CIMAC Congress - Schiff & Hafen

CIMAC CONGRESS | BERGEN 2010
which take the specific boundary conditions for such applications
(e.g. legislative demands, fuel quality and specific operating profile)
into account. The future integration of base engine and aftertreatment
measures will significantly increase the challenges and effort with
regard to system layout as well as calibration. Especially with regard to
large ship and locomotive engines the number of hardware variants
which can be tested in advance to the final application will be
extremely limited. Within this context high-efficient development
tools (such as detailed 1D-simulation of the aftertreatment system,
detailed characterisation of catalysts on a synthetic gas test bench,
assessment of control and sensor concepts based on simulation) as
well as high-efficient calibration procedures (such as DoE based
calibration or offline calibration of the SCR system) which have been
developed for on-road applications, can be used in order to guarantee
a reliable system layout and calibration while maintaining short
development and engine testing times.
Large engine injection systems for future
emission legislations
C. Kendlbacher, P. Müller, M. Bernhaupt,
G. Rehbichler, Robert Bosch AG, Austria
Emissions are one of the driving factors in today’s engine development,
fuel injection systems as well as exhaust aftertreatment technologies
are being developed for large diesel engines. Due to the long life of
large diesel engines many of them are upfitted throughout their lives
to modern fuel systems to be competitive in the market. Large diesel
engines are used in many different industrial applications where they
have to comply with various emission regulations (i.e. TIER, EU,
IMO) over the next years. Engine internal as well as external
modifications (exhaust aftertreatment) are re-quired to meet
upcoming emission standards – on the fuel injection side common
rail is the best approach to find solutions to this challenge. All of the
future fuel injection systems will be based on common rail technology.
This is the most complex but also the most flexible fuel injection
technology on the market. Individual boundary conditions, engine
design constraints and cost drive the type of common rail system
which is being applied on a particular engine type and size. Bosch
provides all kinds of fuel systems to its customers for small automotive
engines to large diesel engines, using many different types of fuels.
15:30 June 14th Room Troldtog
(6–2) Product Development, Component
& Maintenance Technology –
Gas Engines – New Components
Port inlet gas admission valves for large gas
engines
R. Boom, Woodward, Netherlands
The paper is about the latest development in port inlet gas admission
valves for large gas engines. The Solenoid Operated Gas Admission
Valves (SOGAV) has been in the market since the early 1990’s and has
gone through a development program to enhance the design to meet
the future large gas engine requirements. The development is driven
by a demand for higher mass flow rates and reduction of life cycle
cost. The new developed generation of SOGAV has a new design to
allow higher differential pressure and therefore allows a higher mass
flow with the same valve size. The design of the new generation
SOGAV has been changed to allow on engine maintenance and reconditioning.
This reduces engine downtime and increases availability.
The paper will describe design, development and validation testing
on the new valve. Also the market trends driving new technologies
will be presented. The design of the new valve is based on the existing
valve and operational field experiences at numerous different engine
types, running at different fuel gases and at different environmental
conditions. The paper will give a background on the operational
experiences and product improvements. The power demand from gas
engines is increasing more and more. This drives a trend towards gas
engines with a larger cylinder output and thus requiring a higher
mass flow rate of the gas admission valves. Miller valve timing is
reducing the amount of time for gas admission and also the
requirement for lower caloric fuel gases drive the demand for higher
mass flow rates. Maintenance and overhaul of gas admission valves
have been a labor intensive activity. Complete valves have to be taken
of the engine, with complete disassembling of the electrical
connections. Critical stack up tolerances made it difficult to recondition
existing valves after several thousand of hours of operation.
The design has been changed to accommodate on engine replacement
of critical parts. The paper will describe the design of a valve that both
can deal with higher differential pressures and also can be maintained
much more user friendly at lower operational cost.
A new technology electronic ignition which
eliminates the limitations of traditional
ignition systems
J. Lepley, Altronic Inc., USA,
K. Brooks, D. Bell, Altronic, LLC, USA
Electronic ignition systems remain the standard for internal
combustion engines today, in spite of the best efforts of researchers
worldwide to find alternatives. The allocation of so much R&D effort
to find a replacment for the electronic ignition system is in part driven
by a number of limitations in the current electronic ignition systems
which have been seen as difficult, if not impossible to overcome. A
new approach to electronic ignition will be described and its ability
to overcome the various ignition limitations of the past described and
demonstrated. The intention of this presentation is to show that in
terms of electronic ignition systems ’The best is yet to come’.
Development of pre-chamber spark plug for
gas engine
K. Yamanaka, Denso Corporation, Japan,
S. Nishioka, Denso Europe B.V., Netherlands,
Y. Shiraga, S. Nakai, Osaka Gas Co., Ltd., Japan
Recently, CHP (Combined heat and power) systems are receiving
attention because of effect they have on reducing CO 2
emissions. This
is especially seen in the increasing number of gas engines used that
full into the 5kW (residential use) – 10MW (industrial use) range.
Many large gas engines (2MW or above) have prechambers already
installed in the combustion chamber. The flame ignition discharged
from the prechamber can achieve a high thermal efficiency by creating
rapid and stable combustion in a super lean gas mixture area.
However, many medium gas engines (2MW or smaller) have open
combustion chambers, and the flame kernel is formed by the single
spark plug discharge. Therefore the lean gas mixture area is restricted
to only the spark plug discharge, and improving thermal efficiency is
generally harder than in pre-chamber engines. Therefore, we designed
a spark plug with its own pre-chamber (hereinafter PC plug), to
achieve improved flame ignition for open-chamber engines similar
that of the pre-chamber engine. The goal of this research is to improve
thermal efficiency by expanding the lean misfire limit of the openchamber
engine by only changing the spark plug and the engine
calibration without needing to change the entire ignition system. If
this is accomplished, running cost can be reduced without increasing
the initial costs. However, the combustion characteristics depend on
34
Ship & Offshore | 2010 | No. 3