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Variable Geometry Turbocharging of a 1.8 DI Automotive Diesel Engine
Technical Paper
1997-25-0563
Sector:
Event:
ISATA 1997
Language:
English
Abstract
Variable Geometry Turbocharging (VGT) has, in the past, found
limited applications on heavy-duty, "truck-type" diesel
engines with the dual objective of improving torque back-up and
transient response. Recently, diesel passenger cars have appeared
on the market incorporating VGT technology. However, it is now
recognized that VGT offers the potential also to improve the
emission characteristics relative to engines equipped with
conventional waste-gated fixed geometry turbochargers (FGT).
An extensive test program is currently being conducted at the
University of Bath on behalf of the Ford Motor Company on a
prototype passenger car Direct Injection (DI) diesel engine capable
of meeting the proposed European Stage 3 emission legislation with
catalyst exhaust gas after treatment. The investigation is aimed at
assessing the benefits of VGT over conventional turbochargers in
terms of lower fuel consumption and reduced emissions. Steady state
tests have been conducted to determine emission and fuel
consumption trends at discrete engine operating points as functions
of Exhaust Gas Recirculation (EGR) valve position and turbine
nozzle vane setting. These tests have shown that up to 19%
reduction in part-load NOx is possible (at discrete engine
operating points) without compromising fuel consumption.