US20210245856A1 - Method to operate a marine propulsion system in a trolling mode, control unit and marine propulsion system - Google Patents

Method to operate a marine propulsion system in a trolling mode, control unit and marine propulsion system Download PDF

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Publication number
US20210245856A1
US20210245856A1 US17/252,894 US201917252894A US2021245856A1 US 20210245856 A1 US20210245856 A1 US 20210245856A1 US 201917252894 A US201917252894 A US 201917252894A US 2021245856 A1 US2021245856 A1 US 2021245856A1
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United States
Prior art keywords
pressure
clutch
reverse
propulsion system
marine propulsion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US17/252,894
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English (en)
Inventor
Gabriele DE CEGLIA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZF Friedrichshafen AG
ZF Padova SRL
Original Assignee
ZF Friedrichshafen AG
ZF Padova SRL
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Publication date
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Assigned to ZF FRIEDRICHSHAFEN AG, ZF PADOVA Srl. reassignment ZF FRIEDRICHSHAFEN AG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DE CEGLIA, Gabriele
Publication of US20210245856A1 publication Critical patent/US20210245856A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/30—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/02—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing
    • B63H23/08—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing with provision for reversing drive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/02—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing
    • B63H2023/0291—Trolling gears, i.e. mechanical power transmissions comprising controlled slip clutches, e.g. for low speed propulsion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H23/00—Transmitting power from propulsion power plant to propulsive elements
    • B63H23/30—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches
    • B63H2023/305—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches using fluid or semifluid as power transmitting means

Definitions

  • the present invention relates to a method to operate a marine propulsion system with a forward clutch and a reverse clutch in a trolling mode.
  • the invention further comprehends a control unit with means to operate the marine propulsion system according to said method and a marine propulsion system with such a control unit.
  • a trolling mode can be used for low speed maneuvers of a ship. Trolling is used for instance for fishing or for docking maneuvers in a harbor. In the trolling mode a friction clutch of the propulsion system is operated in a slip mode, in order to achieve very low rotation speed at a propeller.
  • a friction clutch of the propulsion system is operated in a slip mode, in order to achieve very low rotation speed at a propeller.
  • internal combustion engine-driven marine propulsion systems are used with preferably one or two propellers.
  • a corresponding propeller shaft is caused to rotate via a transmission downstream of the engine. While the engine speed is usually controllable to determine the cruising speed of the ship, the transmission is usually switchable with respect to the sense of rotation to select between forward and reverse. For this, such a transmission often comprises two clutches, one for forward and one for reverse direction.
  • Each of the clutches is a friction clutch and adjustable with respect to its slip.
  • a trolling speed is controllable by varying the clutch's slip.
  • the engine speed usually remains constant in the range of the idling speed, while the driving speed of the ship is determined by varying the slip of the corresponding clutch. By this, it is possible to adjust the speed of the propeller shaft below the corresponding engine speed.
  • the use of the trolling mode can be limited to a certain engine speed range.
  • a limitation of the engine speed to a range suitable for trolling operation can be carried out by a speed limiting unit.
  • the purpose of the present invention is to avoid the disadvantages of prior art and to provide an improved method to control a marine propulsion system with a forward clutch and a reverse clutch in a trolling mode.
  • the invention shall enable a precise control of the clutch slippage in a wide range, especially in the ranges of low and high slippage.
  • a control unit shall be provided which is able to control the operation of a marine propulsion system according to said method. It is a further purpose of the invention to provide a corresponding marine propulsion system.
  • the invention provides a method to operate a marine propulsion system in a trolling mode.
  • the corresponding marine propulsion system comprises at least one propeller shaft which can be driven by an engine via a pressure operated forward clutch and a pressure operated reverse clutch.
  • Preferably the two pressure operated clutches are part of a transmission of the marine propulsion system.
  • a forward pressure is applied to engage the forward clutch to a certain extent and at the same time a reverse pressure is applied to engage the reverse clutch to a certain extent.
  • the term “at the same time” does not mean that both pressures are applied for the exact same duration. At the same time means that there is at least one period when the forward and the reverse pressures are applied together. It does not matter, if the application of the forward and the reverse pressures does not start or end at the very same instant.
  • the forward and the reverse pressures can be high enough to engage the forward clutch and the reverse clutch at least to such an extent as to transfer a torque on both clutches. At least the one clutch, which causes the propeller shaft to rotate, is operated in a slipping state during this time.
  • the value of the forward pressure is different from the value of the reverse pressure, so that the propeller shaft is caused to rotate by the pressure difference. This means, that the pressure difference between the forward pressure and the reverse pressure must be high enough to cause at least a slow rotation of the propeller shaft in one direction. In the trolling mode the drive torque is transferred via a slipping clutch to the propeller shaft.
  • a forward pressure is applied to the forward clutch which causes the propeller shaft to rotate in forward direction and a reverse pressure, which is lower than the forward pressure, is applied to the reverse clutch.
  • the reverse clutch acts like a brake to modulate the slippage of the forward clutch.
  • the forward pressure is adjusted higher than the reverse pressure, in order to affect forward rotation of the propeller shaft and a forward movement of the ship.
  • the method can be applied in a low slippage range in order to avoid the negative stick-slip phenomenon. Therefore the forward pressure and the reverse pressure are determined to cause a slippage in the range of 0% up to 30% at the forward clutch.
  • a pressure can be applied to the forward clutch, which would cause a slippage of 35-45% without a simultaneous application of the reverse clutch.
  • a pressure is applied to the reverse clutch to keep the slippage at the forward clutch at one specific required percentage below 30%, for example at 10%. Both clutches can be operated with these pressures for a certain time, for example as long as the ship is required to move with low speed in a docking maneuver.
  • the actual slippage at the forward and at the reverse clutch can be detected and determined for example by applying rotation speed sensors on the input side and on the output side of both clutches and by calculating the difference of the corresponding signals at each clutch in an electronic control unit.
  • Another specific advantage of the present invention can be achieved, if the forward clutch is operated in a high slippage range.
  • the forward pressure and the reverse pressure are determined to cause a slippage in the range of 70% up to 100% at the forward clutch.
  • conventional marine propulsion systems it is not possible to precisely control the output speed at the forward clutch in this slippage range. The reason for this is that it is necessary to overcome the inertia of the system and the viscous resistance of the water to start rotating the propeller.
  • conventional marine propulsion systems there is a certain minimum pressure which corresponds to a minimum rotation speed of the propeller shaft. Under that minimum rotation speed it is not possible to control the rotation speed of the propeller shaft constantly and smoothly.
  • the method as proposed by the present invention it is possible to start the rotation of the propeller shaft and then it is possible to brake the output going under the minimum rotation speed which is obtainable with conventional systems.
  • the present invention enabled a precise control in a slippage range between 70% and 100% at the forward clutch.
  • the propeller shaft of the marine propulsion system rotates with a significantly lower speed than the engine shaft, even under consideration of an additional transmission ratio in the drive train.
  • the simultaneous application of pressure to the forward clutch and to the reverse clutch effects a significantly better and more precise control of the slippage at the forward clutch at slippage rates between 70% and 100%.
  • the forward clutch can be engaged at 95% of slippage and then the pressure on the reverse clutch can be slightly increased.
  • the reverse clutch now acts like a brake and affects a kind of a filter on the output rotation speed of the forward clutch, so that inconstancies and unsteadiness in the output rotation speed can be decreased or completely avoided.
  • the inventive method is used for reverse movement in a low slippage range, wherein the forward pressure and the reverse pressure are determined to cause a slippage in the range of 0% up to 30% at the reverse clutch.
  • Another preferred application of the present invention is for reverse movement in a high slippage range, wherein the forward pressure and the reverse pressure are determined to cause a slippage in the range of 70% up to 100% at the reverse clutch which means a significantly higher input rotation speed at the reverse clutch compared to the output rotation speed at the reverse clutch.
  • a prefill pressure can be applied to the forward clutch and to the reverse clutch before applying said forward and reverse pressure.
  • the prefill pressure can be as high as to cause a small torque transmission on both clutches.
  • the prefill pressure shall be smaller compared to the forward pressure which is applied to the forward clutch in order to rotate the propeller shaft forward in trolling mode.
  • the prefill pressure shall not cause a rotation of the propeller shaft.
  • a low torque transmission by said prefill pressure on both clutches can be used to hold the propeller shaft in one position.
  • a torque transmission via one of the clutches does not necessarily mean a simultaneous rotation of an input or output element of the corresponding clutch. Instead a torque can be transmitted from the input element to the output element of the clutch without a rotation of one of the elements.
  • the application of a low prefill pressure to both clutches improves the reactivity of the clutches.
  • the transition from forward to reverse can be done very fast.
  • the two clutches are ready to transmit the higher torque for rotating the propeller shaft very quickly, simply by increasing the pressure on the desired clutch up to said forward pressure.
  • the pressure control can be done by means of a proportional valve, for example.
  • the proposed method requires controlling the pressures applied to the forward and to the reverse clutch independently. Therefor a separate proportional valve for the pressure control of each of the two clutches is required.
  • the present invention includes further a control unit for a marine propulsion system.
  • the control unit is assigned and enabled to control the propulsion system according to a method as described above.
  • the control unit comprises means to operate the marine propulsion system according to the method as described above.
  • the means of the control unit may comprise an electronic control unit (ECU) with a processor, data storage (volatile or non-volatile) and interfaces to be connected to other components of the marine propulsion system or the ship.
  • Said means further comprise application software running on the processor and executing instructions in order to operate the marine propulsion system according to the proposed method.
  • the application software may be stored in said data storage together or separate to additional data which is necessary to operate the marine propulsion system.
  • the control unit may further comprise hydraulic components like a pump, filter, valves and hydraulic connecting components. Above mentioned proportional valves may also be part of the control unit.
  • a corresponding marine propulsion system comprises an engine, a transmission, a propeller shaft which can be driven by the engine via the transmission and a control unit. At least one propeller shaft for each associated propeller is connected to the output side of the transmission.
  • the transmission comprises a pressure operated forward clutch and a pressure operated reverse clutch.
  • the control unit is connected to both of said clutches to control the pressure which is applied to each of the clutches.
  • the clutches can be constructed as pressure operated multi-disc clutches.
  • the clutches can be completely open (no torque is transmitted), completely engaged (no slip, input element rotates with same speed than the output element) or partially engaged (slipping state). A partial engagement of the clutch causes the clutch to slip and the input rotation speed at the clutch is different to the output rotation speed.
  • the degree of slip can be altered at will, by adjusting the pressure which is applied to each clutch under consideration of the load on the propeller shaft.
  • the present invention allows stable trolling speed control in a wide range even with simple single acting cylinders.
  • double acting or special cylinders can be used as well.
  • the forward clutch and the reverse clutch may comprise each one double acting pressure cylinder in order to enhance the precise adjustment of the required slippage in the clutches and the required rotation speed of the propeller shaft.
  • double acting cylinders it is necessary to calculate the pressure difference between the two pressure chambers of each cylinder and to consider the different effective pressure surface on both sides of the corresponding pressure piston. The result of such a calculation can be used for the forward and reverse pressure which is applied to the forward clutch respectively to the reverse clutch.
  • a double acting pressure cylinder allows adjusting the corresponding clutch in any position between fully engaged and fully disengaged.
  • FIG. 1 shows a simplified schematic of a marine propulsion system according to present invention
  • FIG. 2 shows graphs of an example of pressure and slip control according to the invention.
  • the schematic of FIG. 1 shows a marine propulsion system 1 with its essential elements.
  • the marine propulsion system 1 comprises an engine 2 , a transmission 8 and a propeller shaft 6 , which can be driven by the engine 2 via the transmission 8 .
  • a control unit 9 is connected by connections 10 to a pressure operated forward clutch 4 and to a pressure operated reverse clutch 5 .
  • Connections 10 symbolize hydraulic lines from corresponding hydraulic valves which are part of the control unit 9 and each one pressure chamber of the two clutches 4 and 5 .
  • the hydraulic valves may as well be positioned at or inside the transmission 8 near to the clutches 4 , 5 . In this case the hydraulic valves would be connected via electric connections to the control unit 9 .
  • the connection 11 between engine 2 and the control unit 9 is used to monitor and control the engine speed.
  • the connection 11 can be realized as electric cable connection or as a wireless connection.
  • Both clutches 4 , 5 are friction clutches, namely pressure operated multi-disc clutches.
  • Each of the clutches 4 and 5 comprises an inner disc carrier 12 , 14 and an outer disc carrier 13 , 15 .
  • the outer disc carriers 13 and 15 are connected by spur gears 16 , 17 which are fixed to the outer disc carriers 13 , 15 of the two clutches 4 and 5 .
  • Propeller 7 is fixed onto propeller shaft 6 which is permanently connected to the output side of the transmission 8 .
  • the transmission 8 comprises a housing.
  • the forward clutch 4 and the reverse clutch 5 are arranged inside the housing of the transmission 8 .
  • Each outer disc carrier 13 , 15 is the respective input element at both clutches 4 and 5 , whereas the inner disc carriers 12 , 14 are the corresponding output elements.
  • the outer disc carrier 13 of the forward clutch 4 is permanently connected to a drive shaft 3 of the engine 2 .
  • the outer disc carrier 15 of the reverse clutch 5 is driven by the outer disc carrier 13 of the forward clutch 4 by means of spur gears 16 and 17 .
  • Each of the inner disc carriers 12 , 14 is permanently connected to a corresponding drive gear 18 , 19 . Both drive gears 18 and 19 are constantly meshing with driven gear 20 which is fixed to propeller shaft 6 .
  • FIG. 2 shows curves of the forward pressure p FWD , reverse pressure p REV , percentage of slip in the forward clutch and the pressure difference delta P between forward and reverse pressure, during the same time period.
  • the two upper graphs in FIG. 2 show the forward pressure p FWD which is applied to the forward clutch and the reverse pressure p REV which is applied to the reverse clutch over a certain time period from t 0 to t 10 .
  • the next graph shows the percentage of slip (SLIP FWD ) in the forward clutch in the same time period from points in time t 0 to t 10 .
  • the lowest graph shows the pressure difference delta P between the forward pressure and the reverse pressure.
  • the curve of the pressure difference delta P is approximately congruent to the curve of to the rotation speed of the propeller shaft, provided that the load on the propeller stays nearly constant during the considered time.
  • a prefill pressure is applied to the forward clutch and to the reverse clutch. This causes an equal low torque on both clutches and a hold of the propeller shaft.
  • the prefill pressure at both clutches makes them ready to transmit a higher torque very quickly, as soon as the pressure is further increased.
  • the forward pressure p FWD is further increased, while the reverse pressure p REV stays at the low prefill pressure level. This causes the forward clutch to be more engaged and to rotate the propeller shaft to a certain degree in forward direction. Hence, the percentage of slip in the forward clutch changes to about 70%. These conditions are kept until the time t 3 .
  • the system is operated at the conditions before the time t 3 .
  • the forward pressure is raised significantly, while the reverse pressure stays constant, so that the propeller shaft is further accelerated and the percentage of slip in the forward clutch is lowered to about 15%.
  • a stick-slip effect is caused which can be seen at the zigzag curve of the corresponding curve of SLIP FWD .
  • the forward pressure and the reverse pressure are raised slightly after the time t 7 . Again the reverse clutch is engaged a little bit more and acts like a brake against the driving force of the partially closed forward clutch. This stops the stick-slip phenomenon while the percentage of slip in the forward clutch stays constant at about 15%.
  • the forward pressure is lowered to a certain extent after the time t 8 , while the reverse pressure is reduced to zero after the time t 8 .
  • a stick-slip phenomenon occurs again in the forward clutch.
  • the stick-slip phenomenon continues until the time t 9 , when the forward pressure is raised to a level of 100, which corresponds to a completely engaged forward clutch. With the forward clutch being completely engaged, the percentage of slip in the forward clutch logically is zero.
  • the described stick-slip phenomenon between the times t 6 and t 7 and between the times t 8 and t 9 can be completely avoided, if the forward pressure p FWD and the reverse pressure p REV are both raised immediately at time t 6 to the higher level as can be seen in the graphs by dotted lines. So the reverse clutch can act as a counter-brake against the driving torque which is transferred via the forward clutch during this period.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
US17/252,894 2018-07-19 2019-07-03 Method to operate a marine propulsion system in a trolling mode, control unit and marine propulsion system Abandoned US20210245856A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102018212102.8 2018-07-19
DE102018212102 2018-07-19
PCT/EP2019/067792 WO2020016005A1 (fr) 2018-07-19 2019-07-03 Procédé pour faire fonctionner un système de propulsion marine dans un mode de pêche à la traîne, unité de commande et système de propulsion marine

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US20210245856A1 true US20210245856A1 (en) 2021-08-12

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US17/252,894 Abandoned US20210245856A1 (en) 2018-07-19 2019-07-03 Method to operate a marine propulsion system in a trolling mode, control unit and marine propulsion system

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US (1) US20210245856A1 (fr)
EP (1) EP3823894A1 (fr)
WO (1) WO2020016005A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021200780B3 (de) 2021-01-28 2022-07-28 Zf Friedrichshafen Ag Verfahren zum Betreiben eines Schiffantriebs, Schiffsgetriebe und Schiffsantriebsanordnung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5474480A (en) * 1991-08-01 1995-12-12 Zf Friedrichshafen Ag Control system for operating the drive assembly of a ship
US8439800B1 (en) * 2010-11-30 2013-05-14 Brunswick Corporation Marine drive shift control system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4688665A (en) * 1986-05-01 1987-08-25 Caterpillar Inc. Apparatus for preventing engine stall
DE4337401C1 (de) 1993-10-26 1995-05-04 Mannesmann Ag Trollingeinrichtung für eine Schiffsantriebseinheit
FR2729637B1 (fr) * 1995-01-19 1997-04-18 Semt Pielstick Dispositif et procede de reglage de la vitesse d'un navire
US6679740B1 (en) * 1999-09-02 2004-01-20 Yanmar Diesel Engine Co., Ltd. Method of hydraulically controlling a marine speed reducing and reversing machine in crash astern operation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5474480A (en) * 1991-08-01 1995-12-12 Zf Friedrichshafen Ag Control system for operating the drive assembly of a ship
US8439800B1 (en) * 2010-11-30 2013-05-14 Brunswick Corporation Marine drive shift control system

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Publication number Publication date
EP3823894A1 (fr) 2021-05-26
WO2020016005A1 (fr) 2020-01-23

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