JP2016098760A - Electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device that can attain an inexpensive general-purpose engine capable of improving fuel economy and reducing a regulated substance amount in exhaust gas, while performing feedback control in which atmospheric pressure is reflected with a simple structure.SOLUTION: In an electronic control device 100, a fuel injection amount calculation unit 108 calculates a basic fuel injection amount regulated according to an engine rotational frequency, in a case where a highland switch 33 is in an on state, with an oxygen concentration feedback coefficient calculated according to oxygen concentration detected by an oxygen concentration sensor 30 and a first correction coefficient correcting the basic fuel injection amount to one for highland correspondingly to the on state of the highland switch 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic control device applied to an internal combustion engine (engine), and more particularly to an electronic control device applied to a general-purpose engine used for general-purpose machines such as a generator, a pump, a farming machine, and a construction machine.

  Conventionally, general-purpose machines such as an engine generator driven by a general-purpose engine equipped with a mechanical governor that regulates the engine speed by controlling the intake air amount of the engine are known.

  In such a general-purpose engine, the intake air amount is adjusted by a mechanical governor and supplied into the engine, and the fuel is supplied from the carburetor into the engine with the intake air amount (negative pressure) adjusted by the mechanical governor. A general-purpose machine to which a general-purpose engine equipped with such a carburetor is applied is widely used because it is relatively inexpensive.

  On the other hand, in recent years, a general-purpose machine that has an electronic fuel injection valve instead of a carburetor and is applied with a general-purpose engine that is operated by performing air-fuel ratio control based on exhaust gas concentration has been proposed.

  Under such circumstances, Patent Document 1 relates to an electronic fuel injection engine with a mechanical governor, a fuel spark plug 2 provided facing the combustion chamber 1 of the engine, a fuel injection device 4 provided in the intake pipe 3, A throttle valve 5 that controls the amount of air flowing into the combustion chamber 1, a mechanical governor 6 that controls the opening of the throttle valve 5, a rotation speed sensor 9, a pressure sensor 7, a valve opening sensor 8, and a torque sensor 35. The structure provided with the state detection sensor 34 which detects an engine state including and the control part 10 is disclosed.

Japanese Patent No. 3232297

  However, according to the study of the present inventor, in the configuration of Patent Document 1, the state detection sensor 34 that detects the engine state including the rotation speed sensor 9, the pressure sensor 7, the valve opening degree sensor 8, and the torque sensor 35 is provided. In addition, the control unit 10 predicts the intake air flow rate, obtains the air-fuel ratio at the time of steady operation based on the predicted air flow rate and the engine speed n, and determines the operating state of the engine by rotating the governor lever shaft 13. An optimum operating state is obtained by determining the value of the air-fuel ratio corresponding to the operating state by correcting the air-fuel ratio at the time of steady operation based on the detection result obtained by the valve opening sensor 8 or the like that detects the angle. Since the configuration to be maintained is adopted, the types and number of sensors are increased compared to the general-purpose engine equipped with the conventional carburetor, the configuration is complicated, and the product cost is increased. It is considered to be a tendency to become too expensive piling up.

  Further, according to further studies by the inventor, general-purpose machines driven by engines are required to improve fuel efficiency and reduce the amount of regulated substances in exhaust gas worldwide. In this respect, it is considered that the general-purpose engine that controls the operation of the fuel injection valve by the electronic control unit has an advantage.

  In other words, at present, for general-purpose engines that control the operation of fuel injection valves with an electronic control unit, the cost is low, and while performing feedback control that reflects atmospheric pressure, fuel efficiency is improved and the amount of regulated substances in exhaust gas There is a long-awaited situation to realize the reduction of the above.

  The present invention has been made through the above-described studies, and is capable of achieving an improvement in fuel consumption and a reduction in the amount of regulated substances in exhaust gas while performing feedback control reflecting atmospheric pressure with a simplified configuration. An object of the present invention is to provide an electronic control device capable of realizing a cost-effective general-purpose engine.

  In order to achieve the above object, the present invention provides a crank sensor for detecting the rotational speed of an internal combustion engine, an oxygen concentration sensor for detecting an oxygen concentration in exhaust gas of the internal combustion engine, and an intake air amount of the internal combustion engine. In an electronic control device applied to an internal combustion engine having a mechanical governor that regulates the internal combustion engine by controlling, a fuel injection amount calculation unit that calculates a fuel injection amount of the internal combustion engine according to the rotational speed And the fuel injection amount calculation unit adjusts the oxygen concentration detected by the oxygen concentration sensor when the high altitude switch for supplying a first correction coefficient for correcting the basic fuel injection amount for high altitude is in an on state. The fuel injection amount is corrected by correcting the basic fuel injection amount defined according to the rotational speed using the oxygen concentration feedback coefficient calculated in accordance with the first correction coefficient and the first correction coefficient. To calculate a first aspect.

  In addition to the first aspect, the present invention provides that the fuel injection amount calculation unit calculates oxygen in accordance with an oxygen concentration detected by the oxygen concentration sensor when the highland switch is in an off state. It is a second aspect to calculate the fuel injection amount by correcting the basic fuel injection amount using a concentration feedback coefficient and a second correction coefficient for correcting the basic fuel injection amount for low ground.

  In addition to the first or second aspect, the present invention further includes a non-volatile memory, and the fuel injection amount calculation unit is provided in the electronic control device after the previous start-up operation of the electronic control device. The warm-up operation after the internal combustion engine is completely exploded in the current start-up operation when the high-altitude switch has not been switched between the on state and the off state before the current start-up operation. Between the oxygen concentration feedback coefficient calculated and stored in the nonvolatile memory according to the oxygen concentration detected by the oxygen concentration sensor during the previous start-up operation, and further using the stored value of the oxygen concentration feedback coefficient. While calculating the fuel injection amount by correcting the fuel injection amount, the high altitude switch is in the ON state and the OFF state after the previous start operation and before the current start operation. The stored value in the non-volatile memory is reset to a predetermined value of an oxygen concentration feedback coefficient, and the predetermined value is further used during the warm-up operation, It is a third aspect to calculate the fuel injection amount by correcting the basic fuel injection amount.

  Further, according to the present invention, in addition to any one of the first to third aspects, the operation unit of the high altitude switch is parallel to the operation panel surface of the electronic control device when the high altitude switch is switched. The relative movement in the direction is a fourth aspect.

  According to the above-described electronic control device according to the first aspect of the present invention, the fuel injection amount calculation unit that calculates the fuel injection amount of the internal combustion engine according to the rotational speed, and the basic fuel injection amount that is corrected for high altitude use. A high altitude switch that provides a correction coefficient of 1, and when the high altitude switch is in an ON state, the fuel injection amount calculation unit includes an oxygen concentration feedback coefficient calculated according to the oxygen concentration detected by the oxygen concentration sensor, and Since the fuel injection amount is calculated by correcting the basic fuel injection amount defined according to the rotational speed using the first correction coefficient, the carburetor can be used without increasing the type and number of various sensors. Even if a general-purpose machine to which an internal combustion engine is replaced by an electronic fuel injection valve is not equipped with a power source such as a battery, if the environment where the internal combustion engine is located is at a high altitude, the atmospheric pressure Depending can be corrected fuel injection amount of the internal combustion engine. As a result, an electronic control device capable of realizing a low-cost general-purpose engine that can achieve improvement in fuel consumption and reduction in the amount of regulated substances in exhaust gas while performing feedback control reflecting atmospheric pressure with a simplified configuration. can do.

  Further, according to the electronic control device according to the second aspect of the present invention, the fuel injection amount calculation unit calculates the oxygen injection amount according to the oxygen concentration detected by the oxygen concentration sensor when the highland switch is in the off state. The internal combustion engine was placed because the fuel injection amount is calculated by correcting the basic fuel injection amount by using the second correction coefficient for correcting the oxygen concentration feedback coefficient and the basic fuel injection amount for low ground. When the environment is not high, that is, low, the fuel injection amount of the internal combustion engine can be corrected according to the atmospheric pressure defined as the standard value.

  Further, according to the electronic control device according to the third aspect of the present invention, the fuel injection amount calculation unit is performed after the previous activation operation of the electronic control device and before the current activation operation of the electronic control device. If the high altitude switch is not switched between the on state and the off state, during the warm-up operation after the internal combustion engine has completely exploded during the current start-up operation of the electronic control unit, Fuel injection by correcting the basic fuel injection amount by further using the stored value of the oxygen concentration feedback coefficient calculated and stored in the non-volatile memory according to the oxygen concentration detected by the oxygen concentration sensor during the starting operation If the high altitude switch is switched between the on state and the off state after the previous start operation of the electronic control unit and before the current start operation of the electronic control unit The stored value in the nonvolatile memory is reset to a predetermined value of the oxygen concentration feedback coefficient, and the fuel injection amount is calculated by correcting the basic fuel injection amount by further using the predetermined value during the warm-up operation. Therefore, when the correction according to the oxygen concentration in the exhaust gas of the internal combustion engine becomes inaccurate, the correction can be eliminated and the fuel injection amount of the internal combustion engine can be corrected.

  According to the electronic control device of the fourth aspect of the present invention, the operation unit of the high altitude switch is relatively movable in a direction parallel to the operation panel surface of the electronic control device when the high altitude switch is switched. Therefore, it is possible to visually confirm whether or not the operator of the general-purpose machine to which the internal combustion engine is applied is in a state where the high altitude is corrected.

FIG. 1 is a schematic diagram showing the configuration of an electronic control device and an engine to which the electronic control device is applied in an embodiment of the present invention. FIG. 2A and FIG. 2B are schematic views showing the configuration of the highland switch shown in FIG. FIG. 3 is a timing chart for explaining a method for determining the engine stroke when the engine speed does not vary during the warm-up operation in the electronic control unit according to the present embodiment. FIG. 4 is a timing chart for explaining a method for determining the engine stroke when the engine speed fluctuates during the warm-up operation in the electronic control unit according to the present embodiment.

  Hereinafter, an electronic control device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In addition, although this embodiment has shown the example which applied the electronic control apparatus to the general purpose engine used for a generator, it is not limited to this, The electronic control apparatus in this embodiment is a pumping pump, agriculture The present invention is applicable to general-purpose engines used in general-purpose machines other than generators such as machines and construction machines. Further, the generator is not equipped with a power source such as a battery for supplying power to a general-purpose engine or an electronic control unit.

[Configuration of general-purpose engine]
First, with reference to FIG. 1, the configuration of a general-purpose engine to which the electronic control device according to this embodiment is applied will be described in detail.

  FIG. 1 is a schematic diagram showing a configuration of an electronic control device and a general-purpose engine to which the electronic control device is applied in the present embodiment.

  As shown in FIG. 1, an engine 1 to which an electronic control device 100 according to this embodiment is applied is applied to a generator including a power generation coil 2, and the power generator uses a driving force of the engine 1 for power generation. Electric power is generated by rotating the coil 2. The engine 1 to which the electronic control device 100 according to the present embodiment is applied will be described by taking a four-stroke cycle engine as an example, but the electronic control device 100, in principle, also for a two-stroke cycle engine. Applicable.

  Specifically, the engine 1 includes a cylinder block 11, and a coolant passage (not shown) through which coolant for cooling the cylinder block 11 flows is formed in the side wall of the cylinder block 11. A water temperature sensor 1 for detecting the temperature of the coolant flowing through the coolant passage is mounted as an engine temperature sensor 12 on the side wall of the cylinder block 11. The engine temperature sensor 12 detects the temperature of the engine 1 (engine temperature), and other sensors other than the water temperature sensor may be used as long as the engine temperature can be detected. Further, the engine 1 is not limited to the water cooling method, and may be an oil cooling method (air cooling method). In such a case, the lubricating oil of the engine 1 functions as a kind of coolant, What is necessary is just to detect the temperature of the lubricating oil of a predetermined part as engine temperature.

  A piston 13 is disposed in the internal space of the cylinder block 11. The piston 13 is connected via a connecting rod 14 to a crankshaft 16 provided in a crankcase (not shown) in the lower case 15. A power generating coil 2 that rotates coaxially with the crankshaft 16 is mounted on the crankshaft 16. The crankshaft 16 rotates as the piston 13 reciprocates, and the power generating coil 2 generates electric power as the crankshaft 16 rotates. Such electric power can be freely supplied to an external device (not shown), and both are supplied to an electronic control device 100 and an ignition coil 22 described later in detail.

  The crankshaft 16 is provided with a reluctator 17 that rotates coaxially therewith, and an outer peripheral portion of the reluctator 17 is provided with one tooth portion 17a. A crank sensor 18 is attached to the crankcase in the lower case 15 at a position facing the outer periphery of the reluctator 17. The crank sensor 18 outputs an output signal having a rising edge and a falling edge corresponding to the start end position and the end position of the tooth portion 17a every rotation of the crankshaft 16. Here, in principle, when the width between the rising edge and the falling edge of the output signal output from the crank sensor 18 is long, the operation stroke of the engine 1 is in the compression stroke and is output from the crank sensor 18. When the width between the rising edge and the falling edge of the output signal is short, it is assumed that the operation stroke of the engine 1 is in the exhaust stroke. This is because when the operation stroke of the engine 1 is in the compression stroke, the rotation speed of the crankshaft 16, that is, the rotation speed of the engine 1 is reduced due to the compression resistance force.

  A cylinder head 19 is assembled to the upper part of the cylinder block 11. In the internal space of the cylinder block 11, the space between the upper surface of the piston 13 and the cylinder head 19 defines a combustion chamber 20. The cylinder head 19 is provided with a spark plug 21 that ignites the air-fuel mixture in the combustion chamber 20. The ignition operation of the spark plug 21 is controlled by controlling the secondary voltage of the ignition coil 22 by an electronic control device 100 described later.

  The cylinder head 19 includes an intake pipe 23 that communicates with the combustion chamber 20. An intake valve 24 is provided at a connection portion between the combustion chamber 20 and the intake pipe 23. The intake pipe 23 is provided with an electronic fuel injection valve 25 that injects fuel upstream of the intake valve 24. On the upstream side of the electronic fuel injection valve 25, a throttle valve 26 that adjusts the intake air amount of the engine 1, a mechanical governor 27 that regulates the engine 1 by mechanically controlling the opening degree of the throttle valve 26, Is provided. The engine 1 is not provided with an intake pressure sensor for detecting the intake pressure of the engine 1 in its intake system, and is not provided with an atmospheric pressure sensor for detecting the atmospheric pressure around the engine 1.

  Further, the cylinder head 19 includes an exhaust pipe 28 that communicates with the combustion chamber 20. An exhaust valve 29 is provided at a connection portion between the combustion chamber 20 and the exhaust pipe 28. An oxygen concentration sensor 30 that detects the oxygen concentration in the exhaust gas discharged from the combustion chamber 20 is attached to the exhaust pipe 28.

[Configuration and operation of electronic control unit]
Next, the configuration and operation of the electronic control device 100 according to the present embodiment will be described in detail with reference to FIGS. 1 to 4.

  FIG. 2A and FIG. 2B are schematic views showing the configuration of the highland switch shown in FIG. FIG. 3 is a timing chart for explaining a method for determining the engine stroke when the engine speed does not vary during the warm-up operation in the electronic control apparatus according to the present embodiment. FIG. 4 is a timing chart for explaining a method for determining the engine stroke when the engine speed fluctuates during the warm-up operation in the electronic control unit according to the present embodiment.

  As shown in FIG. 1, with respect to the electronic control unit 100 according to the present embodiment, the engine started by being manually cranked after the ignition switch 32 is manually switched from the off state to the on state. The electric power generated by rotating the power generation coil 2 with the driving force of 1 and rectified via the rectifier 31 in the lower case 15 is supplied, and the electronic control unit 100 is activated using the generated current. Works. The electronic control unit 100 is an arithmetic processing unit such as a microcomputer having a CPU (Central Processing Unit), a memory, and the like, and is typically an ECU (Electronic Control Unit). The electronic control device 100 reads out necessary control programs and control data from the memory and executes various processes.

Specifically, the electronic control unit 100 includes a nonvolatile memory 101, a drive circuit 102, and an ignition circuit 103, and in addition to these, a switch state detection unit 104, an engine speed detection unit 105, which are CPU functional blocks, An oxygen concentration feedback (O ₂ F / B) coefficient calculation unit 106, an engine temperature correction coefficient calculation unit 107, a fuel injection amount calculation unit 108, an ignition timing control unit 109, and a stroke determination unit 110 are provided. Any one of the switch state detection unit 104, the engine temperature correction coefficient calculation unit 107, and the stroke determination unit 110 may be simplified or omitted depending on a difference in control processing according to the specifications of the generator. Correspondingly, various sensors and switches can be omitted.

  The nonvolatile memory 101 is a storage device that can store and retain data even when power is not supplied, and is preferably an EEPROM (Electrically Erasable Programmable Read-Only Memory) whose operation is stable.

  The drive circuit 102 controls the fuel injection amount and fuel injection timing by the electronic fuel injection valve 25 in accordance with a control signal from the CPU. The fuel injection amount is calculated by a fuel injection amount calculation unit 108, which will be described in detail later, and the fuel injection timing is calculated by the CPU in detail according to the engine speed calculated by an engine speed calculation unit 105, which will be described later. Is done.

  The ignition circuit 103 controls the ignition timing of the fuel by the ignition coil 22 in accordance with a control signal from the CPU. Specifically, the ignition circuit 22 controls the current flowing from the power generating coil 2 to the ignition coil 22 via the rectifier 31 to control the generation timing of the secondary voltage of the ignition coil 22, thereby Control the ignition timing of the fuel. The ignition timing is calculated by an ignition timing calculation unit 109 described later in detail.

  The switch state detection unit 104 detects the state of the high altitude switch 33 that instructs whether or not to correct the starting fuel injection amount and the basic fuel injection amount of the electronic fuel injection valve 25 according to the engine speed for high altitude, An electric signal indicating the state of the highland switch 33 detected in this way is output to the fuel injection amount calculation unit 108.

  The high altitude switch 33 is a low altitude / high altitude switching switch. Typically, when the high altitude switch 33 is in an OFF state, the fuel injection amount at the start of the electronic fuel injection valve 25 or the basic fuel injection in accordance with the engine speed. If the amount is maintained at the standard lowland value without being corrected for the highland and is in the ON state, the fuel injection amount at the start of the electronic fuel injection valve 25 corresponding to the engine speed and the basic fuel Correct the injection amount for high altitude.

  Here, as shown in FIG. 2A, for example, the highland switch 33 includes a switch main body 331a provided on the operation panel 40, a rotating portion 331b provided on the switch main body 331a, and a rotating portion. And a toggle switch that is turned on / off by rotating the operation unit 331c about the rotation unit 331b as a rotation axis. At this time, the operation unit 331 c is moved in a direction parallel to the panel surface 40 a of the operation panel 40.

  As another example, the highland switch 33 includes a switch body 332a provided on the operation panel 40 and an operation unit 332b provided on the switch body 332a, as shown in FIG. A slide switch that is turned on / off by sliding the operation unit 332b in a direction parallel to the panel surface 40a of the operation panel 40 may be used.

  The engine speed calculation unit 105 calculates the engine speed based on the output signal of the crank sensor 18, and uses the electric signal indicating the engine speed calculated in this way as a fuel injection amount calculation unit 108, an ignition timing calculation unit 109, And output to the stroke determination unit 110.

The O ₂ F / B coefficient calculation unit 106 calculates an O ₂ F / B coefficient based on the oxygen concentration detected by the oxygen concentration sensor 30, and generates an electrical signal indicating the O ₂ F / B coefficient calculated in this way. Output to the fuel injection amount calculation unit 108 and the ignition timing calculation unit 109.

  The engine temperature correction coefficient calculation unit 107 calculates a correction coefficient for the temperature of the engine 1 (engine temperature correction coefficient) based on the engine temperature detected by the engine temperature sensor 12, and indicates the engine temperature correction coefficient thus calculated. The electric signal is output to the fuel injection amount calculation unit 108 and the ignition timing calculation unit 109. The engine temperature correction coefficient is set to a value larger than 1.0 so as to exhibit an air-fuel ratio richer than the stoichiometric air-fuel ratio of the engine 1 when the engine temperature is low, and when the engine temperature is high, the engine 1 What is necessary is just to set to a value smaller than 1.0 so that the air-fuel ratio leaner than the stoichiometric air-fuel ratio may be exhibited.

  The fuel injection amount calculation unit 108 calculates the fuel injection amount of the engine 1 according to the engine speed calculated by the engine speed calculation unit 105.

  Specifically, first, during the start of the engine 1 during the start-up operation of the electronic control device 100 this time (when the engine 1 is cranked), the fuel injection amount calculation unit 108 refers to the map data and the like in the memory. By doing so, the fuel injection amount at start-up is calculated according to the engine speed and the engine temperature.

  At this time, the fuel injection amount calculation unit 108 determines that the generator is located at a high altitude when the high altitude switch 33 detected by the switch state detection unit 104 is on, and starts the engine 1. In order to improve performance, the starting fuel injection amount is corrected using an atmospheric pressure correction coefficient that corrects the starting fuel injection amount for high altitudes. On the other hand, when the state of the highland switch 33 detected by the switch state detection unit 104 is OFF, the fuel injection amount calculation unit 108 determines that the generator is located in a lowland, and determines the fuel injection amount at start-up. Keep the standard lowland values without correcting for highlands. Details of the atmospheric pressure correction coefficient will be described later.

  The fuel injection amount calculation unit 108 corrects the start time fuel injection amount with an engine temperature correction coefficient in order to improve the startability of the engine 1 when the start time fuel injection amount is calculated according to the engine speed. May be.

  3 and 4, after the ignition switch 32 is turned on at the time t = t0, the cranking is started at the time t = t1 and the time t = It is assumed that it corresponds to a period until cranking ends at t2.

  Next, during the warm-up operation after the engine 1 is completely exploded during the start-up operation of the electronic control unit 100 this time, the fuel injection amount calculation unit 108 refers to the map data in the memory, etc. The basic fuel injection amount is calculated according to the rotational speed, and the fuel injection amount is calculated according to the following formula (Equation 1).

Here, the fuel injection amount calculation unit 108, as O _{2 F} / B coefficients in equation (Equation 1), O _{2 F} / B coefficient storage that stores updated in the nonvolatile memory 101 at the time of the last start operation By using the value, the fuel injection amount is calculated by correcting the basic fuel injection amount defined according to the engine speed. This is because the oxygen concentration sensor 30 is not immediately activated during the start-up operation, so the stored value of the O ₂ F / B coefficient is used as an alternative value, and the regulated substance in the exhaust gas is improved while improving the warm-up property of the engine 1 This is to reduce the above. At the same time, the fuel injection amount calculation unit 108 increases the stored value of the O ₂ F / B coefficient so as to exhibit an air / fuel ratio richer than the stoichiometric air / fuel ratio of the engine 1 in order to improve the warm-up performance of the engine 1. The fuel injection amount may be calculated by correcting the basic fuel injection amount using the corrected correction coefficient.

  Further, the fuel injection amount calculation unit 108 determines that the generator is located at a high altitude when the high altitude switch 33 detected by the switch state detection unit 104 is on, and increases the warm-up performance of the engine 1. In order to improve, the basic fuel injection amount is corrected using an atmospheric pressure correction coefficient for correcting the basic fuel injection amount for high altitudes. At this time, the atmospheric pressure correction coefficient for high altitude is assumed to be a high altitude, for example, when the altitude is 2000 m, and the value is set to 0.8 to prevent the air-fuel ratio from becoming excessively high at that altitude. What is necessary is just to set to a grade.

  On the other hand, when the high altitude switch 33 detected by the switch state detection unit 104 is in the off state, the fuel injection amount calculation unit 108 determines that the generator is located in a low altitude, and sets the basic fuel injection amount to the high altitude. The standard lowland values are maintained without correction. In this case, for example, the correction coefficient of the standard for the lowland may be set to 1.0 assuming that the altitude is 0 m and the lowland is a lowland.

At this time, the fuel injection amount calculation unit 108 determines that the high altitude switch 33 has not been switched between the on state and the off state after the previous start operation and before the current start operation. During the warm-up operation after the complete explosion of the engine during the current start-up operation, the non-volatile memory 101 is used during the previous start-up operation in order to reduce the regulated substances in the exhaust gas while improving the warm-up performance of the engine 1. It is preferable to calculate the fuel injection amount by correcting the basic fuel injection amount using the stored value of the O ₂ F / B coefficient updated and stored.

On the other hand, if the high altitude switch 33 is switched between the on state and the off state after the previous start operation and before the current start operation, the fuel injection amount calculation unit 108 is O _2. the stored value of the F / B factor is reset to a predetermined value of the O _{2 F} / B coefficient, between the warm-up _operation, using _O 2 F / B coefficient of further predetermined value, correcting the basic fuel injection amount Thus, it is preferable to calculate the fuel injection amount. For example, the predetermined value may be set to a standard O ₂ F / B coefficient value in a lowland. Thus, by resetting the stored value of the O ₂ F / B coefficient, for example, when the generator is moved to a position where the altitude is different while the engine is stopped, the fuel injection amount during the warm-up operation becomes inappropriate, It is possible to suppress the malfunction of the engine.

  Further, the engine temperature correction coefficient and other correction coefficients in the mathematical formula (Equation 1) may be applied as necessary to further improve the warm-up performance. Other correction coefficients include, for example, an intake air temperature correction coefficient.

  In the period between the warm-up operation of the engine 1, in FIG. 3 and FIG. 4, the time measured by the timer after the ignition switch 32 is turned on at time t = t0 or the engine temperature is It corresponds to the period between time t = t7 when the predetermined warm-up temperature is reached. In the warm-up, an example is shown in which idling up of the engine speed is omitted.

  Next, after the warm-up operation of the engine 1 is completed during the startup operation of the electronic control device 100 this time, the fuel injection amount calculation unit 108 stores the memory in the same manner as during the warm-up operation of the engine 1 at the previous stage. The basic fuel injection amount is calculated according to the engine speed by referring to the map data and the like, and the fuel injection amount is calculated according to the mathematical formula (Equation 1).

However, at this time, the fuel injection amount calculation unit 108 updates the O ₂ F / B coefficient stored in the nonvolatile memory 101 during the previous start-up operation as the O ₂ F / B coefficient in the mathematical formula (Equation 1). rather than using the stored value, by using the O _{2 F} / B coefficient O _{2 F} / B coefficient calculation unit 106 has calculated based on the latest oxygen the oxygen concentration sensor 30 activated detects the basic fuel The fuel injection amount is calculated by correcting the injection amount.

Further, after the activation of the oxygen concentration sensor 30 or the completion of the warm-up operation of the engine 1, the fuel injection amount calculation unit 108 updates the latest O ₂ F / B coefficient calculated by the O ₂ F / B coefficient calculation unit 106. The fuel injection amount is preferably calculated by correcting the basic fuel injection amount using a correction coefficient that gradually increases the stored value of the O ₂ F / B coefficient toward the value. Thereby, it can suppress that engine speed fluctuates suddenly. The activation of the oxygen concentration sensor 30 is typically completed during the warm-up operation of the engine 1.

In addition, the fuel injection amount calculation unit 108 determines the stability of the feedback control when the fluctuation amount of the engine speed becomes equal to or greater than a predetermined value due to factors such as a change in electric load after the warm-up operation of the engine 1 is completed. In consideration of the case where it cannot be ensured, it is preferable to stop the oxygen concentration feedback for correcting the basic fuel injection amount using the O ₂ F / B coefficient. At this time, if the engine speed fluctuates in the upward direction, the fuel injection amount calculation unit 108 corrects the acceleration increase to the basic fuel injection amount from the viewpoint of suppressing the occurrence of unnecessary engine stall. It is preferable to carry out. Further, in such a case, it is more preferable to gradually reduce the acceleration increase correction by the attenuation process. The oxygen concentration feedback is resumed after the engine speed is stabilized.

  The period after the completion of the warm-up operation of the engine 1 corresponds to a period after time t = t7 when the timer time is a predetermined value or the engine temperature is a predetermined value in FIGS. To do.

  The ignition timing calculation unit 109 calculates the ignition timing of the engine 1 according to the engine speed calculated by the engine speed calculation unit 105.

  Specifically, first, at the start of the engine 1 during the start-up operation of the electronic control device 100 this time, the ignition timing calculation unit 109 refers to the map data in the memory, etc., according to the engine speed. Calculate the starting fire timing. At this time, the ignition timing calculation unit 109 may correct the starting ignition timing to the advance side in order to improve the startability of the engine 1.

  Next, during the warm-up operation after the complete explosion of the engine 1 during the start-up operation of the electronic control device 100 this time, the ignition timing calculation unit 109 refers to the map data and the like in the memory, thereby rotating the engine. The basic ignition timing is calculated according to the number, and the ignition timing is calculated according to the following equation (Equation 2).

Here, the ignition timing calculation unit 109 corrects the basic ignition timing defined according to the engine speed to the advance side by using at least one of the output value of the oxygen concentration sensor 30 and the engine temperature correction coefficient. It is preferable to calculate the ignition timing of the engine 1. In such a case, specifically, the ignition timing calculation unit 109 determines whether the oxygen concentration sensor 30 is in a state before activation or in a state after activation while the oxygen concentration sensor 30 is not activated during the starting operation. An engine temperature correction coefficient calculated by the engine temperature correction coefficient calculation unit 107 according to the output value of the oxygen concentration sensor 30 that can be discriminated, and the engine temperature detected by the engine temperature sensor 12 mounted on the internal combustion engine 1; After the oxygen concentration sensor 30 is activated, the latest value of the O ₂ F / B coefficient used for estimating the engine temperature, or the latest value of the O ₂ F / B coefficient and the engine Both temperature correction factors are used.

  In addition, in the mathematical expression (Equation 2), the atmospheric pressure correction coefficient and other correction coefficients may be applied as necessary to improve the warm-up property, and other correction coefficients include, for example, the intake air temperature correction coefficient. Is included.

  Next, after the warm-up operation of the engine 1 is completed at the time of the startup operation of the electronic control device 100 this time, the ignition timing calculation unit 109 refers to the map data in the memory and the like according to the engine speed. A basic ignition timing is calculated and used as the ignition timing. That is, after the warm-up operation of the engine 1 is completed, the ignition timing calculation unit 109 basically does not correct the basic ignition timing.

  The stroke determination unit 110 quickly determines the engine stroke of the engine 1 started by manual cranking.

  Specifically, first, the stroke determination unit 110 determines a temporary engine stroke based on the output signal of the crank sensor 18 according to a predetermined timing during the start-up of the engine 1 or during the warm-up operation after the complete explosion. . The predetermined timing is set to a timing at which the timer counts up to a predetermined fixed time after the ignition switch 32 is turned on, or a timing at which the engine speed reaches a predetermined fixed rotation speed. The temporary engine stroke is determined according to the length between the rising edge and the falling edge of the output signal output from the crank sensor 18 after the timing. Specifically, in the output signal output from the crank sensor 18 after the predetermined timing, the stroke determination unit 110 first outputs an output signal having a long length between the rising edge and the falling edge from the crank sensor 18. The corresponding engine stroke is made to correspond to the compression stroke in the temporary engine stroke. Here, the timing at which the falling edge of the output signal is detected is the completion timing of the compression stroke in the temporary engine stroke and the timing of finalizing the temporary engine stroke.

  In FIG. 3 and FIG. 4, the timing for determining the temporary engine stroke is shown to coincide with the time t = t2 when the cranking ends for convenience of explanation. However, the timing for determining the temporary engine stroke is sufficient if it is after the time t = t1 when the cranking is started and before the time t = t7 when the warm-up is completed.

  Next, the stroke determination unit 110 determines that the engine speed has stabilized during the warm-up operation after the complete explosion of the engine after the provisional determination of the engine stroke, and then the ignition of the engine 1 in the exhaust stroke in the temporary engine stroke. Is detected, and the fluctuation amount of the engine speed at that time is detected. The stroke determination unit 110 may stop both ignition and fuel injection of the engine 1 during the exhaust stroke in the temporary engine stroke, or the engine rotation when the determination of the temporary engine stroke is not appropriate. Although the degree to which the number fluctuates decreases, the fuel injection of the engine 1 may be stopped instead of stopping the ignition of the engine 1.

  The period in which the engine speed is stable during the warm-up operation after the complete explosion of the engine after provisional determination of the engine stroke is shown in FIG. 3 and FIG. 4 between time t = t3 and time t = t4. The timing at which the stroke determination unit 110 stops the ignition of the engine 1 during the exhaust stroke in the temporary engine stroke is indicated by time t = t5 in FIGS.

  Next, the stroke determination unit 110 finally determines the engine stroke according to the detected fluctuation amount of the engine speed. Specifically, when the stroke determination unit 110 determines that the engine rotation speed detected in this way is maintained below a predetermined value and the engine rotation speed is stable, the stroke determination unit 110 The engine stroke is determined as the final engine stroke, and the CPU controls the engine 1 based on the engine stroke thus determined. In this case, the timing control of the fuel injection and the timing control of the ignition are such that the timing is mutually offset by a half cycle of the engine stroke from the viewpoint of reducing the regulated substances in the exhaust gas of the engine 1 and improving the fuel consumption. Sequential control. On the other hand, when the variation amount of the engine speed detected in this way exceeds a predetermined value and the stroke determination unit 110 determines that the engine rotation number varies and is unstable, the stroke determination unit 110 Assume that the temporary engine stroke is deviated half-cycle, and the final engine stroke is an engine stroke that deviates the temporary engine stroke half-cycle so that the compression stroke in the temporary engine stroke is the exhaust stroke. Then, the CPU controls the engine 1 based on the engine stroke thus determined. In this case, the timing control of the fuel injection and the ignition is considered in accordance with the reliability of the engine stroke determined in this way, and the timing is matched every half cycle of the engine stroke in the same manner as before the determination of the engine stroke. Maintained. In addition, in order to improve the reliability of the engine stroke determined in this way, it is preferable that the stroke determination unit 110 repeats the engine stroke determination process using this as a temporary engine stroke again.

  After the stroke determination unit 110 stops the ignition of the engine 1, it is determined that the fluctuation amount of the engine speed is kept below a predetermined value (substantially zero) and the engine speed is stable, and the temporary engine The timing for determining the stroke as the final engine stroke is indicated by time t = t6 in FIG. On the other hand, after the stroke determination unit 110 stops ignition of the engine 1, it is determined that the fluctuation amount of the engine speed exceeds a predetermined value and the engine speed fluctuates (decreases) and is unstable. The timing at which the engine stroke obtained by shifting the temporary engine stroke by a half cycle is determined as the final engine stroke is indicated by time t = t6 in FIG.

  As is clear from the above description, in the electronic control apparatus 100 according to the present embodiment, the fuel injection amount calculation unit 108 is in the on state of the highland switch 33 that provides the first correction coefficient for correcting the basic fuel injection amount for highlands. In this case, the basic fuel injection amount defined according to the engine speed is corrected using the oxygen concentration feedback coefficient calculated according to the oxygen concentration detected by the oxygen concentration sensor 30 and the first correction coefficient. Thus, the fuel injection amount is calculated, so that a power source such as a battery is mounted on a general-purpose machine to which the engine 1 in which the carburetor is replaced with the electronic fuel injection valve 25 is applied without increasing the type and number of various sensors. Even if there is not, the fuel injection amount of the engine 1 can be corrected according to the atmospheric pressure when the environment in which the engine 1 is placed is a high altitude. So, as a result, electronic control that can realize a low-cost general-purpose engine that can improve fuel efficiency and reduce the amount of regulated substances in exhaust gas while performing feedback control that reflects atmospheric pressure with a simplified configuration Can play equipment.

  Further, in the electronic control device 100 according to the present embodiment, the fuel injection amount calculation unit 108 calculates the oxygen concentration feedback calculated according to the oxygen concentration detected by the oxygen concentration sensor 30 when the highland switch 33 is in the OFF state. Since the fuel injection amount is calculated by correcting the basic fuel injection amount using the fourth correction coefficient for correcting the coefficient and the basic fuel injection amount for low ground, the environment in which the engine 1 is placed is not high, that is, In the case of the lowland, the fuel injection amount of the engine 1 can be corrected according to the atmospheric pressure defined as the standard value.

  Further, in the electronic control apparatus 100 according to the present embodiment, the fuel injection amount calculation unit 108 determines that the high altitude switch 33 is between the on state and the off state after the previous start operation and before the current start operation. When the engine is not switched, during the warm-up operation after the engine has completely exploded during the current start-up operation, the non-volatile calculation is performed according to the oxygen concentration detected by the oxygen concentration sensor 30 during the previous start-up operation. The fuel injection amount is calculated by correcting the basic fuel injection amount by further using the stored value of the oxygen concentration feedback coefficient updated and stored in the characteristic memory 101, while the current start operation after the previous start operation If the high altitude switch 33 is switched between the on state and the off state before the hour, the stored value in the nonvolatile memory 31 is changed to a predetermined value of the oxygen concentration feedback coefficient. During the warm-up operation, the fuel injection amount is calculated by correcting the basic fuel injection amount by further using a predetermined value during the warm-up operation, so that correction according to the oxygen concentration in the exhaust gas of the engine 1 is not possible. When it becomes accurate, the correction can be eliminated and the fuel injection amount of the engine 1 can be corrected.

  Further, in the electronic control device 100 according to the present embodiment, the operation unit of the high altitude switch 33 is relatively movable in a direction parallel to the operation panel surface of the electronic control device 100 when the high altitude switch 33 is switched. It is possible to visually confirm whether or not an operator of a general-purpose machine to which the engine 1 is applied is in a state where the high altitude is corrected.

  The electronic control device 100 according to the present embodiment includes the engine temperature sensor 12, but in order to reduce costs, the oxygen concentration sensor 30 is used instead of the engine temperature sensor 12 to calculate or ignite the fuel injection amount. It is also possible to calculate the time.

  Further, the present invention is not limited to the above-described embodiment in terms of the type, shape, arrangement, number, etc. of the members, and the gist of the invention such as appropriately replacing the constituent elements with those having the same effects and the like. Of course, it can be changed as appropriate without departing from the scope.

  As described above, the present invention realizes a low-cost general-purpose engine that can improve fuel efficiency and reduce the amount of regulated substances in exhaust gas while performing feedback control that reflects atmospheric pressure with a simplified configuration. A possible electronic control device can be provided, and it is expected that it can be widely applied to an electronic control device applied to a general-purpose engine used for a general-purpose machine because of its general-purpose universal character.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Coil for electric power generation 11 ... Cylinder block 12 ... Engine temperature sensor 13 ... Piston 14 ... Connecting rod 15 ... Lower case 16 ... Crankshaft 17 ... Retractor 17a ... Tooth part 18 ... Crank angle sensor 19 ... Cylinder head 20 ... Combustion chamber DESCRIPTION OF SYMBOLS 21 ... Spark plug 22 ... Ignition coil 23 ... Intake pipe 24 ... Intake valve 25 ... Electronic fuel injection valve 26 ... Throttle valve 27 ... Mechanical governor 28 ... Exhaust pipe 29 ... Exhaust valve 30 ... Oxygen concentration sensor 31 ... Rectifier 32 ... Ignition switch 33 ... Highlands switch 100 ... electronic control device 101 ... non-volatile memory 102 ... drive circuit 103 ... ignition circuit 104 ... switch state detecting unit 105 ... engine speed detecting unit 106 ... oxygen feedback _(O 2 F / B) coefficient calculator 107 ... Engine temperature correction coefficient calculation unit 108: fuel injection amount calculating unit 109 ... ignition timing control unit 110 ... stroke determination unit

Claims (4)

A crank sensor for detecting the rotational speed of the internal combustion engine, an oxygen concentration sensor for detecting the oxygen concentration in the exhaust gas of the internal combustion engine, and a mechanical for controlling the speed of the internal combustion engine by controlling the intake air amount of the internal combustion engine In an electronic control device applied to an internal combustion engine having a governor,
A fuel injection amount calculation unit that calculates a fuel injection amount of the internal combustion engine according to the rotational speed;
When the high altitude switch that provides a first correction coefficient that corrects the basic fuel injection amount for high altitude is in an on state, the fuel injection amount calculating unit responds to the oxygen concentration detected by the oxygen concentration sensor. An electronic control unit that calculates the fuel injection amount by correcting a basic fuel injection amount that is defined according to the rotational speed by using the calculated oxygen concentration feedback coefficient and the first correction coefficient. .   The fuel injection amount calculation unit corrects the oxygen concentration feedback coefficient calculated according to the oxygen concentration detected by the oxygen concentration sensor and the basic fuel injection amount for low ground when the highland switch is in an off state. The electronic control unit according to claim 1, wherein the fuel injection amount is calculated by correcting the basic fuel injection amount using a second correction coefficient. A non-volatile memory;
The fuel injection amount calculation unit
When the high ground switch has not been switched between the on state and the off state after the previous start operation of the electronic control device and before the current start operation of the electronic control device, During the warm-up operation after the internal combustion engine is completely detonated during the current start-up operation, the non-volatile memory is calculated according to the oxygen concentration detected by the oxygen concentration sensor during the previous start-up operation. While using the stored value of the updated and stored oxygen concentration feedback coefficient to calculate the fuel injection amount by correcting the basic fuel injection amount,
When the high-altitude switch is switched between the ON state and the OFF state after the previous startup operation and before the current startup operation, the stored value in the nonvolatile memory Is reset to a predetermined value of the oxygen concentration feedback coefficient, and during the warm-up operation, the predetermined value is further used to calculate the fuel injection amount by correcting the basic fuel injection amount. The electronic control device according to claim 1 or 2.   4. The operation unit of the high altitude switch is capable of relative movement in a direction parallel to an operation panel surface of the electronic control device when the high altitude switch is switched. The electronic control apparatus as described in.

Images