Abstract: In a lawnmower engine speed control system having an actuator moving a throttle valve and a controller controlling operation of the actuator such that the engine speed becomes equal to a predefined desired engine speed, it is determined whether the lawnmower is under a mowing operation based on a value indicative of a load of the engine including an operation rate or output of the engine, the desired engine speed is changed based on a result of determination, thereby enabling to lower noise, to boost fuel efficiency, and to simplify operation by making manual regulation of engine speed unnecessary, while ensuring stable operation free from engine speed variance.

Abstract: In an engine speed control system mounted on a walk-behind truck having a bed that carries cargo, to power driven wheels through a clutch such that the truck runs and the engine speed is controlled to a desired engine speed, it is detected whether the operator performs operation for disengaging the clutch or for turning the truck, and the desired engine speed is determined to a first value when the operator does not perform any of the operations, while determining it to a second value (lower than the first value) when the operator performs the clutch disengaging or truck turning operation, thereby preventing lurching and sharp turning, protecting cargo against being damaged and falling off, and minimizing fuel consumption and noise.

Abstract: In an engine control system mounted on a machine such as a walk-behind truck through a CVT and having an actuator whose operation is controlled such that a detected engine speed becomes equal to a desired engine speed, the output of the engine is estimated based on the detected engine speed and a detected throttle opening, the desired engine speed is changed when the estimated engine output is greater or smaller than output threshold values, and a speed reduction ratio of the CVT is also changed based on the detected engine speed such that a detected speed of the CVT output shaft speed becomes equal to a desired output shaft speed, thereby enabling to reduce the fuel consumption and noise of the engine.

Abstract: In a failure detection system of coils that produce outputs in response to rotation of a crankshaft of a general-purpose engine (including a power coil that produces an output indicative of the engine speed), the outputs produced by the coils are inputted to determine whether the coils produce the outputs, and it is discriminated that one of the coils (i.e., power coil) has failed when the coil does not produce the output, thereby enabling detection of failure such as wire breaking of the power coil and preventing overrunning of the engine and other such problems.

Abstract: In an auto-choke system for a general-purpose engine, it is determined whether the operator has operated a combination switch to enable ignition in the engine and based on the result of this determination, the operation of a choke motor (actuator) is controlled to regulate the opening of the choke valve, specifically the operation of the choke motor is controlled to fully open the choke valve when ignition is found to be disabled. As a result, jetting of fuel is minimized and flooding prevented when the recoil starter is manipulated with ignition disabled. In addition, the operation of the choke motor is controlled to fully close the choke valve when ignition is found to be enabled, thereby enhancing the starting performance of the engine.

Abstract: A choke valve is controlled finely suited to the running state of an engine. A throttle valve 8 and a choke valve 9 are provided in series on an intake pipe 6, and the opening degree of the choke valve 9 is controlled by a stepping motor. The choke valve opening degree upon start of engine (start opening degree) is determined depending on the engine temperature. The stepping motor 11 is initialized at the fully closed side of the choke valve 9 when the power source for starting the engine is turned on. The start opening degree of the choke valve is judged to be closer to the fully closed side or fully opened side, and the stepping motor 11 is initialized at the fully closed side if judged to be close to the fully closed side, and at the fully opened side if at the fully opened side.

Abstract: In a control system of a lawn mower having an internal combustion engine controlled to a desired engine speed by a throttle actuator, a blade connected to the engine to be driven to cut grass, an engine output is estimated based on a detected throttle position and the desired engine speed, and when the estimated engine output exceeds a prescribed value, the grass bag is determined to be full of cut grass. With this, a full grass bag can be detected and the operator informed without providing a dedicated sensor.

Abstract: In an engine output condition informing system for a snow remover, the engine speed and the throttle position are detected, the output power rate OPrate of the engine is estimated based thereon, the output power condition of the engine is determined based on the estimated output power rate, and the operator is informed of the determined output power condition by the display (informing) device. With this, the output power condition of the engine can be accurately determined and the operator informed with a simple configuration, whereby the burden on the operator can be lightened. Also, it is possible to minimize situations in which the output power condition of the engine is overpowered and the power train of the engine or of the snow removal mechanism and travel mechanism is damaged, as well as situations in which the output power condition of the engine becomes underpowered, the snow remover is unable to perform, and the operating efficiency decreases.

Abstract: In an electrically-actuated throttle device for a general-purpose engine, supply of current to the throttle motor and choke motor for moving the throttle valve and choke valve is started when cranking is detected after activation (power-up) of the electronic control unit (ECU). In other words, supply of current is not started simultaneously with activation of the ECU but is delayed until cranking is detected. Owing to this configuration, no power of the battery is consumed unnecessarily between power-up and starting of the engine. Decrease in the power supplied to the starter motor is therefore prevented, thereby improving the starting performance of the engine. In addition, even if starting of the engine is not commenced after power-up, the battery is not likely to be excessively discharged.

Abstract: In a multipurpose engine throttle device having a throttle body disposed at an intake pipe of the engine and housing a throttle valve, a case is integrally attached to the throttle body and housing an electric motor moving the throttle valve, a speed reducer connecting an output shaft of the motor with the throttle valve, an electronic circuit board having an electronic control unit that controls operation of the motor and a connector mounted thereon, and a harness connecting the motor with the connector, thereby reducing in overall size by efficient layout of these components.

Abstract: In an auto-choke system for a general-purpose engine, it is determined whether the operator has operated a combination switch to enable ignition in the engine and based on the result of this determination, the operation of a choke motor (actuator) is controlled to regulate the opening of the choke valve, specifically the operation of the choke motor is controlled to fully open the choke valve when ignition is found to be disabled. As a result, jetting of fuel is minimized and flooding prevented when the recoil starter is manipulated with ignition disabled. In addition, the operation of the choke motor is controlled to fully close the choke valve when ignition is found to be enabled, thereby enhancing the starting performance of the engine.

Abstract: In a failure detection system of coils that produce outputs in response to rotation of a crankshaft of a general-purpose engine (including a power coil that produces an output indicative of the engine speed), the outputs produced by the coils are inputted to determine whether the coils produce the outputs, and it is discriminated that one of the coils (i.e., power coil) has failed when the coil does not produce the output, thereby enabling detection of failure such as wire breaking of the power coil and preventing overrunning of the engine and other such problems.

Abstract: An inspection method is conducted after the assembly of an industrial engine is complete. An identification code assigned to an industrial engine is read. Basic engine specification data and device-specific engine specification data that correspond to the read identification code are extracted from a database to a completion inspection unit. Various inspections are conducted on the individual engine by the completion inspection unit on the basis of the extracted basic engine specification data. The device-specific engine specification data of the engine that has passed the inspection is written into memory. A confirmation inspection is then conducted by a device-specific inspection machine to determine whether the engine has the output characteristics required by the mounting device.

Abstract: In an electrically-actuated throttle device for a general-purpose engine, supply of current to the throttle motor and choke motor for moving the throttle valve and choke valve is started when cranking is detected after activation (power-up) of the electronic control unit (ECU). In other words, supply of current is not started simultaneously with activation of the ECU but is delayed until cranking is detected. Owing to this configuration, no power of the battery is consumed unnecessarily between power-up and starting of the engine. Decrease in the power supplied to the starter motor is therefore prevented, thereby improving the starting performance of the engine. In addition, even if starting of the engine is not commenced after power-up, the battery is not likely to be excessively discharged.

Abstract: In a throttle device for a multipurpose internal combustion engine having a throttle valve, a throttle shaft connected to the throttle valve and an electric motor housed in a housing to move the throttle valve, both ends of a motor output shaft is configured to protrude from the housing in such a manner that the one end is connected to a power transmission mechanism, whilst the other end is inserted in a hollow boss formed in a fixing component of the motor, thereby ensuring no fluctuation to occur in the positional relation of the output shaft to the throttle shaft, while enabling to prevent friction from being generated in the power transmitting mechanism. In addition, a manual operating lever is provided to allow the engine to be easily started again even when the throttle valve is held nearly closed when the engine is stopped.

Abstract: In an engine speed control system for a snow remover, the engine speed is controlled at the desired speed by driving the throttle valve with an electric motor, the engine output power corresponding to the load acting on the snow removal mechanism or travel mechanism is estimated based on the throttle position and the engine speed, and the desired speed is increased in stepwise fashion to a higher value when the estimated engine output power exceeds first through third ascending threshold values. With this, the engine speed maintained when a small load is acting on the snow removal mechanism or travel mechanism can be set to a lower value, whereby the noise level can be reduced and fuel efficiency improved compared with the prior art wherein a mechanical governor is used to adjust the engine speed.

Abstract: In an engine control system mounted on a machine such as a walk-behind truck through a CVT and having an actuator whose operation is controlled such that a detected engine speed becomes equal to a desired engine speed, the output of the engine is estimated based on the detected engine speed and a detected throttle opening, the desired engine speed is changed when the estimated engine output is greater or smaller than output threshold values, and a speed reduction ratio of the CVT is also changed based on the detected engine speed such that a detected speed of the CVT output shaft speed becomes equal to a desired output shaft speed, thereby enabling to reduce the fuel consumption and noise of the engine.

Abstract: In a multipurpose engine throttle device having a throttle body disposed at an intake pipe of the engine and housing a throttle valve, a case is integrally attached to the throttle body and housing an electric motor moving the throttle valve, a speed reducer connecting an output shaft of the motor with the throttle valve, an electronic circuit board having an electronic control unit that controls operation of the motor and a connector mounted thereon, and a harness connecting the motor with the connector, thereby reducing in overall size by efficient layout of these components.

Abstract: In an engine speed control system mounted on a walk-behind truck having a bed that carries cargo, to power driven wheels through a clutch such that the truck runs and the engine speed is controlled to a desired engine speed, it is detected whether the operator performs operation for disengaging the clutch or for turning the truck, and the desired engine speed is determined to a first value when the operator does not perform any of the operations, while determining it to a second value (lower than the first value) when the operator performs the clutch disengaging or truck turning operation, thereby preventing lurching and sharp turning, protecting cargo against being damaged and falling off, and minimizing fuel consumption and noise.

Abstract: In a throttle device for a multipurpose internal combustion engine having a throttle valve connected to an electric motor and a carburetor, when an instruction to stop the engine is inputted, the electric motor is controlled to move the throttle valve in a fully closed position so as to stop the engine, and then to move the throttle valve in a fully opened direction. With this, throttle valve can be surely opened to facilitate restarting, and the occurrence of dieseling and run-on is prevented without providing a fuel cut valve to the carburetor. Further, a spring is provided to urge the throttle valve in an opening direction. With this, the response in opening the throttle valve is enhanced and the size of the motor is reduced.