Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
METHOD OF PERFORMING SERVICE WORK IN AN INTERNAL COMBUSTION PISTON ENGINE AND AN INTERNAL COMBUSTION PISTON ENGINE
Document Type and Number:
WIPO Patent Application WO/2015/170012
Kind Code:
A1
Abstract:
Invention relates to a method of performing service work in an internal combustion piston engine (10) wherein the service work requires a certain predetermined position of the engine, in which method during a standstill of the engine the position of crank shaft of the engine is rotated by an electric motor-generator (20) arranged in continuous force transmission connection with the crank shaft (16) of the engine at a speed less than required to start the engine and introduction of fuel into combustion chambers of the engine is halted. In the method the crank shaft is rotated until a predetermined service position of the engine is reached and the service work is performed. Invention relates also to an internal combustion engine (10) comprising control system (30) adapted to rotate the crank shaft.

Inventors:
FÅGELKLO BÖRJE (FI)
BACKLUND LEIF (FI)
MESIMÄKI MARKUS (FI)
Application Number:
PCT/FI2015/050312
Publication Date:
November 12, 2015
Filing Date:
May 08, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
WAERTSILAE FINLAND OY (FI)
International Classes:
F02B77/08
Domestic Patent References:
WO2007003693A12007-01-11
Foreign References:
EP1609957A22005-12-28
US20080182466A12008-07-31
Other References:
"Wärtsilä Vasa Maunal - M/S Helena", 1 January 1991, WÄRTSILÄ DIESEL OY, Turku, Finland, pages: 03-1 - 03-3, XP002742934
Attorney, Agent or Firm:
GENIP OY (Kotka, FI)
Download PDF:
Claims:
Claims 1 . Method of performing service work in an internal combustion piston engine (10) wherein the service work requires a certain predetermined position of the engine, in which method during a standstill of the engine the position of crank shaft of the engine is rotated by an electric motor-generator (20) arranged in continuous force transmission connec- tion with the crank shaft (16) of the engine at a speed less than required to start the engine and introduction of fuel into combustion chambers of the engine is halted, characterized in that in the method the crank shaft is rotated until a predetermined service position of the engine is reached and the service work is performed. 2. Method of performing service work in an internal combustion piston engine according to claim 1 , characterized in that the predetermined position is one of many service positions of the engine.

3. Method of performing service work in an internal combustion piston engine according to claim 1 , characterized in that a service work to be performed is set and the respective position is retrieved from a memory medium and used as instruction to rotate the crank shaft to the service position of the service work.

4. Method of performing service work an internal combustion piston engine according to claim 1 , characterized in that a table of pairs of items consisting of identification data of a certain service work and a service position corresponding to the identification data is provided and the service position is defined based on the table.

5. Method of performing service work an internal combustion piston engine according to claim 1 , characterized in that firstly a step to defin- ing the specific service work to be performed is specified and secondly a the predetermined position of the engine corresponding to the service work is retrieved from a memory medium and thirdly the crank shaft is rotated until the predetermined service position of the engine is reached and fourthly the service work is performed.

6. Internal combustion piston engine (10) comprising an electric motor-generator (20) arranged in continuous force transmission connection with a crank shaft (16) of the engine, and a control system (30) adapted to control the operation of the internal combustion engine (10) and the electric motor-generator (20), and wherein the control system (30) is adapted to control the electric motor-generator (20) to rotate the crank shaft during a standstill of the engine at a speed less than required to start the engine and such that introduction of fuel is halted, characterized in that the control system (30) is provided with information of one or more service positions of the engine, and executable instructions to control the electric motor-generator (20) to rotate the crank shaft to a service positions of the engine.

7. Internal combustion piston engine according to claim 5, characterized in that the electric motor-generator (20) is in direct force trans- mission with the crank shaft (16) of the engine.

8. Internal combustion piston engine according to claim 5, characterized in that the electric motor-generator arranged in connection with a fly wheel (22) of the engine.

Description:
Method of performing service work in an internal combustion piston engine and an internal combustion piston engine

Technical field

[001 ] The present invention relates a method of performing service work in an internal combustion piston engine according to the preamble of claim 1 .

[002] The present invention relates also to and internal combustion pis- ton engine.

Background art

[003] In WO2007003693 there is shown a pressure medium operated starting system for a multicylinder piston engine comprising a pressure medium source and a pipe system, which connects the pressure medium source to each cylinder, and a starting valve in conjunction with each cylinder as well as timing equipment for the operation of control valves, which timing equipment comprises a control part, which is in mechanical connection with the rotating part of the engine. [004] It is also known as such to rotate or crank a piston engine by means of an electric motor in order to start the engine. Electric motors are typically used in small sized engines.

[005] There are situations during a standstill where engines where the position of the power components of an internal combustion piston en- gine need to be changed or positioned. This is particularly problematic with large piston engines intended e.g. to operate a power plant or provided in a marine vessel as its prime mover or auxiliary engine. Particularly there is a need to turn the engine into specific and accurate position for tuning and service operations. This is presently mainly performed by mechanical means either with a mechanical turning device or simply by lever engaged on the engine flywheel. Beside the technical complication of engine design the risk for execution mistakes is inherent. [006] Also prior the start-up of an engine a so called slow turning is performed to ensure that engine can be rotated freely and to prevent mechanical damage to the piston mechanism due to e.g. water or oil on top of the piston crown. The main challenge in present applications is to detect the disturbance and to prevent the start procedure in time, thus pre- venting major damages.

[007] An object of the invention is to provide a method of performing service work in an internal combustion piston engine, and an internal combustion piston engine in which the problems relating the prior art are minimized. [008] In this connection the term "rotate the crank shaft" means rotating the crank shaft and moving or rotating all other parts having their connection with the crank shaft such that such movement takes place, based on their manner of connection to the crank shaft, directly or indirectly. In some occasions also a term rotate the engine may be used for the same meaning. Also the expressions "position of the crank shaft" and "position of the engine" has the same meaning in this connection.

Disclosure of the Invention [009] The method according to the invention is characterized by what is disclosed in the characterizing part of independent claim 1 and in the characterizing part of independent claim 6. Other embodiments of the invention are disclosed in other claims. [0010] Service work which requires a certain predetermined position of the engine, is performed such that during a standstill of the engine the position of crank shaft of the engine is rotated by an electric motor- generator arranged in continuous force transmission connection with the crank shaft of the engine at a speed less than required to start the engine and while the introduction of fuel into combustion chambers of the engine is halted. In the method the crank shaft is rotated until a predetermined service position of the engine is reached and the service work is performed.

[001 1 ] According to an embodiment of the invention the predetermined position is one of many service positions of the engine.

[0012] According to an embodiment of the invention a service work to be performed is set and the respective position is retrieved from a memory medium and used as instruction to rotate the crank shaft to the service position of the service work.

[0013] According to an embodiment of the invention a table of pairs of items consisting of identification data of a certain service work and a service position corresponding to the identification data is provided and the service position is defined based on the table.

[0014] According to an embodiment of the invention firstly a step to defin- ing the specific service work to be performed is specified and secondly a the predetermined position of the engine corresponding to the service work is retrieved from a memory medium and thirdly the crank shaft is rotated until the predetermined service position of the engine is reached and fourthly the service work is performed.

[0015] According to an embodiment of the invention method the crank shaft is rotated to provide a clearance status of the engine for starting the engine. [0016] According to an embodiment of the invention during the rotation of the engine the power required to rotate the crank shaft is monitored and the monitored power is compared with a reference values to detect pos- sible disturbance in the engine.

[0017] According to an embodiment of the invention the comparison of the monitored power with a reference values to detect results in clearance to start the engine when no disturbance in the engine is detected. After that the steps to start the engine may be safely initiated.

[0018]

[0019] Internal combustion piston engine where the method is practised comprises an electric motor-generator arranged in continuous force transmission connection with a crank shaft of the engine, and a control system adapted to control the operation of the internal combustion engine and the electric motor-generator, and wherein the control system is adapted to control the electric motor-generator to rotate the crank shaft during a standstill of the engine at a speed less than required to start the engine and such that introduction of fuel is halted, The control system of the engine is provided with information of one or more service positions of the engine, and executable instructions to control the electric motor- generator to rotate the crank shaft to a service positions of the engine. [0020] According to an embodiment of the invention the electric motor- generator is in direct force transmission with the crank shaft of the engine.

[0021 ] According to an embodiment of the invention the electric motor- generator arranged in connection with a fly wheel of the engine. Brief Description of Drawings

[0022] In the following, the invention will be described with reference to the accompanying exemplary, schematic drawing, in which Figure 1 illus- trates an internal combustion piston engine according to an embodiment of the invention.

Detailed Description of Drawings [0023] Figure 1 depicts schematically an internal combustion piston engine 10. The engine has a body part 12 and internal parts 14, such as pistons and gas exchange valves (not shown), most of which are arranged movably in synchronized manner directly or indirectly with the position of the crank shaft 16 of the engine. In this connection rotation of the engine means rotation of the crank shaft 16 in respect to the body part 12. The rotation of the crank shaft may cause movement of other part of the engine as well. Particularly the engine is a large engine capable of producing more than 150 kW per cylinder and having the diameter of the cylinder more than 200 mm. Servicing work in such a large engine is mostly done at site. There is an electric motor-generator 20 arranged in continuous force transmission connection with the crank shaft 16. In this embodiment the motor-generator 20 is directly coupled with the crank shaft by arranging it in connection with the fly wheel 22 of the engine, more particularly integrated with the fly wheel. The fly wheel, in turn, is connected e.g. via a coupling device 24 to a load 26 which may vary depending on the actual application of the engine 10. The load 26 may be for example an electric generator or a propulsion system of a marine vessel. [0024] The engine 10 is provided with a control system 30, which is adapted to control at least the operation of the engine 10 and the electric motor-generator 20. The control system 30 comprises an engine control unit 32 and an electric motor-generator control unit 34 which are adapted to communicate with each other so that the electric motor-generator control unit 34 is adapted to control the operation of the electric motor- generator 20 based on information which the engine control unit 32 makes available to the electric motor-generator control unit 34. The motor-generator 20 is utilized to perform operations to the engine 10.

[0025] In the following a first embodiment of the invention is explained with the reference to Figure 1 . Particularly during a standstill operation of the engine 10 the control system is adapted to control the electric motor- generator 20 to rotate the crank shaft 10 for specific purposes. The standstill means a state of the engine during which the engine is not running i.e. producing mechanical power by combusting fuel in its combustion chambers. Yet, during the standstill the engine may be rotated for the specific purposes by means of the electric motor-generator 20. According to an embodiment of the invention, when the crank shaft is rotated during the standstill by the electric motor-generator, the electric motor-generator control unit 34 is adapted to rotate the crank shaft 10 at speed less than required to start the engine. Preferably the electric mo- tor-generator control unit 34 is adapted to rotate the crank shaft during the standstill at a speed of >0 and < 20 rpm. In order to result in such operation the electric motor-generator control unit 34 is provided with executable instructions to rotate the crank shaft during the standstill at a speed of >0 and < 20 rpm. Additionally the engine control unit 32 is pro- vided with executable instruction to halt the introduction of fuel into the combustion chambers of the engine. This way the internal combustion engine may be rotated during its standstill.

[0026] The engine control unit 32 is connected to the engine to acquire measurement information from the engine as input values and provide operational instruction to the engine as output values based on manipulations making use of the input values and rules provided for the engine control unit 32. The engine is also provided with a position sensor or sensors 28 which is arranged in connection with the engine control unit 32 to provide e.g. the rotational position of the crank shaft available for the control unit 32.

[0027] In the following an embodiment of the invention is explained with the reference to Figure 1 . According to the embodiment of the invention the control unit 30 is provided with executable instructions to set the engine to a selected position by rotating the engine. The engine is provided with a service opening 13, normally covered by a lid (not shown), via which an access to a service target, such as a big end bearing, is provided. In order to be accessible easily the crank shaft should be at a right position, which is advantageously a certain range of crank angel at which the big end bearing is easily reachable via the service opening 13.

[0028] According to an embodiment of the invention the control system is provided with a memory medium 31 and and/or the control system has an access to the memory medium 31 containing information based on which one or more set positions of the engine most suitable for perform- ing service work to the engine can be defined directly (direct position of a service position) of indirectly (a service position defined e.g. via crank angle). Such positions are denoted here as service positions. For example the control system may be provided with a table of pairs of items consisting of identification data of a certain service work and a service position corresponding to the identification data. The service position may in stored e.g. as a crank angle value or status value of a certain position sensor 28 provided in the engine.

[0029] The service positions of the crank shaft correspond also to re- spective service positions of other parts movable in relation to the crank shaft and representing the service positions of the such parts of the engine, The service positions are stored in the memory medium 31 and when a service work to be performed is set and the respective position is retrieved memory medium and used as instruction to rotate the crank shaft to the service position of the service work.

[0030] This provides an effect procedure by means of which one or more parts or the engine may be positioned to desired positions for service purposes.

[0031 ] As an alternative or additional solution the control system may be provided with input means by means of which a user can enter in- struction for the control system about a specific position into which the engine is to be rotated, or a user can simply enter an instruction to commence and maintain rotation manually.

[0032] This may be realized for example so that turning the engine to a specific position is done by inputting the position parameter into the control system, e.g. by selecting a named position (e.g. TDC cyl 6). Based on the information obtained from the position sensor 28 the control system gives instruction to the electric motor-generator control unit 34 to rotate the crank shaft to reach the specified position.

[0033]

[0034] The control system 30 may also comprise a fault detection unit 36 adapted to receive information relating to status of the engine 10 while the electric motor-generator 20 is controlled to rotate the crank shaft dur- ing a standstill. The fault detection unit 36 may be in connection with the engine control unit 32 which makes the information relating to status of the engine 10 available to the fault detection unit 36 and/or the fault detection unit 36 may be directly connected engine to receive such information. The fault detection unit is also in connection with the electric mo- tor-generator control unit 34.

[0035] The fault detection unit 36 is adapted to detect possible disturbance in the engine while the electric motor-generator control unit 34 con- trols the electric motor-generator to rotate the crank shaft 10. Disturbances which are possible to detect are such, which are emerging when the crank shaft is rotated. Provided that the engine is in correct condition the electric motor-generator is able to rotate the crank shaft. The fault detection unit 36 is adapted to analyse the information relating to status of the engine 10 during the electric motor-generator control unit 34 controls the electric motor-generator 20 to rotate the crank shaft 10. The fault detection unit 36 is advantageously adapted to result in clearance information whether the engine may be started or not based on the anal- ysis of an indication of existence of a disturbance in the engine, after a predetermined number of revolutions or time of rotation. The power required to rotate the crank shaft is transmitted or made readable to the fault detection unit 36 may be used as an indication of existence of a disturbance in the engine.

[0036] Purpose of rotating the engine is to prevent damages e.g. to the crank mechanism in starting. Ingress of water or oil on top of the piston could cause hydraulic pressure by far exceeding allowed peak pressure of the cylinder. By the present invention such damages may be prevent- ed.

[0037] Since the position of the engine is known, the positions of the cylinders of the engine are also known. When the crank shaft is rotated and the above described fault detection is practised it is possible to identify e.g. the exact cylinder filled with liquid such as cooling water, oil or fuel.

[0038] So, it is an additional effect of the invention to provide a functionality to identify a possible liquid filled cylinder prior to attempt to start the engine.

[0039] According to an embodiment of the invention the electric motor- generator control unit 34 is adapted to cease rotating and/or prevent starting of the engine in case the information relating to status of the en- gine 10 indicates that circumstances prevailing in the engine are prone to make damage to the engine when rotating and/or running. The engine may further be improved such that the electric motor-generator control unit 34 is adapted to set a maximum torque which the electric motor- generator is allowed to provide. This way it is possible to prevent any damages to the engine even if a disturbance is detected in any one of the cylinders of the engine.

[0040] The control system 30 is provided with instructions to prevent starting the engine conditional to the detection of such disturbance or contents of the clearance information.

[0041 ] The motor-generator may be of permanent magnet design with permanent magnets 20.1 attached to the flywheel of the engine and a surrounding stator winding 20.2. Solution can be of either axial or radial flux type.

[0042] The control system 34 of the motor-generator is such that it allows power transmission in both directions i.e. it may receive power when the fly wheel is rotating and it may transmit power to the fly wheel to rotate it.

[0043] While the invention has been described herein by way of examples in connection with what are, at present, considered to be the most preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various combinations or modifications of its features, and several other applications included within the scope of the invention, as defined in the appended claims. The details mentioned in connection with any embodi- ment above may be used in connection with another embodiment when such combination is technically feasible.




 
Previous Patent: GARMENT

Next Patent: DIVING MASK HAVING A BUILT-IN SNORKEL