JP7600655B2 - Control device for internal combustion engine - Google Patents

Description

The present invention relates to a control device for an internal combustion engine.

An automobile is known that includes an engine having a filter in the exhaust system that removes particulate matter, and a control device that controls the engine. The control device controls the engine to run in a selected mode from among a number of modes, including a first mode that achieves both fuel efficiency and ride comfort, and a second mode that drives the engine at a load higher than a predetermined load.

In addition, when the amount of particulate matter accumulated in the filter is equal to or greater than a threshold value, the control device notifies the driver that driving in the second mode is recommended. If the driver selects the second mode in response to this notification, the sense of discomfort felt by the driver can be reduced even if the engine is operated at high load to regenerate the filter (see Patent Document 1).

JP 2018-167618 A

However, if the driver is notified of the recommendation to drive in the second mode while the vehicle is driving, this may induce an unstable driving state (e.g., inattentive driving, etc.). In addition, even if the vehicle is stopped, if the vehicle stops after completing a drive, such as arriving at a destination, the control device may stop after the vehicle stops, causing the regeneration process to end prematurely.

The purpose of this invention is to avoid the selection of filter regeneration processing while driving and the stopping of the control device during the regeneration processing.

The control device for an internal combustion engine of the present invention is a control device for an internal combustion engine having a filter in an exhaust passage that captures particulate matter in the exhaust, and when the amount of accumulation of the particulate matter is greater than a second threshold value that is smaller than a first threshold value for determining an excessive accumulation state of the accumulation amount, and when a vehicle equipped with the internal combustion engine is stopped and is in a specified vehicle state in which there is no history of vehicle speed indicating traveling after the control device is started, the control device notifies the user of the option of whether or not to perform a regeneration process of the filter , and increases the frequency of notification of the option as the amount of accumulation increases .

The present invention makes it possible to avoid selecting the filter regeneration process while driving and to avoid stopping the control device during the regeneration process.

FIG. 1 is a diagram showing an outline of the configuration of a vehicle. FIG. 2 is a flowchart showing an example of a process executed by the HVECU. Fig. 3A is a graph showing the relationship between the mileage and the amount of PM accumulation, and Fig. 3B is an example of a selection notification shown on the display.

Below, the embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the vehicle 20, which represents an HV (Hybrid Vehicle), includes an engine 22 as an internal combustion engine, an engine ECU (Electronic Control Unit) 24, and a planetary gear 30. The vehicle 20 also includes motors MG1 and MG2, inverters 41 and 42, a motor ECU 40, a battery 50, a battery ECU 52, a boost converter 56, and an HV ECU 70. At least the engine ECU 24 and the HV ECU 70 constitute a vehicle system as a control device. The vehicle 20 runs in an HV driving mode or an electric driving (EV driving) mode. The HV driving mode is a mode in which the vehicle runs with the operation of the engine 22. The EV driving mode is a mode in which the vehicle runs without the operation of the engine 22. The vehicle 20 is not limited to an HV, and may be a gasoline vehicle or a diesel vehicle that does not include the motors MG1 and MG2 or the motor ECU 40.

The engine ECU 24, motor ECU 40, battery ECU 52, and HVECU 70 are all configured as microprocessors with a CPU (Central Processing Unit) at their core. In addition to the CPU, each of these ECUs also has a ROM (Read Only Memory) that stores processing programs, a RAM (Random Access Memory) that temporarily stores data, input ports, output ports, and communication ports.

The engine 22 uses gasoline, diesel, or the like as fuel to output power. The engine 22 is controlled by an engine ECU 24. An exhaust purification device 23 and a PM filter 25 are attached to the exhaust passage of the engine 22. The exhaust purification device 23 is filled with a catalyst 23a that removes unburned fuel and nitrogen oxides from the exhaust. The PM filter 25 is formed as a porous filter using ceramics, stainless steel, or the like. The PM filter 25 captures or removes (hereinafter simply referred to as capture) particulate matter (PM) such as soot. When the engine 22 uses gasoline as fuel, the PM filter 25 is called a GPF (Gasoline Particulate Filter). On the other hand, when the engine 22 uses diesel as fuel, the PM filter 25 is called a DPF (Diesel Particulate Filter).

Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. Examples of signals from the various sensors include a crank position from a crank position sensor that detects the rotational position of the crankshaft 26, an air-fuel ratio from an air-fuel ratio sensor 23b attached upstream of the exhaust purification device 23 in the exhaust passage, and an oxygen signal from an oxygen sensor 23c attached downstream of the exhaust purification device 23.

Furthermore, the signals from the various sensors include a first pressure from a first pressure sensor 25a attached upstream of the PM filter 25, and a second pressure from a second pressure sensor 25b attached downstream of the PM filter 25. When the first pressure and the second pressure are input to the engine ECU 24, the engine ECU 24 calculates the PM accumulation amount Qpm. Specifically, the engine ECU 24 calculates the PM accumulation amount Qpm as an estimated accumulation amount of particulate matter trapped in the PM filter 25 based on the differential pressure between the input first pressure and second pressure. In addition, the engine ECU 24 calculates the filter temperature as an estimated temperature of the PM filter 25 based on the operating state of the engine 22.

Meanwhile, the engine ECU 24 outputs various control signals for controlling the operation of the engine 22 via an output port. Examples of the various control signals include a drive signal to a fuel injection valve, a drive signal to a throttle motor that adjusts the position of the throttle valve, and a control signal to an ignition coil integrated with an igniter. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 controls the operation of the engine 22 according to control signals from the HVECU 70. The engine ECU 24 also outputs data related to the operating state of the engine 22 to the HVECU 70 as necessary.

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

Motor MG1 is configured as a well-known synchronous generator motor with a rotor embedded with a permanent magnet and a stator wound with a three-phase coil, and the rotor is connected to the sun gear of planetary gear 30. Motor MG2 is configured as a synchronous generator motor like motor MG1, and the rotor is connected to drive shaft 36. Motors MG1 and MG2 are driven by motor ECU 40 controlling inverters 41 and 42.

The inverters 41, 42 are connected to a boost converter 56 by a drive voltage system power line 54a. A smoothing capacitor 57 for smoothing and a discharge resistor 58 for discharging are connected in parallel to the drive voltage system power line 54a. The boost converter 56 is connected to the battery 50 and an SMR (System Main Relay) 55 by a battery voltage system power line 54b. The SMR 55 is attached to the output terminal side of the battery 50 on the battery voltage system power line 54b. A smoothing filter capacitor 59 is connected to the boost converter 56 side of the battery voltage system power line 54b.

The motor ECU 40 receives signals necessary for controlling the drive of the motors MG1 and MG2, such as the rotational positions from the rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, via an input port. The motor ECU 40 also receives the drive voltage system voltage, which is the voltage of the smoothing capacitor 57 from a voltage sensor attached between the terminals of the smoothing capacitor 57, and the battery voltage system voltage, which is the voltage of the filter capacitor 59 from a voltage sensor attached between the terminals of the filter capacitor 59.

The motor ECU 40 outputs control signals for driving the inverters 41, 42 and the boost converter 56 via the output port. The motor ECU 40 also communicates with the HVECU 70, and controls the driving of the motors MG1, MG2 using control signals from the HVECU 70, and outputs data regarding the operating state of the motors MG1, MG2 to the HVECU 70 as necessary.

Battery 50 includes, for example, a lithium-ion secondary battery. Battery 50 exchanges power with motors MG1 and MG2 via inverters 41 and 42. Battery ECU 52 manages battery 50. Signals required for managing battery 50 are input to battery ECU 52 via an input port. For example, battery voltage from a voltage sensor installed between the terminals of battery 50, battery current from a current sensor attached to a power line connected to the output terminal of battery 50, etc. are input to battery ECU 52.

The battery ECU 52 communicates with the HVECU 70 and transmits data on the state of the battery 50 to the HVECU 70 via communication as necessary. In order to manage the battery 50, the battery ECU 52 calculates the power storage ratio, which is the ratio of the amount of power that can be discharged from the battery 50 at that time to the total capacity, based on, for example, the integrated value of the charging and discharging current detected by a current sensor.

The HVECU 70 receives various signals necessary for drive control, such as an ignition signal from an ignition switch 80 and a shift position from a shift position sensor 82 that detects the operating position of a shift lever 81. The HVECU 70 also receives an accelerator opening from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, and a brake pedal position from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85. The HVECU 70 also receives vehicle speed from a vehicle speed sensor 88 and a mode switch signal from a mode switch 89 installed near the driver's seat via an input port. The mode switch 89 is a switch that toggles between, for example, a normal mode in which the engine 22 is operated at a predetermined load, an eco mode that prioritizes fuel efficiency even if it impairs ride comfort to some extent, and a sports mode that allows the enjoyment of powerful sports driving.

The HVECU 70 outputs control signals such as a drive signal to the SMR 55 and a display signal to a display 90 attached to an installation panel in front of the driver's seat via an output port. The display 90 may be equipped with a touch panel. 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. Therefore, the HVECU 70 can indirectly control the engine 22 via the engine ECU 24.

Next, the processing executed by the HVECU 70 will be described with reference to FIG. 2 and FIGS. 3(a) and (b). While the vehicle system is running, the HVECU 70 executes various processes periodically (e.g., every second) regardless of whether the vehicle 20 is running or stopped. As shown in FIG. 3(a), the PM accumulation amount Qpm tends to increase according to the driving distance.

First, the HVECU 70 acquires the PM accumulation amount Qpm (step S1). As described above, the PM accumulation amount Qpm is calculated by the engine ECU 24, so the HVECU 70 can acquire the PM accumulation amount Qpm from the engine ECU 24. After acquiring the PM accumulation amount Qpm, the HVECU 70 then determines whether the PM accumulation amount Qpm is greater than a first threshold value (step S2). The first threshold value is a threshold value for determining whether the PM accumulation amount Qpm is in an excessive accumulation state.

As shown in FIG. 3(a), when the PM accumulation amount Qpm is greater than the first threshold value (step S2: YES), the HVECU 70 displays a warehousing notification encouraging the vehicle to be brought to a repair or maintenance company (e.g., a dealer) (step S3). Specifically, the HVECU 70 generates a display signal representing the warehousing notification and outputs the generated display signal to the display 90. This causes the warehousing notification to appear on the display 90. After the HVECU 70 displays the warehousing notification, it ends the process.

On the other hand, if the PM accumulation amount Qpm is equal to or less than the first threshold (step S2: NO), the HVECU 70 determines whether the PM accumulation amount Qpm is greater than the second threshold (step S4). The second threshold is a threshold for determining whether or not to recommend regeneration of the PM filter 25 to the driver. Because the PM accumulation amount Qpm is not in an overaccumulated state, a value smaller than the first threshold described above is used as the second threshold.

As shown in FIG. 3(a), if the PM accumulation amount Qpm is equal to or less than the second threshold (step S4: NO), the HVECU 70 ends the process. On the other hand, if the PM accumulation amount Qpm is greater than the second threshold (step S4: YES), the HVECU 70 judges whether the vehicle is in a predetermined state (step S5). Here, the predetermined vehicle state refers to a vehicle state in which the vehicle 20 is stopped and there is no history of vehicle speed indicating traveling after the start of the vehicle system including the engine ECU 24 and the HVECU 70. In other words, if the period from when the vehicle system is started to when it is stopped is considered to be one process, the predetermined vehicle state refers to the state before the vehicle 20 starts traveling, and immediately after the vehicle system is started during that process.

As described above, since the vehicle speed is input to the HVECU 70, it is possible to determine whether the vehicle 20 is stopped or not based on the input vehicle speed. In this embodiment, stopping includes not only a complete stop where the vehicle speed is 0 (zero) km/h, but also a speed where the absolute value of the vehicle speed corresponds to stopping (e.g., 5 km/h, 3 km/h, etc.). Therefore, the HVECU 70 can determine that the vehicle 20 is in a traveling state if it does not fall under the category of stopping in this embodiment.

The HVECU 70 also manages the history of the input vehicle speed. For example, if the vehicle 20 is temporarily stopped due to a traffic light, sign, railroad crossing, traffic jam, etc., the HVECU 70 determines that the vehicle 20 is in a stopped state, but because there is a history of the vehicle speed indicating travel (e.g., 10 km/h or 30 km/h), it is possible to identify a state after travel has started, when travel toward the destination has already begun. Therefore, even if the HVECU 70 determines that the vehicle 20 is in a stopped state, if there is no vehicle speed history, it is possible to identify a state before travel has started, when travel toward the destination has not yet begun.

Here, if it is determined that the vehicle is not in the specified vehicle state (step S5: NO), the HVECU 70 ends the process. On the other hand, if it is determined that the vehicle is in the specified vehicle state (step S5: YES), the HVECU 70 displays a selection notification that prompts the driver to select whether or not to perform regeneration processing of the PM filter 25 (step S6). Specifically, the HVECU 70 generates a display signal that represents the selection notification, and outputs the generated display signal to the display 90. As a result, the selection notification appears on the display 90, as shown in FIG. 3(b).

Because the selection notification appears while the vehicle 20 is stopped before it starts to travel, there is no risk of the driver being induced into an unstable driving state, such as looking away from the road. In addition, because the vehicle is stopped before it starts to travel, rather than after it has finished traveling, there is no possibility that the vehicle system will stop. Therefore, there is no possibility that the regeneration process will end midway. In this way, with the HVECU 70 according to this embodiment, it is possible to avoid the selection operation of the regeneration process of the PM filter 25 while traveling and the stopping of the vehicle system during the regeneration process. If the driver wishes to regenerate the PM filter 25, the driver selects the positive string "Yes" included in the selection notification, and if the driver rejects the regeneration process, the driver selects the negative string "No" included in the selection notification.

If a positive character string is selected, the HVECU 70 outputs a control signal to the engine ECU 24 requesting regeneration processing and ends the process. When the engine ECU 24 receives a control signal from the HVECU 70 requesting regeneration processing, it executes temperature increase control. Specifically, the engine ECU 24 promotes an increase in the temperature of the PM filter 25. When the temperature of the PM filter 25 reaches or exceeds a regeneration temperature (e.g., 600°C), the engine ECU 24 makes the air-fuel ratio lean or cuts fuel to supply air to the PM filter 25 and burn the particulate matter accumulated in the PM filter 25. On the other hand, if a negative character string is selected, the HVECU 70 ends the process without outputting a control signal requesting regeneration processing.

As described above, the engine 22 according to this embodiment is equipped with a PM filter 25 in the exhaust passage that captures particulate matter in the exhaust. In particular, the HVECU 70, which controls the engine 22 via the engine ECU 24, displays a selection notification when the vehicle 20 mounting the engine 22 is stopped and is in a specified vehicle state in which there is no history of vehicle speed indicating driving after the start of the HVECU 70, etc. This selection notification is a notification that prompts the driver to select whether or not to perform regeneration processing of the PM filter 25. This makes it possible to avoid the selection operation of regeneration processing of the PM filter 25 while driving and the stopping of the vehicle system during the regeneration processing.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims.

For example, in the above embodiment, the first and second thresholds are used, but as shown in FIG. 3(a), multiple thresholds such as a third threshold and a fourth threshold may be set, and the notification frequency may be changed according to the amount of PM accumulation. Specifically, the HVECU 70 may count the number of trips, and display the selection notification once every three times before the start of driving between the second threshold and the third threshold, and display the selection notification every time before the start of driving between the third threshold and the fourth threshold. Furthermore, between the fourth threshold and the first threshold, the selection notification may be displayed every time the vehicle 20 stops, regardless of whether or not there is a driving history. In this way, the frequency of displaying the selection notification may be increased as the amount of PM accumulation increases.

In addition, in the above-described embodiment, the selection notification is displayed on the display 90, but a sound equivalent to the selection notification may be output, or the driver may select whether to execute the regeneration process by voice.

20 Vehicle 22 Engine (internal combustion engine)
24 Engine ECU (control unit)
25 PM filter (filter)
70 HVECU (control device)
88 Vehicle speed sensor

Claims (1)

A control device for an internal combustion engine having a filter in an exhaust passage for collecting particulate matter in exhaust,
The control device includes:
When the amount of deposition of the particulate matter is greater than a second threshold value that is smaller than a first threshold value for determining an excessive deposition state of the deposition amount, and when the vehicle equipped with the internal combustion engine is stopped and is in a predetermined vehicle state in which there is no history of vehicle speed indicating traveling after the control device is started, a selection of whether or not to perform a regeneration process of the filter is notified, and the frequency of the selection notification is increased as the amount of deposition increases .
A control device for an internal combustion engine.

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