Honda Motor Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Tomoki Fukushima

Hayato Matsuda

Shinichi Katsuragawa

Takashi Hashizume

Shigeru Saito

Yoshihisa Shinogi

Takao Tamechika

Kenji Kamimura

Yoshiaki Kotani

Akihisa Shinoda

Makoto Yamamura

Tsutomu Wakitani

Masashi Nakamura

Hiroshi Kobayashi

Hideaki Shimamura

Akihito Kasai

Yoshinori Maekawa

Kouichi Asai

Takeshi Maeda

Naoya Toida

Tadayuki Yoneyama

Yasuhide Ono

Minoru Tamura

In an apparatus for controlling an air/fuel ratio of a general-purpose internal combustion engine using mixed fuel containing alcohol and gasoline and operated at a desired engine speed inputted by the operator while a throttle opening is regulated such that a detected engine speed converges to the inputted desired engine speed, a fuel injection amount determined for mixed fuel based on fuel injection amount characteristics is increased/decreased when a load is kept constant and the output air/fuel ratio is estimated to correct the fuel injection amount by the estimated air/fuel ratio, while a switch (knob) is installed to be manipulated by the operator to switch the fuel injection amount characteristics.

Air/fuel ratio control apparatus for general-purpose engine

In an apparatus for controlling warm-up operation of a general-purpose internal combustion engine having a throttle valve installed in an air intake pipe and connectable to an operating machine to be used as a prime mover of the machine, it is configured to calculate a basic fuel injection amount based on an engine speed and a throttle opening and control engine warm-up operation by calculating a warm-up time fuel injection amount by correcting the calculated basic fuel injection amount based on one of a temperature change amount of a spark plug seat of the engine, the throttle opening and an output of the operating machine and injecting fuel from an injector by the calculated warm-up time fuel injection amount. With this, it becomes possible to calculate a fuel injection amount suitable for the engine warm-up condition by using an appropriate parameter in place of the lubricating oil temperature.

Warm-up control apparatus for general-purpose engine

In an apparatus for controlling an air/fuel ratio of a general-purpose internal combustion engine using mixed fuel containing alcohol and gasoline and operated at a desired engine speed inputted by the operator while a throttle opening is regulated such that a detected engine speed converges to the inputted desired engine speed, a fuel injection amount for mixed fuel determined based on fuel injection amount characteristics is increased/decreased when a load is kept constant and the output air/fuel ratio (at which an output of the engine becomes maximum) is estimated. And the fuel injection amount is corrected based on the estimated air/fuel ratio, thereby enabling to estimate the output air/fuel ratio without using an expensive air/fuel ratio sensor and to feedback-control the fuel injection amount such that the engine is operated at the output air/fuel ratio.

In an apparatus for controlling a general-purpose engine used as a prime mover of an operating machine, the apparatus regulating a throttle opening such that an engine speed is converged to a desired engine speed, calculating a basic fuel injection amount based on the engine speed and throttle opening, and controlling engine warm-up operation by correcting the basic fuel injection amount with a correction coefficient to calculate a warm-up time fuel injection amount after engine start is completed and injecting fuel by the calculated amount, a fuel injection amount with which the engine output becomes maximum is searched based on the throttle opening regulated in response to increase/decrease operation of the warm-up time fuel injection amount conducted when the engine speed is constant; and the correction coefficient is corrected using the searched fuel injection amount. With this, a warm-up correction coefficient appropriate for the engine warm-up condition can be calculated.

Control apparatus for general-purpose engine

In an apparatus for controlling an air/fuel ratio of a general-purpose internal combustion engine using mixed fuel containing alcohol and gasoline and operated at a desired engine speed inputted by the operator while a throttle opening is regulated such that a detected engine speed converges to the inputted desired engine speed, a fuel injection amount prepared for mixed fuel is increased/decreased when a load is kept constant and the output air/fuel ratio (at which an output of the engine becomes maximum) is estimated. A rate of alcohol contained in the fuel is estimated from the estimated air/fuel ratio and the fuel injection amount is corrected based on the estimated alcohol rate, thereby determining the fuel injection amount appropriately in accordance with the estimated alcohol rate.

In a general-purpose engine having a throttle valve installed in an air intake passage connected to a combustion chamber, sucked air mixing with fuel to generate an air-fuel mixture to be ignited to drive a piston to rotate a crankshaft connected to a load, a first warm-up time period during which the engine is warmed up and a second warm-up time period which is longer than the first time period are determined based on detected engine temperature and a fuel quantity is increased during the first time period. The operation of the motor is controlled such that a change rate of throttle valve opening is limited within a range until the measured time exceeds the second warm-up time period after it exceeded the first time period. With this, it becomes possible to complete warm-up operation in a short period of time, while improving rate of fuel consumption and emission performance.

An oil level detection apparatus having a float-type oil level detector () and a mode switching unit. The oil level detector emits a signal indicating that the oil level has dropped when a movable contact disposed on a float () makes contact with fixed contacts once the level of oil (Lu) has dropped to a lower limit level. The mode switching unit switches between one of two modes selected from a first mode for actuating the alarm and stopping the engine () in accordance with the level drop signal, and a second mode for actuating the alarm and continuing to operate the engine () in accordance with the level drop signal.

Engine oil level detection system

In a system for controlling a general-purpose air-cooled internal combustion engine having two cylinders each equipped with a throttle valve and a fuel injector, and a cooling fan that selectively directs air onto the cylinders, a throttle driver selectively drives the respective throttle valve of each cylinder to open or close. The system also includes an injector driver that selectively drives the respective injector of each cylinder to open, and a controller that controls operation of the throttle driver and injector driver in such a way that the throttle opening and an amount of fuel to be injected are different for each cylinder, such that an engine speed becomes substantially constant, thereby enabling the engine to obtain desired output characteristics.

Control system for general-purpose engine

A fuel injection control system corrects the amount of fuel injected by fuel injection valves toward an increased side when an acceleration state resulting from operation of a throttle occurs. A control unit includes a detector, an acceleration state determinor, and an acceleration corrector. When an increase in the detected value is a predetermined value or more within a first predetermined time period, the acceleration state determiner determines that a state is an acceleration state and inputs a signal inducing fuel-amount-increase correction to the acceleration corrector. When the state where an amount of change in the detected value reaches a predetermined value or more in an increasing or decreasing direction within a first predetermined time period continuously occurs a predetermined number of times or more before a second predetermined time period expires, determination of the acceleration state is stopped until a third predetermined time period passes.

Fuel injection quantity control system for general-purpose engine

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.

Industrial engine completion inspection method

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.

Speed control system for lawnmower engine

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.

Engine speed control system for walk-behind truck

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.

Engine control system

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.

Coil failure detection system for general-purpose engine

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.

Growing community of inventors

Wako, Japan

Tomoki Fukushima