Abstract: A positive starting system and circuit prevents false starting of a multicylinder two-cycle internal combustion engine (10). During initial cranking of the engine, starter kick-out is caused by ignition of a residual combustible charge in a cylinder, however the following cylinder does not have a combustible charge, and the engine ceasing running, thus requiring re-engagement of the starter to start the engine. The problem is solved by delaying ignition upon initial cranking until sufficient combustible charge is developed in the remaining cylinders. Upon initial cranking, ignition is disabled, and a timing delay interval is initiated. At the end of such interval, ignition is enabled.

Abstract: A shift speed equalizer is provided in a marine transmission in a marine drive subject to a decrease in engine speed upon shifting from neutral to a forward or reverse gear due to a high propeller pitch or the like, such as in bass boat applications, and subject to an increase in engine speed upon shifting back to neutral. The shift from neutral to forward or reverse is sensed, and engine speed is increased in response thereto, to compensate the decrease in engine speed due to shifting. The return shift back to neutral is sensed, and engine speed is decreased in response thereto, to compensate the increase in engine speed due to shifting. Engine speed is increased by advancing engine spark ignition timing, and engine speed is decreased by retarding or returning engine ignition timing to its initial setting.

Abstract: In a multicylinder internal combustion engine, an overspeed control circuit progressively cuts out ignition to the cylinders depending upon the amount the threshold is exceeded. A monostable multivibrator is set by the ignition pulse of a given cylinder to initiate a given timing interval of fixed duration. A charging capacitor circuit has a first capacitor charged by the output of the monostable multivibrator during the timing interval, and discharged during a second timing interval until the next ignition pulse of the given cylinder. A latching comparator is set by the ignition pulse of the given cylinder and disables a cut-out switch which in turn permits ignition pulses to the cylinders. A second capacitor is also charged during the first timing interval until it reaches a given threshold voltage, corresponding to a given engine threshold speed, and which resets the latching comparator, which in turn actuates the cut-out switch to cut out ignition pulses to the remaining cylinders.

Abstract: A positive starting system and circuit prevents false starting of a multicylinder two-cycle internal combustion engine (10). During initial cranking of the engine, starter kick-out is caused by ignition of a residual combustible charge in a cylinder, however the following cylinder does not have a combustible charge, and the engine ceasing running, thus requiring re-engagement of the starter to start the engine. The problem is solved by delaying ignition upon initial cranking until sufficient combustible charge is developed in the remaining cylinders. Upon initial cranking, ignition is disabled, and a timing delay interval is initiated. At the end of such interval, ignition is enabled.

Abstract: A fuel injector assembly and a low pressure fuel injection system incorporating the fuel injector assembly are provided. The fuel injector assembly includes a fastener housing that functions to secure a reed valve block to a mounting plate which separates the air intake manifold from the crankcase of the internal combustion engine. A fuel injector or check valve is secured to the fastener housing so that fuel directed to the fuel injector passes through the mounting plate and into the crankcase at a location in the vicinity of the air flow outlet from the reed valve block.

Abstract: An assembly is provided for supplying a supplemental source of ambient air into the air intake manifold of a two-cycle internal combustion engine during start-up and abnormally low idle modes during which typically only minimal air would otherwise be available. Upon increase of engine speed, the supplemental ambient air flow is stopped. In one embodiment, a flow path is provided between the crankcase of the engine in order that puddled fuel will be bled from this location and to the location of the supplemental air inlet in order to thereby recycle and burn the puddled fuel during high speed operation of the engine.

Abstract: A fuel control system for an internal combustion engine includes means for pneumatically amplifying sensed air flow pressure differential through an air intake venturi between a first combustion air pressure sensor outside the venturi and a second combustion air pressure sensor in the venturi. Pressure at the inner end of the second pressure sensor is reduced by altering the air flow path to create a vacuum at the inner end of the second pressure sensor relative to the remaining air flow through the venturi. A throttle plate in the venturi has a by-pass hole therethrough directing air flow along a given direction past the inner end of the sensor and through the by-pass hole when the throttle plate is in the idle position. The given direction of air flow past the inner end of the sensor prevents air flow into the inner end of the sensor tube to prevent an increase of sensed pressure thereat, and instead creates a vacuum to pull air out of the inner end of the sensor tube, to reduce pressure thereat.

Abstract: A two cycle internal combustion engine is provided with a fuel system including a low pressure fuel pump (204) and solenoid valve (206) supplying and metering fuel to the engine crankcase through a fuel line, without a carburetor, without a high pressure fuel pump, without high pressure fuel injectors, and without a constant fuel pressure regulator. The system senses the amount of combustion air supplied to the engine, and senses fuel flow velocity using a restriction orifice in the fuel line producing a fuel pressure drop indicating fuel flow velocity. A conduit is connected between the crankcase at a transfer passage and the fuel line downstream of the restriction orifice and passes warm presurized air-fuel mixture from the crankcase through the transfer passage to the fuel line to improve fuel atomization.

Abstract: An auxiliary fuel supply system is provided for a two cycle internal combustion engine (302). A first fuel line (350) supplies fuel from the fuel pump (338) to a solenoid (352) which is continuously cyclable between ON and OFF states during running of the engine, includig high speed operation where detonation may occur. Fuel then flows through a second fuel line (354) to a restriction orifice metering housing (356), and then to a plurality of third branch fuel lines (358, 384, 386, 388, 390 and 392) for delivery to respective cylinders. The restriction orifices provide a pressure drop from the second fuel line to the plurality of third fuel lines, to provide lower fuel pressure in the third fuel lines, to reduce the chance of leakage at the intake manifold (326), and also to reduce fuel pressure fluctuations in the third fuel lines otherwise due to cycling of the solenoid. Metering housing structure is disclosed.

Abstract: A feedback fuel metering control system is provided for an internal combustion engine and eliminates the need for high pressure fuel injectors, a high pressure fuel pump and a constant fuel pressure regulator. The system senses the amount of combustion air supplied to the engine, senses fuel flow velocity, and controls the amount of fuel supplied according to the amount of combustion air the fuel flow velocity.

Abstract: A cold start fuel enrichment circuit for an internal combustion engine includes a thermistor (204) sensing engine temperature, a voltage source (V.sub.DD) continually biasing the thermistor such that the voltage across the thermistor continually varies with engine temperature and provides an output fuel enrichment signal, and a circuit (218, 220) connecting the engine battery (206) through the start switch (208) to the thermistor to additionally bias the thermistor during cranking of the engine. A combination cold start and knock prevention fuel enrichment circuit is also provided.

Abstract: A knock detection circuit includes an audio transducer (2) converting audio signals indicative of engine combustion into output signal voltage including a portion representing background noise and a portion representing detonation. An active variable resistor is provided by a transistor (14) having a gain which adjusts the amplitude of the transducer output voltage. A sampling and controlling circuit (30, 22, 28) samples the portion of the transducer output voltage representing background noise and outputs a variable bias determined by sensed background noise, which bias controls the gain of the transistor to adjust transducer output voltage inversely with sensed background noise. A detonation threshold detector (58) responds to a predetermined increase in the amplitude of the portion of the transducer output voltage representing detonation above the amplitude of the portion of transducer output voltage representing background noise, and outputs a knock-detected signal.

Abstract: A mass flow fuel injection control system is provided for an internal combustion engine and measures mass and flow velocity of combustion air. The length of fuel injection pulses is determined by .sqroot.P.sub.D P.sub.A /T, where P.sub.D is the air pressure drop produced by a venturi (32), P.sub.A is absolute air pressure, and T is air temperature. The system directly determines fuel requirements from the air mass flow and automatically self-adjusts and tracks such requirements from engine to engine or with modifications to the engine, without a preprogrammed look-up table according to throttle setting, and eliminates the need for a throttle position sensor.

Abstract: Interpreted intake-manifold vacuum and engine speed are used to produce an electrical output signal that reflects throttle position. Since the device has no mechanical tie to the throttle, there is none of the hysteresis or mechanical wear that are characteristic of conventional throttle-position sensors. The device comprises a tachometer circuit which is modulated by the signal from a differential-pressure transducer, connected to track the instantaneous pressure drop across the engine throttle. The tachometer output controls the duty cycle of a pulse generator which, in turn, drives an output transistor; a reference potential is applied across the load resistor and emitter of this output transistor, and the output signal is obtained as a d-c control signal, upon filtering the signal from the collector of the output transducer. The transfer function of the device yields maximum output when there is little or no intake vacuum, e.g.

Abstract: Engine overspeed control circuitry (200) includes a comparator (206) comparing tachometer voltage against a reference voltage, and disabling the engine above a given speed. The overspeed protection is defeated by blowing a fuse (222) in circuit with a comparator input (212) changing the impedance thereat, which leaves a permanent record of the defeat for subsequent detection.

Abstract: A resistance switching circuit is toggled immediately prior to cranking but subsequent to power application by the output of a manifold absolute pressure sensor effectively responding to ambient atmospheric pressure as indicative of altitude. The switching circuit is connected in series with the resistance element of the potentiometer which serves as the throttle control and alters the transfer characteristic of the control circuit. The gain of the system is such that the output operational amplifier saturates at an intermediate throttle setting such that the response for slow throttle is y=nx over the entire range of manifold pressure, while for fast throttle the response is y=nx for low manifold pressure and changes to y=mx+b for higher manifold pressure.

Abstract: A timing circuit is provided for stabilizing idling of an internal combustion engine, particularly marine racing applications where idle speed must be reduced to enable gear engagement, notwithstanding the use of a racing cam otherwise requiring higher idling speed. Delay means (8) provides a radical reduction in spark timing along a negative slope (16) relative to a baseline curve (6) up to a predetermined speed such as 900 rpm at which there is maximum relative timing delay (18). As speed increases in this range, there is more retard because of the negative slope, which further retarded timing slows engine speed, hence providing self-stabilization. As engine speed decreases in such range, there is less retard, and the advanced timing increases engine speed, again providing self-stabilization. At engine speed increases above the predetermined speed such as 900 rpm, there is a rapid advance in timing along a steeper positive slope (20) to merge with the baseline curve (6).

Abstract: A signal generator provides a non-linear fuel-control output signal, in response to an analog input-voltage signal which is linearly related to throttle setting. A multi-step switch divides into equal increments the full range of possible throttle-setting signals, and, in conjunction with a resistor network, provides a stepped output, the progression of which is a non-linear function of throttle setting. A dither circuit produces an oscillating sawtooth voltage of amplitude scaled to a one-step increment, and addition of this voltage to the throttle-setting voltage is effective to produce a smooth and effectively continuous non-linear output of the resistor network. A smoothing circuit at output of the resistor network yields a d-c output which is non-linearly related to the throttle setting.

Abstract: The invention contemplates control circuitry applicable to an internal-combustion engine having electronic fuel injection, for fuel-priming upon cranking the engine to start the same. The circuitry is operative only when there is proper fuel pressure at the injectors, and the prime is immediate and simultaneous to all injectors. The duration of the prime is an inverse function of engine temperature. Once the priming fuel has been injected, there cannot be another priming injection until lapse of a period of time following completion of cranking, thus preventing engine-flooding in the event of a quick restart of the engine.

Abstract: A system for use with an internal combustion engine which reduces, or eliminates, engine knock and attendant engine damage. An audio transducer is placed on an engine cylinder to convert audio signals occurring within the combustion chamber into an electrical signal. This signal is sampled and filtered and the amplitudes of two time-sequenced segments are compared. One of those segments is timed for an interval during which detonation, if any, is likely to occur, and the other of these segments is timed for an interval during which no detonation is likely to occur. When the amplitude of the sample from the segment of likely detonation exceeds the amplitude of the sample from the segment of unlikely detonation, by a predetermined amount, extra fuel is momentarily added to the combustion chamber to slow down the rate of combustion and cool the walls of the combustion chamber.