point without B_atmtpl, B_atmtpl is meaningless. (WARNING: only set for application phase!)

Secondary Air Concept with Thermal Reaction in the Exhaust Manifold

CWSLS.0 = true. Secondary air already in the start in FTP-tmst region for quick start of post-reaction, Attention: On-board system load!

CWSLS.3 = true. Lambda exhaust set point --> automatic calculation of lambda-engine from secondary air dilution flamsl_w

CWSLS.4 = true. Transition to lambda-engine when leaving idle, because post-reaction stops anyway

CWSLS.5 = true. Transition to lambda-engine when loading the driving phase, because post-reaction stops anyway

CWSLS.6 = false. No secondary air adaptation

CWSLS.7 = false. KFLASKH set point only when B_atmtpl = true

Secondary Air Design with Further Reaction in the Catalyst

CWSLS.0 = false: no secondary air in the start

CWSLS.1 = true/false depending on the start of partial light-offs in the catalyst (cat-position)

CWSLS.3 = false: lambda engine set point during secondary air injection

CWSLS.6 = false: no secondary air adaptation

Overview of the coding variants of code word CWFASL:

Bit 0: 0: Short test termination if B_fs, vfzg> 0 or B_brems / B_kuppl (see bit 1). 1: no short test termination via B_fs, or vfzg B_brems/B_kuppl possible.

Bit 1: 0: Short test termination if B_brems or B_kuppl. 1: brake and clutch have to be actuated for a short test.

Bit 2: 0: short test can be induced only once in the driving cycle. 1: Short test times can be induced (see bit 3).

Bit 3: 0: Short test only possible after deleting previous fault memory. 1: short test possible without deleting error memory.

WARNING: When bit 3 is set, there is a risk that the catalyst is superheated by repeatedly carrying out short tests.

SLS parameters:

IMLSLMN	0	Secondary air at the same time as B_kh
IMLSLMX	0.9961	Secondary air during entire catalyst heating
TMSSLSTU	15°C	Secondary air from tmst > 15°C is already at the start CWSLS.0 = true
TMSSLSTO	35°C	Secondary air from tmst < 35°C
TMSSLU	15°C	Secondary air with B_kh when tmst > 15°C
TMSSLO	35°C	Secondary air with B_kh when tmst < 35°C
TASLSU	15°C	Secondary air with B_kh when tans > 15°C
TASLSO	35°C	Secondary air with B_kh when tans < 35°C
VSLS	10 km/h	Secondary air only when vehicle speed > 10 km/h when CWSLS.1 = true
MLSLMX	200 kg/h	Termination threshold when ml > 200 kg/h
DPSLV	0 mbar	Termination threshold pressure difference to open the secondary air valve
UBSLMN	9 V	Minimum battery voltage for sufficient secondary air mass
TSLABB	1 sec	Debounce time for secondary air termination after engine start (B_stend)
UBSLMX	16 V	Fan protection during boost start
UBSLSTMN	8 V	B_sls at start when battery voltage > 8 V
TSLUBST	2 sec	Debounce time for battery voltage at start

Secondary air pump parameters

TVSLVON	0.1 sec	Secondary air valve opened at the same time as secondary air pump control
TVSLVOFF	0 sec	Secondary air valve closes at the same time as secondary air pump control
TVDSLOFF	2 sec	Secondary air valve closes 2 seconds after short journey/adaptation
TSLPMN	500 ms	Minimum dwell time of the secondary air pump-relay to the relay protection
TVSLP2	2 sec	Delay time for triggering a second secondary air pump

BMSL parameters:

MSLUB =	Function of battery voltage. Obtained from laboratory measurements of the fan at 100 mbar back pressure, check the details required in the vehicle!
KFFMSML =	Function of engine speed and relative load
FMSRHOL	overall factor = 1, approximate without air density correction
FMSTMOT =	Function of engine temperature overall = 1, approximate without correction
FMSL,-2	1 no single bank correction

BSLPDYN parameters:

ZKSLPON	1s	Fan run-up
ZKSLPOFF	1s	Fan run-down

BSLSOFF parameters

IMLSLA	3.5 g
IMLSLSE	3.0 g	Implementing air mass to clean out the secondary air system

Dynamic SLP:

Dependent on ml:	20	40	60	100	kg/h
ZKSLSONML 0.5 s	1.5 s	1.0 s	0.5 s	0.2 s	Project specific
ZKSLSOFML 0.5 s	1.5 s	1.0 s	0.5 s	0.2 s	Project specific

BFMLSSL parameters

TLMSSLMX 60 s Termination of the thermal reaction (lambda-exhaust set point) after 60 s at idle

TLMSSLAB 1s Debounce time for detection of exit from idle

ZFLMSSL 1s Time constant for transition from lambda-exhaust --> lambda-engine

BKT parameters:

CWFASL s. o

TMFASLMN: 60°C

TFASLAMN: 60 sec

TDDSLA: 25 s

TDSLKT: 10 s

Abbreviations

Parameter	Description
CONT
CWFASL	Code word: calibrator intervention for secondary air diagnostics
CWSLS	Code word for secondary air system
DPSLV	Minimum pressure difference across the secondary air valve
FMSL	Factor for correcting secondary air mass, cylinder bank 1
FMSL2	Factor for correcting secondary air mass, cylinder bank 2
FMSLOFF	Clearing threshold of the secondary air terminated
FMSRHOL	Air density correction of the secondary air mass
FMSTMOT	Engine speed correction of the secondary air mass
IMLSLMN	Minimum ratio factor psum_w/mlsu for switching on SLS
IMLSLMX	Maximum ratio factor psum_w/mlsu for switching on SLS
IMLSLSA	Air mass integral threshold for initiation of secondary air in exhaust
IMLSLSE	Air mass integral threshold for termination of secondary air in exhaust
KFFMSML	Exhaust back-pressure corrections of the secondary air mass
MLSLMX	Maximum engine-air mass for secondary air injection
MSLUB	Secondary air mass dependent on the battery voltage
SY_BATTSG	System constant: twin battery design
SY_SGANZ	System constant: number of ECUs
SY_SLPANST	System constant: activation of the secondary air pump with twin-ECU, 0 = master, 1 = slave, 2 = master & slave. Seperate
SY SLPANZ	System constant for the number of secondary air pumps
SY_SLVANST	System constant: activation of the secondary air valve with twin-ECU, 0 = master, 1 = slave, 2 = master & slave. Seperate
SY_SLWG	System constant condition flag: secondary air/turbo wastegate present
SY_STERVK	System constant condition flag: stereo lambda control before catalytic converter
TASLSO	Upper air intake temperature threshold for secondary air system
TASLSU	Under air intake temperature threshold for secondary air system
TDDSLA	Continuous secondary air injection for adaptation phase
TDSLKT	Continuous short test secondary air diagnose for mass measurement
TFASLAMN	Minimum catalyst heating time for test requirement in secondary air diagnostics
TLMSSLAB	Debounce time for terminating secondary air enrichment
TLMSSLMX	Maximum time for secondary air enrichment during idle
TMFASLMN	Engine temperature threshold test requirement for secondary air diagnostics
TMSSLO	Upper start temperature threshold for secondary air
TMSSLSTO	Upper temperature threshold for secondary air at start
TMSSLSTU	Lower temperature threshold for secondary air at start
TMSSLU	Lower start temperature threshold for secondary air
TSLABB	Delay time for secondary air – termination condition
TSLPMN	Minimum duty cycle of the secondary air pump
TSLUBST	Debounce time for secondary air on at start by UBSLSTMN
TVDSLOFF	Time delay for closing secondary air valve for adaptation/short journey
TVSLP2	Time delay for control of the no. 2 secondary air pump
TVSLVOFF	Time delay on closing the secondary air valve
TVSLVON	Time delay on opening the secondary air valve
UBSLMN	Minimum voltage for secondary air on
UBSLMX	Maximum voltage for secondary air on
UBSLSTMN	Minimum voltage for secondary air on at start
VSLS	Vehicle speed threshold for secondary air control on
ZFLMSSL	Time constant: mixture part secondary air
ZKSLPOFF	Time constant: secondary air fan off/low flow
ZKSLPON	Time constant: secondary air fan on/run-up
ZKSLSOFML	Time constant: evacuation of the secondary air after valve shut
ZKSLSONML	Time constant: introduction of secondary air after valve open
Variable	Description
B_ATMTPL	Condition flag: dew point after catalyst exceeded (last journey)
B_BATNOT	Condition flag: battery emergency start with twin battery design
B_BREMS	Condition flag: brake operated
B_DSLFA	Condition flag: secondary air system requirement for short test
B_DSLRESET	Condition flag: reset secondary air adaptation/short test
B_DSLSET	Condition flag: set secondary air adaption/short test
B_DSLSP4	Condition flag: secondary air system requirement for secondary air adaption/additional diagnostics
B_DSPE	Condition flag: diagnostic secondary air on
B_DWG	Condition flag: wastegate diagnostics
B_ESLPE_C	Condition flag: error secondary air pump (output stage) sent via CAN
B_ESLVE_C	Condition flag: error secondary air valve (output stage) sent via CAN
B_FA	Condition flag: general functional requirement
B_FASLA	Condition flag: external request to activate secondary air system
B_FASLS	Condition flag: function requirement secondary air system
B_FS	Condition flag: driving phase
B_KH	Condition flag: catalyst heating
B_KHA	Condition flag: catalyst-heating requirement
B_KHAB	Condition flag: catalyst-heating terminated
B_KUPPL	Condition flag: clutch actuated
B_LL	Condition flag: idle
B_LMSSLOF	Condition flag: lambda-engine-set point-secondary air part, off
B_MASTERHW	Condition flag: master-ECU in accordance coding pins (plausibility check)
B_MSLMN	Condition flag: insufficient secondary air mass
B_MSLOFF	Condition flag: secondary air mass ausgeräumt after secondary air phase
B_MSLON	Condition flag: steady-state secondary air mass after start of the secondary air
B_NMOT	Condition flag: engine speed > NMIN
B_SLDSL4	Condition flag: enabling secondary air for diagnostics phase 4
B_SLKHOF	Condition flag: switching off the secondary air pump via imlpr-threshold
B_SLKT	Condition flag: enabling secondary air for short test
B_SLP	Condition flag: secondary air pump No. 1
B_SLP2	Condition flag: secondary air pump No. 2
B_SLPANST	Condition flag: for evaluation of the output stage error in secondary air control function
B_SLPENA	Condition flag: switching on the secondary air pump
B_SLPMN	Condition flag: minimum operating time of the secondary air pump
B_SLPOFF	Condition flag: secondary air pump switched off
B_SLPOFST	Condition flag for setting flip-flop B_slpoff
B_SLPT	Condition flag for secondary air pump, temporary intermediate size
B_SLP_C	Condition flag for secondary air pump, sent via CAN
B_SLS	Condition flag: secondary air active
B_SLSADAP	Condition flag: secondary air mass adaptation
B_SLSDIS	Condition flag for switching off the secondary air pump
B_SLSERR	Condition flag for blocking activation of the secondary air pump
B_SLSFZ	Condition flag: secondary air system installed in the vehicle
B_SLSINHI	Condition flag: blocked by setting bit B_sls
B_SLSOAB	Condition flag: secondary air system without implementing the termination criterion
B_SLSOFF	Condition flag: secondary air injection terminated after elimination of the secondary air
B_SLST	Condition flag: secondary air active, temporary intermediate size
B_SLS_C	Condition flag: secondary air active sent via CAN
B_SLV	Condition flag for secondary air valve
B_SLVANST	Condition flag for determining the output stage error in the secondary air control module
B_ST	Condition flag: start
B_STEND	Condition flag: end of start conditions reached
DFP_SLPE	Internal error path number: secondary air pump output stage
DFP_SLS	Internal error path number: secondary air system (cylinder bank 1)
DFP_SLS2	Internal error path number: secondary air system (cylinder bank 2)
DFP SLVE	Internal error path number: secondary air valve output stage
E_SLPE	Error flag: secondary air pump (output stage)
E_SLVE	Error flag: secondary air valve (output stage)
FLAMSL_W	Factor for lambda adjustment through secondary air (cylinder bank 1)
FLAMSL2_W	Factor for lambda adjustment through secondary air, (cylinder bank 2)
FLMSSL	Factor lambda-engine-set point secondary air part
FMSAGD	Exhaust gas back-pressure correction factor for the secondary air mass
FMSLA	Correction factor secondary air mass adaptive (cylinder bank 1)
FMSLA2	Correction factor secondary air mass adaptive (cylinder bank 2)
FMSLDYN	Factor for dynamic specification of secondary air
FMSLKOR	Factor to correct the secondary air mass
FMSLRHO	Air density correction of the secondary air mass
FMSLTM	Engine temperature correction of the secondary air mass
FRHOKOR_W	Factor to address the air density correction of the secondary air
FSLPDYN	Factor for dynamic specification of the secondary air pump
IMLPR	Relative air mass integral during catalyst heating
IMLSLA_W	Air mass integral for introducing the secondary air
IMLSLE_W	Air mass integral for end of secondary air in exhaust
MLBB_W	Air mass flow filtered (word), cylinder bank 1
MLBB2_W	Air mass flow filtered (word), cylinder bank 2
ML_W	Air mass flow filtered (word)
MSL	Secondary air mass flow (cylinder bank 1)
MSL2	Secondary air mass (cylinder bank 2)
MSL2_W	Secondary air mass (cylinder bank 2) 16-Bit value
MSLKORR_W	Corrected secondary air mass flow with consideration of pump dynamics (bank 1)
MSLPUB_W	Secondary air mass flow (battery voltage dependent) 16-Bit
MSLSTAT	Static secondary air mass flow
MSLSTAT_W	Static secondary air mass flow, 16-Bit
MSL_W	Secondary air mass flow 16-Bit value
NMOT	Engine speed
PS_W	Intake absolute pressure (word)
PU	Ambient pressure
RL	Relative air charge
TANS	Ambient air temperature
TMOT	Engine temperature
TMST	Engine start temperature
TNST_W	Time after end of start
UBSQF_W	System voltage, converted into standard quantization and filtered
VERHMSB_W	Number of the cylinder-specific mass flow distribution factor for cylinder bank 1
VERHMSB2_W	Number of the cylinder-specific mass flow distribution factor for cylinder bank 2
VFZG	Vehicle speed
Z_SLS	Cycle flag: secondary air-system (cylinder bank 1)
Z_SLS2	Cycle flag: secondary air-system (cylinder bank 2)

@@ Line 3: / Line 3: @@
 See the ''funktionsrahmen'' for the following diagrams:
-sls-sls Function overview
+sls-sls: Function overview
-slson Conditions for switching on secondary air
+slson: Conditions for switching on secondary air
-slsoff Conditions for switching off secondary air
+slsoff: Conditions for switching off secondary air
-sls-slp Conditions for setting the bits of SLP
+sls-slp: Conditions for setting the bits of SLP
-sls-bmsl Calculating the secondary air mass
+sls-bmsl: Calculating the secondary air mass
-sls-dichte Calculating the correction factors for the secondary air mass
+sls-dichte: Calculating the air density correction factor for the secondary air mass
+sls-bslpdyn: Description of the dynamic of the secondary air pump
-sls-bslpdyn Description of the dynamic of the secondary air pump
+sls-bslsoff: Description of the secondary air dynamic in the exhaust system
-sls-bslsoff Description of the secondary air dynamic in the exhaust system
+sls-bfmlssl: Calculation of enrichment due to secondary air
-sls-bfmlssl Calculation of enrichment due to secondary air
+sls-bkt: Secondary air adaption/short journey
-sls-bkt Secondary air adaption/short journey
 sls-e-slpe E_SLPE: error flag secondary air pump
@@ Line 27: / Line 27: @@
 sls-e-slve E_SLVE: error flag secondary air valve
-sls-e-slpanst Evaluation of the SLP-output stage
+sls-e-slpanst: Evaluation of the SLP-output stage
-sls-slvanst Evaluation of the SLV-output stage
+sls-slvanst: Evaluation of the SLV-output stage
-sls-z-sls Cycle flag: secondary air control (cylinder bank 1)
+sls-z-sls: Cycle flag: secondary air control (cylinder bank 1)
-sls-z-sls2 Cycle flag: secondary air control (cylinder bank 2)
+sls-z-sls2: Cycle flag: secondary air control (cylinder bank 2)
-sls-init Initialisation
+sls-init: Initialisation
-sls-swoff ECU delay
+sls-swoff: ECU delay
 <u>Function Description</u>
@@ Line 59: / Line 60: @@
-<u>Switch-off/termination Conditions:</u>
+<u>Switch-off/termination Conditions</u>
- The secondary air is terminated:
+The secondary air is terminated
 · When the threshold IMLSLMX is crossed (B_slpoff = 1)
@@ Line 82: / Line 83: @@
 · the output stage error has already been switched on
-· A high electrical system voltage is detected (as UBSLMX) from a boost-start, a twin battery system or battery
+· A high electrical system voltage is detected (as UBSLMX) from a boost-start, a twin battery system or battery emergency power.
-emergency power.
-After switching off the secondary air pump, the secondary air valve can be closed after the time delay TVSLOFF. This is possibly required for engine designs in which the secondary air effects an improvement in fuel
+After switching off the secondary air pump, the secondary air valve can be closed after the time delay TVSLOFF. This is possibly required for engine designs in which the secondary air effects an improvement in fuel atomization in the combustion chamber. Closing the secondary air valve later can dampen the load-diminishing effect due to run-down of the secondary air pump. Caution: For designs with a valve check function for the secondary air diagnosis, a delayed switch-off of the secondary air valve is not acceptable, since the pump must work against the closed secondary air valve. After the power is switched off, the function to reinitialize secondary-air (C_ini) is blocked.
-atomization in the combustion chamber. Closing the secondary air valve later can dampen the load-diminishing effect due to run-down of the secondary air pump. Caution: For designs with a valve check function for the secondary air diagnosis, a delayed switch-off of the secondary air valve is not acceptable, since the pump must work against the closed secondary air valve. After the power is switched
-off, the function to reinitialize secondary-air (C_ini) is blocked.
-<u>Description of the Secondary Air Mass:</u>
+<u>Description of the Secondary Air Mass</u>
 The secondary air mass msl is dependent on the electrical system voltage which is predetermined by the characteristic MSLUB and is corrected depending on the operating point from the map KFFMSML and the ambient air density (characteristic FMSRHOL). When the engine is hot, especially during adaptations- additional diagnostic phase, the secondary air mass can still be corrected depending on tmot by the characteristic FMSTMOT.
@@ Line 104: / Line 102: @@
-<u>Calculation of Enrichment due to Secondary Air:</u>
+<u>Calculation of Enrichment due to Secondary Air</u>
-Bit 3 of the code word CWSLS determines whether there is lambda-engine set point during secondary air injection via map KFLMSKH from function LAKH (flmssl = 0) or whether there is lambda-exhaust set-point,
+Bit 3 of the code word CWSLS determines whether there is lambda-engine set point during secondary air injection via map KFLMSKH from function LAKH (flmssl = 0) or whether there is lambda-exhaust set-point, including secondary air via map KFLASKH from function LAKH (flmssl = 1) from an automatic calculation of the required lambda-engine &#8203;&#8203;with consideration of the secondary air dilution factor flamsl. Designs with lambda-exhaust set point can also be dependent on bit 4 realized after leaving the debounced idle or inputting the driving phase (bit 5) of the transition to lambda-engine through a filter with time constants ZFLMSSL. Via bit 2 of the codeword CWSLS, one can select whether with transition from B_slsoff or B_sls flmssl from the PT1-filter output is switched hard to 0.
-including secondary air via map KFLASKH from function LAKH (flmssl = 1) from an automatic calculation of the required lambda-engine &#8203;&#8203;with consideration of the secondary air dilution factor flamsl. Designs with lambda-exhaust set point can also be dependent on bit 4 realized after leaving the debounced idle or inputting the driving phase (bit 5) of the transition to lambda-engine through a filter with time constants ZFLMSSL. Via bit 2 of the codeword CWSLS, one can select whether with transition from B_slsoff or B_sls flmssl from the PT1-filter output is switched hard to 0.
-<u>Secondary Air Adaption/Short Journey:</u>
+<u>Secondary Air Adaption/Short Journey</u>
-The secondary air adaption via B_dslfa is requested from the secondary air diagnosis and switches on the secondary air for the time TDDSLA (B_sldsl4). It occurs in conjunction with the specification for lambda
+The secondary air adaption via B_dslfa is requested from the secondary air diagnosis and switches on the secondary air for the time TDDSLA (B_sldsl4). It occurs in conjunction with the specification for lambda catalyst-heating then the secondary air mass adaptation or diagnosis in diagnostic phases 4, 5 (see also the description of the secondary air diagnosis in DSLSLR or DLSLRS).
-catalyst-heating then the secondary air mass adaptation or diagnosis in diagnostic phases 4, 5 (see also the description of the secondary air diagnosis in DSLSLR or DLSLRS).
@@ Line 124: / Line 120: @@
 <u>Application Notes</u>
-<u>Suggested initial programming:</u>
+<u>Suggested initial programming</u>
 <u>Overview of the coding variants of code word CWSLS:</u>
 {| border="1"
 |-
@@ Line 134: / Line 129: @@
 Bit 0 = 0: secondary air with B_kh
 |
-Bit 0 = 1: secondary air at start already in engine
+Bit 0 = 1: secondary air at start already in engine temperature window
-temperature window
 |-
 |
 Bit 1 = 0: secondary air with B_kh
 |
-Bit 1 = 1: no secondary air until vehicle speed ³ VSLS threshold
+Bit 1 = 1: no secondary air until vehicle speed >= VSLS threshold
 |-
 |
@@ Line 151: / Line 144: @@
 Bit 3 = 0: select lambda-engine
 |
-Bit 3 = 1: select lambda-exhaust ( = secondary air enrichment)
+Bit 3 = 1: select lambda-exhaust (= secondary air enrichment)
 |-
 |
@@ Line 175: / Line 168: @@
-<u>Secondary Air Concept with Thermal Reactor in the Exhaust Manifold:</u>
+<u>Secondary Air Concept with Thermal Reaction in the Exhaust Manifold</u>
-CWSLS.0 = true. Secondary air already in the start in FTP-tmst region for quick start of post-reaction, Attention: On-board system
+CWSLS.0 = true. Secondary air already in the start in FTP-tmst region for quick start of post-reaction, Attention: On-board system load!
-load!
-CWSLS.3 = true. Lambda exhaust set point ® automatic calculation of lambda-engine from secondary air dilution flamsl_w
+CWSLS.3 = true. Lambda exhaust set point --> automatic calculation of lambda-engine from secondary air dilution flamsl_w
 CWSLS.4 = true. Transition to lambda-engine when leaving idle, because post-reaction stops anyway
@@ Line 191: / Line 183: @@
-<u>Secondary Air Design with Further Reaction in the Catalyst:</u>
+<u>Secondary Air Design with Further Reaction in the Catalyst</u>
-CWSLS.0 = false: no secondary air in the false start
+CWSLS.0 = false: no secondary air in the start
 CWSLS.1 = true/false depending on the start of partial light-offs in the catalyst (cat-position)
@@ Line 322: / Line 314: @@
 V
 |
-B_sls at start when battery
+B_sls at start when battery voltage &gt; 8 V
-voltage &gt; 8 V
 |-
 |
@@ Line 333: / Line 324: @@
 |}
-<u>Secondary air pump parameters:</u>
+<u>Secondary air pump parameters</u>
 {| border="1"
@@ Line 350: / Line 341: @@
 sec
 |
-Secondary air valve closes at the same time as secondary air pump down control
+Secondary air valve closes at the same time as secondary air pump control
 |-
 |
@@ Line 392: / Line 383: @@
 FMSRHOL
 |
-overall factor = 1,
+overall factor = 1, approximate without air density correction
-approximate without air density correction
 |-
 |
@@ Line 427: / Line 417: @@
-<u>BSLSOFF parameters:</u>
+<u>BSLSOFF parameters</u>
 {| border="1"
@@ Line 492: / Line 482: @@
-<u>BFMLSSL parameters:</u>
+<u>BFMLSSL parameters</u>
 TLMSSLMX 60 s Termination of the thermal reaction (lambda-exhaust set point) after 60 s at idle
@@ Line 498: / Line 488: @@
 TLMSSLAB 1s Debounce time for detection of exit from idle
-ZFLMSSL 1s Time constant for transition from lambda-exhaust ® lambda-engine
+ZFLMSSL 1s Time constant for transition from lambda-exhaust --> lambda-engine
@@ Line 512: / Line 502: @@
 TDSLKT: 10 s
 <u>Abbreviations</u>
@@ Line 529: / Line 520: @@
 CWFASL
 |
-Code word: calibrator intervention
+Code word: calibrator intervention for secondary air diagnostics
-for secondary air diagnostics
 |-
 |
@@ Line 546: / Line 536: @@
 FMSL
 |
-Factor for correcting secondary
+Factor for correcting secondary air mass, cylinder bank 1
-air mass, cylinder bank 1
 |-
 |

Difference between revisions of "SLS 88.150 (Secondary Air Control)"

From Nefmoto

Latest revision as of 07:17, 28 December 2011

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