Bosch ME7.1.1: Difference between revisions
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For more information regarding the HFM6 sensor, refer to [[:File:HFM6.pdf|HFM6.pdf]] (this is a great document to get a better grasp of HFM) | For more information regarding the HFM6 sensor, refer to [[:File:HFM6.pdf|HFM6.pdf]] (this is a great document to get a better grasp of HFM) | ||
====Reverse flow / pulsations==== | ====Reverse flow / pulsations==== | ||
On some conditions (like intake valve closing, for example), the air might go back through the HFM and influence the readings. Different displacement elements can influence pulsation. To correct these pulsations, the ECU will rely on pulsation map : '''KFPU''', '''KFPUKL1''' | On some conditions (like intake valve closing, for example), the air might go back through the HFM and influence the readings. Different displacement elements can influence pulsation. To correct these pulsations, the ECU will rely on pulsation map : '''<u>KFPU</u>''', '''<u>KFPUKL1</u>''' | ||
The ECU will select a specific pulsation map depending on which elements are influencing pulsations. | The ECU will select a specific pulsation map depending on which elements are influencing pulsations. |
Revision as of 03:56, 19 January 2023
Reading, writing and checksums
For reading and writing procedures refer to Reading and writing ECU (ME7.1.1)
Most flashing tools fix checksums automatically, if you wish to fix them manually, you can use LSuite
Definition file can be found here. If you are getting started with tuning with recommend consulting : Introduction to tuning
Terminology (Acronyms)
Maps and variables names are identified under acronyms. Knowing some of them will be useful and will help you remember map names.
Here is a list of the useful ones.
Acronym | German | English |
---|---|---|
A | Auslaßnockenwelle aktiv | Exhaust camshaft active |
AB | Abregelfaktor | Derating factor for acceleration signal |
AL | Adaptation Lastbereich | Adaptation load range |
ASR | Anti-slip regulation | |
BB | Betriebsbedingungen | Operating conditions |
BG | Berechnete Große | Calculated variable |
BTS | Bauteilschutz | Component protection |
CW | Code word | |
DFPM | Diagnose-Fehlerpad-Managers | Diagnostic Faulth Path Manager |
DK | Drosselklappe | Throttle valve |
DS-S | Pressure sensor (MAP) on intake manifold | |
E | Ersatzwert | Substitute value |
ESUK | Einspritzung Ubergang Kompensation | Injection transition compensation |
FA | Fahrer | Driver |
FGR | FahrgeschwindigKeitsregler | Cruise control |
FK | Faktor | Factor |
FUEREG | Fullungreglers | Filling regulators |
HFM | Hot film air mass sensor | |
KF | Kennfeld | Map |
KL | Kennlinie | Curve |
KN | Klopfereignis | Knock event |
KR | Klopfregelung | Knock control |
KRA | KR-adaptation | KR-Adaptation |
KUPPL | Kupplung | Clutch |
KW | Kurbelvelle Grad | Crankshaft degrees |
LL | Leerlauf | Idle |
LLK | Leerlauf und geoffneter kupplung | Idle and open clutch |
LLRBB | Leerlaufregelung Betriebs dedingungen | Idle control operating conditions |
LU | Laufunruche | Unstediness / roughness |
LUAR | Laufunruhe-Abstandsmass-Referenzwert | Rough running distance measure value |
LUR | Laufunruche-Referenzwert | Rough running reference value |
MBVH | Missbrauchverginderung | Abuse prevention |
MI | Motormoment indiziertes | Indicated torque |
ML | Motor Luftmassendurchsatz | Engine air mass flow |
MN | Minimum | |
MS | Massenstrom | Mass flow |
MX | Maximum | |
N | Normierter | Normalized / NM |
NW | Nockenwellen | Camshafts |
NWS | Nockenwellengsteverrung | Camshaft control |
OP | Optimales | Optimal |
PVD | Pressure vor Drosselklappe | Pressure in front of DK |
RL | relative Luft | Relative air filling (load) |
RLMIN | Relative mimale Luft | Relative minimal air (filling) |
SA | Schubabschatten | Fuel cut-off / overrun |
SOL | Soll | Should |
SW | Schlechtwegstrecke | Rough road |
TPKHFM | TemperaturKorrektur HFM | Temperature correction HFM |
TUM | Umgebungstemperator | Ambient temperature |
TV | Delay time | |
UGD | Ungedroselt | Unthrottled |
V | Verzogert | Delayed |
WDK | DK-Winkel | DK angle |
WKR | Winkelspatverstellung | Angle retard KR |
WL | Warmlauf | Warm up |
ZUL | Zulassig | Allowed limit |
ZW | Zundungs Winkel | Ignition angle |
Engine management
The ME7.1.1 use a ST10F275 micro-controller. This set it apart from most ME7 ecus that use the Infineon C167_SR.
There are no public funktionsrahmen for the ME7.1.1. You will have to refer to the following funktionsrahmen : ME7.5 Funktionsrahmen, MED9.1 Funktionsrahmen and MED17.5 Funktionsrahmen
For the fuel injection and knock control system, you can refer to ME7.5 / MED9.1 FR.
Intake manifold pressure schemes are will be found on the MED17.5 FR.
Most other modules will be based on the MED9.1 architecture.
This ecu is load-dependent. Most map works with the requested load or the actual load.
Air mass
HFM (Aka MAF)
HFM5
The ME7.1.1 use a Bosch HFM5 sensor.
The HFM5 return an analog voltage signal to the ECU. The ECU use this sampled voltage value in the MSHFMU map to determine the air mass flow.
Over time voltage drop can happen in the signal wire, this will influence the measured value. For this reason, Bosch switched from a sampled voltage measurement to a sampled period measurement. Sampled period measurement is covered in HFM6.
For more information regarding the HFM5 sensor, refer to HFM5.pdf
HFM6
The HFM6 is not used on ME7.1.1, but I believe covering this sensor is pertinent and interesting.
The HFM6 use a similar design to the HFM5. The bypass channel is flow-optimized compared to the HFM5.
The HFM6 transmit a digital signal for the measured air mass. The air mass measurement is evaluated by the frequency (period) instead of the signal voltage.
The advantage of using a digital signal is that voltage drop / interference does not influence the measurement, which make it more reliable than the HFM5. If the HFM fails, the ECU will use a substitute air-mass model stored in the ECU, like the BGMSDK module (Calculation from throttle angle)
For more information regarding the HFM6 sensor, refer to HFM6.pdf (this is a great document to get a better grasp of HFM)
Reverse flow / pulsations
On some conditions (like intake valve closing, for example), the air might go back through the HFM and influence the readings. Different displacement elements can influence pulsation. To correct these pulsations, the ECU will rely on pulsation map : KFPU, KFPUKL1
The ECU will select a specific pulsation map depending on which elements are influencing pulsations. When using an aftermarket MAF, if you do not wish to deal with those maps, you can set the pulsation maps to 1.0 to disable the pulsation compensations. It should not have much incidence on the engine safety. Please keep in mind that while the engine is on "boost", the HFM is not affected by reverse flow or pulsations. The pulsation compensations are in place to ensure an accurate air mass reading at all-time which lead to more control for stoichiometric AFR thus resulting in better emissions.
BGMSDK (Calculation from throttle valve angle)
This module calculate an air mass flow based of the throttle valve angle, a pressure ratio (intake manifold pressure / the pressure before the throttle valve) and the gas temperature (since it affects air density)
The map KFMSNWDKVP stores the air mass flow depending of the opening angle and the pressure ratio according to the following standards:
- Pressure in front of throttle valve (before) = 1013 hPa
- Gas temperature = 0°C
A pressure and a temperature correction factor is applied to to the standardized mass air flow (Respectively, ftvdk and fpvdk).
*Gas velocity is equal to the speed of sound under a pressure ratio of 0.528
Interesting to note the temperature correction factor (ftvdk) formula:
273 Kelvin = 0°C
For the pressure ratio (fpvdk), it would be as simple as :
Fuel injection
ESUK (Transient compensations)
This module adjusts the injection for transient conditions. The map WFRL contains the amount of fuel that is stored stationary in the wall-film (fuel puddle) at the respective load (pressure).
When the load (pressure) change, the difference in the fuel quantity of the wall-film (fuel puddle) is calculated to ensure the correct air/fuel mixture on transient condition.
Transient condition
Transient conditions are triggered by acceleration / deceleration. (Any drastic change in manifold pressure)
The transient condition cause a change of pressure that makes the engine run leaner / richer for a short moment until equilibrium is reached again.
Some of the injected fuel forms a fuel film (puddle) on the port. On a steady engine, the fuel film (puddle) evaporate at a constant rate, making it possible to achieve our desired AFR.
On acceleration, the pressure increase. This increased pressure force against the fuel molecules that are trying to evaporate from the fuel film (puddle). This slows the rate of evaporation momentary, making the AFR leaner for that moment. (Remember the engine burn the vapors).
On deceleration, the pressure decrease. The decreased pressure make it easier for the fuel molecules to evaporate. The rate of evaporation is faster momentary, causing the AFR to be richer.
Controlling the AFR
With LAMFA
The LAMFA map stores the desired lambda (λ / AFR ratio relative to the stoichiometric ratio) according to the engine (nmot) and the relative desired torque from the FGR (cruise control) and the accelerator pedal (mrfa_w).
The inconvenience with controlling the AFR with this map is that the map does not use the actual load, but the "desired" load. This means that the engine could be on a low load and the driver could request a high loader that would set the AFR really rich on a low load engine, since the AFR is dependent on the driver wish (desired load) and not the current engine load (rl)
With KFLBTS
The KFLBTS map define which AFR ratio to use when the component protection mode (BTS) is active.
This map has a high resolution that allow to be very precise on multiple engine conditions (load and engine speed).
We can force the engine to go into BTS to use this map at all time to control AFR. One downside of using this method is that we loose one OEM safety feature. It is important to understand why this map exist in the first place. The ECU should use this map to affect the air-mixture only if one component (such as catalytic converter, exhaust gas) reach a temperature threshold. The purpose is to increase the fuel delivery to cool down the components.
Forcing BTS
Set the following threshold to 0 : TKATBTS AND TABGBTS
You can set ZLBTS and ZLBTSDLMX higher if you want to smooth out the enrichment (refer to page 2579 of the MED9.1 FR)
Accelerator pedal
*The driver does not request a throttle angle, but a desired relative torque
KFPED : Relative driver desired torque from accelerator pedal
KFPEDL : Relative torque desired at low speed
KFPEDR : Relative torque desired in reverse gear
Idle speed
NLLMG : Target speed for idle steady-state
NLLMGFS : Target speed when set
KFNLLNST : RPM curve after start
Limiters
Engine speed
NMAX : Engine speed limitation
NMAXFA : Increased speed limit for function request (workshop test)
NMAXGA : Maximum allowable engine speed (stationnary)
NMAXOGGA : Maximum permissible engine speed (temporary increase)
NMXBENOT : Maximum speed with gearbox emergency operation
NMAXTMM : RPM limitation at high engine temperature
NMAXTO : RPM limitation at high oil temperature
NMAXDVG : Speed limit for automatic transmission in the event of speed failure
- Set those maps to the RPM limit you wish (for example 7500rpm)
You can also adjust those map if you want to.
NDNWMX : Maximum speed for camshaft control diagnosis
NNWMX : Max. threshold for switching off the NW adjustement
- Set them over your RPM limit
NMINMBVH : Minimum engine speed to activate the MBVH anti-misuse system
- Set higher than your RPM limit to desactive this system
Vehicule speed
VMAXESP : Maximum permissible speed in the event of ESP failure
VMAXNB : Maximum permissible speed in normal operation
- Max them out (FF FF) to disable the vehicule speed limiter
Brake boost
WPMXBR : Maximum permissible pedal value when brake is actuated
- Max out (FF FF)
Disabling DTC
The DTC are stored under error class that are defined in a "DTC table". The index at which a certain error class/DTC is stored in the DTC table can be calculated with a simple formula.
Before getting started, you should define the following address that you will use for calculations:
- CDC (CARB codes, OBD2 generic) start address : CDCAAA
- CDK (Kundle (Customer) / Manufacturers codes) : CDKAAA
- CLA (Error class aka DTC table) : CLAAAA
You can use the .A2L file that match your ECU:
In this case the CDC start address would be 0xE59C2. (The offset of 0x800000 has been substracted from the address)
Once the start address are defined, we can proceed to the calculation of the DTC index.
For generic codes (Starts with P0XXX):
We will use the table CDC
For manufacturer code:
We will use the table CDK
Finding the index
Let's assume we want to remove the code P0302, this is a generic code, so we will be using the table CDC.
In WinOLS (or your map editor of choice), set the view in 16bits, FF, LoHi
Go to (Control-G) the start address of CDC, in this example it would be 0xE59C2
Search for an hexadecimal (using Control-F) with the DTC code : 0302
You should see 0302 repeating 4 times, we want the address of the first occurence of the block of 4. If you see a block of 6, ignore the first two occurences.
The address of the first occurence of 0302 would be 0xE5DE2.
Now to get the index we use this formula :
Index = (address of the first occurence - start address of the table) / 8
In our example it would be :
(0xE5DE2 - 0xE59C2) / 8 = 0x84
Index is 0x84
Locating the error class in the CLA table
Using the start address provided by CLAAAA, use the following formula:
CLA error class address = CLA start address (CLAAAA) + index
In our example it would be :
CLA error class address = 0xE05B1 + 0x84 = 0xE0635
The address 0xE0635 contains the error class for the DTC P0302.
To disable the DTC set the byte at the address 0xE0635 to 0.