JP7213445B2 - HYBRID SYSTEM, HYBRID SYSTEM CONTROL DEVICE, AND HYBRID SYSTEM CONTROL METHOD - Google Patents

Description

The present disclosure relates to a hybrid system, a hybrid system control device, and a hybrid system control method, and in particular, a hybrid system mounted on a vehicle that is driven by an electric motor using electric power generated using the power of an internal combustion engine. , a control device for a hybrid system, and a control method for a hybrid system.

2. Description of the Related Art Conventionally, in a hybrid vehicle, there has been a control to keep the engine load constant during acceleration (see, for example, Patent Document 1). In the vehicle disclosed in Patent Literature 1, in the early stage of acceleration, the SOC (State Of Charge) of the battery increases by regenerating excess output of the engine by the motor generator as the vehicle travels. In the latter half of the acceleration, the electric power of the battery is used for power running by the motor generator, and the vehicle runs while assisting the insufficient output of the engine. By controlling in this way, it is possible to suppress the generation of smoke.

JP 2005-194886 A

However, in the vehicle of Patent Document 1, it is necessary to rapidly increase the load immediately before the engine load is kept constant. As a result, the amount of smoke (black smoke) and NOx (nitrogen oxides) emitted increases due to the supercharging delay. In addition, when the vehicle is rapidly accelerated while the engine load is kept constant, it is necessary to rapidly increase the engine speed. quantity deteriorates.

This disclosure has been made to solve the above-mentioned problems, and aims to provide a hybrid system capable of reducing black smoke and nitrogen oxide emissions, a control device for the hybrid system, and a hybrid system. It is to provide a control method for the system.

A hybrid system according to this disclosure includes an internal combustion engine, a generator that generates power using the power output from the internal combustion engine, a power storage device that charges the power generated by the power generator, and the power discharged from the power storage device and the power generator. Control to limit at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the electric motor for driving the vehicle, which is driven by using at least one of the generated electric power, and the internal combustion engine. and a device.

Preferably, the control device determines that at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine is such that at least one of the rate of change is such that black smoke is emitted in an amount greater than the first predetermined amount and the nitrogen oxides are Limit to be smaller than at least one of the rate of change at which more than the second predetermined amount is discharged.

More preferably, the control device controls at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine using a predetermined control map.

More preferably, when the SOC of the power storage device is higher than a predetermined value, at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine becomes smaller than when the SOC is lower than the predetermined value. make it

More preferably, the control map includes a map capable of identifying the rotation speed from the required electric power to the generator and the vehicle speed, and a map capable of specifying the target output torque from the required electric power to the generator and the target rotation speed.

Further preferably, the control map includes a region in which power generation is prioritized over control for limiting at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine.

A hybrid system control device according to another aspect of the present disclosure includes an internal combustion engine, a generator that generates power using power output from the internal combustion engine, a power storage device that charges the power generated by the power generator, and a power storage device. and a vehicle-driving electric motor that is driven using at least one of electric power discharged by the generator and electric power generated by the generator. The control device performs control to limit at least one of a change rate of the target rotational speed and a change rate of the target output torque of the internal combustion engine.

A hybrid system control method according to still another aspect of the present disclosure includes an internal combustion engine, a generator that generates power using power output from the internal combustion engine, a power storage device that charges the power generated by the power generator, and a power storage device. A control method by a control device for controlling a hybrid system including a vehicle-driving electric motor driven using at least one of electric power discharged from a device and electric power generated by a generator. The control method includes a step in which the control device controls to limit at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine.

According to this disclosure, at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine is limited in the hybrid system. As a result, it is possible to provide a hybrid system, a hybrid system control device, and a hybrid system control method capable of reducing black smoke and nitrogen oxide emissions.

1 is a diagram showing a schematic configuration of a vehicle in this embodiment; FIG. 4 is a flow chart showing the flow of engine control processing in this embodiment. FIG. 4 is a diagram showing a calculation flow of a target rotational speed of the engine in this embodiment; FIG. 4 is a diagram showing a calculation flow of a target engine output in this embodiment; It is a figure which shows the engine-speed base map in this embodiment. It is a figure which shows the engine-speed correction|amendment base map in this embodiment. FIG. 4 is a diagram showing a target rotation speed SOC correction coefficient map in this embodiment; It is a figure which shows the smoothing coefficient map in this embodiment. It is a figure which shows the minimum engine-speed map in this embodiment. It is a figure which shows the engine target output base map in this embodiment. FIG. 4 is a diagram showing a target output SOC correction coefficient map in this embodiment; FIG. It is a figure which shows the smoothing coefficient map in this embodiment. It is a figure which shows the 1st example of the control result in this embodiment. FIG. 9 is a diagram showing a second example of control results in this embodiment; FIG. 10 is a diagram showing a third example of control results in this embodiment; FIG. 10 is a diagram showing a first example of comprehensive control results in this embodiment; FIG. 10 is a diagram showing a second example of comprehensive control results in this embodiment;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, identical parts are provided with identical reference numerals. Their names and functions are also the same. A detailed description thereof will therefore not be repeated.

FIG. 1 is a diagram showing a schematic configuration of vehicle 100 in this embodiment. Referring to FIG. 1, a vehicle 100 includes a battery 10, a power control unit (hereinafter referred to as "PCU (Power Control Unit)") 11, an engine 20, a motor generator (hereinafter referred to as "MG (Motor Generator)"). ) 31 , MG 32 , and drive wheels 40 . Vehicle 100 further includes various electronic control units (ECUs) such as an HV-ECU 51 and an EG-ECU 52, which will be described later. Battery 10 according to the present embodiment corresponds to an example of the “power storage device” according to the present disclosure.

The engine 20 is an internal combustion engine that outputs power by converting combustion energy generated when fuel (gasoline, light oil, etc.) is burned into kinetic energy of motion elements such as a piston and a crankshaft. MG31 and MG32 are power devices that convert electrical energy into mechanical energy and mechanical energy into electrical energy. In the present embodiment, a diesel engine is employed as engine 20, and three-phase AC synchronous motor generators with permanent magnets embedded in rotors are employed as MG31 and MG32. Engine 20 may include a turbocharger (for example, a variable nozzle turbo) in its intake and exhaust system.

Vehicle 100 according to the present embodiment is a series hybrid vehicle. In vehicle 100, MG 31 (running motor) drives driving wheels 40 by operating as an electric motor, and MG 32 is driven by engine 20 to generate electric power. Power sources for driving MG 31 are power generated by MG 32 and power stored in battery 10 . More specifically, the rotating shaft 21 of the engine 20 and the rotating shaft 22 of the MG 32 are mechanically connected to each other via the gear 23, and the rotating shaft 22 of the MG 32 also rotates as the rotating shaft 21 of the engine 20 rotates. As it rotates, MG32 generates electricity. On the other hand, the rotating shaft 41 of the MG 31 is not mechanically connected with the rotating shafts 21 and 22 but is mechanically connected with the drive shaft 42 via the power transmission gear 43 . Torque (driving force) output to the rotating shaft 41 of the MG 31 is transmitted to the driving shaft 42 via the power transmission gear 43, and the driving force of the MG 31 causes the driving shaft 42 to rotate. As the drive shaft 42 rotates, the drive wheels 40 provided at both ends of the drive shaft 42 rotate.

MG 31 operates as an electric motor during acceleration of vehicle 100 and drives drive wheels 40 of vehicle 100 . On the other hand, during braking of vehicle 100 or during acceleration reduction on a downward slope, MG 31 operates as a generator to generate regenerative power. Electric power generated by MG 31 is supplied to battery 10 via PCU 11 .

MG 32 is configured to use the power output from engine 20 to generate power (engine power generation). The engine-generated electric power generated in MG 32 is supplied from MG 32 to MG 31 or supplied from MG 32 to battery 10 via PCU 11 .

PCU 11 includes two inverters provided corresponding to MG31 and MG32, and a boost converter for boosting the DC voltage supplied to each inverter to the voltage of battery 10 or higher (eg, 600 V). PCU 11 performs power conversion between battery 10 and MG 31 and MG 32 in accordance with a control signal from HV-ECU 51 . PCU 11 is configured to be able to control the states of MG31 and MG32 separately.

Battery 10 is a rechargeable DC power source. The rated voltage of battery 10 is, for example, 300V to 450V. Battery 10 includes, for example, a secondary battery (rechargeable battery). A lithium ion battery, for example, can be used as the secondary battery. Battery 10 may include an assembled battery composed of a plurality of secondary batteries (for example, lithium ion batteries) connected in series and/or in parallel. The secondary battery that constitutes battery 10 is not limited to the lithium ion battery, and other secondary batteries (for example, nickel-metal hydride batteries) may be employed. An electrolyte secondary battery may be employed, or an all-solid secondary battery may be employed. Also, as the battery 10, a large-capacity capacitor or the like can be employed.

A monitoring unit 61 for monitoring the state of the battery 10 is provided for the battery 10 . The monitoring unit 61 includes various sensors that detect the state of the battery 10 (temperature, current, voltage, etc.). HV-ECU 51 is configured to detect the state (SOC, etc.) of battery 10 based on the output of monitoring unit 61 . SOC (State Of Charge) indicates the remaining amount of stored electricity, for example, the ratio of the current amount of stored electricity to the amount of stored electricity in the fully charged state is represented by 0 to 100%. As a method for measuring the SOC, for example, various known methods such as a method based on current value integration (coulomb counting) or a method based on estimation of open circuit voltage (OCV) can be employed.

A monitoring unit 62 for monitoring the state of the engine 20 is provided for the engine 20 . The monitoring unit 62 includes various sensors that detect the state of the engine 20 (cooling water temperature, intake air amount, rotational speed, etc.). HV-ECU 51 and EG-ECU 52 are configured to detect the state of engine 20 based on the output of monitoring unit 62 .

Monitoring units 63 and 64 are provided for MG31 and MG32 to monitor the states of MG31 and MG32, respectively. Monitoring units 63 and 64 include various sensors that detect the states of MG31 and MG32 (temperature, rotational speed, etc.). HV-ECU 51 is configured to detect the states of MG 31 and MG 32 based on the outputs of monitoring units 63 and 64 .

Each ECU (HV-ECU 51, EG-ECU 52) included in vehicle 100 includes a CPU (Central Processing Unit) as an arithmetic unit, a storage device, and an input/output port for inputting/outputting various signals (all shown in FIG. not shown). The storage device includes RAM (Random Access Memory) as a working memory, and storage for preservation (ROM (Read Only Memory), rewritable non-volatile memory, etc.). Each ECU receives signals from various devices (such as sensors) connected to the input port, and controls various devices connected to the output port based on the received signals. Various controls are executed by the CPU executing programs stored in the storage device. However, the control performed by each ECU is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible. HV-ECU 51 and EG-ECU 52 according to the present embodiment function as a "control device" according to the present disclosure.

HV-ECU 51 calculates a required output value for engine 20 and a required output value (for example, a required torque value) for MG 31 and MG 32 . Then, HV-ECU 51 transmits an output request value for engine 20 to EG-ECU 52, and supplies electric power to MG31 and MG32 (and thus output torque of MG31 and MG32) based on the output request value for MG31 and MG32. to control. HV-ECU 51 can control the magnitude (amplitude), frequency, etc. of electric power supplied to MG 31 and MG 32 by controlling PCU 11 and the like. HV-ECU 51 also controls the charging and discharging of battery 10 by controlling PCU 11 and the like.

Various devices connected to the input port of HV-ECU 51 further include an accelerator opening sensor 65 and a vehicle speed sensor 66 in addition to various sensors included in monitoring units 61 , 63 and 64 .

Accelerator opening sensor 65 detects the degree of depression of an accelerator pedal (not shown) of vehicle 100 as an accelerator opening, and outputs the detection result (a signal indicating the accelerator opening) to HV-ECU 51 . The HV-ECU 51 increases the driving force of the MG 31 as the amount of depression of the accelerator pedal increases.

Vehicle speed sensor 66 also detects the speed of vehicle 100 and outputs the detection result (a signal indicating the vehicle speed) to HV-ECU 51 .

The EG-ECU 52 receives an output request value for the engine 20 from the HV-ECU 51, and controls the operation of the engine 20 (fuel injection control, ignition control, intake air amount adjustment control, etc.). Engine power generation is executed by driving engine 20, and engine 20 is stopped when engine power generation is not being performed. Engine generated power is generated in MG 32 by driving engine 20 . EG-ECU 52 also receives detection values of various sensors included in monitoring unit 62 and transmits each detection value to HV-ECU 51 .

Vehicle 100 is driven by MG 31 driving drive wheels 40 . The HV-ECU 51 starts charging the battery 10 with engine generated power when the SOC of the battery 10 becomes equal to or less than the charge start SOC while the vehicle 100 is running, and the SOC of the battery 10 becomes equal to or more than the charge completion SOC. stop the charging.

When the SOC of battery 10 is equal to or lower than the charging start SOC and battery 10 is to be charged by engine-generated power, HV-ECU 51 requests EG-ECU 52 to drive engine 20 under predetermined conditions suitable for power generation. EG-ECU 52 controls engine 20 in accordance with this request, so that MG 32 generates engine-generated electric power greater than the electric power consumed when vehicle 100 runs. The HV-ECU 51 also controls the PCU 11 and the like to supply the generated engine-generated electric power to the battery 10 . As a result, the battery 10 is charged with the power generated by the engine, and the SOC of the battery 10 increases.

When the SOC of the battery 10 becomes equal to or higher than the charging completion SOC, the HV-ECU 51 instructs the EG-ECU 52 to stop the engine 20, and controls the PCU 11 and the like to stop the supply of electric power to the battery 10. Let

In this manner, while vehicle 100 is running, engine 20 is activated each time the SOC of battery 10 becomes equal to or lower than the charging start SOC, and battery 10 is charged with the electric power generated by the engine. As a result, the SOC of battery 10 is generally maintained within a range equal to or higher than the charge start SOC and equal to or lower than the charge completion SOC.

In the present embodiment, vehicle 100 also includes a DPF (Diesel Particulate Filter) 71 and an NSR (NOx Storage Reduction) catalyst 72 as devices for processing exhaust gas from engine 20 . Engine 20, DPF 71 and NSR catalyst 72 are connected by exhaust pipes.

An exhaust temperature sensor 81 and an A/F sensor 82 are provided in an exhaust pipe between engine 20 and DPF 71 . Exhaust temperature sensor 81 detects the temperature of the exhaust from engine 20 and outputs the detection result (signal indicating exhaust temperature) to EG-ECU 52 . A/F sensor 82 analyzes exhaust gas from engine 20 to detect the air-fuel ratio, and outputs the detection result (a signal indicating the air-fuel ratio) to EG-ECU 52 .

The DPF 71 is a filter that collects particulate matter (PM) contained in the exhaust flowing through the exhaust passage of the engine 20 . The collected PM deposits inside the DPF 71 . Therefore, the inside of the DPF 71 is periodically heated to a high temperature to burn and remove the PM, thereby regenerating the DPF 71 .

The NSR catalyst 72 is a storage-reduction type NOx catalyst, and has, for example, alumina (Al2O3) as a carrier, and alkali metals such as potassium (K), sodium (Na), lithium (Li), and cesium Cs are deposited on this carrier. , barium Ba, alkaline earth such as calcium Ca, rare earth such as lanthanum (La) and yttrium (Y), and noble metal such as platinum Pt.

This NSR catalyst 72 absorbs NOx in a state where a large amount of oxygen exists in the exhaust gas, the oxygen concentration in the exhaust gas is low, and the reducing component (for example, the unburned component (HC) of the fuel) is large. Under existing conditions, NOx is reduced to NO2 or NO and released. The NOx released as NO2 and NO quickly reacts with HC and CO in the exhaust gas and is further reduced to N2. By the way, HC and CO themselves are oxidized to H2O and CO2 by reducing NO2 and NO. That is, by appropriately adjusting the oxygen concentration and HC components in the exhaust introduced into the NSR catalyst, HC, CO, and NOx in the exhaust can be purified.

A NOx sensor 83 is provided in the exhaust pipe downstream of the NSR catalyst 72 . NOx sensor 83 detects the amount of NOx contained in the exhaust emitted from NSR catalyst 72 and outputs the detection result (signal indicating the amount of NOx) to EG-ECU 52 .

In the hybrid system mounted on the vehicle 100 driven by the MG 31 using the electric power generated by using the power of the engine 20, when controlling the load of the engine 20 during acceleration to be constant, At the initial stage of acceleration, the MG 32 regenerates the surplus output of the engine 20 while driving, so that the SOC (State Of Charge) of the battery 10 increases. In the latter half of the acceleration, the electric power of the battery 10 is used for power running by the MG 31 to assist the insufficient output of the engine 20 while running. By controlling in this way, it is possible to suppress the generation of smoke.

However, just before holding the load on the engine 20 constant, it is necessary to increase the load abruptly. As a result, the amount of smoke and NOx emissions increases due to the supercharging delay. Further, if the vehicle 100 is to be rapidly accelerated while the load on the engine 20 is kept constant, the rotation speed of the engine 20 must also be increased rapidly. The amount of NOx emissions will worsen.

Therefore, in this embodiment, HV-ECU 51 and EG-ECU 52 perform control so as to limit the rate of change of target rotation speed and target output torque of engine 20 . As a result, smoke and NOx emissions can be reduced.

FIG. 2 is a flow chart showing the flow of engine control processing in this embodiment. This engine control process is called from the main process at predetermined control intervals and executed by the EG-ECU 52 . Referring to FIG. 2, EG-ECU 52 calculates required power for power generation by MG 32 according to vehicle speed, SOC, accelerator opening, etc. (step (hereinafter referred to as "S") 101). This required electric power is the electric power required to drive the vehicle 100 according to the degree of opening of the accelerator or the like. When the SOC of the battery 10 exceeds the charging completion SOC, the requested electric power is set to zero. As a result, the engine 20 is stopped. When the SOC of the battery 10 falls below the charging start SOC, the required electric power is calculated and a power generation request is issued.

Next, the EG-ECU 52 determines whether or not there is a power generation request, that is, whether or not the requested electric power is 0 (S102). When determining that there is no power generation request (NO in S102), the EG-ECU 52 returns the process to be executed to the caller of this process.

On the other hand, if it is determined that there is a power generation request (YES in S102), the EG-ECU 52 calculates the target rotation speed of the engine 20 according to the vehicle speed and the requested electric power (S103). Calculation of the target rotational speed will be described later with reference to FIG. Next, EG-ECU 52 calculates the target output of engine 20 according to the target rotation speed and vehicle speed (S104). Calculation of the target output will be described later with reference to FIG. The EG-ECU 52 controls the engine 20 so as to achieve the calculated target rotation speed and target output (S105), and the EG-ECU 52 returns the process to be executed to the process that called this process.

Control of the rotational speed and output of engine 20 is executed by controlling the rotational speed with MG 32, for example. Specifically, when the rotational speed is set to a high target rotational speed, first, the PCU 11 is controlled to reduce the power generation amount of the MG 32 . Then, since the power generation amount is less than the required electric power, the rotation speed of the MG 32, that is, the rotation speed of the engine 20 is controlled to increase in order to increase the power generation amount. Next, the PCU 11 is controlled to increase the power generation amount of the MG 32 . At this point, the power generation amount is controlled to be higher than the initial power generation amount. Then, since the power generation amount exceeds the required electric power, the rotation speed of the MG 32, that is, the rotation speed of the engine 20 is controlled to decrease in order to decrease the power generation amount. At this point, the rotation speed is controlled to be higher than the initial rotation speed. Furthermore, it controls the PCU 11 so as to reduce the amount of power generated by the MG 32 . Then, since the power generation amount is less than the required electric power, the rotation speed of the MG 32, that is, the rotation speed of the engine 20 is controlled to increase in order to increase the power generation amount. At this point, the rotation speed is controlled to the target rotation speed. Note that control of the rotation speed and output of engine 20 may be executed by other methods.

FIG. 3 is a diagram showing a calculation flow of the target rotation speed of engine 20 in this embodiment. Referring to FIG. 3, first, the engine rotation speed base map is used to specify the base rotation speed corresponding to the vehicle speed and required electric power.

FIG. 5 is a diagram showing an engine rotation speed base map in this embodiment. Referring to FIG. 5, in this map, the column heading value is the vehicle speed, the row heading value is the required output (required electric power, that is, the load applied to the engine 20), and the cell value is the rotational speed. Even if the required electric power changes, the rotation speed is set to be constant as long as the vehicle speed is the same. In addition, from 0 km/h to 60 km/h, even if the vehicle speed changes, the rotation speed is set to be constant, and above 80 km/h, the rotation speed changes gradually as the vehicle speed increases. set to increase. In addition, in FIG. 5, A1<A2<A3<A4. For example, when the vehicle speed is 60 km/h and the required power is 100 kW, A1 rpm is specified as the rotational speed.

When the vehicle speed is 75 km/h and the required power is 150 kW, the cell values corresponding to 60 km in the column heading directly under 75 km/h and 140 kW and 160 kW in the row headings directly under and above 150 kW are shown. Based on A1 rpm and A2 rpm, which is the cell value corresponding to 80 km in the column heading directly above 75 km/h and 140 kW and 160 kW in the column heading directly below and 150 kW directly above 75 km/h, the rotational speed is calculated as (A2 -A1)*(75-60)/(80-60)+A1=(3*A2+A1)/4 rpm.

Returning to FIG. 3, the engine rotation speed correction base map is used to specify the correction rotation speed corresponding to the vehicle speed and the required electric power. The correction rotational speed is the rotational speed used to correct the rotational speed of the base.

FIG. 6 is a diagram showing an engine rotation speed correction base map in this embodiment. Referring to FIG. 6, in this map, column heading values are vehicle speed, row heading values are requested output (required electric power, ie load applied to engine 20), and cell values are rotational speed. Even if the required electric power increases, if the vehicle speed is the same, the corrected rotation speed is set to be constant. Also, in the range of 0 km/h to 100 km/h, a value is set that gradually increases from A1 rpm to A4 rpm when simply added to the value of the engine rotation speed base map. B7 rpm, which is smaller than B6 rpm, is set above 120 km/h. For example, when the vehicle speed is 60 km/h and the required power is 100 kW, B5 rpm is specified as the corrected rotational speed. Simply adding this corrected rotational speed B5 rpm to the rotational speed A1 rpm specified by the engine rotational speed base map at this time results in A1+B5 rpm.

Returning to FIG. 3, the correction coefficient corresponding to the SOC of battery 10 is identified using the SOC correction coefficient map. This correction coefficient is a correction coefficient for increasing the corrected rotational speed when the SOC drops.

FIG. 7 is a diagram showing a target rotational speed SOC correction coefficient map in this embodiment. Referring to FIG. 7, in this map, the column header value is SOC, the row header value is the required output (required power, that is, the load applied to engine 20), and the cell value is the correction factor. Even if the required power increases, the correction coefficient is set to be constant as long as the SOC remains the same. Moreover, when the SOC is 30 or less, the correction coefficient is set to be constant even if the SOC changes. When the SOC is 45 or higher, the correction coefficient is set to be constant even if the SOC changes. For example, if the SOC is 40% and the required power is 100 kW, then C2 is specified as the correction factor.

Returning to FIG. 3, an operation of multiplying the correction engine speed specified by the engine rotation speed correction base map of FIG. 6 by the correction coefficient specified by the target engine speed SOC correction coefficient map of FIG. A calculation (calculation indicated by a "+" symbol in the figure) is performed to add the engine speed specified by the engine speed base map in FIG. For example, when the vehicle speed is 60 km/h, the required power is 100 kW, and the SOC is 40%, the corrected rotational speed B5 rpm specified by the engine rotational speed correction base map is specified by the target rotational speed SOC correction coefficient map. When the product multiplied by the correction coefficient C2 is added to the rotation speed A1 rpm specified by the engine rotation speed base map, the result is A1+B5×C2 rpm.

Next, when the upper limit rotation speed is exceeded, a calculation (calculation indicated by the symbol "MIN" in the figure) is performed to limit the rotation speed to the upper limit. For example, the result of the calculation indicated by the above symbol "+" is J1 rpm, and when the upper limit rotation speed is 1.5 x J1, the upper limit rotation speed is not exceeded, so the calculation indicated by the symbol "MIN" is The result remains J1 rpm.

Next, using the smoothing coefficient map, the smoothing coefficient corresponding to the SOC of battery 10 is specified. This smoothing coefficient is a coefficient for smoothing changes in the rotational speed when the SOC has a margin.

FIG. 8 is a diagram showing a smoothing coefficient map in this embodiment. Referring to FIG. 8, in this map, the column header values are SOC and the cell values are smoothing coefficients. The smoothing coefficient is set so that the degree of smoothing increases as the SOC increases. If the SOC is 30 or less, the smoothing coefficient is set to D1, which indicates no smoothing at all. When the SOC is 50 or more, the smoothing coefficient is set to be constant (D3) even if the SOC changes. For example, if the SOC is 40%, D2 is specified as the smoothing factor.

Returning to FIG. 3, the rotation speed obtained by the calculation for regulating the upper limit rotation speed is subjected to a smoothing process using the smoothing coefficient specified in the smoothing coefficient map shown in FIG. Here, primary smoothing processing is performed as smoothing processing, but secondary smoothing processing or higher-order smoothing processing may be performed. In the primary smoothing process, for example, the difference obtained by subtracting the previous rotation speed from the rotation speed obtained by the calculation indicated by the symbol "MIN" is divided by the smoothing coefficient, and the previous rotation speed is obtained. Perform addition operation. As shown in FIG. 2, the calculation of FIG. 3 is executed every predetermined control cycle, and the "previous time" means the time before the predetermined control cycle. For example, if the smoothing coefficient is D2 corresponding to an SOC of 40%, the rotation speed obtained by the calculation indicated by the symbol "MIN" is J2 rpm, and the previous rotation speed is J2 × 9/10 rpm, then the primary (J2-J2.times.9/10)/D2+J2.times.9/10=(1+9.times.D2).times.J2/(10.times.D2) rpm is obtained by the smoothing operation. Thus, as the smoothing coefficient becomes larger than D1, the change from the previous rotation speed becomes smaller.

Next, the minimum engine speed map is used to identify the minimum engine speed corresponding to the minimum power generation. The minimum generated power is power obtained by subtracting the power that can be output from the battery 10 from the required power.

FIG. 9 is a diagram showing a minimum engine speed map in this embodiment. Referring to FIG. 9, in this map, the column heading value is minimum generated power and the cell value is minimum engine speed. It is necessary to generate at least the amount of power that the battery 10 cannot supply with respect to the required power. Therefore, the minimum engine speed is set to increase as the minimum generated power increases. If the minimum generated power is 40 kW or more, the minimum engine speed is set to be E3 rpm. If the minimum generated power is 0 kW, the minimum engine speed is set to E1 (=0). For example, if the minimum generated power is 20 kW, E2 rpm is specified as the minimum engine speed.

Returning to FIG. 3, after the calculation of the primary smoothing process, if the engine speed is less than the minimum engine speed, a calculation for restricting the lower limit engine speed (calculation indicated by the symbol “MAX” in the figure) is performed. The result of this calculation is the target rotation speed of the engine 20 . For example, if the rotation speed obtained by the calculation of the primary smoothing process is 1.5×E2 rpm and the minimum engine rotation speed is E2 rpm, it will not fall below the minimum engine rotation speed. The target rotational speed of the engine 20, which is the result of the calculation, is 1.5×E2 rpm.

FIG. 4 is a diagram showing a calculation flow of the target output of engine 20 in this embodiment. Referring to FIG. 4, first, the engine target output base map is used to identify the base engine 20 output corresponding to the engine target rotational speed and the required electric power.

FIG. 10 is a diagram showing an engine target output base map in this embodiment. Referring to FIG. 10, in this map, the column heading value is the target rotation speed, the row heading value is the required output (required electric power, that is, the load applied to the engine 20), and the cell value is the output of the engine 20. be. At 2390 rpm or less, the output of the engine 20 is set to be constant (constant load) as long as the rotation speed is the same even if the required electric power changes. At 2395 rpm, if the required power is 50 kW or more, the output of the engine 20 is set to increase as the required power increases (power generation is prioritized). For example, if the target rotation speed of the engine 20 is 1840 rpm and the required power is 100 kW, the value of the cell corresponding to 1600 rpm in the column heading just below 1840 rpm and 100 kW in the row heading and By interpolation, (1840-1600)*(F5-F4)/(2000-1600)+F4=(3*F5+2 *F4)/5 kW is specified.

Returning to FIG. 4, the target output SOC correction coefficient map is also used to specify correction coefficients corresponding to the engine target rotational speed and the SOC of the battery 10 . This correction coefficient is a correction coefficient for increasing the output of engine 20 when the SOC drops.

FIG. 11 is a diagram showing a target output SOC correction coefficient map in this embodiment. Referring to FIG. 11, in this map, the column header values are the SOC of engine 20, and the cell values are correction coefficients. When the SOC is 50 or less, the SOC correction coefficient is set to G1, and when the SOC is 60 or more, the correction coefficient is set to G2. For example, if the SOC is 40%, the correction factor is G1.

Returning to FIG. 4, the calculation of multiplying the output of the engine 20 specified by the engine target output base map of FIG. 10 by the correction coefficient specified by the target output SOC correction coefficient map of FIG. ) is performed. For example, when the output of the engine 20 is J3 kW and the correction coefficient is G1, J3×G1 kW.

Next, using the smoothing coefficient map, the smoothing coefficient corresponding to the engine speed and the SOC of the battery 10 is specified. This smoothing coefficient is a coefficient for smoothing changes in the output of the engine 20 when the SOC has a margin.

FIG. 12 is a diagram showing a smoothing coefficient map in this embodiment. Referring to FIG. 12, in this map, column header values are SOCs, and cell values are smoothing coefficients. The smoothing coefficient is set so that the degree of smoothing increases as the SOC increases. If the SOC is 30 or less, the smoothing coefficient is set to H1, which indicates no smoothing at all. When the SOC is 40 or higher, the smoothing coefficient is set to be constant even if the SOC changes. For example, if the SOC is 40%, H3 is specified as the smoothing factor.

Returning to FIG. 4, the output of the engine 20 obtained by the calculation indicated by the symbol "x" is subjected to a smoothing process using the smoothing coefficient specified in the smoothing coefficient map of FIG. Here, primary smoothing processing is performed as smoothing processing, but secondary smoothing processing or higher-order smoothing processing may be performed. In the primary smoothing process, for example, the difference obtained by subtracting the previous output of the engine 20 from the output of the engine 20 obtained by the calculation indicated by the symbol "x" is divided by the smoothing coefficient. is added to the output of the engine 20 of . As shown in FIG. 2, the calculation of FIG. 4 is executed every predetermined control cycle, and the "previous time" means the time before the predetermined control cycle. For example, if the smoothing coefficient is H3 corresponding to an SOC of 40%, the output of the engine 20 obtained by the calculation indicated by the symbol "x" is J4 kW, and the previous rotation speed is J4 x 9/10 kW, (J4-J4.times.9/10)/H3+J4.times.9/10=(1+9.times.H3).times.J4/(10.times.H3) kW is obtained by the calculation of the first-order smoothing process. Thus, as the smoothing coefficient becomes larger than H1, the change from the previous output of the engine 20 becomes smaller.

After the calculation of the primary smoothing process, when the generated power falls below the minimum generated power, the calculation for limiting the lower limit output of the engine 20 (calculation indicated by the symbol "MAX" in the figure) is performed. The minimum generated power is power obtained by subtracting the power that can be output from the battery 10 from the required power. The result of this calculation is the target output of the engine 20 . For example, if the output obtained by the calculation of the primary smoothing process is J5 + 20 kW and the minimum generated power is J5 kW, the minimum generated power will not be exceeded. is set to J5 + 20 kW.

FIG. 13 is a diagram showing a first example of control results in this embodiment. Referring to FIG. 13, as shown in FIG. 13(A), when vehicle 100 is run at a steady speed of 40 km/h from the initial SOC of battery 10=50%, the dashed line in FIG. 13(C) , the required output for driving the vehicle 100 is a constant value. Further, as shown in FIGS. 13B to 13D, from time 0 to 40 seconds when the SOC of battery 10 has not reached the charge completion SOC, calculation is performed according to the flow shown in FIGS. The engine 20 is controlled so as to achieve the target rotation speed and the target output. After time 40 seconds, the SOC of battery 10 reaches the charge completion SOC, so engine 20 is stopped. In FIGS. 13(C) and 13(D), the graphs are drawn so that the rotation speed and the output suddenly increase from time 0 seconds, but in reality, FIGS. By the smoothing process indicated by , the rotation speed and output are controlled to increase gently.

FIG. 14 is a diagram showing a second example of control results in this embodiment. Referring to FIG. 14, as shown in FIG. 14(A), when vehicle 100 is run at a steady state of 100 km/h from the state where the initial SOC of battery 10 is 50%, the dashed line in FIG. 14(C) , the required output for driving the vehicle 100 is a constant value. Further, as shown in FIGS. 14B to 14D, from time 0 to 85 seconds when the SOC of battery 10 has not reached the charge completion SOC, calculation is performed according to the flow shown in FIGS. The engine 20 is controlled so as to achieve the target rotation speed and the target output. After time 85 seconds, the SOC of battery 10 reaches the charge completion SOC, so engine 20 is stopped. In FIGS. 14(C) and 14(D), the graphs are drawn as if the rotation speed and output suddenly increase from time 0 seconds, but in reality, FIGS. By the smoothing process indicated by , the rotation speed and output are controlled to increase gently.

FIG. 15 is a diagram showing a third example of control results in this embodiment. Referring to FIG. 15, as shown in FIG. 14(A), when vehicle 100 is run at a steady state of 100 km/h from the initial SOC of battery 10=20%, the dashed line in FIG. 15(C) , the required output for driving the vehicle 100 is a constant value. Further, as shown in FIGS. 15B to 15D, the charge completion SOC is not reached in the entire period shown in the figure, so the flow shown in FIGS. The engine 20 is controlled so as to achieve the calculated target rotational speed and target output. Until about 58 seconds when the SOC reaches 40%, the engine 20 is controlled based on the power generation priority output indicated by the cell value of the column heading of FIG. be done. When the SOC reaches 40% around time 58 seconds, the correction coefficient changes as shown in the target rotation speed SOC correction coefficient map of FIG. 7, so the target rotation speed and the target output of the engine are lowered. In FIGS. 15(C) and 15(D), the graphs are drawn as if the rotational speed and output suddenly increase from time 0 seconds, but in reality, FIGS. By the smoothing process indicated by , the rotation speed and output are controlled to increase gently.

FIG. 16 is a diagram showing a first example of comprehensive control results in this embodiment. Referring to FIG. 16, there is shown an example of a case where vehicle 100 is run so as to change the vehicle speed in a running mode (RDE (Real Driving Emission, real road test)) as shown in FIG. 16(A). . In this case, as shown in FIG. 16B, the SOC can be controlled within the range from the charge start SOC to the charge end SOC.

As shown in FIGS. 16(C) and 16(D), during low-load running from time 0 to 1800 seconds, there are many periods during which the rotational speed and output of engine 20 can be zero. In FIG. 16(C), the solid line indicates the output of engine 20 and the broken line indicates the output of MG 31 for driving vehicle 100 .

Further, as shown in FIGS. 16(C) and 16(D), during high-load running from 3900 seconds to 6400 seconds, the rotation speed of engine 20 is reduced by the smoothing process shown in FIGS. And power generation is performed with a suppressed rate of change in output.

FIG. 17 is a diagram showing a second example of comprehensive control results in this embodiment. Referring to FIG. 17, there is shown an example in which vehicle 100 is run such that the vehicle speed changes from 0 km/h to 140 km/h at full throttle acceleration as shown in FIG. 17(A). In this case, as shown in FIG. 17(B), the vehicle runs at full load during the period from 0 seconds to 25 seconds during acceleration, so the SOC drops significantly.

As shown in FIGS. 17(C) and 17(D), during acceleration from 0 seconds to 25 seconds, the driving MG 31 is operated at the maximum output. Accordingly, as shown in FIG. 17(B), the SOC of battery 10 drops sharply, so the output and rotation speed of engine 20 are controlled with priority given to power generation without smoothing. Thereafter, as shown in FIG. 17B, when the SOC of battery 10 reaches the charging start SOC at around time 75 seconds, the output of engine 20 is reduced.

[Modification]
(1) In the above-described embodiment, both MG31 and MG32 are motor generators. However, without being limited to this, the MG 31 may be a generator. MG32 may be an electric motor.

(2) In the above-described embodiment, the rate of change of the target rotation speed and the rate of change of the target output torque of the engine 20 are predetermined from FIG. 5 according to the flow of FIGS. The engine 20 is controlled using the map of FIG. However, the present invention is not limited to this, and other methods may be used for control as long as at least one of the rate of change of the target rotation speed and the rate of change of the target output torque of the engine 20 is limited. Further, it is not limited to limiting at least one of the rate of change of the target rotational speed and the rate of change of the target output torque to be smaller than a predetermined rate of change. At least one of the ratios may be limited to 0 (that is, at least one of the target rotational speed and target output torque may be made constant).

(3) In the above-described embodiment, the configuration of the exhaust treatment device is the combination of the DPF 71 and the NSR catalyst 72 . However, the configuration is not limited to this, and the configuration of the exhaust treatment device may be of any configuration. For example, the DeNOx catalyst that reduces NOx contained in the exhaust may be an SCR catalyst that uses a reducing agent (eg, urea water, HC) instead of the NSR catalyst 72 .

(4) The above-described embodiment can be regarded as disclosure of a hybrid system including engine 20, MG31, MG32, battery 10, and control devices (EG-ECU 52, HV-ECU 51, PCU 11). In addition, it can be regarded as disclosure of such a hybrid system control device or disclosure of a hybrid system control method. Moreover, it can be regarded as disclosure of the vehicle 100 having such a hybrid system.

[effect]
(1) As shown in FIG. 1, the hybrid system includes an engine 20, an MG 32 that generates power using the power output from the engine 20, a battery 10 that charges the power generated by the MG 32, and a battery 10. MG 31 for driving vehicle 100 driven using at least one of discharged power and power generated by MG 32, and a control device (EG-ECU 52, HV-ECU 51, PCU 11). As shown in FIGS. 2 to 12, the control device performs control to limit at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of engine 20. FIG.

Accordingly, in the hybrid system, at least one of the rate of change of the target rotation speed of engine 20 and the rate of change of the target output torque is limited. As a result, black smoke and nitrogen oxide emissions can be reduced.

(2) The calculations shown in the flows of FIGS. 3 and 4 are such that at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the engine 20 is such that more black smoke is emitted than the legal regulation value. It is designed in advance so as to limit the change rate to be smaller than at least one of the change rate at which nitrogen oxides are emitted and the change rate at which nitrogen oxides are discharged more than the legal regulation value. The control device controls the engine 20 according to such calculations. It should be noted that the voluntary regulation value may be used instead of the legal regulation value.

Accordingly, in the hybrid system, at least one of the rate of change of the target rotation speed and the rate of change of the target output torque of the engine 20 at which at least one of black smoke and nitrogen oxides emitted from the engine 20 is emitted more than the legal regulation value The engine 20 is controlled such that at least one of the rate of change of the target rotation speed of the engine 20 and the rate of change of the target output torque of the engine 20 is smaller than the other.

(3) Using the control maps shown in FIGS. 5 to 12, which are used in the calculations shown in the flows of FIGS. Control at least one of the rates.

Accordingly, in the hybrid system, at least one of the rate of change of the target rotation speed and the rate of change of the target output torque of the engine 20 at which at least one of black smoke and nitrogen oxides emitted from the engine 20 is emitted more than the legal regulation value The engine 20 is controlled such that at least one of the rate of change of the target rotation speed of the engine 20 and the rate of change of the target output torque of the engine 20 is smaller than the other.

(4) As shown in FIGS. 16 and 17, the controller compares when the SOC of the battery 10 is higher than the charging start SOC in the calculations shown in the flows of FIGS. At least one of the rate of change of the target rotational speed of the engine 20 and the rate of change of the target output torque is made smaller.

(5) The control maps shown in FIGS. 5 to 12 are based on the engine rotation speed base map in FIG. Includes the engine target output base map of FIG. 10 that can specify the target output torque.

(6) As shown in FIG. 10, the engine target output base map among the control maps is more likely to generate power than the control that limits at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the engine 20. including areas that prioritize It should be noted that giving priority to power generation means that the requested electric power is generated by the output of engine 20 without limiting the rate of change of target rotational speed and the rate of change of target output torque.

Thus, when the SOC of battery 10 is lower than the charging start SOC, power generation can be prioritized over suppression of at least one of the rate of change in target rotational speed and the rate of change in target output torque of engine 20 .

It is also planned to implement each embodiment disclosed this time in appropriate combination. And the embodiment disclosed this time should be considered as an illustration and not restrictive in all respects. The scope of the present disclosure is indicated by the scope of claims rather than the description of the above-described embodiments, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

10 battery, 11 PCU, 20 engine, 21, 22, 41 rotating shaft, 23 gear, 31, 32 MG, 40 drive wheel, 42 drive shaft, 43 power transmission gear, 51 HV-ECU, 52 EG-ECU, 61, 62, 63, 64 monitoring unit, 65 accelerator opening sensor, 66 vehicle speed sensor, 71 DPF, 72 NSR catalyst, 81 exhaust temperature sensor, 82 A/F sensor, 83 NOx sensor, 100 vehicle.

Claims (5)

an internal combustion engine;
a generator that generates power using the power output from the internal combustion engine;
a power storage device that charges power generated by the generator;
a vehicle-driving electric motor driven using at least one of electric power discharged from the power storage device and electric power generated by the generator;
a control device that controls to limit at least one of a rate of change of the target rotational speed and a rate of change of the target output torque of the internal combustion engine;
The control device is
At least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine is a rate of change at which more black smoke is emitted than a first predetermined amount and a rate of change at which more nitrogen oxides are emitted than a second predetermined amount. Restrict to be smaller than at least one of the rate of change that is discharged more,
controlling at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine using a predetermined control map;
the control map includes a region in which power generation is prioritized over control for limiting at least one of a rate of change in target rotational speed and a rate of change in target output torque of the internal combustion engine;
The area in which the power generation is prioritized is when the SOC of the power storage device is lower than the charging start SOC, and when the rotation speed of the internal combustion engine is the same even if the required electric power to the generator changes, the If the rotation speed of the internal combustion engine is higher than a predetermined target rotation speed that is set so that the output of the internal combustion engine is constant, and if the power required for the generator is equal to or greater than a predetermined value, the generator A hybrid system in which the output of the internal combustion engine increases as the required electric power to the hybrid system increases. When the SOC of the power storage device is higher than a predetermined value, the controller controls at least one of a rate of change of the target rotational speed and a rate of change of the target output torque of the internal combustion engine to be smaller than when the SOC is lower than the predetermined value. 2. The hybrid system according to claim 1, wherein: The control map includes a map that can identify the rotation speed of the internal combustion engine from the required electric power to the generator and the vehicle speed, and a target output torque that can be specified from the required electric power to the generator and the target rotation speed of the internal combustion engine. 2. The hybrid system of claim 1, including possible maps. An internal combustion engine, a generator that generates power using the power output from the internal combustion engine, a power storage device that charges the power generated by the power generator, and a power storage device that discharges the power generated by the power storage device and the power generated by the power generator. A control device for controlling a hybrid system comprising a vehicle-driving electric motor driven using at least one of electric power,
controlling to limit at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine;
At least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine is a rate of change at which more black smoke is emitted than a first predetermined amount and a rate of change at which more nitrogen oxides are emitted than a second predetermined amount. Restrict to be smaller than at least one of the rate of change that is discharged more,
controlling at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine using a predetermined control map;
the control map includes a region in which power generation is prioritized over control for limiting at least one of a rate of change in target rotational speed and a rate of change in target output torque of the internal combustion engine;
The area in which the power generation is prioritized is when the SOC of the power storage device is lower than the charging start SOC, and when the rotation speed of the internal combustion engine is the same even if the required electric power to the generator changes, the If the rotation speed of the internal combustion engine is higher than a predetermined target rotation speed that is set so that the output of the internal combustion engine is constant, and if the power required for the generator is equal to or greater than a predetermined value, the generator A control device for a hybrid system, which is a region in which the output of the internal combustion engine increases as the required electric power to the engine increases. An internal combustion engine, a generator that generates power using the power output from the internal combustion engine, a power storage device that charges the power generated by the power generator, and a power storage device that discharges the power generated by the power storage device and the power generated by the power generator. A control method by a control device for controlling a hybrid system including a vehicle-driving electric motor driven using at least one of electric power,
a step in which the control device controls to limit at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine;
At least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine is a rate of change at which more black smoke is emitted than a first predetermined amount and a rate of change at which more nitrogen oxides are emitted than a second predetermined amount. limiting to be less than at least one of the rate of change that is discharged more;
using a predetermined control map to control at least one of the rate of change of the target rotational speed and the rate of change of the target output torque of the internal combustion engine;
the control map includes a region in which power generation is prioritized over control for limiting at least one of a rate of change in target rotational speed and a rate of change in target output torque of the internal combustion engine;
The area in which the power generation is prioritized is when the SOC of the power storage device is lower than the charging start SOC, and when the rotation speed of the internal combustion engine is the same even if the required electric power to the generator changes, the If the rotation speed of the internal combustion engine is higher than a predetermined target rotation speed that is set so that the output of the internal combustion engine is constant, and if the power required for the generator is equal to or greater than a predetermined value, the generator A control method for a hybrid system, wherein the output of the internal combustion engine increases as the required electric power to the engine increases.

Images