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Ignition maps
Minimum ignition map
X axis: RPM
Y axis: Load in %
Unit: grad KW
offset: 0.75
Ignition: basic functions
Der Basiszündwinkel= The base firing angle
Zylinderzahl]= number of cylinders]
Der Array für die Zündausgabe= The array for the ignition output
WOUTA0 Grundwert – ZWOUT[0]= WOUTA0 basic value – ZWOUT[0]
Begrenzung= Limitation
Ignition Function definition
The ignition output of the ME7 is designed for static distribution with single or double spark coils. The ignition coils are controlled via ignition output stages, which are in the control unit (internal) or outside (external). The ignition output stages are controlled via port outputs on the computer, ASIC concepts for ignition output are not provided. The power amplifiers used have partly via a current limitation.
There is no diagnosis available for internal ignition output stages. The ignition’s job is to safely initiate combustion. To do this, it must be ensured that: There is sufficient energy in the ignition coil for ignition at all operating points of the engine. This means that the voltage available at the spark plug must certainly be above the voltage requirement and a minimum spark burning time must not be fallen short of. This is done by controlling the Coil closing times (szout) reached. These are determined via closing time characteristics, usually
characteristic maps Via ub and nmot (KFSZT), applied in such a way that the coil current is in all load points of the motor The range of the rated current results (see %ZUESZ). ¨ Usual spark burning times are in the order of magnitude 1ms, which at 3000 rpm already corresponds to an angular range of 18 degrees. The tension on offer Candle is usually applied at 30KV.
in order to ignite combustion in terms of both exhaust gases and torque, the closing end (i.e. the Ignition and timing) is controlled in such a way that a spark starts as closely as possible to the ignition and angle specification corresponds. Angle events are controlled by counting teeth on the speed sensor For emergency speed sensor operation, these must be created artificially. The remaining angle of the not can be measured by teeth, the event control counts the waiting time to the last one Tooth attached. Temporal events, such as the closing time output at the start, are controlled via a free-running time realized. When outputting time intervals, make sure that they are not longer than one time cycle. This is 52.4ms at a resolution of 800ns. The ignition event is set to one Synchro limited. The closing event can be in ignition range2 up to 3 synchro grids according to the calculation of the event (return from 3-fold overlap to overlap-free operation).
Location of events relative to each other
Assignment of speed (nBM), phase and ignition signal (example 4-cylinder engine, ignition and sequence 1 3 4 2
Figure shows the basic course of the ignition signals on the µController. ¨ About crank and camshaft sensors The synchro grid is created by the controller hardware by counting a number of teeth defined by the tooth spacing generated. The first synchro grid is created immediately after the tooth gap is identified. By querying the level of the camshaft sensor immediately after the tooth gap is detected, the synchronization grid is assigned to the cylinders
At the beginning of the synchro grid, the segment time, i.e. the time between the TR marks, is calculated The synchronous processes of the user software (applicable software) are then called, which are shown below includes, among other things, the calculation of the output ignition angle zwout (see %ZUE). A closing start angle is created from the closing time szout (see %ZUESZ), the segment time tseg_w and the ignition angle zwout (Slsnzahn,Slsninkr) calculated. Closing begins by counting the encoder teeth (Slsnzahn) plus waiting an increment refinement time (Slsninkr*Tinkr) from the controller hardware.
KFTVSA Delay time for fuel cutoff WPHN phase response’
Offset: 0.01
X axis: temperature(offset:0.75)
Y axis:RPM(offset:40)
Fuel cut-off/restart operating range FDEF BBSAWE 18.150 Function definition
SAEB: SA release conditions
BTMSA: SA approval from the exhaust gas temperature model
Increase in fuel cut-off speed by tester
CWSAWE FW Code word shut off fuel – reinsert
DNSAH FW Delta n SA high related to nWE
DNSAL FW Delta n SA low related to nWE
DNSATIP FW Fuel cut-off and speed increase at Tipsgasse
DNSLL FW Fuel cut-off hysteresis when WE is idling
DNVSA FW Fuel cut-off, speed increase at low speeds
DNWEELLS FW Delta WE speed in case of idle actuator error
DNWEK FW Delta n for WE at climate (AC)
DVSA FW delta speed threshold for SA speed increase
ENSAKHG FW Enable fuel cut-off for catalytic heaters depending on the gear
KFNWEGM TMOT GANGI KF restart speed map
KFTVSA TMOT NMOT KF Delay time for fuel cutoff
KFTVSAKAT NMOT TKATM KF Delay time for fuel cut-off at high speeds and high catalytic converter temperatures
NGDNSA FW Speed gradient when the fuel cut-off hysteresis is set
NSAFAN FW Fuel cut-off speed during tester intervention
Functional description
Task:
The function’s task is to recognize the engine operating range in which fuel cut-off is permitted. This is done by the Condition for fuel cut-off readiness B_sab = 1 displayed. Otherwise B_sab = 0.
Generation of fuel cut-off readiness
To generate the fuel cut-off readiness condition (B_sab = 1), the following state is necessary:
The engine speed nmot is above the SA speed threshold nsa = nwe + dnsa & after the end of the start, a motor temperature-dependent time TVSATM has elapsed & the modeled cat temperatures are below their upper limits (B_tatmsa = true) & the condition idle B_ll is set &the condition Dashpot B_dash is not set & no SA ban from FGR B_savfgr, no SLS diagnosis and no cat heating &no SA ban due to torque requirement (B_savmd = false)
For systems with direct gasoline injection (SY_BDE = true), the bit B_denox is also used for the condition B_sab taken into account if bit 1 of CWSAWE = 1. B_denox = true prevents fuel shutdown during cat regeneration.
After the above state occurs, the condition B_sab is delayed by the temperature and speed-dependent blocking time KFTVSA set as long as the clutch switch is activated. This is intended to avoid fuel cut-off during gear changes. At If the clutch switch is open, the condition B_sab is immediately set in the above state. You can use the code word CWSAWE[Bit0] = 1 The blocking time KFTVSA can be activated independently of the clutch switch. This means that this can also be done in projects without a clutch switch Fuel cut-off when changing gears can be avoided. In gear 0, the fuel cut-off can be delayed by an applicable time TVSAG0
If the above conditions are no longer met, or if the restart speed nwe is not reached, B_sab becomes without delay reset.
Calculation of speed thresholds
The restart speed nwe and the fuel cutoff hysteresis dnsa are thresholds for fuel cutoff and restart:
– nwe: if the limit is undershot, it must be reinserted.
– nsa = nwe + dnsa: if exceeded, fuel cut-off is permitted,
The restart speed nwe depends on the engine temperature tmot and speed gradient ngfil (NWENG). With vending machines
Once the gear is engaged, the speed hardly drops when you restart it. Therefore the WE speed only needs to be increased slightly
(NWENGFS). The WE speed is further increased when the air conditioning compressor (B_koe) is switched on.
In non-E-gas systems, the WE speed can be increased (DNWEELLS) if the LL actuator B_ells fails. This avoids
The engine will stop if the filling of the WE is too low when the actuator is closed.
For projects with CVT transmissions (B_cvt = true), depending on the condition B_sacvt, a selection is made between KFNWEGM and NWECVTM performed.
After leaving the idle range, the hysteresis is ramped down from the DNSAH value to DNSAL.
NGDNSA indicates the (negative) slope with which the control takes place.
When restarting at idle, the fuel cut-off speed is increased by the DNSLL value. This is particularly the case with automatic transmissions
Prevents the speed overshoot from causing the fuel to be switched off again when it is reinserted.
At low vehicle speeds (vfzg < VSAA), the hysteresis width is additionally increased by DNVSA.
If the vehicle speed exceeds the threshold VSAA+DVSA, this increase is reversed.
In projects with CVT transmissions (B_cvt = true), the fuel cut-off speed when driving in the tip lane (B_tippg = 1) can be increased by the value DNSATIP can be raised
Timing diagram of the threshold
nsa(t) depends on B_ll for constant reinstatement setting speed nwe and without Increase for small vehicle sizes speed.
Application instructions
DANGER:Using KFNWEGM(tmot,gangi), fuel cut-off can be prohibited depending on the gear by increasing the WE speed. A general one Ban on the SA for gear 0 is strictly prohibited, otherwise diagnosis of vfzg is no longer possible!!! In gear 0, the SA can be delayed for an applicable time TVSAG0. This means that a ban on SA at Tip-In can be implemented.
The function can be configured using the code word CWSAWE
Application KFTVSA:
This map is used to delay the catalytic converter at high catalytic temperatures and rich engine operation (near full load).to achieve fuel cut-off. This is to prevent the rich mixture from being switched off together with the fuel oxygen in the catalyst creates temperature peaks. If this map is updated, care must be taken to that a fuel cut-off release is not prevented via the exhaust gas temperature thresholds in the subfunction BTATMSA. B_tatmsa must be true for KFTVSA to work The ENSAKHG bit mask can be used to select the enable of the fuel cut-off for catalytic converter heaters depending on the speed.
Dead time for fuel cut-off at gear 0
Fuel shutoff/restart operating range
This map is intended to produce a similar speed curve in cases where catalytic heating is not active after starting.To do this, for the same tmot, the values in KFNLLNST must be smaller than the value in KFNLLKHM (or: KFNFSKHM) from % BBKHZ. For the largest tnst, all values in KFNLLNST must be
smaller than all values in NLLM or NLL2M. For the largest tmot value, the values in KFNLLNST must also be smaller than all values in NLLM or NLL2M.In Temperature ranges that are so high that catheating is active must be KFNLLNST = 0. The duration of a speed increase, through KFNLLNST must never be longer than the catalytic heating time. An increase in speed with KFNLLNST is only permitted in temperature ranges below TMNSMN=TANSMN (%MDZUL). The use of the KFNLLNST map is critical in the sense of levels 1 and 2 of the monitoring concept.