New softwar e ha s been loaded t o th e ECM for EGR
control. This is du e t o the wider operat ing r ange a nd
lar ger volume of recir culated gas. There is a con sid-
erable number of new, adapted, and optim ized func-
tions, part icularly with r egar d to injection, E GR,
boost control, sen sing of t he in put par amet ers an d
the signalin g of the act uators (Fig. 3).
• Th e rail pressure contr ol achieved by signa lin g
the quan tit y control va lve in the high pr essu re pump
and the pressure regula tor results in redu ced power
consumpt ion of high pressure pump and in lowering
fuel pr essu res
• Individu al cylinder tor que contr ol for smoot h
engine ru nning: using th e cr ankshaft position sensor
signals, the ECM detect n on-uniform engine run ning
results from uneven torque contributions of the indi-
vidual cylinders and adjust the injection qu ant ities of
the individual in ject ors so th at all cylin ders make the
sa me tor que con tribution
• A relay is used for a ctivating the electr ic in-t ank
fuel pu mp
• Heated cran kcase ven tilation to ensu re pressure
compensation even at low temper atu res
• Improved boost pressur e con trol using an elec-
tric variable nozzle turbine actuator with position
feed back
• Con trolled fu el hea ting using the high pressure
pu mp closed-loop control
• Tra nslation of the drive input received fr om the
accelerat or pedal module which is equ ipped with
du al h all sensors
• Measurem ent of th e inta ke air mass using new
mass air flow (MAF) sensor with in crease precision
and extended measuring range
• O2 sensor for mea su rin g th e amount of oxygen
in th e exha ust in or der t o calculate th e air t o fuel
ratio. With the int ake air m ass being known, t he
injected fu el quantity ca n be calculated fr om th e air
to fuel ra tio
• Activa tion of the O2 sensor heater to bu rn off
deposits
• Full load EGR wit h a more pr ecise, model based
EGR closed-loop cont rol. The ECM calculates th e
EGR rate fr om th e various sensor signals. Using th e
calcu late EGR rat e in percent instea d of the fresh a ir
mass flow as a contr ol para meter ena bles a more pr e-
cise con trol of the EGR ra te as well as better cor rec-
tion of t he ta rget value.
The oxygen sensor signal can be used in combin a-
tion with the ma ss air flow signal, the injection
qu a n t it y s ign a l a n d pr es su r e a n d t em per a t u r e sig-
nals to perfor m the followin g fun ctions for optimized
closed loop control and monitor ing of emissions
rela ted componen ts:
• Injection valve quan tity drift compen sa tion in
pa rtial load r ange: the oxygen conten t in the exh aust
is calculated from th e a ir mass and from injection
quan tity signal and is compared to the air-fuel rat io
as measured by the sensor. If t he calcula ted air-fuel
ratio differs from the measured air-fuel ratio, the is
no correction of the in ject ion quan tity bu t th e E GR
Fig. 3 ECM CONTROL
VA ELECTRONIC CONTROL MODULES 8E - 5
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