Feature 1 | Finland’s marine industries
Feature 3
On the EVE of discovery
Finnish universities have developed a medium-speed extreme value
engine (EVE) that offers higher pressure densities without increasing fuel
consumption. Clare Nicholls observed the engine in action.
P
art of the vast remit of the EU-
funded IP Hercules project to
research the next generation of
marine engines, the extreme value engine
(EVE) was specifically designed for test
purposes only by Helsinki University
of Technology (HUT), in collaboration
with Tampere University of Technology.
The engine is able to withstand increased
mechanical and thermal loads, features
which will be utilised to develop medium-
speed engines so that they can operate at
higher power densities without increasing
fuel oil consumption.
The design of the EVE was initiated in
2000, and the resulting engine was first
ignited in February 2004 at HUT. It has
been built to endure a combustion pressure
of up to 400bar, a mean effective pressure Optical setup of the EVE engine with measured fuel spray, 40bar cylinder pressure,
of up to 40bar, and a piston speed of up to 900rev/min, and injection pressure at 1400bar.
15m/s. For lower peak pressures, the engine
can be equipped with combustion chamber
windows for visual access. installed, with a different cylinder head, and the cylinder charge, thereby lowering the
The engine is flexible and there is no the common rail fuel injection system. cylinder pressure. This can be compensated
hydraulic piping. Charge air pressure, From March 2004 to September 2006, to some extent by increasing the charge air
temperature, and exhaust back pressure can several new or modified components were pressure, but the valve control system needs
be remotely controlled. Remote adjustment installed, including rearrangement of the further programming in order to achieve
of valve timing without the need for air supply, rearrangement of the exhaust earlier intake valve opening.
camshaft changes can also be achieved system, and optical components. The EVE’s operation has proved to be
with the EVE’s electro-hydraulic valve The engine was restarted in early 2006 reliable, but the intended original values
actuation (EHVA) system, which replaces and showed significant improvements of 50bar indicated mean effective pressure
the camshaft, push rods, and rocker arms. in reliability and controllability during and mean piston speed of 15m/s have
The design has a modified Wärtsilä W20 testing. Testing was continued by operating not yet been achieved. A higher power
cylinder head with a common rail injection the engine with fuel injection and a mean density is the main aim for the future, with
system, and a 200mm diameter cylinder, effective pressure of 24bar. The results development required for combustion
designed to take double the power of a revealed a need for earlier intake valve chamber components capable of handling
standard W20 engine. The cylinder liner, opening and later exhaust valve closing in extreme values.
anti-polishing ring, and cylinder head have order to have a better comparability with Flexibility of the gas exchange valve and
separate cooling circuits with water flow and cam-driven engines of the same size. charge air systems will be the most important
temperature measurements. Testing mainly involved five areas: variable issue when studying these new combustion
valve timing; variable valve overlap; variable technologies. All EHVA parameters are
Modifications and testing valve lift; variable charge air/exhaust back able to be reprogrammed, enabling easy
During the testing process in 2005, it became pressure; and run-up timing. The tests were modification of the gas exchange process.
apparent that some modifications to the done without firing the engine, and were Miller timing research has already
EHVA and auxiliary systems were required intended to validate different systems and commenced, but this work will continue,
in order to reach the targeted design value of find operational limits. along with further engine development
400bar maximum cylinder pressure, which Results showed that early exhaust gas valve such as improved control of valve lift,
led to a second generation system being closing and late intake valve opening reduce timing, position, and movement. NA
The Naval Architect February 2008 75
NA Feb 08 -
p75.indd 75 05/02/2008 09:49:16
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