Multi-speed marine propulsion system with improved automatic shifting strategy based soley on engine speed
AssigneeBrunswick Corporation
InventorsPhilip Scott, William C. Stephenson
Life of this patent
Estimating the term…
Abstract
A marine propulsion system is provided with a gear shifting apparatus and method that changes a transmission from a low gear to a high gear, and vice versa, based solely on the engine speed. Engine speed is measured and a rate of change of engine speed is determined as a function of the actual change in engine speed over a measured time interval. Several threshold magnitudes are preselected and used to define one or more engine speed ranges. At least one threshold magnitude is used to compare the actual rate of change of engine speed to a preselected value. Both up shifting and down shifting of a transmission are controlled as a function of engine speed and rate of change of engine speed.
Claims19
A marine propulsion system, comprising:
- an engine having a crankshaft;
- a propeller shaft;
- a propeller attached to said propeller shaft;
- a gear shifting mechanism connected in torque transmitting association to said crankshaft and to said propeller shaft and having at least a low gear and a high gear, said low gear providing a greater gear reduction between said crankshaft and said propeller shaft than said high gear;
- an engine speed sensor which provides a speed signal which is representative of a rotational speed of said crankshaft;
- a timer which provides a time signal representative of elapsed time;
- and
- a controller connected to said engine speed sensor and timer to receive said speed and time signals and provide an output signal to said shifting mechanism to control said shifting mechanism as a function of said engine speed and the rate of change of said engine speed.
A method for controlling a gear shifting mechanism of a marine propulsion system, comprising:
- measuring an instantaneous rotational speed of a motive shaft;
- providing a multi-speed transmission connected to said motive shaft and to a propeller shaft that is attached to a marine propeller;
- measuring a change in said instantaneous rotational speed over a time interval;
- determining a rate of change of said instantaneous rotational speed;
- selecting a chosen operating gear ratio for said multi-speed transmission as a function of said rate of change of said instantaneous rotational speed;
- and
- shifting said multi-speed transmission into said chosen operating gear ratio.
A marine propulsion system, comprising:
- means for measuring the instantaneous rotational speed of a motive shaft;
- means for providing a multi-speed transmission connected to said motive shaft and to a propeller shaft that is attached to a marine propeller;
- means for measuring a change in said instantaneous rotational speed over a time interval;
- means for determining a rate of change of said instantaneous rotational speed;
- means for selecting a chosen operating gear ratio for said multi-speed transmission as a function of said rate of change of said instantaneous rotational speed;
- and
- means for shifting said multi-speed transmission into said chosen operating gear ratio.
Dependencies are inferred from the claim text.