|
|
|
Title: Variable
compression ratio engine: A future power plant for automobiles -
an overview
Author(s): Amjad Shaik, N Shenbaga Vinayaga Moorthi,
R Rudramoorthy
Source: Proceedings of the I MECH E Part D Journal
of Automobile Engineering
Volume: 221 Number 9 Page: 1159-1168. September
2007
DOI: 10.1243/09544070JAUTO573
Publisher: Professional Engineering Publishing
Abstract: Increasingly stringent emissions and
fuel economy standards have long remained a source of challenges
for research in automobile engine technology development towards
the more thermally efficient and less polluting engine. Spark ignition
(SI) engines have lower part-load efficiency when compared with
the diesel engines. The greatest opportunity for improving SI engine
efficiency is by way of higher compression ratio, variable valve
timing, low friction, reducing throttling losses, boosting, and
down-sizing. Variable compression ratio (VCR) technology has long
been recognized as a method for improving the fuel economy of SI
engines. In order to vary the compression ratio, some method of
varying the geometric compression ratio through changing the clearance
volume is required. There are several ways of doing this; various
patents have been filed and designs presented, including modification
of the compression ratio by moving the cylinder head, variation
of combustion chamber volume using a secondary piston or valve,
variation of piston deck height, modification of connecting rod
geometry, moving the crankpin within the crankshaft, and moving
the crankshaft axis. The potential of these technologies needs to
be evaluated by a trade-off between cost and consumption benefit.
This paper reviews the geometric approaches and solutions used to
achieve VCR, considers the results of prior research, and forecasts
what benefits, if any, a VCR would bring to present engine design.
|
| |
Title: An
automatic gear-shifting strategy for manual transmissions
Author(s): B Mashadi, A Kazemkhani, R Baghaei Lakeh
Source: Proceedings of the I MECH E Part I Journal
of Systems and Control Engineering
Volume: 221, No 5 Page: 757-768. August 2007
DOI: 10.1243/09596518JSCE253
Publisher: Professional Engineering Publishing
Abstract: Based on two different criteria, namely
the engine working conditions and the driver's intention, the governing
parameters in decision making for gear shifting of an automated
manual transmission are discussed. The gear-shifting strategy was
designed by taking into consideration the effects of these parameters,
with the application of a fuzzy control method. The controller structure
is formed in two layers. In the first layer, two fuzzy inference
modules are used to determine the necessary outputs. In the second
layer a fuzzy inference module makes the decision of shifting by
upshift, downshift, or maintain commands. The behaviour of the fuzzy
controller is examined by making use of ADVISOR software. It is
shown that at different driving conditions the controllers make
correct decisions for gear shifting accounting for the dynamic requirements
of the vehicle. It is also shown that the controller based on both
the engine state and the driver's intention eliminates unnecessary
shiftings that are present when the intention is overlooked. A microtrip
is designed in which a required speed in the form of a step function
is demanded for the vehicle on level or sloping roads. Both strategies
for the vehicle to reach the maximum speed starting from rest allow
the gear shift to be made consecutively. Considerable differences
are observed between the two strategies in the deceleration phase.
The engine-state strategy is less sensitive to downshift, taking
even unnecessary upshift decisions. The state intention strategy,
however, interprets the driver's intention correctly for decreasing
speed and utilizes engine brake torque to reduce the vehicle speed
in a shorter time.
|
| |
Title: A
multi-physics multi-scale approach in engine design analysis
Author(s): M S M Perera, S Theodossiades, H Rahnejat
Source: Proceedings of the I MECH E Part K Journal
of Multibody Dynamics
Volume: 221 Number 3 Page: 335-348. July 2007
DOI: DOI 10.1243/14644193JMBD78
Publisher: Professional Engineering Publishing
Abstract: Vibration behaviour of an internal combustion
engine depends on rigid body inertial dynamics, structural modal
characteristics of its elastic members, tribological behaviour of
loadbearing contacts, and piston-cylinder interactions. Therefore,
it is essential to use a multi-physics approach that addresses all
these physical properties in a single integrative model as presented
in this paper. This approach can be regarded as holistic and a good
aid for detailed design. Particular attention is paid to the critical
elements in the system, such as load-bearing conjunctions (crankshaft
main bearings) and piston-cylinder wall interactions. Another important
feature is the integrated analysis across the physics of motion
from microscale fluid film formation to submillimetre structural
deformations and onto large displacements of inertial members. In
order to succeed in predictions within sensible industrial time
scales, analytical methods have been used as far as possible rather
than numerical approaches. Model predictions show good agreement
with fired engine test data.
|
| |
Title: Fault
detection in internal combustion engines using fuzzy logic
Author(s): M B Çelik, R Bayir
Source: Proceedings of the I MECH E Part D Journal
of Automobile Engineering
Volume: 221 Page: 579-587. May 2007
DOI: 10.1243/09544070JAUTO366
Publisher: Professional Engineering Publishing
Abstract: In this study, a complementary fuzzy-logic-based
fault diagnosis system was developed to diagnose the faults of an
internal combustion engine (ICE) and the system incorporated with
an engine test stand. The input variables of the fuzzy logic classifier
were acquired via a data acquisition card and RS-232 port. The rule
base of this system was developed by considering the theoretical
knowledge, the expert knowledge, and the experiment results. The
accuracy of the fuzzy logic classifier was tested by experimental
studies which were performed under different fault conditions. Using
the developed fault diagnosis system, ten general faults which were
observed in the internal combustion engine were successfully diagnosed
in real time. With these characteristics, the system could easily
be used for fault diagnosis in test laboratories and in service
workshops.
|
| |
| Title: An
ultrasonic sound speed sensor for measuring exhaust gas recirculation
levels
Author(s): J S Olfert, M D Checkel
Source: Proceedings of the Institution of Mechanical
Engineers, Part D: Journal of Automobile Engineering
Volume: 221 No 2 Page: 181-189; February 2007
DOI: DOI 10.1243/09544070JAUTO194
Publisher: Professional Engineering Publishing
Abstract: Exhaust gas recirculation (EGR) has been
used for years to improve the performance of internal combustion
engines. This paper shows that acoustic methods can be used to measure
EGR. Theory is presented which shows that measurements of the speed
of sound can be used to measure the amount of EGR in the intake
manifold. In particular, a new method called the discrete acoustic
wave and phase detection (DAWPD) method can be used to measure EGR
levels with a fast-response time. Experimental results show that
a DAWPD sensor can be used to measure EGR levels with adequate accuracy
(± 1.3 per cent EGR) at steady state. Transient measurements
were not possible owing to engine limitations. The sensor's performance
was limited by the ultrasonic transducers used. It is postulated
that sensor performance could be improved with smaller and temperature-independent
non-resonant transducers.
|
| Title: Use
of in-cylinder pressure measurement and the response surface method
for combustion feedback control in a diesel engine
Author(s): R Reitz, J von der Ehe
Source: Proceedings of the Institution of Mechanical
Engineers, Part D: Journal of Automobile Engineering
Volume: 220 No 11 Page: 1657-1666; 2006
DOI: DOI 10.1243/09544070JAUTO30
Publisher: Professional Engineering Publishing
Abstract: An engine control algorithm was designed
and implemented on a heavy-duty diesel engine. The goal was to develop
a control system that could adjust split injection parameters to
accommodate changes in operating parameters such as fuel and ambient
air conditions, and mechanical wear during engine operation. An
in-cylinder pressure transducer was chosen for the closed-loop feedback
signal to be used in conjunction with the control algorithm. The
control algorithm incorporated a version of the response surface
method (RSM) to adjust the fuel injection parameters and to locate
the optimum settings. Optimizations of double injections at 821
r/min and 25 per cent load and 0, 15, and 30 per cent exhaust gas
recirculation (EGR) were first performed using a combination of
the genetic algorithm (GA) and the RSM to provide baseline cylinder
pressure data and to develop control criteria. These optima were
then used to calibrate the control system by providing target values
for the RSM control algorithm. Tests were conducted using a heat
release estimate to control heat release phasing and magnitude.
The control algorithm was able to adjust the timing of the first
and second injections, as well as the amount of fuel injected in
each pulse to phase combustion properly.
|
| Title: An
Alternative Fuel for Spark Ignition Engines
Author(s): A Hull, I Golubkov, B Kronberg, T Marandzheva,
J van Stam
Source: International Journal of Engine Research
Volume: 7 No 3 Page: 203 - 214; 2006
DOI: DOI 10.1243/14680874JER02504
Publisher: Professional Engineering Publishing
Abstract: Alternative fuels have been developed
for standard spark ignition engines. The fuels, which contain generic
bio-components, maintain all the advantages of ethanol, i.e. the
ability to increase considerably the octane number of gasoline and
to reduce the amount of harmful pollutants in the exhaust emissions
of engines operating on such blends. In contrast with ethanol the
new fuel components do not increase the vapour pressure of gasoline-ethanol
blends, have a better tolerance to water, and do not increase the
fuel consumption. The bio-component-based fuels also compare favourably
with mineral-sourced octane boosters such as methyl tert-butyl ether.
Additionally reformulation of the base gasoline becomes unnecessary.
|
| Title: Active
valvetrain for homogeneous charge compression ignition
Author(s): N Milovanovic, J G W Turner, S A Kenchington,
G Pitcher, D W Blundell
Source: International Journal of Engine Research
Volume: 6 No 4 Page: 377 - 397; 2005
DOI: 10.1243/146808705X30396
Publisher: Professional Engineering Publishing
Abstract: Homogeneous charge compression ignition
(HCCI), also known as controlled autoignition (CAI) or the premixed
charge compression ignition (PCCI) engine concept, has the potential
to be highly efficient and to produce low NOx, carbon dioxide, and
particulate matter emissions. However, it experiences problems with
cold start in a gasoline HCCI engine, running at idle and at high
loads, which, together with controlling the combustion over the
entire speed/load range, limits its practical application. A way
to overcome these problems is to operate the engine in 'hybrid mode',
where the engine operates in HCCI mode at low, medium, and cruising
loads and can switch to or from spark ignition (SI) or diesel (CI)
mode for a cold start, idle, and higher loads. Such an engine will
have frequent changes in engine load and speeds and therefore frequent
transitions between HCCI and SI combustion modes. The valvetrain
and engine management system (EMS) have to provide a successful
control of HCCI mode and a fast and smooth transition keeping all
relevant engine parameters within an acceptable range. Consequently,
this leads to high demands on the valvetrain and therefore a need
for a very high degree of flexibility. The aim of this paper is
to present the potential of a fully variable valvetrain (FVVT) system,
the Lotus active valvetrain (AVT), for controlling HCCI combustion
and enabling fast and smooth mode transitions in a HCCI/SI engine
fuelled with commercially available gasoline (95 RON) and in a HCCI/DI
engine fuelled with diesel (50 CN) fuel.
|
| Title: An
electrostatic trap for control of ultrafine particle emissions from
gasoline-engined vehicles
Author(s): L Rubino1; R I Crane2; J S Shrimpton3;
C Arcoumanis4
Source: Proceedings of the I MECH E Part D Journal
of Automobile Engineering
Volume: 219 Page: 535 - 546. April 2005
DOI: 10.1243/095440705X6668
Publisher: Professional Engineering Publishing
Abstract: Health concerns over ultrafine (<100
nm) particles in the urban atmosphere have focused attention on
measurement and control of particle number as well as mass. Gasoline-engined
as well as diesel-engined vehicles are likely to be within the scope
of future particulate matter (PM) emission regulations. As a potential
option for after-treatment of PM emissions from gasoline engines,
the trapping performance of a catalysed wire-cylinder electrostatic
trap has been investigated, first in a laboratory rig with simulated
PM and then in the exhaust of a direct injection spark ignition
engine. In the simulation experiments, the trap achieved capture
efficiencies by total particle number exceeding 90 per cent at wire
voltages of 7-10 kV, gas temperatures up to 400 °C, and operating
durations up to one hour, with no adverse effects from a catalyst
coating on the collecting electrode. In the engine tests, at moderate
speeds and loads, capture efficiency was 60-85 per cent in the homogeneous
combustion mode and 50-60 per cent, of a much larger number of engine-out
particles, in the stratified (overall-lean) mode. Gas residence
time in the trap appeared to be a major factor in determining efficiency.
The electrical power requirement and the effect on engine back-pressure
were both minimal.
|
|
Title: Research
and development of an advanced combustion system for the direct
injection diesel engine
Author(s): W H Su1; T J Lin2; H Zhao3; Y Q Pei4
Source: Proceedings of the I MECH E Part D Journal
of Automobile Engineering
Volume: 219 Page: 241 - 252. Feb 2005
DOI: 10.1243/095440705X6604
Publisher: Professional Engineering Publishing
Abstract: In order to obtain a simultaneous reduction
in both NOx and particulate emissions from a direct injection (DI)
diesel engine, an advanced combustion system has been researched
and developed in the authors' laboratory. The new combustion system
comprises homogeneous charge compression ignition (HCCI) combustion
at low load by early and multiple injections, combined HCCI, and
lean diffusion burning at medium and higher load conditions by means
of a novel combustion chamber design and multiple injections. In
this paper, the research and development of the enhanced mixing
by means of a raised round object (referred to in this paper as
BUMP) and its application to a diesel combustion chamber design
is described. Then the experimental results from a DI diesel engine
equipped with a multiple injection common rail (CR) fuel injection
system and the new combustion chamber design will be presented and
discussed.
Engine testing has shown that the BUMP combustion chamber was very
effective in reducing both NOx and smoke emissions. HCCI combustion
by means of multiple injections leads to extremely low NOx emissions
under low load operations. At medium and higher load operation conditions,
quasi HCCI combustion combined with the BUMP combustion chamber
could significantly reduce NOx emissions without sacrificing particulate
emission and fuel consumption.
|
Title:
Review of engine cooling technologies for modern engines
Author(s): H H Pang1; C J Brace2
Source: Proceedings of the I MECH E Part D Journal
of Automobile Engineering
Volume: 218 Page: 1209 - 1215. November 2004
DOI: 10.1243/0954407042580110
Publisher: Professional Engineering Publishing
Abstract: The performance of the conventional engine-cooling
system has always been constrained by the passive nature of the
system and the need to provide the required heat-rejection capability
at high-power conditions. This leads to considerable losses in the
cooling system at part-load conditions where vehicles operate most
of the time. A set of design and operating features from advanced
enginecooling systems is reviewed and evaluated for their potential
to provide improved engine protection while improving fuel efficiency
and emissions output. Although these features demonstrate significant
potential to improve engine performance, their full potential is
limited by the need to balance between satisfying the engine-cooling
requirement under all operating ambient conditions and the system
effectiveness, as with any conventional engine-cooling system. The
introduction of controllable elements allows limits to be placed
on the operating envelope of the cooling system without restricting
the benefits offered by adopting these features. The integration
of split cooling and precision cooling with controllable elements
has been identified as the most promising set of concepts to be
adopted in a modern engine-cooling system.
|
|
 |
|
