Abstract: A self-adapting method for inhibiting corrosion of a component of a marine vessel performs a monitoring step during which a signal from the electrode is compared to a predetermined threshold magnitude. If the electrode is not connected to the circuit, the measured voltage will be approximately 0 volts. If the electrode is connected to the circuit, but in an inoperable condition, the voltage will also be lower than the threshold magnitude. In either of these situations, the present invention operates as an open loop control system. If, on the other hand, an appropriate signal is received from the electrode, the control system is operated in a closed loop manner. As a result, the circuit is able to adapt to the presence or absence of an operable electrode in the system.

Abstract: A trim tab monitoring circuit is provided which receives a signal that is representative of a voltage potential across a stator winding of a motor which is attached to the trim tab. This signal is passed through a high pass filter to remove the DC component of the signal, amplified, and passed through a low pass filter to remove certain high frequencies components of the signal. A zero crossing detector is used to discern individual pulses which are then received by a counter that provides a single output pulse for a predetermined number of input pulses. The series of output pulses from the counter are conditioned and, in conjunction with a direction sensor, provided to an up/down counter controller that provides digital signals to a signal output circuit. The signal output circuit provides a DC voltage output to a display and the DC output voltage is representative of the position of the trim tab.

Abstract: A monitoring circuit is provided to determine the proper operating condition of a cathodic protection circuit including a plurality of diodes and a capacitor. The monitoring circuit determines whether or not any of the diodes are shorted or open and whether or not the capacitor is open or operating properly. In addition, it determines whether or not the cathodic protection circuit is properly connected between a boat ground point and a shore ground point.

Abstract: An electrically conductive surface is combined with a protective surface of glass in order to provide an anode from which electrons can be transferred to seawater for the purpose of generating gaseous chlorine on the surface to be protected. Ambient temperature cure glass (ATC glass) provides a covalent bond on an electrically conductive surface, such as nickel-bearing paint. In this way, boat hulls, submerged portions of outboard motors, and submerged portions of stern drive systems can be protected effectively from the growth of marine organism, such as barnacles. The electrically conductive surface generates electrons into the seawater in order to create chlorine gas at the surface which inhibits and discourages marine growth. The protective coating of glass inhibits the migration of metal ions from the electrically conductive surface into the seawater and therefore inhibits corrosive degradation as a result of galvanic action.

Abstract: A tetherless occupant detector system uses an infrared sensor and a monitor circuit that provides a deactivation signal to an engine control unit or other control mechanisms in the event of an operator of the marine vessel leaving a preselected control position at its helm. The infrared sensor provides an output signal that is generally representative of the heat produced by an occupant within the control position of a marine vessel. The monitor circuit reacts to a sudden decrease in this heat magnitude and provides a deactivation signal in response to detecting this sudden decrease. The deactivation signal provided by the monitor circuit can be received by an engine control unit which then, in turn, deactivates a marine propulsion system. Alternatively, the deactivation signal itself can cause a deactivation of the marine propulsion system.

Abstract: A safety for a marine vessel provides an infrared sensor with a tube having a central cavity in order to define a viewing angle which is more narrow than the inherent viewing angle of the infrared sensor. The central cavity of the tube also defines a line of sight that can be directed toward a particular region near a marine vessel that is to be monitored for the presence of a heat generating object, such as a human being. An alarm circuit is responsive to signals from the infrared sensor and deactivates the marine propulsion system when a heat generating object is near the marine propulsion system. The length and diameter of the tube are selected to provide a desired viewing angle for the infrared sensor. An audible alarm output is provided if an attempt is made to manipulate a joystick that controls the marine propulsion system when a heat generating object is sensed by the infrared sensor.

Abstract: A system for inhibiting marine organism growth on underwater surfaces provides an electric current generator which causes an electric current to flow proximate the underwater surface. A source of power, such as a battery, provides electrical power to the electric current generator. The flow of current passes from the underwater surface through water surrounding the surface or in contact with the surface, and a point of ground potential. The point of ground potential can be a marine propulsion system attached to a boat on which the underwater surface is contained.

Abstract: A galvanic monitor system uses two annunciators, such like light emitting diodes, to alert a boat operator of the current status of the boat's galvanic protection system. A reference electrode is used to monitor the voltage potential at a location in the water and near the component to be protected. The voltage potential of the electrode is compared to upper and lower limits to determine if the actual sensed voltage potential is above the lower limit and below the upper limit. The two annunciators lights are used to inform the operator if the protection is proper or if the component to be protected is either being over protected or under protected.

Abstract: A marine fouling prevention system comprises two conductive surfaces and a device that alternates the direction of electric current between the two surfaces. The current is caused to flow through sea water in which the two surfaces are submerged or partially submerged. A monitor measures the current flowing from one of the two conduction surfaces and compares it to the current flowing into the other conduction surface to assure that no leakage of current of substantial quantity exists. The system applies a low magnitude current density, of approximately 0.10 to 0.50 milliamperes per square foot, for an extended duration of time of approximately 10 to 20 minutes. By alternating current direction between the two surfaces, both surfaces can be provided with sufficient chlorine gas bubbles to prevent marine growth from attaching to the surfaces.

Abstract: A running quality evaluator for an internal combustion engine for optimizing the running quality of the engine. The running quality evaluator includes an engine speed circuit which conditions a series of trigger pulses from the engine. The conditioned trigger pulses from the engine speed circuit are converted by an integrating circuit into an engine speed signal. The engine speed signal increases as the frequency of the trigger pulses from the internal combustion engine increase. Thus, the engine speed signal changes as the frequency of the trigger pulses from the engine change. The engine speed signal from the integrating circuit is then converted into an engine quality signal by a differentiating circuit. The engine quality signal increases as the rate of change of the engine speed signal increases. The engine quality signal from the differentiating circuit is then integrated into an output signal by an output circuit.

Abstract: A tachometer interface circuit is provided for use with a multi-functional measuring device. The tachometer interface circuit includes a conditioning circuit which receives a series of ignition pulses from an internal combustion engine. The conditioning circuit converts the series of ignition pulses into a series of output pulses each having a constant pulse width. The tachometer interface circuit further includes a magnitude sensing circuit and an offset circuit. The magnitude sensing circuit senses the magnitude of the ignition pulses and activates the offset circuit when the magnitude exceeds a predetermined limit. Upon activation, the offset circuit inserts a resistor into the conditioning circuit to reduce the magnitude of the ignition pulses entering the conditioning circuit. In this manner, the tachometer interface circuit of the present invention is able to operate with ignition pulses having a variety of magnitudes.

Abstract: An internal combustion engine is provided with a top hat piston disposed in a cylinder having first and second portions of different diameters. The piston, with first and second portions of different diameters, is disposed within the cylinder and defines a compression chamber between a cylinder step and a piston step created by the different diameters. The compression chamber is connected in fluid communication with a fuel supply, such as a carburetor or fuel injector, which provides a fuel/air mixture into the compression chamber during the downstroke of the piston. When the piston is moving upward, it compresses the fuel/air mixture within the compression chamber until a second end of a transfer passage is moved into fluid communication with a transfer port formed in the wall of the first portion of the cylinder. This occurs after the exhaust port is closed by the piston and therefore significantly diminishes the chance for unburned fuel to pass directly out the exhaust port from the combustion chamber.

Abstract: A galvanic isolator to protect against galvanic corrosion of a submersible metal marine drive. The galvanic isolator is positioned between shore ground and boat ground to prevent the flow of destructive galvanic currents between the shore ground and the boat ground, while maintaining the safety function of neutral ground. The galvanic isolator of the invention includes a blocking element positioned between the boat ground and the shore ground that can be switched between an open and a closed state by a trigger circuit. The trigger circuit closes the blocking element when the voltage difference between the boat ground and the shore ground exceeds a threshold value, such as 1.4 volts. During operation of the galvanic isolator during the high fault current situation, power is dissipated only by the blocking element, rather than by the combination of the blocking element and the trigger device.

Abstract: An oil flow sensor and circuit to indicate the presence of oil flow in a multi-cylinder internal combustion engine. The oil sensor includes a heating element positioned within the oil line directly in the oil flow path. Positioned upstream and downstream from the heating element are an upstream heat sensor and a downstream heat sensor. Each of the heat sensors is a negative temperature coefficient resistive device, such that the resistance of the heat sensor varies depending upon oil temperature at the sensor. The output of both the upstream and downstream sensor is coupled to a comparator. The comparator compares the value of the signals from the heat sensors and triggers a switching circuit when the temperature at the sensors approach one another, thus detecting that there is not adequate oil flow to the engine. The switching circuit is connected to a signaling device that indicates whether oil flow to the engine is adequate.

Abstract: A clutch controller and method for selectively engaging and disengaging one of the propellers in a twin propeller marine propulsion unit for a watercraft. The clutch controller is connected to a solenoid controlled valve to selectively engage and disengage one of a pair of counter-rotating propellers. The clutch controller includes a frequency-to-voltage converter which converts the engine speed to a voltage. The voltage based on the engine speed is compared to an upper limit such that the propeller is disengaged until the engine speed reaches the upper limit. Once the engine speed exceeds the specified upper limit, the second propeller is engaged. The clutch controller maintains engagement of the second propeller until the engine speed drops below a second intermediate limit. After falling below this intermediate limit, the second propeller is again disengaged.

Abstract: A speed limiting circuit measures the speed of the engine through the use of a device that functions generally as a tachometer. A speed signal is provided and is a function of the frequency of a plurality of pulses provided by a pulse generator. The frequency of the plurality of signal pulses, in a preferred embodiment, is representative of the frequency of a plurality of voltage pulses provided by an ignition coil. Since the voltage pulses from the ignition coil are directly related to the speed of the engine, the speed signal from an integrator can be used as an accurate representation of the engine speed. This speed signal can then be differentiated to determine the acceleration of the engine. The speed signal and acceleration signal are combined by an adder and the combined signal that results is compared to a threshold magnitude.

Abstract: A nozzle is provided for a fuel injection system in which a cap is disposed around a common termination of a first and second conduit. The first and second conduits are associated in coaxial and concentric relation with each other. A liquid fuel is transmitted through the first conduit and air is transmitted through the second conduit. The air is taken into the second conduit at atmospheric pressure without the need for an air compressor. An opening is formed in the cap of the nozzle to allow the fine mist formed at the common termination of the first and second conduit to flow out of the nozzle and into an air stream, such as within an intake manifold, for transport in the air stream to the combustion chamber of a cylinder within the internal combustion engine.

Abstract: A system and method for testing and monitoring the operation of a galvanic isolator. The galvanic isolator is positioned between shore ground and boat ground to prevent the flow of destructive galvanic currents between the shore ground and the boat ground. The monitoring system transmits a test current through the galvanic isolator at specific time intervals to test the effectiveness of the galvanic isolator. The monitoring system includes a first counter that outputs an enabling signal after a desired period of time. The enabling signal allows a test current to flow through the galvanic isolator for a brief period of time determined by a second counter. As the test current flows through the galvanic isolator, a current sensing circuit measures the test current and activates an alarm if the test current flowing through the galvanic isolator falls outside a predetermined range. In this manner, the monitoring system of the invention monitors and periodically tests a galvanic isolator.

Abstract: A fuel control solenoid valve for metering fuel flow through a low pressure fuel injection system of an internal combustion system is provided. The low pressure fuel injection system including the fuel flow solenoid valve is especially suitable for use in providing fuel to a two-cycle internal combustion engine, particularly those that are suitable for use as marine outboard motors. The fuel control solenoid valve includes a non-magnetic spacer which substantially prevents the development of engine surging as peak power conditions are approached or reached.

Abstract: In a two cycle internal combustion engine (10), a reed block (52) has a fuel spray rail flow passage (72) integrally formed therein and supplying fuel atomized by combustion air flow therepast. The fuel spray rail passage extends longitudinally (78) along the apex (60) of a V-shaped reed block (52) at the downstream end thereof, and has discharge ports (74, 76) formed by openings through the sides (56, 58) of the V-shaped member, which ports (74, 76) are opened and closed by the downstream ends of the reed valve flaps (62, 64). When the reed valves are open, air flows across and parallel to the face of the discharge port opening and perpendicular to the direction of fuel flow out of such openings, for enhanced atomization of the fuel. When the reed valves are closed, the downstream ends of the reed valve flaps engage the reed block sides and cover and close the discharge ports such that fuel is blocked from draining into the crankcase.