JP2009127548A - Internal combustion engine control device and internal combustion engine control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device capable of improving the drivability and stability of an engine rotational speed, while the operational state of the internal combustion engine is switched to a fuel efficiency priority mode when a remaining fuel level is low. <P>SOLUTION: The internal combustion engine control device includes: a mode switching means in steps S17 and S18 for switching the operational state of the engine between a normal driving mode and an eco-friendly mode in which fuel consumption is further reduced more than that in the normal driving mode; a remaining fuel level determination means in step S11 for determining whether or not a remaining fuel level in a fuel tank is lower or equal to a previously determined value, that is, in a low remaining fuel level state; and a driving mode determination means in steps S12, S13, S14, S15, and S16 for determining whether or not the driving state of a vehicle is in a predetermined fuel efficiency priority approval driving state. If the vehicle is determined to be in the low remaining fuel level state, and at the same time, in the fuel efficiency priority approval driving state, the operational state of the engine is switched to the eco-friendly mode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device capable of switching an operation state of an internal combustion engine between a normal traveling mode and a fuel efficiency priority mode in accordance with the remaining amount of fuel in a fuel tank.

Reduces the possibility that the internal combustion engine will stop due to running out of gas and become unable to run when the fuel level in the fuel tank is below the specified value (low fuel level) while the vehicle is running Therefore, conventionally, the control described in Patent Document 1 is known. That is, the control is switched to the fuel consumption priority mode for improving the fuel consumption rate (fuel consumption) when the low remaining amount state is reached.
JP 2006-63959 A

  However, depending on the running state of the vehicle, it may be desirable not to switch to the fuel efficiency priority mode even in a low remaining amount state, so driving is performed against deterioration in drivability and instability of engine speed (engine speed). May have strong dissatisfaction.

  Specifically, if the driver is accelerating to request acceleration, the driver will not be able to fully demonstrate the drivability according to the driving operation when the fuel consumption priority mode is switched. May be dissatisfied. In addition, if the engine speed is unstable (when the fluctuation in the instantaneous rotational speed is large), such as during idling, if you switch to the fuel efficiency priority mode, the engine speed will become even more unstable and the driver will be dissatisfied. The vibration of the internal combustion engine increases as the engine is held. In some cases, the internal combustion engine is stopped (engine stalled).

  The present invention has been made in order to solve the above-mentioned problems, and its object is to improve drivability while switching the operating state of the internal combustion engine to the fuel efficiency priority mode when the remaining amount of fuel is low. An object of the present invention is to provide an internal combustion engine control device that improves the stability of engine rotation speed.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

In invention of Claim 1,
Applied to a vehicle that travels using combustion energy obtained by burning fuel in a fuel tank in a combustion chamber of an internal combustion engine as a drive source;
Mode switching means for switching the operating state of the internal combustion engine between a normal travel mode and a fuel consumption priority mode that improves the fuel consumption rate compared to the normal travel mode;
A remaining amount determining means for determining whether or not the remaining amount of fuel in the fuel tank is in a low remaining amount state where the fuel remaining amount is not more than a predetermined value set in advance;
Traveling state determination means for determining whether the traveling state of the vehicle is a preset fuel consumption priority permitted traveling state;
With
The mode switching means switches to the fuel efficiency priority mode when it is determined that the low remaining amount state and the fuel efficiency priority permitted travel state are set.

  According to this, in the case of the low remaining amount state on the condition that it is determined that the traveling state of the vehicle is the preset fuel consumption priority permitted traveling state only by being in the low remaining amount state and not being switched to the fuel consumption priority mode. Switch to the fuel efficiency priority mode. Therefore, by setting the fuel consumption priority permission driving state so that the driver does not have a strong dissatisfaction with the deterioration of drivability and the instability of the engine rotation speed (engine rotation speed), the fuel consumption is reduced only in the low remaining amount state. Compared with the control described in Patent Document 1 for switching to the priority mode, it is possible to improve the drivability and improve the stability of the engine rotation speed.

  Here, when the normal driving mode is switched to the fuel efficiency priority mode, the output of the internal combustion engine decreases. However, when such a decrease in output occurs at the time of a driver's high-load driving request, the driver's dissatisfaction with deterioration of drivability occurs. Is big. In view of this point, in the invention according to claim 2, the traveling state determination means is configured to reduce the fuel consumption for a high load driving request state that a driver requests to operate the internal combustion engine at a high load of a predetermined value or more. It is determined that the vehicle is not in the priority-permitted running state. Therefore, when the driver demands high load driving, switching to the fuel efficiency priority mode is prohibited, and a decrease in the output of the internal combustion engine is avoided, so that the driver's dissatisfaction with the deterioration in drivability can be avoided.

  The following invention is mentioned as a specific example of the above-mentioned “high load operation request state”. That is, the acceleration travel state (the invention according to claim 3), the high speed travel state where the vehicle speed becomes a predetermined value or more (the invention according to claim 4), the opening of the throttle valve is increased, and the amount of intake air to the combustion chamber is reduced. When increasing, the change amount of the opening is larger than a set value (invention of claim 5), and the opening of the throttle valve is larger than a first set value (invention of claim 6).

  Here, when the opening degree of the throttle valve is small, the engine rotational speed is likely to be unstable (a state where the fluctuation of the instantaneous rotational speed is large), and in such an unstable state, the normal driving mode is switched to the fuel consumption priority mode. As a result, the engine rotational speed becomes more unstable, and the vibration of the internal combustion engine increases as the driver becomes dissatisfied. In some cases, the internal combustion engine is stopped (engine stalled).

  In view of this point, in the invention according to claim 7, the travel state determination means is in a state where the opening of the throttle valve for adjusting the intake air amount to the combustion chamber is smaller than a second set value (for example, low speed travel operation or idle The driving state is determined not to be the fuel consumption priority permission traveling state. Therefore, when the throttle valve opening is small, switching to the fuel efficiency priority mode is prohibited and the engine rotation speed destabilization promotion is avoided, so that the driver's dissatisfaction with the engine rotation speed destabilization promotion can be avoided. .

  In particular, during idle operation in which the throttle valve opening is small when traveling is stopped, an engine stall due to misfire is more likely to occur even when the valve opening is the same. In view of this point, the invention according to claim 8 is characterized in that it is determined that the idling operation state is not the fuel consumption priority permission traveling state. Therefore, in the idling state in which engine stall is likely to occur, switching to the fuel efficiency priority mode is prohibited and the promotion of instability of the engine rotation speed is avoided. The risk of engine stalls can be avoided.

  The invention according to claim 9 is characterized in that the traveling state determination means determines that the fuel consumption priority permitted traveling state is in a state where the warm-up operation of the internal combustion engine is completed. Therefore, if the warm-up operation has not been completed, switching to the fuel efficiency priority mode is prohibited, so that a delay in completion of the warm-up operation due to switching to the fuel efficiency priority mode can be avoided.

  The invention according to claim 10 is characterized in that the traveling state determination means determines that the fuel consumption priority permission traveling state is not satisfied when the rotational speed fluctuation of the output shaft of the internal combustion engine is larger than a predetermined fluctuation. To do. For this reason, when the engine speed fluctuation is large (unstable), switching to the fuel efficiency priority mode is prohibited and the promotion of destabilization is avoided. The risk of occurrence can be avoided.

  In the invention according to claim 11, the fuel efficiency priority mode is classified into a plurality of modes having different degrees of improvement in the fuel consumption rate, and the fuel efficiency priority permitted travel state is at least one of a plurality of travel conditions. The mode switching means switches to a mode at a different level from among the fuel efficiency priority modes depending on which of the plurality of driving conditions is satisfied.

  According to this, since the mode is switched to the fuel efficiency priority mode having a different fuel efficiency improvement degree (fuel efficiency importance level) for each driving condition, the fuel efficiency improvement degree can be finely set according to the vehicle driving state. In addition, since the degree of improvement in fuel efficiency is switched to multiple levels even in the fuel efficiency priority mode, it is possible to suppress a sudden change in the operating state of the internal combustion engine.

  Specific examples of the operating state of the internal combustion engine in the fuel efficiency priority mode include prohibition of asynchronous injection, prohibition of increase correction, and leaning of the air-fuel ratio. By executing these, fuel efficiency is improved in the fuel efficiency priority mode. Can be easily realized.

  That is, in the invention according to claim 12, in the normal running mode, in addition to the synchronous injection in which the fuel is injected in synchronization with the crank angle of the internal combustion engine, the asynchronous injection in which the fuel is injected at the driver's acceleration request timing is executed The asynchronous fuel injection is prohibited in the fuel consumption priority mode. In the invention according to claim 13, in the normal travel mode, acceleration increase correction for increasing the fuel injection amount at the driver's acceleration request timing can be executed, and in the fuel consumption priority mode, the increase correction is prohibited. It is characterized by. The invention according to claim 14 is characterized in that in the fuel consumption priority mode, the air-fuel ratio is made leaner than in the normal travel mode.

  The invention according to claim 15 is characterized by comprising notifying means for notifying the driver of the fact that the internal combustion engine is being driven in the state of switching to the fuel efficiency priority mode. According to this, it can suppress that a driver | operator feels uncomfortable because the driving | running state of an internal combustion engine switches automatically.

  According to a sixteenth aspect of the present invention, the internal combustion engine control device includes at least one of a remaining amount detecting unit that detects a remaining amount of fuel in the fuel tank and a traveling state detecting unit that detects a traveling state of the vehicle. Is an internal combustion engine control system. According to this internal combustion engine control system, the various effects described above can be exhibited in the same manner.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. This embodiment is intended for two-wheeled vehicles that use a gasoline engine, which is an internal combustion engine, as a travel drive source. First, an overall schematic configuration diagram of an engine control system centering on an engine and an electronic control unit (hereinafter referred to as an ECU) is shown. This will be described with reference to FIG.

  In the engine 10 shown in FIG. 1, an air cleaner 12 is provided at the most upstream portion of the intake pipe 11, and an air flow meter 13 for detecting the intake air amount is provided downstream of the air cleaner 12. A throttle valve 14 whose opening is adjusted by an actuator such as a DC motor and a throttle valve opening sensor 15 for detecting the throttle valve opening are provided on the downstream side of the air flow meter 13. A surge tank 16 is provided downstream of the throttle valve 14, and an intake pipe pressure sensor 17 for detecting the intake pipe pressure is provided in the surge tank 16. In the case of a multi-cylinder engine, an intake manifold 18 that introduces air into each cylinder of the engine 10 is connected to the surge tank 16, and fuel is injected and supplied to the vicinity of the intake port of each cylinder in the intake manifold 18. An electromagnetically driven fuel injection valve 19 is attached.

  The fuel injection valve 19 is supplied with fuel from a fuel tank 31 mounted on the vehicle through a fuel pump 32 and a fuel pipe 33. The fuel tank 31 is configured to accommodate a predetermined amount of fuel (gasoline). A fuel pump 32 is provided in the fuel tank 31, and a suction port 32 a of the pump 32 is set at the lower part of the fuel tank 31. The fuel pump 32 sucks up fuel from a suction port 32 a located under the fuel tank 31 and pressurizes and supplies the sucked up fuel to the fuel pipe 33.

  The fuel pump 32 has a float type fuel sensor 34. The float type fuel sensor 34 detects the remaining amount of fuel based on the float position of the float member that floats on the fuel. The ECU 40 calculates the remaining amount of fuel in the fuel tank 31 based on the detection signal from the float type fuel sensor 34.

  An intake valve 21 and an exhaust valve 22 are respectively provided in the intake port and the exhaust port of the engine 10, and an air / fuel mixture is introduced into the combustion chamber 23 by the opening operation of the intake valve 21, and the exhaust valve 22. By the opening operation, the exhaust gas after combustion is discharged to the exhaust pipe 24.

  A spark plug 25 is attached to each cylinder head of the engine 10 for each cylinder, and a high voltage is applied to the spark plug 25 at a desired ignition timing through an ignition device 26 including an ignition coil. By applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 25, and the air-fuel mixture introduced into the combustion chamber 23 is ignited and used for combustion.

  The cylinder block of the engine 10 has a cooling water temperature sensor 29 mainly for detecting the temperature of the cooling water circulating in the engine 10 and a predetermined value for detecting a crank position (rotation angle), an engine rotation speed, and the like. A crank angle sensor 30 that outputs a crank angle signal having a rectangular shape for each crank angle (for example, in a cycle of 30 ° CA) is attached.

  The exhaust pipe 24 is provided with a catalyst device 27 such as a three-way catalyst for purifying CO, HC, NOx and the like in the exhaust gas. An air-fuel ratio sensor 28 for detecting the fuel ratio is provided.

  As is well known, the ECU 40 is mainly composed of a microcomputer including a CPU, a ROM, a RAM, and the like. In addition to the various sensors described above, the ECU 40 grasps the engine operating state and the driver's request based on various detection signals input from various sensors mounted on the vehicle as needed, and performs various controls in accordance with the control program. Running according to.

  Specifically, the ECU 40 detects the air / fuel ratio based on the detection signal from the air / fuel ratio sensor 28. Based on the detection of the air-fuel ratio, the ECU 40 normally calculates the air-fuel ratio correction coefficient FAF according to the deviation between the target air-fuel ratio and the target air-fuel ratio when the target air-fuel ratio is stoichiometric (theoretical air-fuel ratio). Then, air-fuel ratio feedback control is performed to set the next fuel injection amount by multiplying the base fuel injection amount by the calculated air-fuel ratio correction coefficient FAF. That is, when the air-fuel ratio shifts to the rich side, the ECU 40 decreases the air-fuel ratio correction coefficient FAF so as to keep the air-fuel ratio stoichiometric, and decreases the next fuel injection amount. When the air-fuel ratio shifts to the lean side, the ECU 40 increases the air-fuel ratio correction coefficient FAF so as to keep the air-fuel ratio stoichiometric, and increases the next fuel injection amount.

  Further, the ECU 40 performs various corrections on the basic injection amount as follows to calculate the target fuel injection amount. That is, the basic injection amount is calculated based on the engine speed calculated from the detection value of the crank angle sensor 30 and the engine load. The engine load is calculated from the throttle valve opening calculated from the detection value of the throttle valve opening sensor 15, the intake air amount calculated from the detection value of the air flow meter 13, and the like. Examples of the correction for the basic injection amount include an acceleration increase for improving acceleration responsiveness, an increase after start, an increase in warm air, and the like.

  In addition, a fuel cut is executed to reduce the fuel injection amount to zero during traveling at a reduced speed. As for fuel injection timing, synchronous injection is performed at a timing synchronized with the crank angle during normal traveling, and asynchronous injection is performed when the engine load is large, such as during acceleration traveling, regardless of the crank angle.

  By the way, when the remaining amount of fuel in the fuel tank becomes a predetermined value or less (low remaining amount state) while the vehicle is running, there is a risk that the engine will stop due to lack of gas and become unable to run. . Particularly in a two-wheeled vehicle, the frequency of the user falling into such a gas-out state is higher than that in a four-wheeled vehicle. In order to avoid such a gas shortage, the following mode switching control is executed in the present embodiment.

  That is, when the remaining amount of fuel in the fuel tank 31 is greater than a predetermined value set in advance, engine control is executed in the normal travel mode, and when a low remaining amount state where the remaining amount of fuel becomes a predetermined value or less is entered, When various conditions to be satisfied are satisfied, the engine control is executed by switching to the eco mode (fuel consumption priority mode) that improves the fuel consumption as compared with the normal driving mode.

  Next, such mode switching processing will be described in detail with reference to the flowchart of FIG. The series of processes shown in FIG. 2 is a process repeatedly executed by the microcomputer of the ECU 40 at a predetermined cycle (for example, the calculation cycle performed by the CPU described above) or at a predetermined crank angle, triggered by the ignition switch being turned on. .

  First, in step S10, it is determined whether or not a predetermined time has elapsed since switching from one of the normal travel mode and the eco mode to the other. When it is determined that the predetermined time has not elapsed (S10: NO), it is determined that the predetermined time has elapsed since the series of processes in FIG. In the case (S10: YES), the processing after step S11 is executed. This prevents the driving state (mode state) from becoming unstable due to frequent switching of modes.

  In subsequent step S11, it is determined whether or not the remaining amount of fuel calculated based on the detection signal from the float type fuel sensor 34 is in a low remaining amount state in which the amount is not more than a predetermined value set in advance. When it is determined that it is not in the low remaining amount state (S11: NO), it is switched to the normal running mode in step S18 (mode switching means), and when it is determined that it is in the low remaining amount state (S11: YES). In step S17 (mode switching unit), the mode is switched to the eco mode when the vehicle is in a vehicle traveling state that satisfies all the conditions of the subsequent steps S12 to S16 (running state determination unit).

  Hereinafter, the contents of steps S12 to S16, which are conditions for switching to the eco mode, will be described. In step S12, the completion of the warm-up operation executed after the engine is started is set as a condition for switching to the eco mode. This prohibits switching to the eco mode during the warm-up operation, thereby achieving early completion of the warm-up operation. In other words, priority is given to the early completion of the warm-up operation over the reduction in fuel consumption even in the low remaining amount state. The determination of the completion of the warm-up operation may be, for example, determined as the completion of the warm-up operation when the engine coolant temperature has risen to a predetermined value or more, or a preset time (for example, 10,000 ms) has elapsed after the engine is started. It may be determined that the warm-up operation is complete.

  In steps S13 to S16, switching to the eco mode is prohibited in a high load operation request state in which the driver requests that the engine be operated with a high load of a predetermined value or more. Thus, even when the remaining amount is low, the high load driving request by the driver is given priority over the reduction in fuel consumption. Therefore, the driver's dissatisfaction with the deterioration of drivability due to the eco-mode switching can be avoided at the time of high load driving request.

  Hereinafter, each condition will be specifically described. In step S13, when the throttle valve opening is larger than a preset first opening TH1 (first set value), it is a high load operation request state. And switching to the eco mode is prohibited. In place of the throttle valve opening, it may be considered that the high-load operation request state exists when the accelerator operation amount operated by the driver is larger than a set value.

  In step S14, in order to increase the intake air amount by increasing the opening degree of the throttle valve 14, if the change amount of the throttle valve opening is larger than the preset first opening change amount ΔTH1, Switching to the eco mode is prohibited by assuming that it is in a load operation request state. It should be noted that instead of the throttle valve opening change amount, the high load operation request state may be considered when the accelerator operation change amount is larger than the set value.

  In step S15, when the vehicle is accelerating and the vehicle acceleration ΔV is greater than a preset first acceleration ΔV1, it is considered that the vehicle is in a high load driving request state and switching to the eco mode is prohibited. To do. In step S16, when the vehicle speed V is higher than the first speed V1 set in advance, the high-load driving request state is considered and switching to the eco mode is prohibited.

  When the mode is switched to the eco mode in step S17, the mode state display device 50 (notification unit) for notifying the driver that the control is switched to the eco mode is turned on or blinked. In addition to the display, a warning sound may be emitted as the notification means. In the present embodiment, a travel mode changeover switch 51 that is manually operated by the driver is provided. The operation content of the switch 51 has priority over the mode switching process shown in FIG. 2, and the ECU 40 switches between the normal travel mode and the eco mode based on the operation content of the switch 51.

  When the mode is switched to the eco mode, the engine control content is changed so as to improve the fuel efficiency as compared with the normal driving mode. However, the eco mode according to the present embodiment is divided into a plurality of modes having different degrees of improving the fuel efficiency. ing. Specifically, the level is switched between level 1 where the degree of improvement in fuel efficiency is small and level 2 where the degree of improvement in fuel efficiency is high according to the vehicle running state (level switching conditions will be described in detail later).

  In the eco mode, the engine control content is changed so as to improve the fuel efficiency compared to the normal driving mode. However, the engine control change points in the level 1 eco mode are the prohibition of asynchronous injection and the acceleration increase correction described above. Prohibition of ban or accelerated increase is implemented. Further, in level 2, in addition to the change in level 1, the target air-fuel ratio is changed to the lean side (air-fuel ratio is made lean).

  Here, when the air-fuel ratio is made lean, fuel efficiency can be improved, but as a contradiction, a large output torque cannot be obtained and the engine rotation speed is unstable as in idle operation (combustion is unstable). In the state), the unstable state is promoted. Therefore, as will be described in detail later, the level is switched to level 2 where the degree of improvement in fuel efficiency is large, on condition that a large output torque is not required and that the engine speed is stable.

  Hereinafter, the process of switching the level of the eco mode will be described in detail with reference to the flowchart of FIG. The series of processes shown in FIG. 3 is performed by the microcomputer of the ECU 40 at a predetermined cycle (for example, the calculation cycle performed by the CPU described above) or at a predetermined crank angle during the period of switching to the eco mode by the process of step S17 of FIG. This process is repeatedly executed.

  First, in step S20, it is determined whether or not a predetermined time has elapsed since switching from one of level 1 and level 2 to the other. If it is determined that the predetermined time has not elapsed (S20: NO), it is determined that the predetermined time has elapsed since the series of processes in FIG. In the case (S20: YES), the processing after step S21 is executed. This prevents the eco-level from switching frequently and the running state from becoming unstable.

  Then, when the vehicle is in a vehicle running state that satisfies all the conditions of subsequent steps S21 to S27 (running state determination means), the level of the eco mode is switched to level 2 in step S28, and one condition of steps S21 to S27 is set. However, if not satisfied, the level of the eco mode is switched to level 1 in step S29. Note that the mode state display device 50 (notification unit) may display whether the eco mode is being executed at level 1 or level 2 in the eco mode. Further, the level 1 and the level 2 may be switched based on the operation content of the travel mode changeover switch 51.

  Hereinafter, the contents of steps S21 to S27, which are conditions for switching to the eco mode, will be described. In step S21, the condition for switching to level 2 is that the engine is not in an idling state where the accelerator operation amount is zero and the vehicle speed is zero, and the level is switched to level 2 during idling where the engine speed is unstable. Is prohibited. During such idling, there is a risk of promoting the unstable state described above. In this case, the engine speed is switched over to level 1 to give priority to the stability of the engine speed over the reduction of fuel consumption.

  In step S22, the condition for switching to level 2 is that the vehicle speed is at a medium to high speed that is equal to or higher than a predetermined value and the vehicle is in a stable running (steady running) state without acceleration and deceleration. Switch. If the vehicle is not in such a steady running state, the above-described unstable state may be promoted. In this case, the level is switched to level 1 to prioritize the stability of the engine speed over the reduction in fuel consumption.

  In step S23, the switching condition to level 2 is that the fluctuation occurring during one combustion cycle of the engine rotation speed is not greater than the predetermined fluctuation. If the fluctuation is large, switching to level 1 is performed. In such a large fluctuation state, the above-described unstable state may be promoted. In this case, the level is switched to level 1, and the stability of the engine speed is prioritized over the reduction in fuel consumption.

  In steps S24 to S27, switching to level 2 is prohibited in a high-load operation request state where the driver requests that the engine be operated with a high load equal to or greater than a predetermined value. As a result, fuel efficiency is reduced while satisfying the high load driving request by the driver to some extent. Therefore, the driver's dissatisfaction with the deterioration of drivability due to switching to level 2 can be suppressed at the time of a high load driving request.

  Hereinafter, each condition will be described in detail. In step S24, when the throttle valve opening is larger than a preset second opening TH2 (second set value), it is a high load operation request state. And switching to level 2 is prohibited. The value of the second opening TH2 is set to a value smaller than the value of the first opening TH1 according to step S13 in FIG. In place of the throttle valve opening, it may be considered that the high-load operation request state exists when the accelerator operation amount operated by the driver is larger than a set value.

  In step S25, when increasing the amount of intake air by increasing the opening of the throttle valve 14, if the amount of change in the throttle valve opening is greater than a preset second opening change amount ΔTH2, Switching to level 2 is prohibited by assuming that it is in a load operation request state. The value of the second opening change amount ΔTH2 is set to a value smaller than the value of the first opening change amount ΔTH1 according to step S14 in FIG. It should be noted that instead of the throttle valve opening change amount, the high load operation request state may be considered when the accelerator operation change amount is larger than the set value.

  In step S26, when the vehicle is accelerating and the acceleration ΔV of the vehicle is larger than the preset second acceleration ΔV2, it is regarded as a high-load driving request state and switching to level 2 is prohibited. To do. The value of the second acceleration ΔV2 is set to a value smaller than the value of the first acceleration ΔV1 according to step S15 in FIG. In step S27, when the vehicle speed V is higher than the preset second speed V2, it is considered that the vehicle is in a high load operation request state, and switching to the eco mode is prohibited. The value of the second speed V2 is set to a value smaller than the value of the first speed V1 according to step S16 in FIG.

  As described above, according to the present embodiment, when the fuel in the fuel tank 31 is in the low remaining amount state, the vehicle running state is not changed to the eco mode only in such a low remaining amount state, and the vehicle traveling state is changed from step S12 to step S12. When the condition of S16 is satisfied, the mode is switched to the eco mode. These conditions are set so that the driver does not have a strong dissatisfaction with the deterioration of drivability or the instability of the engine speed, so that the drivability is improved and the stability of the engine speed is improved. Can do.

  Furthermore, in the present embodiment, when the eco mode is executed, the level is switched between level 1 where the degree of improvement in fuel efficiency is small and level 2 where the degree of improvement in fuel efficiency is high. Is switched. Therefore, it is possible to finely set the fuel efficiency improvement degree according to the vehicle running state.

  Further, in this embodiment, when switching from the normal travel mode to the eco mode, the drivability is drastically lowered if the control is performed so that the switching to the level 2 is prohibited and only the switching to the level 1 is permitted. Since this can be suppressed, the uncomfortable feeling given to the driver can be reduced, which is preferable. Similarly, if the switching from the level 2 to the normal driving mode is prohibited and only the switching from the level 2 to the level 1 is permitted, it is possible to suppress drastic improvement in the drivability. The feeling of strangeness given to the driver can be reduced, which is preferable.

(Other embodiments)
The above embodiments may be implemented with the following modifications. Further, the present invention is not limited to the description of the above embodiment, and the characteristic structures of the embodiments may be arbitrarily combined.

  -The following control may be performed as an engine control change point in the eco mode. That is, in the eco mode, acceleration annealing that slows down the response of the throttle valve opening may be performed. Further, when the acceleration restriction is performed so as not to exceed the predetermined upper limit value, the upper limit value may be lowered. Further, when the vehicle speed restriction is performed so as not to exceed the predetermined upper limit value, the upper limit value may be lowered. Further, when setting the gear ratio of the reduction gear that reduces the rotational speed of the crankshaft, the setting may be changed so as to shift to the low speed side.

  -When the eco-mode is implemented, if the driving state at level 1 continues for a predetermined time or longer, even if the level 2 condition is not satisfied, the mode is automatically switched to level 2 and the fuel efficiency improvement level is high. You may be prompted to drive. In addition, when it switches to level 2 automatically in this way, what is necessary is just to make it return to level 1 on condition that the driver | operator operated so that the amount of throttle operation may be enlarged.

  The engine to which the present invention is applied is not limited to a multi-cylinder engine, and may be a single-cylinder engine. Moreover, you may apply not only to a two-wheel vehicle but to a four-wheel vehicle.

It is a lineblock diagram showing the whole engine control system outline in one embodiment of the present invention. It is a flowchart which shows the content of the mode switching process which ECU of FIG. 1 performs. It is a flowchart which shows the content of the level switching process of the eco mode which ECU of FIG. 1 performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine (internal combustion engine), 31 ... Fuel tank, S11 ... Remaining amount determination means, S12, S13, S14, S15, S16 ... Travel state determination means, S17, S18 ... Mode switching means.

Claims (16)

Applied to a vehicle that travels using combustion energy obtained by burning fuel in a fuel tank in a combustion chamber of an internal combustion engine as a drive source;
Mode switching means for switching the operating state of the internal combustion engine between a normal travel mode and a fuel consumption priority mode that improves the fuel consumption rate compared to the normal travel mode;
A remaining amount determining means for determining whether or not the remaining amount of fuel in the fuel tank is in a low remaining amount state where the fuel remaining amount is not more than a predetermined value set in advance;
Traveling state determination means for determining whether the traveling state of the vehicle is a preset fuel consumption priority permitted traveling state;
With
The internal combustion engine control apparatus according to claim 1, wherein the mode switching means switches to the fuel efficiency priority mode when it is determined that the low remaining amount state and the fuel efficiency priority permitted travel state are established.   The driving state determination means determines that the fuel consumption priority permission driving state is not satisfied for a high load driving request state requested by a driver to operate the internal combustion engine with a high load of a predetermined value or more. The internal combustion engine control device according to claim 1.   The internal combustion engine control device according to claim 2, wherein the high load operation request state is an acceleration traveling state.   The internal combustion engine control device according to claim 2 or 3, wherein the high-load operation request state is a high-speed running state in which the vehicle speed is a predetermined value or more.   The high load operation request state is a state in which the amount of change in the opening is larger than a set value when the opening of the throttle valve is increased to increase the intake amount into the combustion chamber. Item 5. The internal combustion engine control device according to any one of Items 2 to 4.   The high load operation request state is a state in which an opening of a throttle valve that adjusts an intake air amount into the combustion chamber is larger than a first set value. The internal combustion engine control apparatus described.   The traveling state determination means determines that the fuel consumption priority permission traveling state is not satisfied for a state in which an opening of a throttle valve that adjusts an intake air amount to the combustion chamber is smaller than a second set value. The internal combustion engine control device according to any one of claims 1 to 6.   8. The internal combustion engine control device according to claim 7, wherein the traveling state determination means determines that the fuel consumption priority permission traveling state is not satisfied with respect to an idle operation state.   The travel state determination means determines that the fuel consumption priority permit travel state is in a state where the warm-up operation of the internal combustion engine has been completed. The internal combustion engine control device.   10. The traveling state determining means determines that the fuel consumption priority permission traveling state is not satisfied for a state where the rotational speed fluctuation of the output shaft of the internal combustion engine is larger than a predetermined fluctuation. An internal combustion engine control device according to claim 1. The fuel efficiency priority mode is divided into a plurality of modes with different degrees of improving the fuel consumption rate,
The fuel consumption priority permission traveling state is a state that satisfies at least one of a plurality of traveling conditions,
The said mode switching means switches to the mode of a different level among the said fuel consumption priority modes according to which of these driving conditions is satisfy | filled, The any one of Claims 1-10 characterized by the above-mentioned. The internal combustion engine control device. In the normal running mode, in addition to synchronous injection that performs fuel injection in synchronization with the crank angle of the internal combustion engine, asynchronous injection that performs fuel injection at the driver's acceleration request timing can be executed.
The internal combustion engine control device according to any one of claims 1 to 11, wherein the asynchronous injection is prohibited in the fuel consumption priority mode. In the normal traveling mode, acceleration increase correction for increasing the fuel injection amount at the driver's acceleration request timing can be executed,
The internal combustion engine control device according to any one of claims 1 to 12, wherein the increase correction is prohibited in the fuel consumption priority mode.   The internal combustion engine control device according to any one of claims 1 to 13, wherein in the fuel consumption priority mode, the air-fuel ratio is made leaner than in the normal travel mode.   The internal combustion engine according to any one of claims 1 to 14, further comprising notification means for notifying a driver of the fact that the internal combustion engine is being operated in the state of switching to the fuel efficiency priority mode. Engine control device. An internal combustion engine control device according to any one of claims 1 to 15,
At least one of remaining amount detecting means for detecting the remaining amount of fuel in the fuel tank, and traveling state detecting means for detecting the traveling state of the vehicle;
An internal combustion engine control system comprising:

Images