Abstract:
A method of adjusting engine throttle in an electronic shift and throttle system comprises determining a position of a control lever which allows an operator to manually control throttle functions. A throttle command is calculated based on the position of the control lever. The throttle command is adjusted in response to an input received from an input means. The position of the control lever remains constant as the throttle command is being adjusted.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electronic shift and throttle systems and, in particular, to increasing and decreasing engine throttle. 
     2. Description of the Related Art 
     Vehicles such as marine vessels are often provided with electronic shift and throttle systems. These systems typically allow an operator to control the shift and throttle functions of a propulsion unit using a control lever which is pivotally mounted on a control head. The control lever is moveable between a forward wide open throttle (forward WOT) position and a reverse wide open throttle (reverse WOT) position, through a neutral position. A controller reads the position of the control lever as the control lever moves through its operational range. The controller sends shift commands and throttle commands which drive a shift actuator and a throttle actuator based on the position of the control lever. 
     For example, U.S. Pat. No. 7,330,782 issued on Feb. 12, 2008 to Graham et al. and the full disclosure of which is incorporated herein by reference, discloses an electronic shift and throttle system in which a position sensor is used to sense the position of a control lever. The position sensor is electrically connected to an electronic control unit (ECU) and sends an electrical signal to the ECU. The ECU is able to determine the position of the control lever based on the voltage level of the electrical signal received from the position sensor. The ECU then determines the positions to which the output shafts of the shift actuator and the throttle actuator should be set. 
     Each of the output shafts is also coupled to a corresponding position sensor. Electrical signals sent by these position sensors may be used to determine the positions of the output shafts. This feedback may be used to govern the ECU. This is beneficial because variances and play between components used to link throttle actuators to throttles make it desirable to calibrate throttle controls. Calibrated throttle controls allow an operator to more accurately increase or decrease engine throttle in a marine vessel. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved method and system for increasing or decreasing engine throttle in a marine vessel. 
     There is accordingly provided a method of adjusting engine throttle in an electronic shift and throttle system. The method comprises determining a position of a control lever which allows an operator to manually control throttle functions. A throttle command is calculated based on the position of the control lever. The throttle command is adjusted in response to an input received from an input means. The position of the control lever remains constant as the throttle command is being adjusted. 
     In a one embodiment of the method, the throttle command is calculated using a throttle curve and the throttle command is adjusted by 1% in response to each input received from the input means to a maximum of 5%. In another embodiment of the method, the throttle command is adjusted by 0.5% in response to each input received from the input means to a maximum of 10%. The throttle command may be increased or decreased. The throttle command is only adjusted if all running engines are in forward gear and the adjusted throttle signal is sent to engine controllers of all running engines. The adjusted throttle command is cancelled when the control lever is moved. 
     Also provided is an electronic shift and throttle system which comprises a control head including a pivotable control lever for manually controlling throttle functions of an engine. The control lever is moveable through a range of positions. The engine includes a throttle and a throttle actuator for moving the throttle between an idle position and a wide open throttle position. An engine control unit provides a throttle command causing the throttle actuator move the throttle based on a position of the control lever. An input means is provided to allow an operator to increases or decrease the throttle command without having to move to control lever. Preferably the input means is a button disposed on the control head. 
     The present invention provides an improved system and method for increasing or decreasing engine throttle which allows an operator fine tune engine throttle. The present invention also allows an operator increase or decrease engine throttle without having to move a control lever. 
    
    
     
       BRIEF DESCRIPTIONS OF DRAWINGS 
       The invention will be more readily understood from the following description of the embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a marine vessel provided with a plurality of propulsion units and an improved electronic shift and throttle system; 
         FIG. 2  is a side view of an engine of one of the propulsion units of  FIG. 1 ; 
         FIG. 3  is a top view of the a control head of the marine vessel of  FIG. 1 ; 
         FIG. 4  is a schematic diagram illustrating the electronic shift and throttle system of  FIG. 1 ; 
         FIG. 5  is an elevation view of the control head of  FIG. 3  illustrating an operational range of a control lever thereof; 
         FIG. 6  is a table illustrating the lighting of indicator or gear lamps as the control lever of  FIG. 5  is moved through the operational range; 
         FIG. 7  is side elevation view of a shift actuator of the propulsion unit of  FIG. 2  illustrating an operational range of an actuator arm thereof; 
         FIG. 8  is a side elevation view of a throttle actuator of the propulsion unit of  FIG. 2  illustrating an operational range of an actuator arm thereof; 
         FIG. 9  is a side elevation view of the throttle actuator of  FIG. 8  illustrating a second side thereof; 
         FIG. 10  is a perspective view of the throttle actuator of  FIG. 8  illustrating the first side thereof; 
         FIG. 11  is a perspective view of the throttle actuator of  FIG. 8  illustrating the second side thereof; 
         FIG. 12  is a sectional view taken along line A-A of  FIG. 11 ; 
         FIG. 13  is a fragmentary side view, partially in section and partly schematic, of the throttle actuator of  FIG. 8 , a throttle, and a linkage therebetween; 
         FIG. 14  is a sectional view of the throttle of  FIG. 13  illustrating the throttle in an idle position; 
         FIG. 15  is a sectional view of throttle of  FIG. 13  illustrating the throttle in a wide open throttle (WOT) position; 
         FIG. 16  is a sectional view of throttle of  FIG. 13  illustrating movement of the throttle as the throttle controls are being calibrating; and 
         FIG. 17  is a flow chart illustrating the logic of a throttle calibration method disclosed herein; 
         FIGS. 18A and 18B  are charts illustrating a plurality of forward throttle curves; 
         FIGS. 19A and 19B  are charts illustrating a plurality of reverse throttle curves; and 
         FIG. 20  is a plan view of a switch panel which supports an RPM adjustment input means. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings and first to  FIG. 1 , this shows a marine vessel  10  which is provided with a plurality of propulsion units in the form of three outboard engines  12   a ,  12   b  and  12   c . However, in other examples, the marine vessel  10  may be provided with any suitable number of inboard and/or outboard engines. It is common to see two engines and practically up to five engines in pleasure marine vessels. The marine vessel  10  is also provided with a control head station  14  that supports a control head  16 . The control head  16  is provided with a microprocessor (not shown). 
     A first one of the engines, namely the port engine  12   a , is best shown in  FIG. 2 . The port side engine  12   a  includes a shift actuator  18   a , a throttle actuator  20   a , and an electronic servo module (ESM)  22   a ; all of which are disposed within a cowling  24 . Second and third ones of the engines, namely the center engine  12   b  and starboard  12   c  engine, have substantially the same structure as the port engine  12   a  and are accordingly not described in detail herein. 
     The control head  16  is best shown in  FIG. 3 . The control head  16  includes a housing  26 . A port control lever  30  and starboard control lever  40  are each pivotally mounted on the housing  26 . The port control lever  30  normally controls the shift and throttle functions of the port engine  12   a  but, in this example, also controls the shift and throttle functions of the center engine  12   b  both of which are shown in  FIG. 1 . The starboard control lever  40  controls the shift and throttle functions of the starboard engine  12   c  which is also shown in  FIG. 1 . In a marine vessel with five engines, the port control lever would control the shift and throttle functions of the port, center port and center engines while the starboard control lever would control the shift and throttle functions of the starboard engine and starboard center engine. 
     The port control lever  30  is provided with a master trim switch  50  which allows an operator to simultaneously trim all of the engines. The port and starboard engines are trimmed individually using a respective port trim button  31  and starboard trim button  41 , which are both disposed on the housing  26 . The center engine  12   b  is under the control of a center trim button  31  (not shown). 
     The housing  26  also supports a plurality of indicator or gear lamps which, in this example, are LED lamps. A port forward indicator  32 , port neutral indicator  34 , and port reverse indicator  36  are disposed on a side of housing  26  adjacent the port control lever  30 . A starboard forward indicator  42 , starboard neutral indicator  44 , and a starboard reverse indicator  46  are disposed on a side of housing  26  adjacent the starboard control lever  40 . A port neutral input means  38  and starboard neutral input means  48  are also disposed on the housing  26 . An RPM input means  52 , synchronization (SYNC) input means  54 , and SYNC indicator lamp  56  are also all disposed on the housing  26 . In this example, the port neutral input means  38 , starboard neutral input means  48 , RPM input means  52 , and SYNC input means  54  are buttons but any suitable input devices may be used. 
     As best shown in  FIG. 4 , the control head  16  and the engines  12   a ,  12   b  and  12   c , together with their corresponding shift actuators  18   a ,  18   b  and  18   c ; throttle actuators  20   a ,  20   b  and  20   c ; and ESMs  22   a ,  22   b  and  22   c , form part of an electronic shift and throttle system  60 . The electronic shift and throttle system  60  further includes a gateway  62  and a plurality of engine management modules (EMMs)  64   a ,  64   b  and  64   c . Each EMM is associated with a corresponding ESM. The control head, gateway, ESMs, and EMMs communicate with each other over a private CAN network  66 . The electronic shift and throttle system  60  is designed to support two control heads and control up to five engines. Components of optional fourth and fifth engines  12   d  and  12   e  as well as an optional second control head  17  are shown in ghost. 
     A single master ignition switch  68  provides power to the entire private CAN network  66 . However, start and stop functions are achieved by individual switches  70  read by the control head  16  as discrete inputs or serial data. Any command an operator inputs to the control head  16  to start, stop, trim, shift or accelerate one of the engines  12   a ,  12   b  or  12   c  is sent to the corresponding ESM  22   a ,  22   b  or  22   c  and corresponding EMM  64   a ,  64   b  or  64   c  over the CAN network  66 . The ESMs and EMMs are each provided with a microprocessor (not shown). In this example, a private network cable  72  that carries the CAN lines from the control head  16  to the engines  12   a ,  12   b  and  12   c  has two separate wires used to shut down the engines in the event that the CAN network  66  fails. 
     Information from the electronic shift and throttle system  60  is made available to devices on a NMEA2K public network  74  through the gateway  62 . The gateway  62  isolates the electronic shift and throttle system  60  from public messages, but transfers engine data to displays and gauges (not shown) on the public network  74 . The gateway  62  is also provided with a plurality of analog inputs  76  which may be used to read and broadcast fuel senders or oil senders or other resistive type senders such as rudder senders or trim tab senders on the public network  74 . 
     Referring now to  FIG. 5 , the port side  30  control lever is moveable between a forward wide open throttle (forward WOT) position and a reverse wide open throttle (reverse WOT) position, through a neutral position. An operator is able to control the shift and throttle functions of the port engine  12   a  by moving the port control lever  30  through its operational range. The port control lever  30  is also provided with a forward detent, neutral detent, and reverse detent all disposed between the forward WOT position and reverse WOT position. This allows the operator to physically detect when the port control lever  30  has moved into a new shift/throttle position. As shown in  FIG. 6 , the port forward indicator  32 , port neutral indicator  34 , and port reverse indicator  36  light up to reflect the position of the port control lever  30  shown in  FIG. 5 . 
     Referring back to  FIGS. 4 and 5 , the microprocessor supported by the control head  16  reads the position of the port control lever  30  and sends shift and throttle commands to the ESM  22   a  via the private CAN network  66 . The ESM  22   a  commands the shift actuator  18   a  and throttle actuator  20   a  which are best shown in  FIGS. 7 and 8 , respectively.  FIG. 7  shows that the shift actuator  18   a  has an actuator arm  19   a  which is moveable between a forward position and a reverse position with a neutral position therebetween.  FIG. 8  shows that the throttle actuator  20   a  has an actuator arm  21   a  which is moveable between an idle position and a wide open throttle (WOT) position. An actuator position sensor  142 , shown in  FIG. 12 , signals the actuator position to the ESM  22   a  shown in  FIG. 4 . This feedback may be used to govern the control head  16 . The shift and throttle functions of the port side engine  12   a  are thereby controlled. 
     It will be understood by a person skilled in the art that the shift and throttle functions of the starboard engine  12   c  are controlled in a similar manner using the starboard control lever  40  shown in  FIG. 2 . The shift and throttle functions of the center engine  12   b  are under the control of the port control lever  30  in this example. Accordingly, as thus far described, the electronic shift and throttle system  60  is conventional. 
     However, the electronic shift and throttle control system  60  disclosed herein is provided with an improved shift actuator  18   a  and throttle actuator  20   a  as shown in Figures actuators as shown in  FIGS. 7 and 8  respectively. The shift and throttle actuators are both rotary actuators which have substantially the same structure and function in substantially the same manner, with the exception of the actuator arm  19   a  or  21   a . This will be understood by person skilled in the art. Accordingly, only the throttle actuator  20   a  is described in detail herein. 
     Referring to  FIGS. 7 through 11 , the throttle actuator  20   a  of the port engine  12   a  is shown in greater detail. The throttle actuator  20   a  generally includes a waterproof housing  112  which encases various components, a motor  114  extending from and bolted to the housing  112 , and a harness  116  for electrically connecting the throttle actuator  20   a  to the electronic shift and throttle system  60 . The housing  112  is provided with a plurality of mounting holes  118   a ,  118   b ,  118   c , and  118   d  allowing the throttle actuator  112  to be mounted as needed. In this example, the housing  112  also includes a body  120  and a cover  121  bolted the body  120 . Removing the cover  121  provides access to the various components encased in the housing  112 . The motor  114  may be rotated in either a first rotational direction or a second rotational direction opposite to the first direction depending on the direction of the electric current supplied to the motor  114 . As best shown in  FIG. 11 , the harness  16  is wired to the motor  114  and supplies an electric current thereto. 
     Referring now to  FIG. 12 , the housing  112  encases a worm gear  122  which is coupled to an output shaft (not shown) of the motor  114 . The worm gear  122  engages a worm wheel  124  which is integrated with a spur gear pinion  126 . The worm gear  122  imparts rotary motion to both the worm wheel  124  and spur gear pinion  126 . The spur gear pinion  126  imparts rotary motion to a sector spur gear  128  which is integrated with an output shaft  130  of the throttle actuator  20   a . The output shaft  130  is thereby rotated by the motor  114 . Bearings  132   a  and  132   b  are provided between the output shaft  130  and the housing  112  to allow free rotation of the output shaft  130  within the housing  112 . A sealing member in the form of an O-ring  134  is provided about the output shaft  130  to seal the housing. 
     As best shown in  FIG. 11 , the distal end  136  of the output shaft  130  is splined. There is a longitudinal, female threaded aperture  138  extending into the output shaft  130  from the distal end  136  thereof. The aperture  138  is designed to receive a bolt to couple the output shaft  130  to the actuator arm  21   a  as shown in  FIG. 8 . Referring back to  FIG. 12 , there is a magnet  140  disposed at a proximal end  141  of the output shaft  130 . There is also a position sensor  142  which senses a position of the magnet  140  as the output shaft  130  rotates. The position sensor  142  is thereby able to determine the rotating position of the output shaft  142 . In this example, the position sensor  142  is a Hall Effect sensor but in other embodiments the sensor may be a magnetoresistive position sensor or another suitable magnetic rotational sensor. The position sensor  142  is mounted on a circuit board  144  which is mounted on the throttle actuator housing  112 . More specifically, in this example, the circuit board  144  is mounted on the housing cover  121 . As best shown in  FIGS. 9 and 10 , the circuit board  144  is wired to the harness  116  allowing the position sensor  142  to send an electrical signal to the ESM  22   a  which is shown in  FIG. 4 . 
     As best shown in  FIG. 13 , the actuator arm  21   a  is coupled to a throttle  150  of the port engine  12   a , shown in  FIG. 2 , by a throttle linkage  152 . The throttle  150  includes a throttle body  154  and a throttle plate  156  mounted on a rotatable throttle shaft  158 . There is also a throttle position sensor (TPS)  159  mounted on top of the throttle shaft  158  which senses the position of the throttle shaft as it rotates. In this example, the TPS  159  is a potentiometer and communicates with the EMM  64   a  shown in  FIG. 4 . Together the plate  156 , the shaft  158  and the TPS  159  form a butterfly valve member which is spring loaded to a closed position shown in  FIG. 14 . Referring back to FIG.  13 , rotation of the actuator output shaft  130  drives the actuator arm  21   a  to rotate the throttle shaft  158 . Rotation of the throttle shaft  158  causes the throttle  150  to move between an idle position shown in  FIG. 14  and a WOT position shown in  FIG. 15 . Whether the throttle  150  is in the idle position or WOT position is dependent on the rotational position of output shaft  130 . The throttle actuator  20   a  is an external actuator, the electronic shift and throttle system  60  may be installed as a kit on an existing engine. 
     To correlate position of the throttle  150  with the position of the actuator arm  21   a , it is necessary calibrate the throttle controls of the electronic shift and throttle system  60 . Once calibrated, the idle position of the actuator arm  21   a  will correspond to the idle position of the throttle  150 . 
     The ESM  22   a , shown in  FIG. 4 , calibrates the throttle controls by using the voltage level sent by the TPS  159 , the duty cycle of the electrical signal sent by the actuator position sensor  142  and the amount of current flowing into the actuator motor  114 . The voltage level of TPS  159  varies with the position of the throttle plate  156 . In this example, the voltage level of TPS  159  is low when the throttle plate  156  is perpendicular and in contact with throttle housing  154 , as shown in  FIG. 14 , and the voltage level of the TPS  159  is high when the throttle plate  156  is parallel with throttle housing  154  as shown in  FIG. 15 . The duty cycle of the electrical signal sent by the actuator position sensor  142  varies with the position of the throttle actuator arm  21   a . In this example and as shown in  FIG. 13 , the duty cycle of position sensor  142  is low when the actuator arm  21   a  at the idle position and is high when the actuator arm  21   a  is at the WOT position. The amount of current flowing into the actuator motor  114  is low when the actuator arm  21   a  moves freely and increases when the throttle plate  156  is in contact with the throttle housing  154  thereby stalling the motor  114 . 
     The ESM  22   a  calibrates the throttle controls by determining the throttle position where the TPS voltage is the lowest, while avoiding residual tension in the throttle linkage  152 . This is done by  20  opening the throttle  150  and moving it back to the idle position in increments. This is best shown in ghost in  FIG. 16 . The ESM  22   a  controls the opening of the throttle  150  and moves the throttle  150  back to the idle position. In this example, the throttle  150  is moved back in increments of 1° towards a hard stop, i.e. where the throttle plate  156  comes into contact with the throttle housing  154 . At each increment the ESM  22   a  communicates  25  with the EMM  64   a  and requests the voltage level of the TPS  159  shown in  FIG. 13 . The ESM  22   a  stores the value. This is repeated until the throttle plate  156  comes to the hard stop. The ESM  22   a  determines if the throttle  150  is at the hard stop by measuring the current flowing in the actuator motor  114 . The ESM  22   a  assumes that the throttle  150  is at the hard stop if the current is above a pre-determined value. The ESM  22   a  then establishes the idle position as being where the lowest valid voltage level that is at least a minimal distance away from hard stop was measured. The minimal distance from the hard stop ensures that the tension created in the throttle linkage  152  while moving the throttle plate  156  against the hard stop is released. In this example, the minimal distance is defined in degrees and set to 0.75°. However, the minimal distance may range for example between 0.3° and 1.5°. 
     In this example, the calibration procedure will terminate successfully if the following parameters are met:
     1. The voltage level of the signal from the throttle position sensor has changed more than the movement amount while calibrating (in this example 0.2V). This amount confirms the actuator actually moved the throttle plate.   2. The minimum expected idle position voltage level (in this example 0.3V)&lt;=the voltage level of the signal from the throttle position sensor in the idle position&lt;=the maximum expected idle position voltage level (in this example 0.62V).
 
The values may vary in other embodiments.
   

       FIG. 17  best shows the above described calibration procedure. The new calibration position is stored in EEPROM if the calibration procedure terminates successfully. A similar calibration procedure is used for the center and starboard engines. 
     Referring back to  FIG. 3 , once the calibration procedure is completed the operator can more accurately increase or decrease the engine throttle by moving the port control lever  30  or starboard control lever  40  through its operational range, knowing the exact location of the idle position. The control head  16  uses a throttle curve to determine a throttle command based on the position of the control lever. A throttle curve is a two dimensional table which defines a relationship between a throttle value determined from the position of the control lever and the actual command sent to an ESM  22   a ,  22   b  or  22   c  shown in  FIG. 4 . In the electronic shift and throttle system disclosed herein a throttle curve is defined with five points. Interpolation is used to calculate the throttle command for control lever positions that fall in between the points. As shown in  FIGS. 18 and 19 , in this example, the control head  16  holds a total of eight forward throttle curves and eight reverse throttle curves. However, the control head  16  only uses one forward throttle curve and one reverse throttle curve at any given time. The default forward throttle curve is forward throttle curve number six. The default reverse curve is reverse throttle number six. The throttle curves being used can be selected by changing the control head settings. 
     The operator can also increase and decrease engine throttle without having to move the control levers  30  and  40  shown in  FIG. 3 . The RPM input means  52  of the control head  16  includes an RPM+ input means  51  which increases engine speed and RPM− input means  53  which decreases engine speed. In this example, the RPM+ input means and RPM− means are buttons but any suitable input devices may be used. Pressing the RPM+ input means  51  increases the throttle command sent through the CAN network to the ESM by a predetermined amount, e.g. 0.5% to 1%. Increasing the engine throttle with the predetermined amount, e.g. 0.5%, normally results in a repeatable amount of engine RPM increase, e.g. 50 RPM when the vessel is on plane. Pressing the RPM− input means  53  decreases the throttle command sent through the CAN network to the ESM by a predetermined amount, e.g. 0.5% to 1%. The increases and decreases to the throttle command are added to the throttle command as determined based on the position of the control lever and the throttle curve being used. The throttle command is only adjusted when all running engines are in the forward gear. The adjusted throttle command is applied to all running engines. 
     In this example, the throttle command adjustment is limited to a 5% adjustment. Pressing the RPM+ input means  51  when the throttle command has already been increased by 5% or the throttle reaches 100% will not result in further adjustment. Similarly, pressing the RPM− input means  53  when the throttle command has already been decreased by 5% or the throttle reaches 0% will not result in further adjustment. A throttle command of 0% corresponds to the idle position and a throttle command of 100% corresponds to the WOT position. 
     Moving either of the control levers  30  or  40  in any direction cancels the adjusted throttle command and disengages the adjustment function. The throttle command is then based on the position of the control levers  30  or  40  and the throttle curve being used. The new throttle command may be also be adjusted by pressing the RPM+ input means  51  or RPM− input means  53  as required. Accordingly, the electronic shift and throttle system disclosed herein allows the operator finely increase or decrease engine throttle. The electronic shift and throttle system disclosed herein also allows the operator increase or decrease engine throttle without having to move a control lever. 
     In this example, the throttle command may be adjusted by 5%. The total adjustment can be defined as an adjustment range required to change engine RPM. The optimal adjustment range is between 3% and 10%. The lower limit of the optimal adjustment range provides enough adjustment change engine RPM. The upper limit of the optimal adjustment range ensures that when the RPM adjustment function is disengaged, the increase or decrease to engine RPM is not too large and remains predictable. 
     In other embodiments, as shown in  FIG. 20 , an RPM input means  252  can be mounted on a switch panel  255 . A new throttle command is adjusted by pressing the RPM+ input means  251  or RPM− input means  53  as required. The enable button  260  activates the feature while the cancel button  270  deactivates the feature. The switch panel  252  may be mounted anywhere on a marine vessel as an aftermarket accessory. For example, the switch panel  252  may be mounted on the dock or stern to allow fine adjustment of the throttle command. Fine control of the engine speed is important, especially while trolling or water skiing. 
     It will be understood by a person skilled in the art that the method and system for increasing or decreasing engine throttle disclosed herein may be implemented in any electronic shift and throttle control system, regardless of whether the vehicle is a marine vessel. 
     It will further be understood by a person skilled in the art that many of the details provided above are by way of example only, and are not intended to limit the scope of the invention which is to be determined with reference to following claims.