vehicle

Abstract

To prevent deterioration of drivability.SOLUTION: A vehicle comprises: an engine with a filter collecting particulate matters installed on an exhaust system thereof; a manual transmission which transfers power from the engine to drive wheels while shifting a gear stage in response to shift operation of a driver; a clutch which can release connection between the engine and the manual transmission in response to clutch pedal operation of the driver; and a control device which prohibits a fuel cut for the engine when an accumulation amount of the particulate matters is less than a predetermined amount and a filter temperature is equal to or higher than a first predetermined temperature. The control device permits the fuel cut when the shift stage is changed even though the accumulation amount of the particulate matters is less than the predetermined amount and the filter temperature is equal to or higher than the first predetermined temperature.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to vehicles. [Background technology]

[0002] A conventional vehicle of this type is equipped with an engine having a filter attached to the exhaust system that captures particulate matter. When a fuel cut condition is met, a fuel cut process is executed to stop fuel injection from a fuel injection valve, and when the cumulative amount of intake air becomes equal to or exceeds a predetermined value while the fuel cut process is being executed, the fuel cut process is stopped (see, for example, Patent Document 1). In this vehicle, by executing the fuel cut process, oxygen is supplied to the filter, which burns the particulate matter accumulated on the filter and regenerates the filter. Furthermore, by stopping the fuel cut process, the filter is prevented from overheating due to the combustion of a large amount of particulate matter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-165564 Summary of the Invention [Problem to be solved by the invention]

[0004] In such vehicles, if the amount of particulate matter accumulated on the filter is too small, the degree to which the filter captures particulate matter is reduced. Therefore, when the amount of particulate matter accumulated is less than a predetermined amount and the filter temperature is above a predetermined temperature (when the particulate matter is within a temperature range in which it can be used as fuel), engine fuel cut-off is prohibited. In a manual transmission vehicle equipped with a manual transmission that transmits power from the engine to the drive wheels by changing the gear position in response to the driver's shift operation, and a clutch that can disconnect the engine from the manual transmission in response to the driver's clutch pedal operation, when changing the gear position of the manual transmission, the clutch is basically released by depressing the clutch pedal, the gear position is changed in response to the shift operation, and the clutch returns to an engaged state via a slip engagement state as the clutch pedal is gradually released. If engine fuel cut-off is prohibited at this time, there is a concern that the engine will rev up and drivability will deteriorate.

[0005] The vehicle of the present disclosure has a primary objective of suppressing deterioration in drivability. [Means for solving the problem]

[0006] The vehicle of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The vehicle of the present disclosure includes: A vehicle comprising: an engine having an exhaust system equipped with a filter that captures particulate matter; a manual transmission that transmits power from the engine to drive wheels while changing gears in response to a driver's shift operation; a clutch that can disconnect the engine from the manual transmission in response to a driver's operation of a clutch pedal; and a control device that prohibits fuel cut-off of the engine when an amount of accumulated particulate matter is less than a predetermined amount and the temperature of the filter is equal to or higher than a first predetermined temperature, The control device permits the fuel cut when the gear position is changed even when the amount of accumulated particulate matter is less than the predetermined amount and the temperature of the filter is equal to or higher than the first predetermined temperature. The gist of this is as follows.

[0008] In the vehicle of the present disclosure, when the amount of particulate matter accumulation is less than a predetermined amount and the filter temperature is equal to or higher than a first predetermined temperature, engine fuel cut is basically prohibited. However, even when the amount of particulate matter accumulation is less than the predetermined amount and the filter temperature is equal to or higher than the first predetermined temperature, fuel cut is permitted when changing gears. This makes it possible to suppress engine revving when changing gears in the manual transmission and to suppress deterioration of drivability. Here, when changing gears in the manual transmission, it may be the period from when the clutch is turned off to when the gear is changed and the clutch is turned on, or it may be the period from when the gear change begins to when the change is completed.

[0009] In the vehicle of the present disclosure, the control device may prohibit the fuel cut when the temperature of the filter is equal to or higher than a second predetermined temperature that is higher than the first predetermined temperature, regardless of whether the gear position is being changed or not. This makes it possible to prevent the filter from overheating due to the execution of a fuel cut to the engine. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a vehicle 20 according to an embodiment of the present disclosure. [Figure 2] 2 is a schematic diagram of an engine 22 mounted on a vehicle 20. FIG. [Figure 3] 4 is a flowchart showing an example of a permission / prohibition determination routine executed by the electronic control unit 50. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a vehicle 20 according to an embodiment of the present disclosure. Fig. 2 is a schematic configuration diagram of an engine 22 mounted on the vehicle 20. The vehicle 20 according to the embodiment is configured as a manual transmission vehicle (MT vehicle), and includes the engine 22, a manual transmission 30, a clutch 40, and an electronic control unit 50, as shown in Fig. 1.

[0012] The engine 22 is a multi-cylinder internal combustion engine that uses fuel such as gasoline or diesel oil and outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel into an intake port and an in-cylinder injection valve 127 that injects fuel into a cylinder. The engine 22 operates in one of a port injection mode, an in-cylinder injection mode, and a combined injection mode. In the port injection mode, air cleaned by an air cleaner 122 is drawn into an intake pipe 123 and passes through a throttle valve 124 and a surge tank 125. Fuel is injected from the port injection valve 126 downstream of the surge tank 125 into the intake pipe 123, mixing the air and fuel. The air-fuel mixture is drawn into a combustion chamber 129 via an intake valve 128 and explosively combusted by an electric spark generated by a spark plug 130. The resulting energy pushes down a piston 132 in the cylinder bore, and the reciprocating motion of the piston 132 is converted into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129, as in the port injection mode, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke or compression stroke, and is explosively combusted by an electric spark from the spark plug 130, thereby generating rotational motion of the crankshaft 23. In the combined injection mode, fuel is injected from the port injection valve 126 when air is drawn into the combustion chamber 129, and fuel is also injected from the in-cylinder injection valve 127 during the intake stroke or compression stroke, and is explosively combusted by an electric spark from the spark plug 130, thereby generating rotational motion of the crankshaft 23. Exhaust gas discharged from the combustion chamber 129 into an exhaust pipe 134 via an exhaust valve 133 is then discharged into the outside air via a purification device 135 and a PM filter 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). PM filter 136 is formed as a porous filter using ceramics, stainless steel, or the like, and captures particulate matter (PM) such as soot in the exhaust gas. Note that instead of PM filter 136, a four-way catalyst may be used that combines the purification function of a three-way catalyst with the function of capturing particulate matter.

[0013] 1, the manual transmission 30 is configured as a six-speed transmission, and has an input shaft connected to the crankshaft 23 of the engine 22 via a clutch 40, and an output shaft connected to a drive shaft DS that is connected to drive wheels DW via a differential gear DG. Depending on the driver's operation of a shift lever 32, the manual transmission 30 establishes forward gears (first to sixth gears) and reverse gears, or releases the connection between the input shaft and the output shaft.

[0014] 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 when the clutch pedal 42 is depressed, it is in a slip-engaged state or a released state depending on the amount of depression.

[0015] The electronic control unit 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. As shown in Figures 1 and 2, the electronic control unit 50 receives signals from various sensors via input ports.

[0016] Examples of signals input to the electronic control unit 50 include signals required for controlling the operation of the engine 22. Examples of signals required for controlling the operation of the engine 22 include a crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and a coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant for the engine 22. Other examples of signals required for controlling the operation of the engine 22 include cam angles θci and θco from a cam position sensor 144 that detects the rotational position of an intake camshaft that opens and closes the intake valve 128 and the rotational position of an exhaust camshaft that opens and closes the exhaust valve 133. Other examples include a throttle opening TH from a throttle valve position sensor 124a that detects the position of the throttle valve 124, an intake air amount Qa from an air flow meter 123a attached upstream of the throttle valve 124 in the intake pipe 123, an intake air temperature Ta from a temperature sensor 123t attached upstream of the throttle valve 124 in the intake pipe 123, and a surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Other examples include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached upstream of the purification device 135 in the exhaust pipe 134, a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached between the purification device 135 and the PM filter 136 in the exhaust pipe 134, and a differential pressure ΔP from a differential pressure sensor 136a that detects a differential pressure before and after the PM filter 136 (a differential pressure between the upstream side and the downstream side).

[0017] Further, the signals input to the electronic control unit 50 include an ignition signal from an ignition switch 51, an accelerator opening Acc from an accelerator pedal position sensor 54 that detects the amount of depression of an accelerator pedal 53, a brake pedal position BP from a brake pedal position sensor 56 that detects the amount of depression of a brake pedal 55, and a vehicle speed V from a vehicle speed sensor 58.

[0018] The electronic control unit 50 outputs, via an output port, various control signals for controlling the operation of the engine 22. Examples of signals output by the electronic control unit 50 include a control signal to the throttle valve 124, a control signal to the port injection valve 126, a control signal to the in-cylinder injection valve 127, and a control signal to the spark plug 130.

[0019] 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. The engine ECU 24 also calculates a load factor KL (the ratio of the volume of air actually taken in per cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 123a and the rotation speed Ne of the engine 22. The engine ECU 24 also calculates a PM accumulation amount Qpm as the accumulation amount of particulate matter accumulated on the PM filter 136 based on the differential pressure ΔP from the differential pressure sensor 136a, and calculates a filter temperature tf as the temperature of the PM filter 136 based on the rotation speed Ne of the engine 22 and the load factor KL.

[0020] In the vehicle 20 of the embodiment, the electronic control unit 50 sets the target load rate KL* of the engine 22 based on the accelerator opening Acc, and performs operation control of the engine 22 (intake air amount control, fuel injection control, ignition control, etc.) so that the engine 22 operates based on the target load rate KL*.

[0021] Furthermore, in the vehicle 20 of the embodiment, the electronic control unit 50 executes a fuel cut of the engine 22 when the accelerator is released. When the fuel cut of the engine 22 is executed while the filter temperature Tf is equal to or higher than the threshold value Tfref, air (oxygen) is supplied to the PM filter 136, and the particulate matter deposited on the PM filter 136 reacts with the oxygen, burning the particulate matter and regenerating the PM filter 136. Here, the threshold value Tfref is the lower limit of the temperature range in which the PM filter 136 can be regenerated (particulate matter can be burned).

[0022] Next, a description will be given of the operation of the vehicle 20 according to this embodiment, in particular, the process of determining whether or not to permit fuel cut of the engine 22. Fig. 3 is a flowchart showing an example of a permission / prohibition determination routine executed by the electronic control unit 50. This routine is executed repeatedly.

[0023] 3 is executed, the electronic control unit 50 first determines whether the filter temperature Tf is equal to or higher than a superheat temperature Tfot that is higher than the threshold value Tfref (step S100). Here, the superheat temperature Tfot is defined as a temperature used to determine whether the PM filter 136 is likely to overheat due to the execution of a fuel cut of the engine 22. The superheat temperature Tfot may be a constant value, or may be set to be lower as the PM accumulation amount Qpm increases. The latter is because, when a fuel cut of the engine 22 is executed, the amount of heat generated by the combustion of particulate matter increases as the PM accumulation amount Qpm increases, and the filter temperature Tf is more likely to become high.

[0024] If it is determined in step S100 that the filter temperature Tf is less than the overheat temperature Tfot, it is determined that there is a sufficiently low possibility that the PM filter 136 will overheat even if a fuel cut is performed on the engine 22, and it is determined whether the PM deposition amount Qpm is less than a threshold Qpmref (step S110) and whether the filter temperature Tf is equal to or greater than a threshold Tfref (step S120). If the PM deposition amount Qpm is too small, the particulate matter capture efficiency of the PM filter 136 decreases. The thresholds Qpmref and Tfref are thresholds used to determine whether there is a possibility that the particulate matter will be burned and the PM deposition amount Qpm will become too small when a fuel cut is performed on the engine 22.

[0025] When it is determined in step S110 that the PM accumulation amount Qpm is equal to or greater than the threshold value Qpmref, it is determined that there is a sufficiently low possibility that the PM accumulation amount Qpm will become too small even if fuel is cut off to the engine 22 and particulate matter is burned, and fuel cut to the engine 22 is permitted (step S150), and this routine is terminated.

[0026] When it is determined in step S120 that the filter temperature Tf is less than the threshold value Tfref, it is determined that even if fuel is cut to the engine 22, the possibility that the PM deposition amount Qpm will become too small because particulate matter is difficult to burn is sufficiently low, and fuel cut to the engine 22 is permitted (step S150), and this routine is terminated.

[0027] If it is determined in step S110 that the PM deposition amount Qpm is less than the threshold value Qpmref and if it is determined in step S120 that the filter temperature Tf is equal to or greater than the threshold value Tfref, it is determined that executing a fuel cut of the engine 22 may result in the combustion of particulate matter, which may cause the PM deposition amount Qpm to become too small, and it is then determined whether it is time to change the gear position of the manual transmission 30 (step S130). In a manual transmission vehicle, when changing the gear position of the manual transmission 30, basically, the clutch 40 is released by depressing the clutch pedal 42, the gear position of the manual transmission 30 is changed in response to operation of the shift lever 32, and the clutch 40 returns to an engaged state via a slip engagement state as the clutch pedal 42 is gradually released. Based on this, the time when the gear position of the manual transmission 30 is changed may be the period from when depression of the clutch pedal 42 begins to end (from when the clutch 40 is disengaged to when it returns to an engaged state), or it may be the period from when the shift position of the manual transmission 30 begins to change to when the shift position is completed.

[0028] If it is determined in step S130 that the manual transmission 30 is not currently being changed in gear position, the fuel cut of the engine 22 is prohibited (step S140), and the routine ends. This prevents the PM accumulation amount Qpm from becoming too small due to the execution of the fuel cut of the engine 22.

[0029] If it is determined in step S130 that it is time to change the gear position of the manual transmission 30, fuel cut-off of the engine 22 is permitted (step S150), and this routine is terminated. If fuel cut-off of the engine 22 is prohibited when changing the gear position of the manual transmission 30, there is a concern that the engine 22 may rev up and drivability may deteriorate. In contrast, in the embodiment, by permitting fuel cut-off of the engine 22 when changing the gear position of the manual transmission 30, it is possible to suppress rev-up of the engine 22 and suppress deterioration of drivability. Note that the inventors have confirmed through experiments and analysis that the time required to change the gear position of the manual transmission 30 is generally about several tens to several hundreds of msec, and that the amount of reduction in the PM accumulation amount Qpm due to fuel cut-off of the engine 22 is relatively small, and that the amount of reduction in the particulate matter collection efficiency of the PM filter 136 is also relatively small (within an acceptable range). In addition, in order to more fully suppress revving of the engine 22, it is preferable to change the gear stage of the manual transmission 30 during the period from when the clutch pedal 42 starts to when it ends (from when the clutch 40 is released from its engaged state to when it returns to its engaged state), rather than during the period from when the gear stage of the manual transmission 30 starts to when it ends.

[0030] If the filter temperature Tf is equal to or higher than the overheat temperature Tfot in step S100, it is determined that there is a possibility that the PM filter 136 will overheat due to the execution of a fuel cut of the engine 22, and the fuel cut of the engine 22 is prohibited (step S140), and this routine is terminated. This makes it possible to prevent the PM filter 136 from overheating due to the execution of a fuel cut of the engine 22.

[0031] In the vehicle 20 of the present embodiment described above, when the PM accumulation amount Qpm is less than the threshold Qpmref and the filter temperature Tf is equal to or greater than the threshold Tfref, fuel cut-off of the engine 22 is basically prohibited. However, even when the PM accumulation amount Qpm is equal to or less than the threshold Qpmref and the filter temperature Tf is equal to or greater than the threshold Tfref, fuel cut-off of the engine 22 is permitted when changing the gear position of the manual transmission 30. This makes it possible to suppress revving of the engine 22 when changing the gear position of the manual transmission 30, and to suppress deterioration of drivability.

[0032] Furthermore, in the vehicle 20 of this embodiment, when the filter temperature Tf is equal to or higher than an overheat temperature Tfot that is higher than the threshold value Tfref, fuel cut of the engine 22 is prohibited regardless of whether or not the gear position of the manual transmission 30 is being changed. This makes it possible to prevent the PM filter 136 from overheating due to the execution of fuel cut of the engine 22.

[0033] In the above-described embodiment, the engine 22 has the port injection valve 126 and the in-cylinder injection valve 127. However, the engine 22 may have only one of the port injection valve 126 and the in-cylinder injection valve 127.

[0034] In the above-described embodiment, the manual transmission 30 is configured as a six-speed transmission. However, the manual transmission 30 may be configured as a four-speed transmission, a five-speed transmission, an eight-speed transmission, or the like.

[0035] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the engine 22 corresponds to the "engine," the manual transmission 30 corresponds to the "manual transmission," and the electronic control unit 50 corresponds to the "control device."

[0036] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0037] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0038] The present disclosure is applicable to the vehicle manufacturing industry and the like. [Explanation of symbols]

[0039] 20 vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 30 manual transmission, 32 shift lever, 40 clutch, 42 clutch pedal, 50 electronic control unit, 51 ignition switch, 53 accelerator pedal, 54 accelerator pedal position sensor, 55 brake pedal, 56 brake pedal position sensor, 58 vehicle speed sensor, 122 air cleaner, 123 intake pipe, 123a air flow meter, 123t temperature sensor, 124 throttle valve, 124a throttle valve position sensor, 125 surge tank, 125a pressure sensor, 126 port injection valve, 127 in-cylinder injection valve, 128 intake valve, 129 combustion chamber, 130 spark plug, 132 piston, 133 exhaust valve, 134 exhaust pipe, 135 purification device, 136 PM filter, 136a Differential pressure sensor, 137 front air-fuel ratio sensor, 138 rear air-fuel ratio sensor, 140 crank position sensor, 142 water temperature sensor, 144 cam position sensor.

Claims

1. A vehicle comprising: an engine having an exhaust system equipped with a filter that captures particulate matter; a manual transmission that transmits power from the engine to drive wheels while changing gears in response to a driver's shift operation; a clutch that can disconnect the engine from the manual transmission in response to a driver's operation of a clutch pedal; and a control device that prohibits fuel cut-off of the engine when an amount of accumulated particulate matter is less than a predetermined amount and the temperature of the filter is equal to or higher than a first predetermined temperature, the control device permits the fuel cut when the gear position is changed even when the amount of accumulated particulate matter is less than the predetermined amount and the temperature of the filter is equal to or higher than the first predetermined temperature. vehicle.

2. 2. The vehicle according to claim 1, the control device prohibits the fuel cut when the temperature of the filter is equal to or higher than a second predetermined temperature that is higher than the first predetermined temperature, regardless of whether the gear position is being changed or not. vehicle.

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