# Calculation of basic parameters for torque interface (MDBAS)

### From Nefmoto

*This is a translation from the Funktionsrahmen*

# MDBAS abbreviations

Parameter Source-X Source-Y Type DesignationParameter | Source-X | Source-Y | Type | Designation | |
---|---|---|---|---|---|

AGRRMAX | FW | maximum possible EGR rate | |||

WMDBAS | FW | code word Including the ZW correction for EGR operation | |||

ZWNWSUE | WNWUE | KL | Delta ignition point depending on camshaft overlap | ||

ZWOLA | LAMBAS | KL | Lambda-dependence of the optimal ignition angle relative to lambda 1 | ||

ZWOM | TMOT | KL | temperature dependent offset of the optimal ZW | ||

TADZW | DZWB | KL | ZW-efficiency as a function of delta ZW | ||

TALAM | LAMBAS | KL | Lambda-efficiency | ||

FDZWOAGR | NMOT_W | RL_W | KF | Offset of the optimal operation with AGR ZW | |

FMIOP | NMOT_W | RL_W | KF | Map optimum engine torque | |

FZWOP | NMOT_W | RL_W | KF | optimum firing angle | |

FZWOP2 | NMOT_W | RL_W | KF | optimum firing angle variation 2 | |

Variable | Source | Type | Designation | ||

AGRR | BGSRM | EIN | Exhaust gas recirculation rate | ||

B_AGR | EIN | A condition AGR | |||

DZWOAG | MDBAS | AUS | exhaust gas recirculation rate dependent optimum ignition angle of the ZW | ||

DZWOL | MDBAS | AUS | lambda dependent of the optimal ignition angle ZW | ||

DZWOTM | MDBAS | DOK | temperature-dependent optimal ignition angle of the ZW | ||

ETALAB | MDBAS | AUS | Lambda efficiency without intervention, based on optimum torque at lambda = 1 | ||

ETATRMN | MDBAS | AUS | minimum value in the efficiency drum | ||

ETAZWB | MDBAS | AUS | Ignition angle of the basic ignition angle | ||

ETAZWBM | MDBAS | AUS | averaged ignition angle of the basic ignition angle | ||

FNWUE | NWWUE | EIN | Weighting factor overlap camshafts (intake) | ||

LAMBAS | LAMKO | EIN | Base-Lambda | ||

MIBAS_W | MDBAS | AUS | indexed base torque | ||

MIOPTL1_W | MDBAS | DOK | optimal indexed engine torque at lambda = 1 | ||

MIOPT_W | MDBAS | AUS | best indexed time | ||

NMOT_W | BGNMOT | EIN | Motor speed | ||

RL_W | EGFE | EIN | relative air charge (Word) | ||

R_SYN | GGDPG | EIN | Synchro-grid | ||

SY_NWS | PROKONAL | EIN | System constant cam timing: no, 2-pt. or continuous | ||

TMOT | GGTFM | EIN | Motor temperature | ||

WNWUE | NWWUE | EIN | Camshaft overlap angle | ||

ZWBAS | ZUE | EIN | Base ignition | ||

ZWOPT | MDBAS | AUS | optimum firing angle |

# MDBAS Functional Description

Calculate the optimum moment mioptl1_w at lambda = 1 with the characteristic field KFMIOP. Edit this moment about the Lambda influence by multiplying by the Lambda efficiency etalab. The oxygen efficiency is made of the characteristic ETALAM obtained. By multiplying by the ignition angle to the base torque is mibas. This corresponds the indicated torque that sets in when the combustion to the base Lambda lambas and the base ignition zwbas takes place.

Determine the optimum ignition angle at lambda = 1 on the map KFZWOP. The partial function ZW_NWS describes the influence of the optimum firing angle may depend on an existing valve timing (NWS). The measures provided for equipment options are not, 2-point or continuous NWS. In the case of the 2-point control is through the factor fnwue steadily between KFZWOP and the map KFZWOP2 switched. For steady NWS is dependent on the NW-overlapping angle wnwue a ZW correction added to KFZWOP. The determined optimum ignition angle zwoptl1 applies again for lambda = 1 The currently valid NWS version is determined by the system constant SY_NWS at the SW creation:

SY_NWS = 0: No NWS = 1: 2-point NWS = 2: continuous NWS > 2: not defined.

The software is translated conditionally, i.e. it is only a variation in EPROM. SY_NWS is not in the EPROM and not to apply.

Additive corrections depending on lambda, the exhaust gas recirculation rate AGRR and the engine temperature is taken into account. The resulting firing angle zwopt now forms the basis for the ignition angle efficiency calculation. The basic ignition angle efficiency is calculated by the characteristic ETADZW, the input variable is the difference formed between zwopt and zwbas. This is followed by an averaging of the basis of efficiency across all cylinders and it is the basis of efficiency etazwbm.

The ZW-correction for EGR operation is be the code word CWMDBAS either included or accessible only B_agr = true. A case of permanent calculation ZW-jumps are avoided by switching off B_agr.

# MDBAS Application Notes

EGR inactive at all the measurements! For the parameterization, the following measurements are taken:

- Lambda = 1 operation:
- Firing angle grinding on the engine test stand at lambda = 1 on the following operating points, the engine is warm:

n = 500,750,1000,1250,1500,2000,2500,3000,3500,4000,4500,5000,5500,6000,6500 (if possible) rpm rl = 10,20,30,40,50,60,70,80,90,100%

- The firing angle grinding start firing angle at which the maximum torque is achieved (if not movable at the knock limit). In steps of 4.5 degrees KW is now adjusted in the late direction until the deadlines are moveable firing angle is achieved. The following data are taking notes for each measuring point: nmot, rl, lambda, clutch torque, ignition angle.

- Lambda function
- Zw loops over lambda at the measuring points:

n = 1000, 2000, 3000 rpm rl = 30, 50, 70% Lambda = .8, .85, .9, .95,1,1.05,1.1,1.15,1.2 Measurements as above

- Drag torque
- For all measurement points at 1 must present the Resistance. Measurement on the test bed, non-fired engine operating temperature.

- Evaluation
- The measured results are in K3/ESY4-Hes.

*Special thanks to phila_dot for translating this section.*