Engine device

Abstract

To inhibit the reduction speed of an increase correction amount for the fuel injection amount of an engine from becoming too large.SOLUTION: In an engine apparatus comprising an engine and a control device for controlling the engine, after determination after starting of the engine is switched from off to on, the control device reduces an increase correction amount for a fuel injection amount of the engine with the lapse of time by using a damping coefficient that becomes smaller as an off time storage value related to an off time of the determination after starting is shorter and becomes smaller as an engine cooling water temperature is higher. With this, it becomes possible to inhibit the off time storage value from becoming too short when the off time of the determination after starting is relatively short, and to inhibit a reduction speed of the increase correction amount for the fuel injection amount from becoming too large after the determination after starting becomes on from off.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an engine device.

Background Art

[0002] Conventionally, as this type of engine device, from the start of fuel increase correction by the start-up increase correction coefficient until a predetermined time has elapsed after the engine is started cold, the start-up increase correction coefficient is attenuated by a first attenuation coefficient, and after the predetermined time has elapsed, a fuel injection valve is controlled to operate so as to return the start-up increase correction coefficient to zero by a second attenuation coefficient (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such an engine device, it is considered that the above-described attenuation coefficient is made smaller as the off-time before the engine is started cold is shorter. In this case, when the off-time is relatively short, for example, when fuel cut is performed and fuel injection is restarted and the engine is started before the engine speed decreases and stops rotating, the attenuation coefficient may become too small and the decrease rate of the increase correction amount may become too large.

[0005] The main object of the engine device of the present invention is to suppress the increase correction amount of the fuel injection amount of the engine from increasing too much.

Means for Solving the Problems

[0006] The engine device of the present invention has taken the following means in order to achieve the above-described main object.

[0007] The engine device of the present invention is an engine, a control device for controlling the engine, and is an engine device comprising after the start-up determination of the engine switches from off to on, the control device decreases the increased correction amount of the fuel injection amount of the engine over time using a decay coefficient such that the off-time storage value related to the off-time of the start-up determination becomes smaller as it is shorter and the cooling water temperature of the engine becomes higher as it is higher, furthermore, the control device sets the off-time storage value by lower-limit guarding the off-time using a lower-limit guard value. This is the gist.

[0008] In the engine device of the present invention, after the start-up determination of the engine switches from off to on, the increased correction amount of the fuel injection amount of the engine is decreased over time using a decay coefficient such that the off-time storage value related to the off-time of the start-up determination becomes smaller as it is shorter and the cooling water temperature of the engine becomes higher as it is higher. In this case, the off-time storage value is set by lower-limit guarding the off-time using a lower-limit guard value. Thereby, it is possible to suppress the off-time storage value from becoming too short when the off-time of the start-up determination is relatively short, and to suppress the decrease rate of the increased correction amount of the fuel injection amount from becoming too large after the start-up determination switches from off to on. Here, the start-up determination may each switch from on to off when the engine speed reaches a predetermined speed (for example, about several hundred rpm) that is somewhat lower than the idle speed, and then switch from off to on when the engine speed becomes less than the predetermined speed. Also, the off-time means the duration of the off state of the start-up determination, and for example, it may be reset to value 0 when the start-up determination switches from on to off and held, and then increase with the passage of time, and be held when the start-up determination is on. Therefore, examples of when the off-time is relatively short include when fuel cut of the engine is performed, the engine speed becomes less than the predetermined speed, and fuel injection is started (resumed) before the engine stops rotating and the engine speed increases to the predetermined speed or more.

[0009] In the engine device of the present invention, the control device may decrease the lower guard value from the value when the post-start determination switches from off to on with the passage of time. By doing so, the lower guard value can be set more appropriately.

[0010] In this case, the control device may decrease the lower guard value more steeply when the post-start determination is on than when it is off. By doing so, the lower guard value can be decreased more appropriately based on whether the engine is on or off.

[0011] In the engine device of the present invention, when the post-start determination is off, the control device may set the off-time storage value by lower guard protecting the off time using the lower guard value, and when the post-start determination is on, the control device may hold the off-time storage value.

[0012] In the engine device of the present invention, when the post-start determination switches from off to on, the control device may set the initial value of the increment correction amount so that the longer the off time is, the larger the increment correction amount becomes, and may decrease the increment correction amount from the initial value with the passage of time using the attenuation coefficient.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] Next, a mode for carrying out the present invention will be described using examples.

EXAMPLE

[0015] FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an engine device as an embodiment of the present invention. FIG. 2 is a configuration diagram showing an outline of the configuration of an engine 22 mounted on the hybrid vehicle 20. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch K0, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0016] The engine 22 is configured as a six-cylinder engine that outputs power through four strokes of intake, compression, expansion (explosive combustion), and exhaust using fuel such as gasoline or diesel fuel. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel into the intake port and an in-cylinder injection valve 127 that injects fuel into the cylinder. By having the port injection valve 126 and the in-cylinder injection valve 127, the engine 22 can be operated in any of a port injection mode, an in-cylinder injection mode, and a common injection mode. In the port injection mode, air cleaned by the air cleaner 122 is inhaled into the intake pipe 123, passed through the throttle valve 124 and the surge tank 125, and fuel is injected from the port injection valve 126 on the downstream side of the surge tank 125 in the intake pipe 123 to mix the air and fuel. Then, this air-fuel mixture is inhaled into the combustion chamber 129 through the intake valve 128 and explosively combusted by an electric spark from the spark plug 130, converting the reciprocating motion of the piston 132 pushed down by the energy in the cylinder bore into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is inhaled into the combustion chamber 129 in the same manner as in the port injection mode, fuel is injected from the in-cylinder injection valve 127 during the intake stroke and the compression stroke, and explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. In the common injection mode, fuel is injected from the port injection valve 126 when air is inhaled into the combustion chamber 129, and fuel is also injected from the in-cylinder injection valve 127 during the intake stroke and the compression stroke, and explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. These injection modes are switched based on the operating state of the engine 22. The exhaust discharged from the combustion chamber 129 to the exhaust pipe 134 through the exhaust valve 133 is discharged to the outside air through the purification device 135 and the PM filter 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in the exhaust. The PM filter 136 is formed as a porous filter using ceramics, stainless steel, etc., and collects particulate matter (PM) such as soot in the exhaust.Note that instead of the PM filter 136, a four-way catalyst that combines the purification function of a three-way catalyst and the collection function for particulate matter may be used.

[0017] The engine 22 is under operation control by an engine electronic control unit (hereinafter referred to as "engine ECU") 24. The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, although not shown. Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via the input ports. Examples of the signals input to the engine ECU 24 include the crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant of the engine 22. Also included are the cam angles θci and θco from a cam position sensor 144 that detects the rotational positions of the intake camshaft that opens and closes the intake valve 128 and the exhaust camshaft that opens and closes the exhaust valve 133. Further examples include the throttle opening TH from a throttle valve position sensor 124a that detects the position of the throttle valve 124, the intake air amount Qa from an air flow meter 123a attached upstream of the throttle valve 124 in the intake pipe 123, the intake air temperature Ta from a temperature sensor 123t attached upstream of the throttle valve 124 in the intake pipe 123, and the surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Also included are the 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, the 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 the differential pressure ΔP from a differential pressure sensor 136a that detects the differential pressure (the difference between the upstream side and the downstream side) across the PM filter 136.

[0018] From the engine ECU 24, various control signals for controlling the operation of the engine 22 are output via the output ports. Examples of the signals output from the engine ECU 24 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 engine ECU 24 is connected to the HV ECU 70 via a communication port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. Further, the engine ECU 24 calculates the load factor KL (the ratio of the volume of air actually inhaled in one 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 rotational speed Ne of the engine 22. Furthermore, the engine ECU 24 calculates the PM deposition amount Qpm as the deposition amount of particulate matter deposited on the PM filter 136 based on the differential pressure ΔP from the differential pressure sensor 136a, or calculates the filter temperature tf as the temperature of the PM filter 136 based on the rotational speed Ne and the load factor KL of the engine 22.

[0020] As shown in FIG. 1, a starter motor 25 for cranking the engine 22 and an alternator 26 for generating power using the power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter motor 25 and the alternator 26 are connected to the low-voltage side power line 63 together with the low-voltage battery 62 and are controlled by the HV ECU 70.

[0021] The motor 30 is configured as a synchronous generator motor and includes a rotor with permanent magnets embedded in the rotor core and a stator with three-phase coils wound around the stator core. The rotary shaft 31, to which the rotor of this motor 30 is fixed, is connected to the crankshaft 23 of the engine 22 via the clutch K0 and is also connected to the input shaft 41 of the automatic transmission 45. The inverter 32 is used to drive the motor 30 and is connected to the high-voltage side power line 61. The motor 30 is rotationally driven by switching control of a plurality of switching elements of the inverter 32 by a motor electronic control unit (hereinafter referred to as "motor ECU") 34.

[0022] Although not shown, the motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the motor ECU 34 via the input ports. Examples of the signals input to the motor ECU 34 include the rotational position θmg from the rotational position sensor 30a that detects the rotational position of the rotor (rotary shaft 31) of the motor 30, and the phase currents Iu and Iv from the current sensors that detect the phase currents of each phase of the motor 30. Control signals to the inverter 32 and the like are output from the motor ECU 34 via the output ports. The motor ECU 34 is connected to the HVECU 70 via the communication port. The motor ECU 34 calculates the rotational speed Nmg of the motor 30 based on the rotational position θmg of the rotor (rotary shaft 31) of the motor 30 from the rotational position sensor 30a.

[0023] The clutch K0 is configured as, for example, a hydraulically driven friction clutch and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotary shaft 31 of the motor 30.

[0024] The automatic transmission 40 has a torque converter 43 and an automatic transmission 45 with, for example, six forward speeds. The torque converter 43 is configured as a general fluid transmission device, and amplifies and transmits the power of the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the transmission input shaft 44, which is the input shaft of the automatic transmission 45, or transmits it as it is without amplifying the torque. The automatic transmission 45 has a transmission input shaft 44, an output shaft 42 connected to the drive wheels 49 via a differential gear 48, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). Each of the plurality of friction engagement elements has a hydraulic servo constituted by a piston, a plurality of friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. The automatic transmission 45 forms forward and reverse gears from the first speed to the sixth speed by engaging and disengaging the plurality of friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. The clutch K0 and the automatic transmission 45 are supplied with hydraulic oil pressure regulated from a mechanical oil pump or an electric oil pump by a hydraulic control device (not shown). The hydraulic control device has a valve body in which a plurality of oil passages are formed, a plurality of regulator valves, a plurality of linear solenoid valves, and the like. This hydraulic control device is controlled by the HVECU 70.

[0025] The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of about several hundred volts, and is connected to the high-voltage side power line 61 together with the inverter 32. The low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12V or 14V, and is connected to the low-voltage side power line 63 together with the starter motor 25 and the alternator 26. The DC / DC converter 64 is connected to the high-voltage side power line 61 and the low-voltage side power line 63. This DC / DC converter 64 supplies the power of the high-voltage side power line 61 to the low-voltage side power line 63 with a voltage step-down.

[0026] The HVECU 70 includes, although not shown, a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include the rotational speed Nin from the rotational speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotational speed Nmi from the rotational speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotational speed Nout from the rotational speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Also included are the voltage Vbh of the high-voltage battery 60 from the voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from the current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from the voltage sensor attached between the terminals of the low-voltage battery 62. Further examples are the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operating position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 87.

[0027] Various control signals are output from the HVECU 70 via the output ports. Examples of signals output from the HVECU 70 include the control signal to the starter motor 25 and the control signal to the alternator 26. Also included are the control signals to the clutch K0 and the automatic transmission 40 (hydraulic control device), and the control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via the communication ports. The HVECU 70 calculates the speed ratio Gt of the automatic transmission 40 by dividing the rotational speed Nin of the input shaft 41 of the automatic transmission 40 from the rotational speed sensor 41a by the rotational speed Nout of the output shaft 42 of the automatic transmission 40 from the rotational speed sensor 42a.

[0028] In the embodiments, the engine device corresponds to the engine 22 and the engine ECU 24.

[0029] In the hybrid vehicle 20 of the embodiment configured in this way, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled so as to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode) by the cooperative control of the HV ECU 70, the engine ECU 24, and the motor ECU 34. Here, the HV driving mode is a mode in which the clutch K0 is engaged and the vehicle travels using the power of the engine 22, and the EV driving mode is a mode in which the clutch K0 is disengaged and the vehicle travels without using the power of the engine 22.

[0030] Also, in the hybrid vehicle 20 of the embodiment, when the stop condition of the engine 22 is satisfied, such as when the accelerator is turned off while the engine 22 is being operated, stop control is executed by the cooperative control of the HV ECU 70, the engine ECU 24, and the motor ECU 34. In the stop control, basically, the fuel injection and ignition of the engine 22 are stopped, and when the rotational speed Ne of the engine 22 reaches below a threshold value Neref1 (for example, about 600 rpm to 800 rpm) that is somewhat lower than the idle rotational speed Nid for idling operation, the clutch K0 is disengaged.

[0031] And when the start condition of the engine 22 is satisfied, such as when the accelerator is turned on while the fuel cut of the engine 22 is being performed, start control is executed. Examples of the start control method include FC (Fuel Cut) return start control, self-sustaining COM (Change Of Mind) start control, COM start control, TDC (Top Dead Center) start control, and the like. Note that the fuel injection control during the start control is performed in the in-cylinder injection mode.

[0032] The FC return control is basically performed when the start condition of the engine 22 is satisfied and the rotational speed Ne of the engine 22 is equal to or higher than the threshold value Neref1. In the FC return control, the fuel injection and ignition of the engine 22 are started (resumed) while continuing the engagement of the clutch K0.

[0033] The self - standing COM start control is basically performed when the starting condition of the engine 22 is satisfied, and when the rotational speed Ne of the engine 22 is less than the threshold value Neref1 (with the clutch K0 disengaged) and is equal to or higher than a lower threshold value Neref2 (for example, several hundred rpm lower). In the self - standing COM start control, basically, while continuing to disengage the clutch K0, fuel injection and ignition of the engine 22 are started (resumed), and the engine 22 is controlled so that the differential rotational speed ΔN between the rotational speed Nmg of the motor 30 and the rotational speed Ne of the engine 22 becomes small. When the engagement condition of the clutch K0 is satisfied, such as when the differential rotational speed ΔN reaches less than the threshold value ΔNref (for example, about 50 rpm to 150 rpm), the clutch K0 is engaged (fully engaged).

[0034] The COM start control is basically performed when the starting condition of the engine 22 is satisfied, and when the rotational speed Ne of the engine 22 is less than the threshold value Neref2 and is greater than the value 0 (the engine 22 is rotating). In the COM start control, basically, the clutch K0 is semi - engaged (slip - engaged), and while cranking the engine 22 using the cranking torque from the motor 30, fuel injection and ignition of the engine 22 are resumed. While controlling the engine 22 so that the differential rotational speed ΔN becomes small, the clutch K0 is disengaged. When the engagement condition of the clutch K0 is satisfied, the clutch K0 is engaged (fully engaged).

[0035] The TDC start control is basically performed when the starting condition of the engine 22 is satisfied, and when the rotational speed Ne of the engine 22 is equal to the value 0 (the engine 22 is stopped). In the TDC start control, basically, the clutch K0 is semi - engaged (slip - engaged), and the engine 22 is cranked using the cranking torque from the motor 30. The first fuel injection and ignition are performed in the cylinder that first or second reaches the compression top dead center. While controlling the engine 22 so that the differential rotational speed ΔN becomes small, the clutch K0 is disengaged. When the engagement condition of the clutch K0 is satisfied, the clutch K0 is engaged.

[0036] In the embodiment, during self - standing COM start control, COM start control, and TDC start control, when the fuel injection of the engine 22 is started and the rotational speed Ne of the engine 22 reaches a threshold value Neref3 (for example, the same rotational speed as the above - mentioned threshold value Neref1) or more, the post - start determination is switched from off to on, and the post - start determination flag Fst is switched from the value 0 to the value 1. Then, when the fuel injection of the engine 22 is stopped thereafter and the rotational speed Ne of the engine 22 reaches less than the threshold value Neref3, the post - start determination is switched from on to off, and the post - start determination flag Fst is switched from the value 1 to the value 0. Also, when starting this trip (when the ignition switch 80 is turned on), the intermittent stop history flag Fio is set to the value 0, and when the intermittent stop history of the engine 22 changes from none to having in this trip (when the post - start determination flag Fst is switched from the value 1 to the value 0 for the first time), the intermittent stop history flag Fio is switched to the value 1. Further, an off - time Tsp is calculated, which is the duration during which the post - start determination flag Fst is the value 0 when the intermittent stop history flag Fio is the value 1 in this trip. The off - time Tsp is obtained by converting the value of the off - time counter Csp into time. The off - time counter Csp is held at the value 0 when the intermittent stop history flag Fio is the value 0, and when the intermittent stop history flag Fio is the value 1, when the post - start determination flag Fst is switched from the value 1 to the value 0 and held, it is reset to 0 and then counted up as time elapses, and when the post - start determination flag Fst is the value 1, the value is held.

[0037] Also, in the embodiment, when the intermittent stop history flag Fio is the value 1 and the post - start determination flag Fst is switched from the value 0 to the value 1 and held, in order to cope with fuel vaporization failure when the intake pipe 123 and the combustion chamber 129 are at a low temperature, an increment correction of the fuel injection amount of the engine 22 is performed. In the increment correction, when the post - start determination flag Fst is switched from the value 0 to the value 1, an initial value Qfupst is set for the increment correction amount Qfup for increment correction, and then, an update process of multiplying the previous increment correction amount (previous Qfup) by a decay coefficient ka smaller than 1 is repeatedly executed to update the increment correction amount Qfup, so that the increment correction amount Qfup is gradually decreased as time elapses.

[0038] Here, the initial value Qfupst can be set by, for example, lower-guarding a temporary initial value Qfuptmp with a lower guard value Qfupgd. The temporary initial value Qfuptmp can be set, for example, by previously determining the relationship between the off-time Tsp and the temporary initial value Tfuptmp through experiments, analysis, machine learning, etc., storing it as a map, and deriving the corresponding temporary initial value Qfuptmp from this map when the off-time Tsp is given. The temporary initial value Qfuptmp is set such that it increases as the off-time Tsp becomes longer. This is based on the assumption that the intake pipe 123 and the combustion chamber 129 of the engine 22 are cooled more as the off-time Tsp becomes longer. The lower guard value Qfupgd is set to the increment correction amount Qfup immediately before the start determination flag Fst was switched from the value 1 to the value 0 last time. By setting the initial value Qfupst by lower-guarding the temporary initial value Qfuptmp with the lower guard value Qfupgd in this way, when the temporary initial value Qfuptmp is relatively small due to the relatively short off-time Tsp, it is possible to suppress the initial value Qfupst from becoming relatively small, that is, the increment correction amount Qfup from becoming insufficient.

[0039] The decay coefficient ka can be set, for example, by experimentally determining in advance the relationship between the off-time memory value Tspmm, the coolant water temperature Tw, and the decay coefficient ka through experiments, analysis, machine learning, etc., storing it as a map, and deriving the corresponding decay coefficient ka from this map when the off-time memory value Tspmm and the coolant water temperature Tw are given. The off-time memory value Tspmm is a memory value related to the off-time Tsp and is set by the off-time memory value setting process described later. The decay coefficient ka is set such that it becomes smaller as the off-time memory value Tspmm becomes shorter and also becomes smaller as the coolant water temperature Tw becomes higher. As described above, the decay coefficient ka is used for updating the increment correction amount Qfup of the fuel injection amount increase correction after the intermittent stop history flag Fio has a value of 1 and the start-after determination flag Fst is switched from a value of 0 to a value of 1. The increment correction amount Qfup is updated by multiplying the previous increment correction amount (previous Qfup) by the decay coefficient ka. Therefore, after the start-after determination flag Fst is switched from a value of 0 to a value of 1, the increment correction amount Qfup is attenuated more steeply as the off-time memory value Tspmm becomes shorter, and the increment correction amount Qfup is attenuated more steeply as the coolant water temperature Tw becomes higher. This is based on the assumption that the intake pipe 123 and the combustion chamber 129 of the engine 22 are warmer when the off-time memory value Tspmm is short and the coolant water temperature Tw is high, and fuel vaporization failure is less likely to occur.

[0040] Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the process of setting the off-time memory value Tspmm, will be described. FIG. 3 is a flowchart showing an example of the off-time memory value setting process executed by the engine ECU 24. This routine is repeatedly executed.

[0041] When the off-time memory value setting process in FIG. 3 is executed, the engine ECU 24 first inputs data such as the off-time Tsp, the start-after determination flag Fst, and the intermittent stop history flag Fio (step S100). Here, the values set as described above are input for the off-time Tsp, the start-after determination flag Fst, and the intermittent stop history flag Fio.

[0042] Next, it is determined whether the intermittent stop history flag Fio has a value of 0 or a value of 1 (step S110). When it is determined that the intermittent stop history flag Fio has a value of 0, that is, there is no intermittent stop history of the engine 22 in the current trip, the lower guard value Tspgd is set to the value 0 (step S120), the off-time storage value Tspmm is set to the value 0 (step S130), and this process ends.

[0043] When it is determined in step S110 that the intermittent stop history flag Fio has a value of 1, that is, there is an intermittent stop history of the engine 22 in the current trip, it is determined whether the post-start determination flag Fst has a value of 0 or a value of 1 (step S140). When it is determined that the post-start determination flag Fst has a value of 0, that is, the post-start determination is off, as shown in Equation (1), the off-time Tsp is lower-guarded by the value obtained by subtracting the rate value R1 from the previous lower guard value (previous Tspgd), and the current lower guard value Tspgd is set (step S150). Subsequently, the set lower guard value Tspgd is set to the off-time storage value Tspmm (step S160), and this process ends.

[0044] Tspgd = max(Tsp, previous Tspgd - R1) (1)

[0045] When it is determined in step S140 that the post-start determination flag Fst has a value of 1, that is, when the post-start determination is on, as shown in Equation (2), the current lower guard value Tspgd is set by lower-guarding the value obtained by subtracting a rate value R2 greater than the rate value R1 from the previous lower guard value (previous Tspgd) with a value of 0 (step S170). Subsequently, the off-time storage value Tspmm is held at the previous value (step S180), and this process ends. Therefore, the off-time storage value Tspmm is held at the value immediately after the intermittent stop history flag Fio has a value of 1 and the post-start determination flag Fst switches from a value of 0 to a value of 1. After the intermittent stop flag Fio has a value of 1 and the post-start determination flag Fst switches from a value of 0 to a value of 1, as described above, an increment correction of the fuel injection amount is performed using the increment correction amount Qfup that has decreased over time from the initial value Qfst using the attenuation coefficient ka based on the off-time storage value Tspmm and the coolant water temperature Tw.

[0046] Tspgd = max(previous Tspgd - R2, 0) (2)

[0047] Thus, when the intermittent stop flag Fio has a value of 1, when the post-start determination flag Fst has a value of 0, the lower guard value Tspgd is set according to the above-described Equation (1), and the set lower guard value Tspgd is set to the off-time storage value Tspmm. When the post-start determination flag Fst has a value of 1, the off-time storage value Tspmm is held. As a result, when the post-start determination flag Fst switches from a value of 0 to a value of 1 in a state where the off-time Tsp is relatively short, such as when self-sustaining COM start control or COM start control is performed after the fuel injection and ignition of the engine 22 are stopped, it is possible to suppress the off-time storage value Tspmm from becoming too short. Therefore, it is possible to suppress the attenuation coefficient ka from becoming too small and suppress the decrease rate of the increment correction amount Qfup from becoming too large (becoming too steep). Moreover, when the coolant water temperature Tw increases, the attenuation coefficient ka can be decreased and the decrease rate of the increment correction amount Qfup can be increased.

[0048] 4 is a time chart showing an example of the intermittent stop history flag Fio, the post-start determination flag Fst, the off time Tsp, the lower limit guard value Tspgd, and the off time stored value Tspmm. As shown in the figure, when the ignition switch 80 is turned on and the intermittent stop history flag Fio is set to the value 0, the off time Tsp, the lower limit guard value Tspmin, and the off time stored value Tspmm are held at the value 0. Then, when the post-start determination flag Fst is switched to the value 1 for the first time and then to the value 0 (time t11), the intermittent stop history flag Fio is switched from the value 0 to the value 1. Then, when the post-start determination flag Fst is held at the value 0 (times t11 to t12), the off time Tsp increases, and the lower limit guard value Tspgd and the off time stored value Tspmm increase accordingly. Thereafter, when the post-start determination flag Fst is switched from value 0 to value 1 and held (times t12 to t13, t14 to t15, t16 to t17), the off-time Tsp and the off-time stored value Tspmm are held and the lower limit guard value Tspgd is decreased. Also, when the post-start determination flag Fst is switched from value 1 to value 0 and held (times t13 to t14, t15 to t16, t17 onwards), the off-time Tsp is reset to value 0 and then increases, and the lower limit guard value Tspgd and the off-time stored value Tspmm decrease or increase in conjunction with the off-time Tsp. This makes it possible to prevent the off-time stored value Tspmm from becoming too short, such as decreasing to value 0. In particular, when the post-start determination flag Fst is switched from value 0 to value 1 (time t16) while the off-time Tsp is relatively short, such as when performing independent COM start control or COM start control, it is possible to prevent the off-time stored value Tspmm from becoming too short. This makes it possible to prevent the damping coefficient ka from becoming too small due to the off-time stored value Tspmm, and to prevent the rate of decrease of the boost correction amount Qfup from becoming too large (too steep).

[0049] In the engine device included in the hybrid vehicle 20 of the embodiment described above, when the intermittent stop flag Fio has a value of 1, after the start determination flag Fst is switched from a value of 0 to a value of 1, an increment correction amount Qfup using the decay coefficient ka based on the off-time storage value Tspmm and the coolant temperature Tw is taken into account, and an increment correction of the fuel injection amount is performed. In this case, when the start determination flag Fst has a value of 0, the off-time Tsp is lower-limited using the lower-limit guard value Tspgd to set the off-time Tspmm. Thereby, when the start determination flag Fst is switched from a value of 0 to a value of 1 in a state where the off-time Tsp is relatively short, it is possible to suppress the off-time storage value Tspmm from becoming too short. Therefore, it is possible to suppress the decay coefficient ka from becoming too small and suppress the decrease rate of the increment correction amount Qfup from becoming too large (becoming too steep). Moreover, when the coolant temperature Tw increases, the decay coefficient ka can be decreased and the decrease rate of the increment correction amount Qfup can be increased.

[0050] In the engine device included in the hybrid vehicle 20 of the embodiment, when the intermittent stop flag Fio has a value of 1, the rate value R1 used for setting the lower-limit guard value Tspgd when the start determination flag Fst has a value of 0 and the rate value R2 used for setting the lower-limit guard value Tspgd when the start determination flag Fst has a value of 1 are made different. However, the rate value R1 and the rate value R2 may be the same value.

[0051] In the engine device included in the hybrid vehicle 20 of the embodiment, when the intermittent stop flag Fio has a value of 1, when the start determination flag Fst has a value of 0, the off-time Tsp is lower-limited using the lower-limit guard value Tspgd to set the off-time storage value Tspmm, and when the start determination flag Fst has a value of 1, the off-time storage value Tspmm is held at the previous value. However, regardless of the value of the start determination flag Fst, the off-time Tsp may be lower-limited using the lower-limit guard value Tspgd to set the off-time storage value Tspmm. In this case, as the lower-limit guard value Tspgd, a fixed value slightly larger than 0 may be used.

[0052] In the hybrid vehicle 20 of the embodiment, an automatic transmission 45 with six forward speeds is provided. However, an automatic transmission with four forward speeds, five forward speeds, eight forward speeds, or the like may also be provided.

[0053] In the hybrid vehicle 20 of the embodiment, an engine ECU 24, a motor ECU 34, and an HV ECU 70 are provided. However, at least two of these may be integrally configured.

[0054] In the engine device of the embodiment, it is mounted on the hybrid vehicle 20, but it may be mounted on a moving body other than a vehicle or incorporated into equipment that does not move.

[0055] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the "engine", and the engine ECU 24 corresponds to the "control device".

[0056] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the column of means for solving the problems in the embodiment. Therefore, it does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0057] As described above, the embodiments have been used to explain the forms for implementing the present invention. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Industrial Applicability

[0058] The present invention can be used in the manufacturing industry of engine devices and the like.

Description of Symbols

[0059] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine ECU, 25 Starter motor, 26 Alternator, 30 Motor, 30a Rotation position sensor, 31 Rotation shaft, 32 Inverter, 34 Motor ECU, 40 Automatic transmission, 41 Input shaft, 41a Rotational speed sensor, 42 Output shaft, 42a Rotational speed sensor, 43 Torque converter, 44 Transmission input shaft, 44a Rotational speed sensor, 45 Automatic transmission, 48 Differential gear, 49 Driving wheel, 60 High-voltage battery, 61 High-voltage side power line, 62 Low-voltage battery, 63 Low-voltage side power line, 64 DC / DC converter, 70 HVECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 87 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. An engine, a control device for controlling the engine, and an engine device comprising: after the start-up determination of the engine has switched from off to on, the control device decreases the increment correction amount of the fuel injection amount of the engine over time using a decay coefficient that decreases as the off-time storage value related to the off-time, which is the duration of the off state of the start-up determination and starts to be reset to 0 when the start-up determination switches from on to off and then increases with the passage of time, becomes shorter and also decreases as the coolant water temperature of the engine becomes higher, further, when the start-up determination is off, the control device sets the off-time storage value by lower-limit guarding the off-time using a lower-limit guard value, and when the start-up determination is on, the control device holds the off-time storage value at the previous value, an engine device.

2. The engine device according to claim 1, wherein the control device decreases the lower-limit guard value over time from the value when the start-up determination switches from off to on, an engine device.

3. The engine device according to claim 2, wherein the control device decreases the lower-limit guard value more steeply when the start-up determination is on than when the start-up determination is off, an engine device.

Images