JP2021032102A - vehicle - Google Patents

Abstract

To suppress the occurrence of the frequent hunting of a load rate and a rotation number of an engine at accelerator-off.SOLUTION: At accelerator-off, when a first condition in which a state where a rotation number change rate being a change amount of an engine rotation number per unit time is equal to a prescribed change rate or higher is continued for a first period of time is established, a load rate of an engine is lowered compared with the case before the establishment of the first condition. After that, when a second condition including at least either of a condition in which a state where an absolute value of a speed ratio change rate being a change amount of a speed ratio between the engine rotation number and a vehicle speed per unit time is equal to a prescribed value or lower is continued for a second period of time, and a condition in which a state where the speed ratio is included in any of gear change ratio ranges corresponding to gear change stages of a manual transmission is continued for a third period of time is established, a control device increases the load rate of the engine by mild change processing.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle, and more particularly to a vehicle including an engine, a manual transmission and a clutch.

Conventionally, as a vehicle of this type, a vehicle including an engine, a manual transmission connected to a drive wheel, and a clutch provided between the engine and the manual transmission has been proposed (for example, Patent Documents). 1). In this vehicle, if the relationship between the current vehicle speed and the current engine speed deviates from the range of gear ratios that the transmission can achieve, or the amount of change in the current vehicle speed per unit time and the current engine. When the amount of change in the number of revolutions per unit time does not match, it is determined that the engine and the drive wheels are in neutral, which is disconnected by the clutch or the manual transmission. In this way, it is possible to detect that the engine and the drive wheels have been separated by the driver.

Japanese Unexamined Patent Publication No. 2018-168819

In the vehicles described above, in recent years, in order to improve fuel efficiency (energy efficiency), the friction of the engine has been reduced. Therefore, the engine speed may increase when the accelerator is off and in neutral. In this case, it is considered to reduce the load factor of the engine to suppress a further increase in the engine speed. After that, it is possible that the neutrality was resolved by using the amount of change in the speed ratio between the engine speed and the vehicle speed per unit time (the engine and the drive wheels were connected via a clutch or a manual transmission). When it is determined that there is, if the load factor of the engine is suddenly increased, the engine speed becomes steep when the neutral is actually continued (the engine and the drive wheels are not connected). There is a possibility that the load factor of the engine will be reduced again by determining that the engine speed has risen sharply in neutral and the engine speed has risen sharply. That is, frequent hunting of the engine load factor and the number of revolutions may occur.

The main object of the vehicle of the present invention is to suppress frequent hunting of the engine load factor and the number of revolutions when the accelerator is off.

The vehicle of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The vehicle of the present invention
With the engine
A manual transmission connected to the drive wheels,
A clutch provided between the engine and the manual transmission,
The control device that controls the engine and
It is a vehicle equipped with
The control device is
When the accelerator is off
When the first condition is satisfied in which the state in which the rotation speed change rate, which is the amount of change in the rotation speed of the engine per unit time, continues to be equal to or higher than the predetermined change rate for the first time, before the first condition is satisfied. In comparison, the load factor of the engine is lowered.
After that, the condition that the absolute value of the speed ratio change rate, which is the amount of change in the speed ratio between the engine speed and the vehicle speed per unit time, is equal to or less than a predetermined value continues for the second time, and the speed. A condition in which the ratio is included in any of the gear ratio ranges corresponding to the gears of the manual transmission continues for the third time, and a second condition including at least one of them. When it is established, the load ratio of the engine is increased by the slow change process.
The gist is that.

In the vehicle of the present invention, when the accelerator is off, the state in which the rotation speed change rate, which is the amount of change in the engine rotation speed per unit time, is equal to or higher than the predetermined change rate continues for the first hour. When the first condition is satisfied, the load factor of the engine is lowered as compared with before the first condition is satisfied. The "first condition" is a condition in which it can be determined that the engine speed is increasing in neutral when the engine and the drive wheels are disconnected by a clutch or a manual transmission. When the first condition is satisfied, the load factor of the engine is reduced, so that a further increase in the engine speed can be suppressed. After that, the control device continued to be in a state where the absolute value of the speed ratio change rate, which is the amount of change in the speed ratio between the engine speed and the vehicle speed per unit time, was equal to or less than a predetermined value for the second time. A condition including at least one of a condition and a condition in which the speed ratio is included in any of the gear ratio ranges corresponding to each gear of the manual transmission for a third time. When the two conditions are satisfied, the load ratio of the engine is increased by the slow change process. The "second condition" is a condition in which it can be determined that the neutral may have been eliminated (the engine and the drive wheels are connected via a clutch or a manual transmission). When the second condition is satisfied, the load factor of the engine is increased by the slow change process, and the load factor of the engine is sharply increased. Compared to the case where the load factor is actually maintained in neutral (engine and drive). When the second condition is only temporarily satisfied without being connected to the wheel), the first condition is suppressed from being re-established in a very short time, and the load factor of the engine is reduced in a very short time. It is possible to suppress the decrease again. That is, frequent hunting of the engine load factor and the number of revolutions can be suppressed.

In such a vehicle of the present invention, when the accelerator is off, when the first condition is satisfied, when the rotation speed of the engine is equal to or higher than a predetermined rotation speed, the load factor of the engine is determined by the first condition. The second load factor is smaller than the first load factor before the establishment, and when the rotation speed of the engine is less than the predetermined rotation speed, the load factor of the engine is smaller than the first load factor and the second load. When the third load factor is set to be larger than the rate and the second condition is satisfied, the load factor of the engine is increased by the slow change process from the second load factor or the third load factor toward the first load factor. It may be made to. Therefore, after the first condition is satisfied and before the second condition is satisfied, when the engine speed is less than the predetermined speed, the engine load factor is set to the third load factor. Regardless, it is possible to suppress the occurrence of engine stall as compared with the case where the load factor of the engine is set to the second load factor.

In the vehicle of the present invention, when the accelerator is off, if the second condition is satisfied after the first condition is satisfied, the control device determines that the first condition is satisfied and the second condition is satisfied. When the second condition is not satisfied and the first condition is re-established while the load factor of the engine is being increased by the slow change process, the load factor of the engine is re-established. It may be lowered. In this way, fluctuations in the engine load factor and the number of revolutions can be further suppressed.

In the vehicle of the present invention, when the accelerator is off, when the first condition is satisfied, the fuel cut permitted rotation speed of the engine is increased as compared with before the first condition is satisfied. May be good. In this way, it is possible to suppress the fuel cut of the engine.

In this case, when the accelerator is off, the control device holds the fuel cut permitted rotation speed when the fourth time has not elapsed since the satisfaction of the first condition is resolved, and the first condition is satisfied. When the fourth time elapses after the establishment is resolved, the fuel cut permitted rotation speed may be lowered. In this way, the fuel cut of the engine is suppressed immediately after the first condition is satisfied, as compared with the case where the fuel cut permitted rotation speed is lowered immediately when the first condition is satisfied. be able to. In this case, if the second condition is satisfied after the first condition is satisfied, the control device may determine that the first condition is satisfied.

It is a block diagram which shows the outline of the structure of the automobile 20 as one Example of this invention. It is a block diagram which shows the outline of the structure of the engine 22. It is a flowchart which shows an example of the lower limit load factor setting routine executed by an electronic control unit 50. It is a flowchart which shows an example of the fuel cut permission rotation speed setting routine executed by an electronic control unit 50. When the accelerator is off, the lower limit load factor KLmin of the engine 22, load factor KL, rotation speed Ne, fuel cut return rotation speed Nfcr, fuel cut permitted rotation speed Nfcp, speed ratio change rate ΔNV, vehicle speed V, presence or absence of fuel cut , Is an explanatory diagram showing an example of the state of the flags F1 and F2. It is a flowchart which shows an example of the lower limit load factor setting routine of a modification.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an automobile 20 as an embodiment of the present invention. FIG. 2 is a configuration diagram showing an outline of the configuration of the engine 22. The automobile 20 of the embodiment is configured as a manual transmission vehicle (MT vehicle), and includes an engine 22, a manual transmission 30, a clutch 40, and an electronic control unit 50, as shown in FIG.

The engine 22 is configured as an internal combustion engine that outputs power using gasoline, light oil, or the like as fuel. As shown in FIG. 2, the engine 22 sucks the air cleaned by the air cleaner 122 into the intake pipe 123 and passes it through the throttle valve 124, and at the same time, the fuel injection valve 126 is downstream of the throttle valve 124 of the intake pipe 123. Fuel is injected from and the air and fuel are mixed. Then, the engine 22 sucks this air-fuel mixture into the combustion chamber 129 via the intake valve 128, explodes and burns the sucked air-fuel mixture by electric sparks from the spark plug 130, and reciprocates the piston 132 pushed down by the energy. Is converted into the rotational movement of the crankshaft 23. The exhaust gas discharged from the combustion chamber 129 to the exhaust pipe 133 via the exhaust valve 131 is discharged to the outside air via the purification device 134. The purification device 134 has a purification catalyst (three-way catalyst) that purifies harmful components of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in the exhaust gas. The engine 22 is operated and controlled by the electronic control unit 50.

The manual transmission 30 is configured as a 6-speed transmission, and as shown in FIG. 1, the input shaft is connected to the crankshaft 23 of the engine 22 via the clutch 40, and the output shaft is the drive wheel DW. It is connected to the drive shaft DS connected via the differential gear DG. The manual transmission 30 forms each of the first to sixth forward gears and disconnects the input shaft and the output shaft according to the operation of the shift lever 32 by the driver.

The clutch 40 is provided between the engine 22 and the input shaft of the manual transmission 30, and is in an engaged state when the clutch pedal 42 is not depressed by the driver, and slips when the clutch pedal 42 is depressed. It becomes engaged or released.

The electronic control unit 50 is configured as a microprocessor centered on a CPU. In addition to the CPU, the electronic control unit 50 includes a ROM for storing processing programs, a RAM for temporarily storing data, and an input / output port. As shown in FIGS. 1 and 2, signals from various sensors are input to the electronic control unit 50 from input ports.

As the signal input to the electronic control unit 50, a signal necessary for operating and controlling the engine 22 can be mentioned. Examples of this signal include a crank angle θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and a cooling water temperature Tw from the water temperature sensor 142 that detects the temperature of the cooling water of the engine 22. be able to. Cam angles θci and θco from the cam position sensor 144 that detect the rotational position of the intake camshaft that opens and closes the intake valve 128 and the rotational position of the exhaust camshaft that opens and closes the exhaust valve 131 can also be mentioned. Throttle opening TH from the throttle position sensor 124a that detects the position of the throttle valve 124, intake air amount Qa from the air flow meter 148 attached to the intake pipe 123, and intake from the temperature sensor 149 attached to the intake pipe 123. The temperature Ta can also be mentioned. The air-fuel ratio AF from the air-fuel ratio sensor 135a attached to the exhaust pipe 133 and the oxygen signal O2 from the oxygen sensor 135b attached to the exhaust pipe 133 can also be mentioned.

Further, as the signals input to the electronic control unit 50, the ignition signal from the ignition switch 51, the accelerator opening degree Acc from the accelerator pedal position sensor 54 that detects the depression amount of the accelerator pedal 53, and the depression amount of the brake pedal 55 are used. The brake pedal position BP from the detected brake pedal position sensor 56 and the vehicle speed V from the vehicle speed sensor 58 can also be mentioned.

From the electronic control unit 50, various control signals for controlling the operation of the engine 22 and the like are output via the output port. Examples of the signal output from the electronic control unit 50 include a control signal to the throttle motor 124b for adjusting the position of the throttle valve 124, a control signal to the fuel injection valve 126, and a control signal to the spark plug 130. ..

The electronic control unit 50 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140, or changes the rotation speed as the amount of change in the rotation speed Ne of the engine 22 per unit time. The rate ΔNe is calculated. Further, the electronic control unit 50 is actually sucked in one cycle based on the load factor (the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 148 and the rotation speed Ne of the engine 22. The ratio of the volume of air) KL is calculated. Further, the electronic control unit 50 calculates the speed ratio NV by dividing the rotation speed Ne of the engine 22 by the vehicle speed V, or calculates the speed ratio change rate ΔNV as the amount of change in the speed ratio NV per unit time. doing.

In the automobile 20 of the embodiment configured in this way, the electronic control unit 50 first sets the required load factor KLtag required for the engine 22 based on the accelerator opening degree Acc when the accelerator is on, and also sets the required load factor KLtag of the engine 22. A predetermined value KL0 is set in the lower limit load factor KLmin. Here, the predetermined value KL0 is defined as the load factor KL required for idle operation of the engine 22 at a relatively low rotation speed (for example, 1000 rpm, 1100 rpm, 1200 rpm, etc.), and is, for example, 14%, 15%, 16 % Etc. are used. Subsequently, the electronic control unit 50 limits the required load factor KLtag of the engine 22 by the lower limit load factor KLmin (lower limit guard) to set the target load factor KL *, and the engine 22 operates based on the target load factor KL *. The operation control of the engine 22 (intake air amount control, fuel injection control, ignition control, etc.) is performed so as to be performed.

Further, when the accelerator is off, the electronic control unit 50 sets the lower limit load factor KLmin of the engine 22 to the target load factor KL *, and operates the engine 22 so that the engine 22 is operated based on the target load factor KL *. Control. Here, a method of setting the lower limit load factor KLmin of the engine 22 when the accelerator is off will be described later.

Further, when the accelerator is off, the electronic control unit 50 executes the fuel cut of the engine 22 (fuel injection) when the rotation speed Ne of the engine 22 reaches the fuel cut permitted rotation speed Nfcp or more during the operation of the engine 22. When the engine 22 speed Ne reaches a fuel cut return speed Nfcr or less lower than the fuel cut permitted speed Nfcp during the fuel cut of the engine 22, the fuel cut of the engine 22 is terminated (fuel injection is performed). resume). Here, the method of setting the fuel cut permitted rotation speed Nfcp will be described later. As the fuel cut return rotation speed Nfcr, for example, 850 rpm, 900 rpm, 950 rpm, or the like is used.

Next, the operation of the automobile 20 of the embodiment configured in this way, particularly the operation when the accelerator is off will be described. FIG. 3 is a flowchart showing an example of the lower limit load factor setting routine executed by the electronic control unit 50. FIG. 4 is a flowchart showing an example of a fuel cut permitted rotation speed setting routine executed by the electronic control unit 50. Each of these routines is repeated when the accelerator is off. Hereinafter, the lower limit load factor setting routine of FIG. 3 and the fuel cut permitted rotation speed setting routine of FIG. 4 will be described in this order.

When the lower limit load factor setting routine of FIG. 3 is executed, the electronic control unit 50 first inputs the rotation speed Ne and the rotation speed change rate ΔNe of the engine 22 calculated in parallel with this routine (step S100). ), The input engine speed Ne is compared with the threshold value Neref1 (step S110). Then, when the rotation speed Ne of the engine 22 is less than the threshold value Nerf1, the electronic control unit 50 sets a predetermined value KL1 in the lower limit load factor KLmin of the engine 22 (step S130), and ends this routine.

Here, the threshold value Nerf1 is a threshold value used for determining whether or not to allow the lower limit load factor KLmin (target load factor KL *) of the engine 22 to be lower than the predetermined value KL1, and is, for example, 790 rpm. , 800 pm, 810 rpm and the like are used. As the predetermined value KL1, for example, the same value as the above-mentioned predetermined value KL0 is used.

When the rotation speed Ne of the engine 22 is equal to or higher than the threshold value Nerf1 in step S110, the electronic control unit 50 determines that it is allowed to lower the lower limit load factor KLmin of the engine 22 below the predetermined value KL1, and changes the rotation speed of the engine 22. It is determined whether or not the rotation increase condition is satisfied by using the rate ΔNe (step S120).

Here, as the rotation increase condition, a condition is used in which the state in which the rotation speed change rate ΔNe of the engine 22 is equal to or higher than the threshold value ΔNeef continues for a predetermined time T1. The threshold value ΔNeef is a threshold value used for determining whether or not the rotation speed Ne of the engine 22 is increasing, and for example, 0.010, 0.015, 0.020 rpm / msec or the like is used. The predetermined time T1 is a time required to determine that the rotation speed Ne of the engine 22 is increasing, and for example, 0.2 sec, 0.3 sec, 0.4 sec, or the like is used.

When the condition for increasing the rotation is satisfied when the accelerator is off, the rotation of the engine 22 is increased in neutral (hereinafter referred to as "neutral rotation increase") in which the engine 22 and the drive wheel DW are disconnected by the clutch 40 or the manual transmission 30. It is assumed that it was. The process of step S120 is a process of determining whether or not a neutral rotation increase has occurred in consideration of this.

When the rotation increase condition is not satisfied in step S120, the electronic control unit 50 determines that the neutral rotation increase has not occurred, and sets a predetermined value KL1 in the lower limit load factor KLmin of the engine 22 (step S130). End this routine.

When the rotation increase condition is satisfied in step S120, the electronic control unit 50 determines that the neutral rotation increase has occurred, and sets the value 1 in the flag F1 (step S140). Here, the flag F1 is a flag indicating whether or not a neutral rotation increase has occurred, and a value 0 as an initial value is set when the operation of the engine 22 is started, and a value 1 is set when the rotation increase condition is satisfied. Is set, and then the value 0 is set (reset) by the processing described later in this routine.

Subsequently, the electronic control unit 50 inputs the rotation speed Ne of the engine 22 (step S150), and compares the input rotation speed Ne of the engine 22 with the threshold value Neef2 smaller than the threshold value Nerf1 described above (step S160). Then, when the rotation speed Ne of the engine 22 is equal to or higher than the threshold value Neef2, the electronic control unit 50 sets the lower limit load factor KLmin of the engine 22 to a predetermined value KL2 smaller than the predetermined value KL1 (step S170).

Here, as the predetermined value KL2, for example, 8%, 9%, 10%, or the like is used. In this way, by setting the predetermined value KL2 in the lower limit load factor KLmin of the engine 22, the rotation speed Ne of the engine 22 is further increased as compared with the case where the predetermined value KL1 is set in the lower limit load factor KLmin of the engine 22. The rise can be suppressed. Further, the threshold value Neref2 determines whether or not there is a concern that engine stall may occur when the engine 22 is operated by setting a predetermined value KL2 to the lower limit load factor KLmin (target load factor KL *) of the engine 22. For example, 740 rpm, 750 rpm, 760 rpm, and the like are used.

When the rotation speed Ne of the engine 22 is less than the threshold value Nerf2 in step S160, the electronic control unit 50 sets a predetermined value KL3 smaller than the predetermined value KL1 and larger than the predetermined value KL2 in the lower limit load factor KLmin of the engine 22 (. Step S180). Here, as the predetermined value KL3, for example, 11%, 12%, 13% and the like are used. In this way, by setting the predetermined value KL3 in the lower limit load factor KLmin of the engine 22, the further decrease in the rotation speed Ne of the engine 22 is suppressed as compared with the case where the predetermined value KL2 is set in the lower limit load factor KLmin. However, it is possible to suppress the occurrence of engine stall.

When the lower limit load factor KLmin of the engine 22 is set in step S170 or step S180, the electronic control unit 50 inputs the speed ratio change rate ΔNV calculated in parallel with this routine (step S190), and the speed ratio change rate ΔNV. Is used to determine whether or not the rate ratio change rate condition is satisfied (step S200).

Here, as the rate ratio change rate condition, a condition in which the absolute value of the rate ratio change rate ΔNV is equal to or less than the threshold value ΔNVref is used for a predetermined time T2. The threshold value ΔNVref is a threshold value used to determine whether or not the absolute value of the rate ratio change rate ΔNV is relatively small (the speed ratio NV is substantially stable), and is, for example, 5 rpm / (km / h). , 7 rpm / (km / h), 10 rpm / (km / h), and the like are used. The predetermined time T2 is the time required to determine that the absolute value of the rate ratio change rate ΔNV has become relatively small, and for example, 0.4 sec, 0.5 sec, 0.6 sec, or the like is used.

When the speed ratio change rate condition is satisfied after the neutral rotation increase occurs, the neutral may be canceled, that is, the connection between the engine 22 and the drive wheel DW via the clutch 40 or the manual transmission 30 (hereinafter, referred to as “)”. It is assumed that (referred to as "drive system connection") may have been made. The process of step S200 is a process of determining whether or not a drive system connection may have been made in consideration of this. Further, in the embodiment, if it is determined that the drive system may have been connected, it is determined that the condition for increasing the rotation has been eliminated (the neutral rotation increase has been eliminated).

When the speed ratio change rate condition is not satisfied in step S200, the electronic control unit 50 determines that the drive system is not connected, and returns to step S150. When the speed ratio change rate condition is satisfied in step S200 while the processes of steps S150 to S200 are being repeatedly executed in this way, the electronic control unit 50 determines that the drive system connection may have been made, and sets a flag. A value 1 is set in F2 (step S210), and it is determined that the satisfaction of the rotation increase condition is resolved (neutral rotation increase is resolved), and a value 0 is set in the flag F1 (step S220). Here, the flag F2 is a flag indicating whether or not the drive system connection may have been made, and a value 0 as an initial value is set when the operation of the engine 22 is started, and the speed ratio change rate. The value 1 is set when the condition is satisfied, and then the value 0 is set (reset) when the absolute value of the velocity ratio change rate ΔNV becomes larger than the threshold value ΔNVref.

Subsequently, as shown in the equation (1), the electronic control unit 50 limits (upper limit guard) the value obtained by adding the rate value α to the lower limit load factor (previous KLmin) of the previous engine 22 with a predetermined value KL1. The lower limit load factor KLmin of the new engine 22 is set (step S230), and the set lower limit load factor KLmin of the engine 22 is compared with the predetermined value KL1 (step S240). Then, when the lower limit load factor KLmin of the engine 22 is smaller than the predetermined value KL1, the process returns to step S230.

KLmin = min (previous KLmin + α, KL1) (1)

By repeatedly executing the processes of steps S230 and S240 in this way, the lower limit load factor KLmin of the engine 22 is gradually increased from the predetermined value KL2 or the predetermined value KL3 toward the predetermined value KL1 by rate processing. Then, when the lower limit load factor KLmin of the engine 22 becomes equal to the predetermined value KL1 in step S240, this routine ends.

As described above, in the embodiment, when there is a possibility that the drive system is connected, the lower limit load factor KLmin of the engine 22 is gradually increased by rate processing from the predetermined value KL2 or the predetermined value KL3 toward the predetermined value KL1. Let me. As a result, compared to the case where the lower limit load factor KLmin of the engine 22 is immediately switched to the predetermined value KL1 (the value is sharply increased to the predetermined value K1), the neutral state is actually continued (engine 22 and drive wheel DW). The lower limit load factor KLmin of the engine 22 is suppressed by suppressing the re-establishment of the rotation increase condition in a very short time when the speed ratio change rate condition is only temporarily satisfied without being connected to. It is possible to suppress the re-decrease to the predetermined value KL2 or the predetermined value KL3 in a very short time. That is, it is possible to suppress frequent hunting of the lower limit load factor KLmin (target load factor KL *) of the engine 22, and thus the load factor KL and the rotation speed Ne.

Next, the fuel cut permitted rotation speed setting routine of FIG. 4 will be described. When this routine is executed, the electronic control unit 50 first inputs the flag F1 (step S300), examines the value of the input flag F1 (step S310), and when the flag F1 has a value of 0, the flag The value of F3 is also examined (step S320). Here, the flag F3 is a flag indicating whether or not there is a history of an increase in neutral rotation, and a value 0 as an initial value is set when the operation of the engine 22 is started, and then the value 0 as an initial value is set, which will be described later in this routine. The value 1 or the value 0 is set by the process of.

When the values F1 and F3 are both 0 in steps S310 and S320, the electronic control unit 50 determines that the neutral rotation speed increase has not occurred and has no history of occurrence, and sets a predetermined value ΔNfc1 to the rotation speed hiss ΔNfc. Set (step S360), add the set rotation speed hiss ΔNfc to the above-mentioned fuel cut return rotation speed Nfcr, set the rotation speed (Nfcr + ΔNfc1) to the fuel cut permitted rotation speed Nfcp (step S400), and end this routine. To do. Here, as the predetermined value ΔNfc1, for example, 250 rpm, 300 rpm, 350 rpm, or the like is used.

When the flag F1 is a value 1 in step S310, the electronic control unit 50 determines that a neutral rotation increase has occurred, sets the value 1 in the flag F3 (step S370), and sets the value 0 in the counter C (step S380). ). Here, the counter C means the time from when the flag F1 changes from the value 1 to the value 0.

Subsequently, the electronic control unit 50 sets a predetermined value ΔNfc2 larger than a predetermined value ΔNfc1 in the rotation speed hiss ΔNfc (step S390), and adds the set rotation speed hiss ΔNfc to the fuel cut return rotation speed Nfcr (rotation speed (step S390). Nfcr + ΔNfc2) is set to the fuel cut permitted rotation speed Nfcp (step S400), and this routine is terminated. Here, as the predetermined value ΔNfc2, for example, 550 rpm, 600 rpm, 650 rpm, or the like is used. By such processing, the rotation speed Ne of the engine 22 is suppressed from reaching the fuel cut permission rotation speed Nfcp or more as compared with the case where the rotation speed (Nfcr + ΔNfc1) is set to the fuel cut permission rotation speed Nfcp of the engine 22, and the engine It is possible to suppress the fuel cut of 22.

When the flag F1 has a value of 0 in step S310 and the flag F3 has a value of 1 in step S320, the electronic control unit 50 determines that the problem has been resolved after the neutral rotation rise has occurred, and increments and updates the counter C by the value 1. (Step S330), and the updated counter C is compared with the threshold value Clef (step S340). Here, the threshold value Clef is a threshold value used to determine whether or not a certain amount of time has elapsed since it is determined that the increase in neutral rotation has been resolved (after the flag F1 has changed from a value of 1 to a value of 0). Yes, for example, values corresponding to 1.5 sec, 2.0 sec, 2.5 sec, and the like are used.

When the counter C is less than the threshold value Clef in step S340, the electronic control unit 50 determines that a certain amount of time has not elapsed since it is determined that the neutral rotation increase has been eliminated. Then, a predetermined value ΔNfc2 is set in the rotation speed hiss ΔNfc (step S390), and the rotation speed (Nfcr + ΔNfc2) obtained by adding the set rotation speed hiss ΔNfc to the fuel cut return rotation speed Nfcr is set in the fuel cut permitted rotation speed Nfcp. (Step S400), this routine is terminated.

When the counter C is equal to or higher than the threshold value Clef in step S340, the electronic control unit 50 determines that a certain amount of time has elapsed since it is determined that the increase in neutral rotation has been eliminated, and sets the value 0 in the flag F3 (step S350). ). Then, a predetermined value ΔNfc1 is set in the rotation speed hiss ΔNfc (step S360), and the rotation speed (Nfcr + ΔNfc2) obtained by adding the set rotation speed hiss ΔNfc to the fuel cut return rotation speed Nfcr is set in the fuel cut permitted rotation speed Nfcp. (Step S400), this routine is terminated.

When the neutral rotation speed increases, the rotation speed Ne of the engine 22 may be a relatively high rotation speed, for example, a rotation speed (Nfcr + ΔNfc1) or more and less than the rotation speed (Nfcr + ΔNfc2). Therefore, when it is determined that the neutral rotation speed increase is to be eliminated, if the fuel cut permitted rotation speed Nfcp is immediately changed from the rotation speed (Nfcr + ΔNfc2) to the rotation speed (Nfcr + ΔNfc1), the engine 22 is immediately determined to eliminate the neutral rotation speed increase. There is a possibility that the engine 22 will be fuel-cut when the rotation speed Ne of the above becomes equal to or higher than the fuel cut permitted rotation speed Nfcp. On the other hand, in the embodiment, even if it is determined that the neutral rotation speed increase is eliminated, when a predetermined time (time required for the counter C to reach the threshold value Cref or higher) has not elapsed from the judgment, the fuel cut permitted rotation is performed. The number Nfcp is held as a value (Nfcr + ΔNfc2). As a result, it is possible to suppress the rotation speed Ne of the engine 22 from becoming equal to or higher than the fuel cut permitted rotation speed Nfcp immediately after determining the elimination of the neutral rotation speed increase, and it is possible to suppress the fuel cut of the engine 22. ..

FIG. 5 shows the lower limit load factor KLmin and load factor KL of the engine 22, the rotation speed Ne, the fuel cut return rotation speed Nfcr, the fuel cut permitted rotation speed Nfcp, the speed ratio change rate ΔNV, and the vehicle speed V when the accelerator is released. It is explanatory drawing which shows an example of the presence / absence of a fuel cut, and the state of flags F1 and F2. As shown in the figure, when the accelerator is off (time t10), when the engine 22 rotation speed Ne is equal to or higher than the fuel cut permitted rotation speed Nfcp, the fuel cut of the engine 22 is executed and the engine 22 rotation speed Ne is fuel. When the cut return rotation speed reaches Nfcr or less (time t11), the fuel injection of the engine 22 is restarted.

Then, when the rotation speed Ne of the engine 22 is equal to or higher than the threshold Neref1 and the rotation increase condition is satisfied (time t12), it is determined that the neutral rotation increase has occurred, the flag F1 is switched from the value 0 to the value 1, and the engine 22 The lower limit load factor KLmin is lowered from the predetermined value KL1 to the predetermined value KL2, and the fuel cut permitted rotation speed Nfcp of the engine 22 is further increased from the rotation speed (Nfcr + ΔNfc1) to the rotation speed (Nfcr + ΔNfc2). Then, the lower limit load factor KLmin of the engine 22 is switched between the predetermined value KL2 and the predetermined value KL3 according to the change in the magnitude relationship between the rotation speed Ne of the engine 22 and the threshold value Neef2 (time t13, t14, t15).

Then, when the speed ratio change rate condition is satisfied (time t16), it is determined that the drive system may have been connected (neutral is canceled), and the rotation increase condition is satisfied (neutral rotation increase is eliminated). The flag F2 is switched from the value 0 to the value 1, the flag F1 is switched from the value 1 to the value 0, and the lower limit load factor KLmin of the engine 22 is gradually increased toward the predetermined value KL1 by rate processing. As a result, compared to the one in which the lower limit load factor KLmin of the engine 22 is immediately switched to the predetermined value KL1, it is suppressed that the rotation increase condition is re-established in an extremely short time when the neutral is actually continued. , It is possible to suppress the lower limit load factor KLmin of the engine 22 from being lowered to the predetermined value KL2 or the predetermined value KL3 again in a very short time. That is, it is possible to suppress frequent hunting of the lower limit load factor KLmin (target load factor KL *) of the engine 22, and thus the load factor KL and the rotation speed Ne.

In the automobile 20 of the embodiment described above, when the accelerator is off, if the rotation increase condition is satisfied, it is determined that the neutral rotation increase has occurred, and the lower limit load factor KLmin of the engine 22 is set to a predetermined value KL2 smaller than the predetermined value KL1. change. After that, when the speed ratio change rate condition is satisfied, it is determined that the drive system may have been connected (neutral may have been eliminated), and the lower limit load factor KLmin of the engine 22 is set to a predetermined value KL1. Gradually increase by rate processing toward. As a result, compared to the one in which the lower limit load factor KLmin of the engine 22 is immediately switched to the predetermined value KL1, it is suppressed that the rotation increase condition is re-established in an extremely short time when the neutral is actually continued. , It is possible to suppress the lower limit load factor KLmin of the engine 22 from being lowered to the predetermined value KL2 or the predetermined value KL3 again in a very short time. That is, it is possible to suppress frequent hunting of the lower limit load factor KLmin (target load factor KL *) of the engine 22, and thus the load factor KL and the rotation speed Ne.

In the automobile 20 of the embodiment, after the rotation increase condition is satisfied (determined that the neutral rotation increase has occurred), the electronic control unit 50 is in a state where the absolute value of the speed ratio change rate ΔNV is equal to or less than the threshold value ΔNVref for a predetermined time T2. When the continuous speed ratio change rate condition was satisfied, it was judged that the drive system connection might have been made. However, after the rotation increase condition is satisfied, the electronic control unit 50 has a speed ratio NV of any of the shift ranges corresponding to the shift stages (forward first speed to sixth speed) of the manual transmission 30. When the gear ratio condition in which the state included in the above is continued for a predetermined time T3 is satisfied, it may be determined that the drive system connection may have been made. As the predetermined time T3, for example, the same time as the predetermined time T2 is used. Further, the electronic control unit 50 may determine that the drive system may have been connected when the speed ratio change rate condition and the gear ratio condition are satisfied after the rotation increase condition is satisfied.

In the automobile 20 of the embodiment, the electronic control unit 50 has a lower limit load factor KLmin of the engine 22 when the speed ratio change rate condition is satisfied (the drive system may be connected) after the rotation increase condition is satisfied. Was increased from the predetermined value KL2 or the predetermined value KL3 toward the predetermined value KL1 by rate processing. However, at this time, the electronic control unit 50 may increase the lower limit load factor KLmin of the engine 22 from the predetermined value KL2 or the predetermined value KL3 toward the predetermined value KL1 by annealing.

In the automobile 20 of the embodiment, the electronic control unit 50 is said to have satisfied the condition for increasing the rotation speed (determined that the increase in the neutral rotation has occurred) and then the condition for increasing the rotation speed has been eliminated (the increase in the neutral rotation has been eliminated). At the time of determination, when the predetermined time has not elapsed from the determination, the fuel cut permitted rotation speed Nfcp is held at the rotation speed (Nfcr + ΔNfc2). However, when it is determined that the condition for increasing the rotation speed is satisfied, the fuel cut permitted rotation speed Nfcp may be immediately reduced from the rotation speed (Nfcr + ΔNfc2) to the rotation speed (Nfcr + ΔNfc1).

In the automobile 20 of the embodiment, when the rotation speed increase condition is satisfied (determined that the neutral rotation speed increase has occurred), the electronic control unit 50 changes the fuel cut permitted rotation speed Nfcp from the rotation speed (Nfcr + ΔNfc1) to the rotation speed (Nfcr + ΔNfc2). ). However, at this time, the fuel cut permitted rotation speed Nfcp may not be increased from the rotation speed (Nfcr + ΔNfc1) to the rotation speed (Nfcr + ΔNfc2), that is, it may be held at the rotation speed (Nfcr + ΔNfc1).

In the automobile 20 of the embodiment, the electronic control unit 50 is assumed to execute the lower limit load factor setting routine of FIG. However, instead of this, the electronic control unit 50 may execute the lower limit load factor setting routine shown in FIG. The lower limit load factor setting routine of FIG. 6 is the same as the lower limit load factor setting routine of FIG. 3 except that the processes of steps S400 to S460 are added. Therefore, among the lower limit load factor setting routines of FIG. 6, the same processes as those of the lower limit load factor setting routine of FIG. 3 are assigned the same step numbers, and detailed description thereof will be omitted. Of the lower limit load factor setting routines in FIG. 6, the processes of steps S100 to S130 and S150 to S210 are not shown.

In the lower limit load factor setting routine of FIG. 6, when the value 0 is set to the flag F1 in step S220, the electronic control unit 50 inputs the speed ratio change rate ΔNV (step S400), and the input speed ratio change rate ΔNV is absolute. The value is compared with the threshold ΔNVref described above (step S410). Then, when the absolute value of the rate ratio change rate ΔNV is equal to or less than the threshold value ΔNVref, the electronic control unit 50 holds the determination that the drive system connection may have been performed, and processes in steps S230 and S240 described above. Is executed, and when the lower limit load factor KLmin of the engine 22 is smaller than the predetermined value KL1 in step S240, the process returns to step S400.

When the absolute value of the rate ratio change rate ΔNV is larger than the threshold value ΔNVref in step S410, the electronic control unit 50 determines that the drive system connection has not been made (neutral has continued), and sets the value to flag F2. Set 0 (step S420). Then, the electronic control unit 50 inputs the rotation speed Ne of the engine 22 and the rotation speed change rate ΔNe (step S430) in the same manner as in the processes of steps S100 to S120, and compares the rotation speed Ne of the engine 22 with the threshold Neref1. At the same time (step S440), it is determined whether or not the rotation speed increase condition is satisfied by using the rotation speed change rate ΔNe of the engine 22 (step S450).

When the rotation speed Ne of the engine 22 is less than the threshold value Nerf1 in step S440, or when the rotation speed increase condition is not satisfied in step S450, the electronic control unit 50 sets the lower limit load factor KLmin of the engine 22 to be smaller than the predetermined value KL1. It is determined that the reduction is not allowed, or it is determined that the neutral rotation speed increase has not occurred, the processing of steps S230 and S240 described above is executed, and the lower limit load factor KLmin of the engine 22 is set from the predetermined value KL1 in step S240. When the value is small, the process returns to step S400.

When the rotation speed Ne of the engine 22 is equal to or higher than the threshold value Nerf1 in step S440 and the rotation increase condition is satisfied in step S450, the electronic control unit 50 lowers the lower limit load factor KLmin of the engine 22 below the predetermined value KL1. It is determined that the neutral rotation speed has increased while allowing the above, and the value 1 is set in the flag F1 (step S460), and the process returns to step S150.

By such processing, while the lower limit load factor KLmin of the engine 22 is gradually increased from the predetermined value KL2 or the predetermined value KL3 toward the predetermined value KL1 by the rate processing, the flag F2 becomes the value 0 and the flag F1 becomes the value 0. When the value reaches 1, the lower limit load factor KLmin of the engine 22 is stopped increasing and returned to the predetermined value KL2 or the predetermined value KL3. As a result, fluctuations in the load factor KL and the rotation speed Ne of the engine 22 can be further suppressed.

In the automobile 20 of the embodiment, a 6-speed transmission is used as the manual transmission 30. However, as the manual transmission 30, a 3-speed transmission, a 4-speed transmission, a 5-speed transmission, or the like may be used.

The correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the engine 22 corresponds to the "engine", the manual transmission 30 corresponds to the "manual transmission", the clutch 40 corresponds to the "clutch", and the electronic control unit 50 corresponds to the "control device". ..

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of the means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the vehicle manufacturing industry and the like.

20 automobiles, 22 engines, 23 crankshafts, 30 manual transmissions, 32 shift levers, 40 clutches, 42 clutch pedals, 50 electronic control units, 51 ignition switches, 53 accelerator pedals, 54 accelerator pedal position sensors, 55 brake pedals, 56 Brake pedal position sensor, 58 vehicle speed sensor, 122 air cleaner, 123 intake pipe, 124 throttle valve, 124a throttle position sensor, 124b throttle motor, 126 fuel injection valve, 128 intake valve, 129 combustion chamber, 130 ignition plug, 131 exhaust valve, 132 Piston, 133 Exhaust Pipe, 134 Purifier, 135a Air Fuel Ratio Sensor, 135b Oxygen Sensor, 140 Crank Position Sensor, 142 Water Temperature Sensor, 144 Cam Position Sensor, 148 Air Flow Meter, 149 Temperature Sensor, DG Differential Gear, DS Drive Shaft, DW drive wheel.

Claims (5)

With the engine
A manual transmission connected to the drive wheels,
A clutch provided between the engine and the manual transmission,
The control device that controls the engine and
It is a vehicle equipped with
The control device is
When the accelerator is off
When the first condition is satisfied in which the state in which the rotation speed change rate, which is the amount of change in the rotation speed of the engine per unit time, continues to be equal to or higher than the predetermined change rate for the first time, before the first condition is satisfied. In comparison, the load factor of the engine is lowered.
After that, the condition that the absolute value of the speed ratio change rate, which is the amount of change in the speed ratio between the engine speed and the vehicle speed per unit time, is equal to or less than a predetermined value continues for the second time, and the speed. A condition in which the ratio is included in any of the gear ratio ranges corresponding to the gears of the manual transmission continues for the third time, and a second condition including at least one of them. When it is established, the load ratio of the engine is increased by the slow change process.
vehicle. The vehicle according to claim 1.
The control device is
When the accelerator is off
When the first condition is satisfied, when the engine speed is equal to or higher than the predetermined engine speed, the load factor of the engine is set to a second load factor smaller than the first load factor before the first condition is satisfied. When the engine speed is less than the predetermined engine speed, the load factor of the engine is set to a third load factor which is smaller than the first load factor and larger than the second load factor.
When the second condition is satisfied, the load factor of the engine is increased by the slow change process from the second load factor or the third load factor toward the first load factor.
vehicle. The vehicle according to claim 1 or 2.
The control device is
When the accelerator is off
If the second condition is satisfied after the first condition is satisfied, it is determined that the first condition is satisfied.
If the second condition is not satisfied and the first condition is re-established while the load factor of the engine is being increased by the slow change process when the second condition is satisfied, the engine Reduce the load factor again,
vehicle. The vehicle according to any one of claims 1 to 3.
When the accelerator is off, when the first condition is satisfied, the control device increases the fuel cut permitted rotation speed of the engine as compared with before the first condition is satisfied.
vehicle. The vehicle according to claim 4.
When the accelerator is off, the control device holds the fuel cut permitted rotation speed when the fourth time has not elapsed since the first condition was satisfied, and the first condition is satisfied. After that, when the fourth time elapses, the fuel cut permitted rotation speed is lowered.
vehicle.

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