JP7480586B2 - Hybrid Vehicles - Google Patents

Description

The present invention relates to a hybrid vehicle, and more specifically, to a hybrid vehicle equipped with an engine, a motor, an electricity storage device, and a charger.

Conventionally, this type of hybrid vehicle has been proposed to include an engine (internal combustion engine), a motor, a power storage device (battery), and a charger (power receiving plug) (see, for example, Patent Document 1). The engine outputs power by burning fuel. The power storage device exchanges power with the motor. The charger charges the power storage device using power from an external power source. In this hybrid vehicle, the engine and the motor are controlled to run in a first mode that prioritizes motor running between hybrid running, in which the vehicle runs using power from the engine and the motor so as to reduce the storage ratio of the power storage device, and motor running, in which the vehicle runs using power from the motor with the engine stopped, and a second mode that switches between hybrid running and motor running to maintain the storage ratio within a predetermined range.

JP 2019-156176 A

As the above-mentioned hybrid vehicle, one equipped with an engine equipped with a filter for removing particulate matter in the exhaust system is in widespread use. In such hybrid vehicles, when the driving distance in motor driving becomes long, the engine may be started near the end of a trip (the period from starting the system to stopping it) and the system may be stopped immediately. If the engine is started near the end of such a trip, unburned fuel may remain in the combustion chamber and mix with the lubricating oil that lubricates the engine, or the unburned fuel may reach the filter and a relatively large amount of particulate matter may accumulate on the filter, causing the system to be stopped in such a state. When the system is stopped, the power storage device is charged using power from an external power source, and the next system start-up is often performed with a high storage rate of the power storage device. If the storage rate is high at the time of system start-up, there will be more opportunities for motor driving after the system is started, and there will be fewer opportunities for the engine to be started. If the engine is started less often, it will be difficult to eliminate the state in which unburned fuel mixes with the lubricating oil or a relatively large amount of particulate matter accumulates on the fuel filter. For these reasons, in hybrid vehicles that can charge a power storage device using electricity from an external power source, it is recognized that an important issue is to ensure that the engine is operated properly in order to prevent unburned fuel from contaminating the lubricating oil or a large amount of particulate matter from accumulating in the filter.

The main objective of the present invention is to ensure that the engine is operated properly in a hybrid vehicle that can charge a power storage device using power from an external power source.

The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main objective.

The hybrid vehicle of the present invention is
an engine having a filter for removing particulate matter in an exhaust system, which outputs power by burning fuel and is lubricated by lubricating oil;
A motor;
a power storage device that exchanges power with the motor;
a charger that charges the power storage device using electric power from an external power supply;
a control device that controls the engine and the motor to run the vehicle by switching between a plurality of modes including a first mode in which a hybrid running mode in which the vehicle runs using power from the engine and power from the motor so as to reduce a power storage ratio of the power storage device and a motor running mode in which the vehicle runs using power from the motor with the engine stopped are prioritized, and a second mode in which the vehicle runs by switching between the hybrid running mode and the motor running mode so as to maintain the power storage ratio within a predetermined range;
A hybrid vehicle comprising:
The control device, in the first mode, when the amount of the fuel mixed into the lubricating oil or the amount of the particulate matter deposited on the filter is equal to or greater than a predetermined amount, controls the engine and the motor to prohibit motor driving and to drive in hybrid driving.

In the hybrid vehicle of the present invention, the engine and the motor are controlled to switch between a plurality of modes, including a first mode in which the hybrid driving mode, in which the vehicle runs using power from the engine and power from the motor, so that the storage ratio of the power storage device is reduced, and a second mode in which the vehicle runs by switching between hybrid driving and motor driving so as to maintain the storage ratio within a predetermined range. In the first mode, when the amount of fuel mixed into the lubricating oil or the amount of particulate matter deposited on the filter is equal to or greater than a predetermined amount, the engine and the motor are controlled to prohibit motor driving and run in hybrid driving. The predetermined amount is a threshold value for determining whether or not to start the engine early. In this way, by increasing the opportunities for hybrid driving when the amount of fuel mixed into the lubricating oil or the amount of particulate matter deposited on the filter is equal to or greater than a predetermined amount, the opportunities for proper engine operation can be ensured.

In such a hybrid vehicle of the present invention, the control device may control the engine and the motor so that, when the power storage ratio is greater than a first ratio when the system is started, the vehicle runs in the first mode until the power storage ratio becomes equal to or less than a second ratio lower than the first ratio, and runs in the second mode after the power storage ratio becomes equal to or less than the second ratio. In this way, when the amount of fuel mixed into the lubricating oil or the amount of particulate matter deposited on the filter is equal to or greater than a predetermined amount, an opportunity to operate the engine early after the system is started can be ensured.

The hybrid vehicle of the present invention may further include a first motor, a planetary gear having three rotating elements connected to the first motor, the engine, and a drive shaft connected to an axle, and a second motor connected to the drive shaft, the power storage device exchanges power with the first and second motors, and the control device may prohibit the motor driving during hybrid driving when the mixing amount or the deposition amount is equal to or greater than the predetermined amount in the first mode, and control the engine and the first and second motors so that the vehicle runs at the required power while operating the engine at a rotation speed equal to or greater than a lower limit rotation speed. Because the engine is operated at a rotation speed equal to or greater than the lower limit rotation speed, the power output from the engine can be increased, and the mixing of fuel into the lubricating oil and the deposition of particulate matter in the filter can be eliminated more quickly.

In this case, in the hybrid driving mode when the mixing amount or the deposition amount is equal to or greater than the predetermined amount in the first mode, the motor driving mode may be permitted when the charging power for charging the power storage device exceeds an input limit, which is the maximum value of the charging power allowed for the power storage device. In this way, the power storage device can be prevented from being charged with a power that exceeds the input limit.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention; FIG. 2 is a diagram showing an outline of the configuration of an engine 22. 4 is a flowchart showing an example of a PM accumulation amount calculation processing routine executed by an engine ECU 24. 4 is a flowchart showing an example of a mixed fuel amount calculation process routine executed by an engine ECU 24. 4 is a flowchart showing an example of a post-system start-up control routine executed by an HVECU 70. 4 is a timing chart showing an example of changes over time in the start-up state of the system, the mode (CD, CS mode), the PM accumulation amount Mpm, a start request to the engine 22 in the CD mode, and the rotation speed Ne of the engine 22.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 according to one embodiment of the present invention. Figure 2 is a schematic diagram showing the configuration of an engine 22. As shown in the figure, the hybrid vehicle 20 according to the embodiment includes the engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, a charger 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

The engine 22 is configured as a multi-cylinder internal combustion engine that uses a hydrocarbon fuel such as gasoline or diesel to output power through each of the intake, compression, expansion (explosive combustion), and exhaust strokes. The engine 22 draws air purified by the air cleaner 122 into the intake pipe 125 via the throttle valve 124, and injects fuel from the fuel injection valve 126 to mix the air and fuel. This mixture is then drawn into the combustion chamber 129 via the intake valve 128a, where it is explosively combusted by an electric spark from the ignition plug 130, and the reciprocating motion of the piston 132, which is pushed down by the energy of the resulting combustion, is converted into the rotational motion of the crankshaft 26. The exhaust gas discharged from the combustion chamber 129 to the exhaust pipe 133 through the exhaust valve 128b is passed through an exhaust purification device 134 having a purification catalyst (three-way catalyst) 134a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), and a gasoline particulate filter (hereinafter referred to as "GPF") 25. The GPF 25 is formed as a porous filter using ceramics, stainless steel, or the like, and captures particulate matter (PM) such as soot. The operation of the engine 22 is controlled by the engine ECU 24.

The engine ECU 24 is configured as a microprocessor centered around a CPU (not shown), and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, input/output ports, and communication ports.

Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via input ports. Examples of signals input to the engine ECU 24 include the crank angle θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 26, and the cooling water temperature Tw from the water temperature sensor 142 that detects the temperature of the cooling water of the engine 22. In addition, cam angles θca and θcb from cam position sensors 144a and 144b that detect the rotational position of the intake camshaft that opens and closes the intake valve 128a and the exhaust camshaft that opens and closes the exhaust valve 128b can also be mentioned. In addition, the throttle opening TH from the throttle valve position sensor 146 that detects the position of the throttle valve 124, the intake air volume Qa from the air flow meter 148 attached to the intake pipe 125, and the intake air temperature Ta from the temperature sensor 149 attached to the intake pipe 125 can also be mentioned. Examples of the air-fuel ratio AF from the air-fuel ratio sensor 135a attached to the upstream side of the exhaust purification device 134 of the exhaust pipe 133, the oxygen signal O2 from the oxygen sensor 135b attached to the downstream side of the exhaust purification device 134 of the exhaust pipe 133, the catalyst temperature Tsc from the temperature sensor 135c that detects the temperature of the three-way catalyst 134a, etc. can also be mentioned. In addition, the GPF temperature Tgpf from the temperature sensor 25c that detects the temperature of the GPF 25 can also be mentioned. In addition, the oil temperature Toil from the temperature sensor 150a that detects the temperature of the engine oil stored in the oil pan 150 for lubricating the engine 22 can also be mentioned.

Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. Examples of signals output from the engine ECU 24 include a drive control signal to the throttle motor 136 that adjusts the position of the throttle valve 124, a drive control signal to the fuel injection valve 126, and a drive control signal to the ignition coil 138 integrated with the igniter.

The engine ECU 24 calculates the rotation speed of the crankshaft 26, i.e., the rotation speed Ne of the engine 22, based on the crank angle θcr. The engine ECU 24 also calculates the volumetric efficiency KL (the ratio of the volume of air actually taken 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 148 and the engine 22 rotation speed Ne. Furthermore, the engine ECU 24 calculates the integrated intake air amount ΣQa, which is the integration of the intake air amount Qa during the period from when the engine 22 is started to when it is stopped, and the time since start tst, which is the time since the engine 22 is started. The integrated intake air amount ΣQa and the time since start tst are reset to 0 when the engine 22 is stopped.

The engine ECU 24 executes a PM accumulation amount calculation processing routine illustrated in FIG. 3 to calculate the PM accumulation amount Mpm as the estimated accumulation amount of particulate matter trapped in the GPF 25. The PM accumulation amount calculation processing routine is repeatedly executed at predetermined time intervals (e.g., every few msec).

When the PM accumulation amount calculation processing routine is executed, the engine ECU 24 executes a process of inputting necessary data such as the cooling water temperature Tw, the GPF temperature Tgpf, the engine 22 rotation speed Ne, the intake air amount Qa, and the cumulative intake air amount ΣQa (step S100). The cooling water temperature Tw is inputted from the water temperature sensor 142. The GPF temperature Tgpf is inputted from the temperature sensor 25c. The intake air amount Qa is inputted from the air flow meter 148. The engine 22 rotation speed Ne is inputted from the calculation based on the crank angle θcr. The cumulative intake air amount ΣQa is inputted from the intake air amount Qa accumulated during the period from when the engine 22 is started to when it is stopped.

After inputting the necessary data in this manner, it is determined whether or not fuel injection is being performed in the engine 22 (step S110). When fuel injection is being performed in the engine 22, it is determined that particulate matter is being discharged from the combustion chamber 129 toward the GPF 25, and the amount of particulate matter discharged from the combustion chamber 129 to the GPF 25 (PM emission amount) Mpmex is set (step S120).

The PM emission amount Mpmex is set by multiplying the value (=f1(Ne, Qa, Tw, ΣQa)) derived as the corresponding PM emission amount by the emission setting map by applying the engine 22 rotation speed Ne, the intake air amount Qa, the cooling water temperature Tw, and the accumulated intake air amount ΣQa to the emission setting map, and multiplying it by the coefficient kex. In the emission setting map, the PM emission amount is set so that when the engine 22 rotation speed is high, the PM emission amount is larger than when it is low, when the intake air amount is large, the PM emission amount is larger than when it is low, when the cooling water temperature is low, the PM emission amount is larger than when it is high, and when the accumulated intake air amount is small, the PM emission amount is larger than when it is large. The coefficient kex is set so that when the intake air amount Qa is small, the PM emission amount is larger than when it is large. This is because when the engine 22 speed is high, the amount of particulate matter discharged from the combustion chamber 129 per unit time is greater than when the engine 22 speed is low; when the engine 22 intake air volume is large, the amount of particulate matter flowing into the GPF 25 is greater than when the engine 22 intake air volume is small; when the cooling water temperature is low, the engine 22 is not warmed up sufficiently and the amount of particulate matter discharged from the combustion chamber 129 is greater than when the cooling water temperature is high; when the cumulative intake air volume is small, the amount of particulate matter discharged from the combustion chamber 129 is greater than when the cumulative intake air volume is large; and when the intake air volume is small, the amount of particulate matter discharged from the combustion chamber 129 is greater than when the cumulative intake air volume is large.

Once the PM emission amount Mpmex is set, the PM deposition amount Mpm is set to the sum of the PM deposition amount Mpm (previous Mpm) set when the previous PM deposition amount calculation processing routine was executed and the PM emission amount Mpmex (=previous Mpm + Mpmex) (step S130), and the PM deposition amount calculation processing routine is terminated.

When fuel injection to the engine 22 is not being performed in step S110 (for example, when the accelerator pedal 83 described below is released and fuel supply is stopped), it is determined that particulate matter is being burned in the GPF 25, and the amount of particulate matter burned (PM combustion amount) Mpmc in the GPF 25 is set (step S140).

The PM combustion amount Mpmc is set by multiplying the value (=f2(previous Mpm, Tgpf, Qa)) derived as the corresponding PM combustion amount by the combustion amount setting map obtained by previously determining the relationship between the PM accumulation amount, the temperature of the GPF 25, the intake air amount of the engine 22, and the PM combustion amount when this routine was last executed by experiments, analysis, etc., and storing it in ROM as a combustion amount setting map. In the combustion amount setting map, the PM combustion amount is set so that when the PM accumulation amount when this routine was last executed is large, it is larger than when it is small, when the temperature of the GPF 25 is high, it is larger than when it is low, and when the intake air amount of the engine 22 is large, it is larger than when it is small. The coefficient kc is set so that when the intake air amount Qa is large, it is larger than when it is small. This is because the amount of particulate matter burned in the GPF 25 is greater when the amount of PM accumulation the previous time this routine was run, compared to when it was small, when the temperature of the GPF 25 is high compared to when it is low, and when the intake air volume is large compared to when it is small.

Once the PM combustion amount Mpmc is set, the PM accumulation amount Mpm is set to the value obtained by subtracting the set PM combustion amount Mpmc from the previous Mpm (= previous Mpm - Mpmc) (step S150), and the PM accumulation amount calculation processing routine ends. In this way, the engine ECU 24 calculates the PM accumulation amount Mpm.

The engine ECU 24 executes the mixed fuel amount calculation processing routine illustrated in FIG. 4 to calculate the mixed fuel amount Vfc as the estimated amount of fuel mixed into the engine oil. The mixed fuel amount calculation processing routine is repeatedly executed at predetermined time intervals (e.g., every few msec).

When the mixed fuel amount calculation processing routine is executed, the engine ECU 24 executes a process of inputting necessary data such as the cooling water temperature Tw, the oil temperature Toil, the accumulated intake air amount ΣQa, and the elapsed time after start tst (step S200). The cooling water temperature Tw is inputted from the water temperature sensor 142. The GPF temperature Tgpf is inputted from the temperature sensor 25c. The accumulated intake air amount ΣQa is inputted from the accumulation of the intake air amount Qa during the period from when the engine 22 is started to when operation is stopped. The elapsed time after start tst is inputted from the measurement of the elapsed time since the engine 22 is started.

After inputting the necessary data in this manner, it is determined whether the cumulative intake air amount ΣQa is equal to or greater than the threshold value Sth (step S210) and whether the operation of the engine 22 is stopped (step S220). The threshold value Sth is a threshold value for determining whether a certain period of time has passed since the engine 22 was started. When the cumulative intake air amount ΣQa is equal to or greater than the threshold value Sth, or when the operation of the engine 22 is stopped even if the cumulative intake air amount ΣQa is less than the threshold value Sth, it is determined that the amount of fuel mixed into the engine oil has increased, and an additional amount Vfcadd is set as the increase in the amount of fuel mixed into the engine oil (step S250).

The additional amount Vfcadd is set by multiplying the value (=f3(ΣQa, tst)) derived as the corresponding additional amount by applying the cumulative intake air amount ΣQa and the elapsed time after starting tst to the additional amount setting map, and multiplying it by the coefficient kadd. In the additional amount setting map, the additional amount is set to be larger when the cumulative intake air amount is small compared to when it is large, and larger when the elapsed time is short compared to when it is long. The coefficient kadd is set to be larger when the cooling water temperature Tw is low compared to when it is high. This is because when the cumulative intake air volume is small, the temperature of the engine 22 is lower than when it is large, when the elapsed time is short compared to when it is long, and when the cooling water temperature Tw is low compared to when it is high, the amount of fuel remaining in the combustion chamber 129 is greater, and the amount of fuel mixed into the engine oil increases.

When the added amount Vfcadd is set, the mixed fuel amount Vfc is set to the value (= previous Vfc + Vfcadd) obtained by adding the added amount Vfcadd set to the mixed fuel amount Vfc (previous Vfc) set when the mixed fuel amount calculation processing routine was executed last time (step S260), and the mixed fuel amount calculation processing routine is terminated.

When the engine 22 is operating even if the cumulative intake air amount ΣQa is less than the threshold value Sth in steps S210 and S220, it is determined whether the time since starting tst is equal to or greater than the threshold value tref (step S230) and whether the cooling water temperature Tw is equal to or greater than the threshold value Twref (step S240). The threshold values tref and Twref are threshold values for determining whether the warm-up of the engine 22 is complete and the fuel mixed in the engine oil is volatilizing and decreasing. When the time since starting tst is less than the threshold value tref or the cooling water temperature Tw is less than the threshold value Twref, it is determined that the warm-up of the engine 22 is not complete and the fuel mixed in the engine oil is not decreasing, and the mixed fuel amount calculation processing routine is terminated. At this time, the mixed fuel amount Vfc is maintained at the previous Vfc.

When the time since startup tst is equal to or greater than the threshold value tref and the cooling water temperature Tw is equal to or greater than the threshold value Twref in steps S230 and S240, it is determined that the warm-up of the engine 22 is complete and the amount of fuel mixed in the engine oil is decreasing, and a subtraction amount Vfcsb is set as the amount of fuel mixed in the engine oil that is being reduced (step S270).

The subtraction amount Vfcsb is set as a value (=f4(previous Vfc, Toil)) derived by applying the previous Vfc and the oil temperature Toil to the subtraction amount setting map, which is obtained by experimenting or analyzing the relationship between the amount of mixed fuel set when the mixed fuel amount calculation processing routine was executed last time, the temperature of the engine oil, and the subtraction amount as the reduction amount of fuel mixed into the engine oil. In the subtraction amount setting map, the subtraction amount is set to be larger when the mixed fuel amount set when the mixed fuel amount calculation processing routine was executed last time is large compared to when it is small, and larger when the oil temperature is high compared to when it is low. This is based on the fact that the amount of fuel volatilized in the engine oil is larger when the mixed fuel amount set when the mixed fuel amount calculation processing routine was executed last time is large compared to when it is small, and when the oil temperature is high compared to when it is low.

Once the subtraction amount Vfcsb is set, the mixed fuel amount Vfc is set to the value obtained by subtracting the set subtraction amount Vfcsb from the previous Vfc (= previous Vfc - Vfcsb) (step S280), and the mixed fuel amount calculation processing routine ends. In this way, the engine ECU 24 calculates the mixed fuel amount Vfc.

The planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The ring gear of the planetary gear 30 is connected to a drive shaft 36 which is connected to drive wheels 38a, 38b via a differential gear 37. The carrier of the planetary gear 30 is connected to the crankshaft 26 of the engine 22 via a damper 28.

Motor MG1 is configured, for example, as a synchronous generator motor, and as described above, the rotor is connected to the sun gear of planetary gear 30. Motor MG2 is configured, for example, as a synchronous generator motor, and the rotor is connected to drive shaft 36. Inverters 41, 42 are connected to battery 50 via power line 54. Motors MG1, MG2 are driven to rotate by motor electronic control unit (hereinafter referred to as "motor ECU") 40 controlling the switching of multiple switching elements (not shown) of inverters 41, 42.

The motor ECU 40 is configured as a microprocessor centered on a CPU (not shown), and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. Signals from various sensors necessary for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via the input port. Examples of signals input to the motor ECU 40 include rotational positions θm1 and θm2 from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and phase currents from current sensors that detect the currents flowing through each phase of the motors MG1 and MG2. The motor ECU 40 outputs switching control signals to multiple switching elements (not shown) of the inverters 41 and 42 via the output port. The motor ECU 40 is connected to the HVECU 70 via a communication port, and drives and controls the motors MG1 and MG2 using control signals from the HVECU 70, and outputs data regarding the driving state of the motors MG1 and MG2 to the HVECU 70 as necessary. The motor ECU 40 calculates the rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position detection sensors 43 and 44.

The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. As described above, the battery 50 is connected to the inverters 41, 42 via the power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as the "battery ECU") 52.

Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of signals input to the battery ECU 52 include a battery voltage Vb from a voltage sensor 51a installed between the terminals of the battery 50, a battery current Ib from a current sensor 51b attached to the output terminal of the battery 50, and a battery temperature Tb from a temperature sensor 51c attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via a communication port, and outputs data regarding the state of the battery 50 to the HVECU 70 as necessary. The battery ECU 52 calculates the power storage ratio SOC based on the integrated value of the battery current Ib from the current sensor 51b. The power storage ratio SOC is the ratio of the capacity of the power that can be discharged from the battery 50 to the total capacity of the battery 50. In addition, the battery ECU 52 calculates the input limit Win based on the calculated power storage ratio SOC and the battery temperature Tb from the temperature sensor 51c. The input limit Win is the maximum allowable power that may be charged and discharged from the battery 50.

The charger 60 is connected to the power line 54, and is configured to be able to charge the battery 50 using power from the external power source 69 when the power plug 61 is connected to an external power source 69 such as a household power source. The charger 60 includes an AC/DC converter and a DC/DC converter. The AC/DC converter converts AC power from the external power source 69, supplied via the power plug 61, into DC power. The DC/DC converter converts the voltage of the DC power from the AC/DC converter and supplies it to the battery 50. When the power plug 61 is connected to the external power source 69, the charger 60 supplies power from the external power source 69 to the battery 50 by controlling the AC/DC converter and the DC/DC converter by the HVECU 70.

Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory 72, an input/output port, and a communication port. Signals from various sensors are input to the HVECU 70 via the input port. Examples of signals input to the HVECU 70 include an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, and a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85. In addition, a vehicle speed V from a vehicle speed sensor 88 can be included. In addition, a connection signal SWC from a connection switch 62 that is attached to the power plug 61 and determines whether the power plug 61 is connected to an external power source 69 can be included. A control signal to the charger 60 and the like are output from the HVECU 70 via the output port. As described above, the HVECU 70 is connected to the engine ECU 24, motor ECU 40, and battery ECU 52 via communication ports, and exchanges various control signals and data with the engine ECU 24, motor ECU 40, and battery ECU 52.

In the hybrid vehicle 20 of the embodiment thus configured, when the power plug 61 is connected to the external power source 69 while the vehicle is parked with the system off (system stopped) at a charging point such as a home or a charging station, the charger 60 is controlled so that the battery 50 is charged using power from the external power source 69. Then, when the system is turned on (system started) after the battery 50 is charged, the vehicle runs in CD (Charge Depleting) mode (first mode) until the charge ratio SOC of the battery 50 falls below the threshold value Shv, and after the charge ratio SOC of the battery 50 falls below the threshold value Shv, the vehicle runs in CS (Charge Sustaining) mode (second mode) until the system is turned off.

Here, the CD mode is a mode in which the storage rate SOC of the battery 50 is reduced, and the CS mode is a mode in which the storage rate SOC of the battery 50 is maintained within a management range including the control center SOC* (e.g., threshold value Shv). In the embodiment, in the CD mode, the storage rate SOC of the battery 50 is reduced by prioritizing electric (motor) driving (EV driving) in which the engine 22 is stopped from rotating over hybrid driving (HV driving) in which the engine 22 is rotated (operated). In addition, in the CS mode, the storage rate SOC of the battery 50 is maintained within the management range by switching between EV driving and HV driving as necessary.

In HV driving, the HV ECU 70 basically sets the driving torque Td* required for driving (required from the drive shaft 36) based on the accelerator opening Acc and the vehicle speed V, and calculates the driving power Pd* required for driving by multiplying the set driving torque Td* by the rotation speed Nd of the drive shaft 36 (the rotation speed Nm2 of the motor MG2). Next, the charge/discharge required power Pb* of the battery 50 (a positive value when discharging from the battery 50) is set so that the value (SOC-SOC*) obtained by subtracting the control center SOC* from the charge ratio SOC of the battery 50 is close to 0, and the required power Pe* required for the vehicle (required from the engine 22) is set by subtracting the charge/discharge required power Pb* of the battery 50 from the driving power Pd*. Then, the target revolution speed Ne* and target torque Te* of the engine 22 and the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are set so that the required power Pe* is output from the engine 22 and the running torque Td* is output to the drive shaft 36. The target revolution speed Ne* and target torque Te* of the engine 22 are then transmitted to the engine ECU 24, and the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are transmitted to the motor ECU 40. Upon receiving the target revolution speed Ne* and target torque Te* of the engine 22, the engine ECU 24 performs operation control of the engine 22 (specifically, intake air amount control, fuel injection control, ignition control, etc.) so that the engine 22 is operated based on the target revolution speed Ne* and target torque Te*. When the motor ECU 40 receives the torque commands Tm1* and Tm2* for the motors MG1 and MG2, it controls the drive of the motors MG1 and MG2 (specifically, controls the switching of multiple switching elements of the inverters 41 and 42) so that the motors MG1 and MG2 are driven by the torque commands Tm1* and Tm2*.

In EV driving, the HVECU 70 sets the driving torque Td* based on the accelerator opening Acc and the vehicle speed V, sets the torque command Tm1* of the motor MG1 to a value of 0, sets the torque command Tm2* of the motor MG2 so that the driving torque Td* is output to the drive shaft 36, and transmits the torque commands Tm1* and Tm2* of the motors MG1 and MG2 to the motor ECU 40. The drive control of the motors MG1 and MG2 by the motor ECU 40 has been described above.

Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when the system is started, will be described. FIG. 5 is a flowchart showing an example of a post-system start-up control routine executed by the HVECU 70. The post-system start-up control routine is repeatedly executed at predetermined time intervals (e.g., several msec) after the system is started.

When the control routine is executed after the system is started, the HVECU 70 executes a process to input data such as the PM accumulation amount Mpm, the mixed fuel amount Vfc, and the rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 (step S300). The PM accumulation amount Mpm and the mixed fuel amount Vfc are calculated by the engine ECU 24 and input via communication. The rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 are calculated by the motor ECU 40 and input via communication.

Once the data has been input in this way, it is determined whether or not the vehicle is in CD mode (step S310). If the vehicle is not in CD mode, motor driving is permitted (step S390), and the control routine ends after system startup. In this case, since the vehicle is in CS mode, the vehicle will switch between EV driving and HV driving as necessary to drive while maintaining the storage ratio SOC of the battery 50 within a management range.

When the mode is CD in step S310, it is determined whether the PM deposition amount Mpm is equal to or greater than a threshold value Mth (step S320) and whether the mixed fuel amount Vfc is equal to or greater than a threshold value Vfcth (step S330). The threshold value Mth is a threshold value for determining whether it is better to start the engine 22 early to warm up the engine 22 and raise the GPF 25 to a temperature that promotes the combustion of particulate matter, and is set to, for example, 1.5 g, 1.8 g, 2.1 g, etc. The threshold value Vfcth is a threshold value for determining whether it is better to start the engine 22 early to warm up the engine 22 and raise the engine oil to a temperature that promotes the evaporation of fuel, and is set to, for example, 4.5× ^{10-4 m3} , 5.0× ^{10-4 m3} , 5.5× ^{10-4 m3} , etc.

When the PM accumulation amount Mpm is less than the threshold value Mth in step S320 and the fuel mixing amount Vfc is less than the threshold value Vfcth in step S330, it is determined that there is no need to start the engine 22 early, EV driving is permitted (step S390), and the post-system startup control routine is terminated. Since we are now considering the case where the vehicle is in CD mode, if EV driving is permitted, driving in the above-mentioned CD mode, i.e., electric (motor) driving (EV driving) with the engine 22 stopped rotating is prioritized over hybrid driving (HV driving) with the engine 22 rotating (operating), and driving is performed so as to reduce the storage rate SOC of the battery 50.

When the PM accumulation amount Mpm is equal to or greater than the threshold value Mth in step S320, or when the PM accumulation amount Mpm is less than the threshold value Mth in step S320 but the fuel mixing amount Vfc is equal to or greater than the threshold value Vfcth in step S330, it is determined whether the charge/discharge power Pchg for charging/discharging the battery 50 after the engine 22 is started and operation is commenced is equal to or greater than the input limit Win (negative value) (steps S340 to S380).

In step S340, the provisional rotation speed Ntmp and the target torque Te* of the engine 22 are set so that the required power Pe* described above is output from the engine 22, and the larger of the provisional rotation speed Ntmp and the lower limit rotation speed Nmin (e.g., 1200 rpm, 1300 rpm, 1400 rpm, etc.) is set as the target rotation speed Ne* of the engine 22. The lower limit rotation speed Nmin is a rotation speed that is determined in advance by experiment, analysis, etc. as the lower limit value of the rotation speed at which the engine 22 can be operated while outputting torque, and is set to a rotation speed slightly higher than the idle rotation speed when the engine 22 is operated autonomously. In this way, by limiting the rotation speed Ne of the engine 22 with the lower limit rotation speed Nmin, the power output from the engine 22 can be increased to a certain extent.

Next, the target rotation speed Nm1* of the motor MG1 is set by the following formula (1) using the target rotation speed Ne* of the engine 22, the rotation speed Nm2 of the motor MG2, and the gear ratio ρ of the planetary gear 30, and the torque command Tm1* of the motor MG1 is set by formula (2) based on the set target rotation speed Nm1* and the input rotation speed Nm1 of the motor MG1 (step S350). Here, formula (1) is a dynamic relational expression for the rotating elements of the planetary gear 30. Formula (1) can be easily derived by using a collinear diagram showing the dynamic relationship between the rotation speed and torque of the rotating elements of the planetary gear 30 when traveling with power output from the engine 22. Formula (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotation speed Nm1*, and in formula (2), "k1" in the second term on the right side is the gain of the proportional term, and "k2" in the third term on the right side is the gain of the integral term.

Nm1*=Ne*・(1+ρ)/ρ-Nm2/（ρ） (1)
Tm1* = -ρ Te* / (1 + ρ) + k1 (Nm1* - Nm1) + k2 ∫ (Nm1* - Nm1) dt (2)

Then, the torque command Tm2* of the motor MG2 is calculated by adding the torque command Tm1* set to the required torque Tr* divided by the gear ratio ρ of the planetary gear 30 (step S360) according to the following equation (3). Here, equation (3) can be easily derived from the alignment chart used to derive equation (1).

Tm2*=Tr*+Tm1*/ρ (3)

Next, the charge/discharge power Pchg (a negative value when charging the battery 50) for charging and discharging the battery 50 is calculated using the following equation (4) (step S370): The sum of the torque command Tm1* multiplied by the rotation speed Nm1 of the motor MG1 and the torque command Tm2* multiplied by the rotation speed Nm2 of the motor MG2.

Pch=Tm1*Nm1+Tm2*Nm2 (4)

When the charge/discharge power Pchg is calculated, it is determined whether the charge/discharge power Pchg is equal to or greater than the input limit Win (step S380). When the charge/discharge power Pchg is equal to or greater than the input limit Win, it is determined that the power to charge the battery 50 will not exceed the input limit Win even if the engine 22 is operated at the target rotation speed Ne* and target torque Te* set in step S340, and EV driving is prohibited (step S400), and the target rotation speed Ne* and target torque Te* are transmitted to the engine ECU 24, and torque commands Tm1* and Tm2* are transmitted to the motor ECU 40 (step S410), and the control routine after system startup is terminated. When the engine ECU 24 receives the target rotation speed Ne* and target torque Te* of the engine 22, it performs operation control of the engine 22 (specifically, intake air amount control, fuel injection control, ignition control, etc.) so that the engine 22 is operated based on the target rotation speed Ne* and target torque Te*. When the motor ECU 40 receives the torque commands Tm1*, Tm2* for the motors MG1, MG2, it controls the drive of the motors MG1, MG2 (specifically, controls the switching of the multiple switching elements of the inverters 41, 42) so that the motors MG1, MG2 are driven by the torque commands Tm1*, Tm2*. This results in the vehicle running as an HV with the engine 22 running. Note that if the engine 22 is stopped when step S410 is executed, a request to start the engine 22 is made, and the engine 22 is started by motoring it with the motor MG1.

When the charge/discharge power Pchg is less than the input limit Win in step S380, it is determined that the power to charge the battery 50 will exceed the input limit Win if the engine 22 is operated at the target rotation speed Ne* and target torque Te* set in step S340, and EV driving is permitted (step S390), and the post-system startup control routine is terminated. As a result, EV driving is prioritized over hybrid driving (HV driving), and driving is performed that reduces the storage ratio SOC of the battery 50.

Figure 6 is a timing chart showing an example of the time change of the system start state and mode (CD, CS mode), the PM accumulation amount Mpm, the start request to the engine 22 in the CD mode, and the rotation speed Ne of the engine 22. As shown in the figure, when the engine 22 is operated near the end of the Nth trip (N is a natural number), the PM accumulation amount Mpm increases, and when the PM accumulation amount Mpm exceeds the threshold value Mth, the system may be stopped and the Nth trip may end (time t1). In the hybrid vehicle 20 of the embodiment, during the period from the end of the Nth trip to the next time the system is started and the (N+1)th trip is started (the period between time t1 and time t2), the power plug 61 is connected to the external power source 69, the battery 50 is charged using power from the external power source 69, and the storage ratio SOC is often high. Therefore, if the storage ratio SOC of the battery 50 exceeds the threshold value Shv when the system is started next time and the (N+1)th trip is started, the vehicle will run in the CD mode (time t2). At this time, when the PM accumulation amount Mpm exceeds the threshold value Mth, EV running is prohibited on condition that the charge/discharge power Pchg is equal to or greater than the input limit Win, and the engine 22 is started in response to a request to start the engine 22, and the vehicle runs in HV running. When the engine 22 is warmed up during HV running, the temperature of the GPF 25 rises, promoting the combustion of particulate matter accumulated in the GPF 25, and the PM accumulation amount Mpm decreases. Then, when the PM accumulation amount Mpm falls below the threshold value Mth, EV running is permitted on condition that the fuel mixing amount Vfc is less than the threshold value Vfcth, and the request to start the engine 22 is removed and the operation of the engine 22 is stopped (after time t3). In this way, by prohibiting EV running and running HV in the CD mode, it is possible to ensure an opportunity for the engine 22 to be operated appropriately.

According to the hybrid vehicle 20 of the embodiment described above, in CD mode, when the fuel mixing amount Vfc is equal to or greater than the threshold value Vfcth, or the PM accumulation amount Mpm is equal to or greater than the threshold value Mth, the engine 22 and the motors MG1 and MG2 are controlled to prohibit EV driving and drive in HV driving, thereby ensuring that the engine 22 is operated appropriately.

In the hybrid vehicle 20 of the embodiment, the engine 22 rotation speed Ne is limited to a lower limit rotation speed Nmin in step S340 of the post-system start control routine in FIG. 5. However, the target torque Te* and the target rotation speed Ne* may be set so that the engine 22 outputs the target power Pe without such a lower limit protection.

In the hybrid vehicle 20 of the embodiment, in steps S370 and S380, it is determined whether the charge/discharge power Pchg for charging/discharging the battery 50 is equal to or greater than the input limit Win (negative value). However, steps S400 and S410 may be executed without executing steps S370 and S380.

In the embodiment, the present invention is illustrated as being applied to a hybrid vehicle 20 equipped with an engine 22, motors MG1 and MG2, and a planetary gear 30, but it may also be applied to a type of hybrid vehicle 20 equipped with an engine 22 and a motor MG2 without a motor MG1 and a planetary gear 30.

The following describes the relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem. In the embodiment, the GPF 25 corresponds to the "filter", the engine 22 corresponds to the "engine", the motor MG2 corresponds to the "motor", the battery 50 corresponds to the "electricity storage device", the charger 60 corresponds to the "charger", and the engine ECU 24, the motor ECU 40, and the HVECU 70 correspond to the "control device".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the spirit of the present invention.

The present invention can be used in the hybrid vehicle manufacturing industry, etc.

20 Hybrid vehicle, 22 Engine, 24 Engine electronic control unit (engine ECU), 25 Gasoline particulate filter (GPF), 25c Temperature sensor, 51c, 135c, 149 Temperature sensor, 26 Crankshaft, 28 Damper, 30 Planetary gear, 36 Drive shaft, 37 Differential gear, 38a, 38b Drive wheels, 40 Motor electronic control unit (motor ECU), 41, 42 Inverter, 43, 44 Rotational position detection sensor, 50 Battery, 51a Voltage sensor, 51b Current sensor, 52 Battery electronic control unit (battery ECU 52), 54 Power line, 60 Charger, 61 Power plug, 62 Connection switch, 69 External power source, 70 Hybrid electronic control unit (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, 88 vehicle speed sensor, MG1, MG2 motor, 122 air cleaner, 124 throttle valve, 125 intake pipe, 126 fuel injection valve, 128a intake valve, 128b exhaust valve, 129 combustion chamber, 130 spark plug, 132 piston, 133 exhaust pipe, 134 exhaust purification device, 134a three-way catalyst, 135a air-fuel ratio sensor, 135b oxygen sensor, 136 throttle motor, 138 ignition coil, 140 crank position sensor, 142 water temperature sensor, 144a, 144b cam position sensor, 146 throttle valve position sensor, 148 air flow meter.

Claims (1)

an engine having a filter for removing particulate matter in an exhaust system, which outputs power by burning fuel and is lubricated by lubricating oil;
A motor;
a power storage device that exchanges power with the motor;
a charger that charges the power storage device using electric power from an external power supply;
a control device that controls the engine and the motor to run the vehicle by switching between a plurality of modes including a first mode in which a hybrid running mode in which the vehicle runs using power from the engine and power from the motor so as to reduce a power storage ratio of the power storage device and a motor running mode in which the vehicle runs using power from the motor with the engine stopped, the first mode giving priority to the motor running mode, and a second mode in which the vehicle runs by switching between the hybrid running mode and the motor running mode so as to maintain the power storage ratio within a predetermined range;
A hybrid vehicle comprising:
A first motor;
a planetary gear having three rotating elements connected to the first motor, the engine, and a drive shaft connected to an axle;
a second motor connected to the drive shaft;
Further comprising:
The power storage device exchanges electric power with the first and second motors;
The control device includes:
In the first mode, when the amount of the fuel mixed into the lubricating oil or the amount of the particulate matter deposited on the filter is equal to or greater than a predetermined amount, the motor running is prohibited and the vehicle is run in the hybrid running mode, and the engine and the first and second motors are controlled so that the vehicle runs at a required power required for the vehicle while operating the engine at a rotation speed equal to or greater than a lower limit rotation speed in the hybrid running mode.
In the hybrid traveling mode in which the mixing amount or the deposition amount is equal to or greater than the predetermined amount in the first mode, when the charging power for charging the power storage device exceeds an input limit that is a maximum value of the charging power allowed for the power storage device, the motor traveling is permitted.
Hybrid vehicle.

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