This is a translation from the Funktionsrahmen

MDBAS abbreviations

Parameter Source-X Source-Y Type Designation

Parameter	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:

1. 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%

1. • 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.

1. 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

1. Drag torque
   • For all measurement points at 1 must present the Resistance. Measurement on the test bed, non-fired engine operating temperature.
2. Evaluation
   • The measured results are in K3/ESY4-Hes.

Special thanks to phila_dot for translating this section.