JP2020093699A - Vehicular hybrid system control apparatus - Google Patents

Abstract

To provide a vehicular hybrid system control apparatus capable of suppressing engine output torque variation while suppressing a system efficiency from deteriorating.SOLUTION: A vehicular hybrid system control apparatus includes: surge determination means for determining whether a surge has occurred in a hybrid vehicle mounted with an internal combustion engine and a motor; knock detection means for detecting a knock occurring in the internal combustion engine; ignition timing adjustment means for adjusting ignition timing depending upon whether or not the knock detection means has detected a knock; and motor output correction means for correcting an output target value of the motor so as to suppress engine torque variation in accordance with the event of the ignition timing adjustment means adjusting the ignition timing in a case where the surge determination means determines the occurrence of a surge, with the knock detection means detecting the knock.SELECTED DRAWING: Figure 3

Description

The present invention relates to a control device for a vehicle hybrid system.

Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 2013-068160, an internal combustion engine that performs knock suppression control is known. The above-described conventional knock suppression control retards the engine ignition timing when a knock occurs. The above-described conventional knock suppression control is constructed so as to advance the ignition timing once retarded to eliminate the knock stepwise when the knock is not generated.

JP, 2013-068160, A

The engine torque fluctuates by changing the ignition timing. If it is attempted to always compensate for this engine torque fluctuation with the motor torque, there is a problem that the system efficiency decreases. On the other hand, a low-frequency vibration called a surge may occur while the vehicle is traveling, and this surge also causes a discomfort to an occupant. The inventor of the present application, as a result of earnest research, has found a new and useful vehicle hybrid system control device in consideration of the relationship between ignition timing control, motor output control, and surge.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a control device for a vehicle hybrid system that can suppress engine output torque fluctuation while suppressing a decrease in system efficiency. And

The control device of the vehicle hybrid system according to the present invention is
A surge determining means for determining whether or not a surge occurs in a hybrid vehicle equipped with an internal combustion engine and a motor,
Knock detection means for detecting the knock generated in the internal combustion engine,
Ignition timing adjustment means for adjusting the ignition timing based on the detection of the knock by the knock detection means,
When the surge determining unit determines that the surge is occurring and the knock detecting unit detects the knock, the engine torque fluctuation according to the ignition timing being adjusted by the ignition timing adjusting unit. Motor output correction means for correcting the output target value of the motor so as to suppress
Equipped with.

If the engine output torque periodically fluctuates due to ignition timing control for knock suppression, a drive surge may occur in the vehicle in accordance with the fluctuating period. The inventor of the present application has noticed that a drive surge is likely to occur with knock suppression ignition timing control. According to the present invention, the motor output correction means can suppress the surge by compensating the engine torque change generated by the knock control with the motor when the surge is detected. Since the knock avoidance is performed by the ignition timing control, it is possible to prevent the engine operating point from deviating from the conforming point (optimal fuel consumption point) as compared with the control in which the knock avoiding is performed by the decrease of the intake air amount. As a result, it is possible to suppress power consumption and also suppress a decrease in SOC level. As a result, it is possible to suppress a decrease in system efficiency while suppressing an engine output torque fluctuation that causes a surge.

It is a block diagram which shows an example of the hardware constitutions of the vehicle system concerning embodiment. 6 is a time chart for explaining an ignition timing operation in which the ignition timing is advanced little by little after the ignition timing is retarded. 3 is a flowchart of a routine executed by an electronic control unit in the vehicle system according to the exemplary embodiment. It is a figure for explaining the surge determination method concerning an embodiment. It is a figure for explaining the surge determination method concerning an embodiment. It is a block diagram which shows the operation|movement implement|achieved by the process group concerning embodiment.

The outline of the problems dealt with in the embodiments will be described below. The low frequency vibration generated during steady running of the vehicle causes an occupant to feel uncomfortable. One type of low frequency vibration is a phenomenon called surge. The surge is a vehicle longitudinal vibration of 2 to 20 [Hz].

Surge occurs when the input from the engine or tire is synchronized with the drive system torsional resonance frequency of the vehicle. What is caused by engine input is called "driving surge", and what is caused by tire input is called "rolling surge". This case deals with "driving surge" that occurs due to engine knock control.

The problems focused on by the inventor of the present application and the reasons why they occur will be described. In engine knocking, a knock sensor attached to a cylinder block picks up vibration at a knock frequency, and the peak value of vibration is used to detect the presence or absence of vibration and the magnitude of vibration.

When a knock is detected, the knock control retards the ignition timing by a fixed angle according to the magnitude of the knock until the knock no longer occurs. The knock control is a control for advancing the ignition timing by a constant angle when the knock does not occur.

FIG. 2 is a time chart for explaining the ignition timing operation in which the ignition timing is gradually advanced after the ignition timing is retarded. Under an operating condition where steady running and knocking occur periodically, an ignition timing operation of "advancing little by little after ignition retarding" as shown in FIG. 2 occurs. At this time, the engine output torque fluctuates in synchronization with the ignition timing operation. If this fluctuation period matches the torsional resonance frequency of the drive system, a drive surge will occur. The driving surge causes the occupant to feel discomfort.

Note that the knock avoiding method includes methods such as ignition retard, air amount suppression, and fuel enrichment. As can be seen from the ignition timing operation shown in FIG. 2, the present embodiment adopts the ignition retard, the intake air amount is constant, and the exhaust temperature rises.

The configuration for controlling the motor generator driving force in accordance with the knock control control of the engine is as follows.

FIG. 1 is a configuration diagram illustrating an example of a hardware configuration of a vehicle system 10 according to the embodiment. The vehicle system 10 illustrated in FIG. 1 is a FR-type two-motor hybrid system that does not have a torque converter.

The vehicle system 10 includes an engine 1, a first motor generator 2 as a generator connected to the engine 1, a transmission 3 connected to the first motor generator, a clutch 4 included in the transmission 3. A second motor generator 5 that is a drive motor and a second motor generator speed reduction mechanism 6 are provided.

The vehicle system 10 further includes a differential gear 7 connected to the transmission 3, tires 8 connected to the differential gear 7, an electronic control unit (ECU) 50 for performing control of the vehicle system 10, Various sensors and an electric system (not shown) including a battery, an inverter, a power control unit, and the like are provided.

In this specification and the accompanying drawings, the motor generator may be simply referred to as “MG”.

The engine 1 is a spark ignition type gasoline internal combustion engine that requires knock control. The electronic control unit 50 detects the engine speed from an engine speed sensor (not shown), detects an intake air amount from an intake air amount sensor (not shown), and detects an air-fuel ratio from an air-fuel ratio sensor (not shown). And means for detecting the ignition timing. As a result, "engine operating point information" including the engine speed, the intake air amount, the air-fuel ratio, and the ignition timing is detected. The electronic control unit 50 further includes means for estimating the engine torque from the engine operating point information.

The electronic control unit 50 includes ignition timing control logic (that is, knock control logic). This ignition timing control logic is constructed so as to detect knock occurrence based on a signal from a knock sensor (not shown), and avoid the knock based on the information to optimize engine efficiency.

The electronic control unit 50 further includes means for detecting the vehicle longitudinal acceleration, the vehicle speed, and the accelerator pedal opening, respectively. The electronic control unit 50 stores a history of the detected vehicle longitudinal acceleration, a history of the detected vehicle speed, and a history of the detected accelerator pedal opening, respectively, until a time point that is traced back from the latest time by a predetermined fixed period. Further, the apparatus further comprises means for maintaining a history of those.

The plurality of means described above may be provided as the functions of the electronic control unit 50. The electronic control unit 50 includes a non-volatile memory and an arithmetic processing circuit. Each of the above means may be realized by executing the processing time stored in the nonvolatile memory of the electronic control unit 50 in the form of a program by the arithmetic processing circuit.

FIG. 3 is a flowchart of a routine executed by the electronic control unit in the vehicle system 10 according to the embodiment. In the routine shown in FIG. 3, first, the electronic control unit 50 executes a process of determining whether or not the vehicle system 10 is hybrid-driving (step S100). If the determination result of this step is negative (NO), this routine ends.

When the determination result of step S100 is affirmative (YES), the electronic control unit 50 acquires the accelerator pedal opening θ _PA (step S101).

Next, the electronic control unit 50 determines whether or not the vehicle is running normally (step S102). This steady running determination is based on information such as vehicle speed, accelerator pedal opening, and its acceleration, and determines whether the vehicle is running steady. If the vehicle is not in steady running, this routine ends.

When it is determined in step S102 that the vehicle is traveling normally, the electronic control unit 50 then acquires the vehicle longitudinal acceleration a _v (step S103).

Next, the electronic control unit 50 carries out surge determination processing (step S104). As described above, the "drive surge" caused by the engine input causes discomfort to the occupant. As described with reference to FIG. 2, when the engine output torque periodically fluctuates due to knock control, a drive surge may occur depending on the relationship between the fluctuation period and the torsional resonance frequency of the drive system. is there. According to the processing of step S104, it is possible to detect the "driving surge" caused by knock control.

An example of the surge determination processing executed in step S104 will be described. 4 and 5 are diagrams for explaining the surge determination method according to the embodiment. The electronic control unit 50 may store the vehicle acceleration for a certain period of time (see FIG. 4) and execute the FFT process (fast Fourier transform process) for analyzing the frequency component of the time series signal.

FIG. 5 is a graph showing the result of performing the FFT processing. The electronic control unit 50 outputs a determination result that a surge has occurred when the peak frequency is in a predetermined surge frequency region and the signal strength exceeds a predetermined threshold level. You may. If it is not determined that the surge has occurred, this routine ends.

If it is determined in step S104 that a surge has occurred, then the electronic control unit 50 performs knock determination processing (step S105). An example of knock determination processing will be described. The electronic control unit 50 may detect the knock sensor signal over a predetermined section, and if the output peak value is larger than a predetermined knock threshold value, it may determine that knock has occurred.

Following the determination process of step S105, the electronic control unit 50 executes the process of each step included in the process group S200. In the processing group S200, different processing steps are defined depending on whether knocking occurs or no knocking occurs. According to the series of processes including steps S104 and S105 and the process group S200, the surge can be eliminated by the motor generator output compensation only when it is determined that the surge is present.

During execution of the routine shown in FIG. 3, the above-mentioned "ignition timing control logic" provided separately is repeatedly executed. The parameters such as the ignition timing retard amount SA _ret acquired in the processing group S200 are the values read by the electronic control unit 50 when the ignition timing control is executed in the "ignition timing control logic". is there.

(When knock occurs)
If it is determined in step S105 that knock has occurred, the process proceeds to step S201 and subsequent steps. First, in step S201, the electronic control unit 50 acquires the ignition timing retard amount SA _ret .

Next, the electronic control unit 50 acquires the engine rotation speed NE (step S202), and subsequently acquires the engine charging efficiency KL (step S203). Next, the electronic control unit 50 calculates the engine torque decrease amount ΔTQ _d due to the ignition retard (step S204).

Next, the electronic control unit 50 corrects the motor generator torque target value TQ _MGt according to the following formula (step S205). In other words, a value obtained by adding .DELTA.TQ _d to the current _{TQ mgt,} calculated as the latest _{TQ mgt.}
TQ _MGt ← TQ _MGt + ΔTQ _d

Next, the electronic control unit 50 instructs the motor generator about the output torque (TQ _MGt after the correction in the above step S205) (step S206). After that, this routine ends.

(When no knock occurs)
On the other hand, if it is determined in step S105 that knock has not occurred, the process proceeds to step S211 and subsequent steps. First, in step S211, the electronic control unit 50 acquires the engine rotation speed NE (step S211).

Next, the electronic control unit 50 acquires the engine charging efficiency KL (step S212), calculates the base ignition timing SA _base (step S213), and acquires the ignition timing SA (step S214). Next, the electronic control unit 50 determines whether SA<SA _base is satisfied (step S215).

If SA<SA _base is not satisfied, that is, SA≧SA _base , the current routine is ended.

If SA<SA _base is satisfied, then the electronic control unit 50 calculates the engine torque increase amount ΔTQ _i due to the ignition advance (step S216).

Next, the electronic control unit 50 corrects the motor generator torque target value TQ _MGt according to the following formula (step S217). In other words, a value obtained by subtracting the .DELTA.TQ _i from the current _{TQ mgt,} calculated as the latest _{TQ mgt.}
TQ _MGt ← TQ _MGt − ΔTQ _i

Next, the electronic control unit 50 instructs the motor generator (second motor generator 5) on the output torque (TQ _MGt corrected in step S217) (step S206). After that, this routine ends.

FIG. 6 is a configuration diagram showing an operation realized by the processing group according to the embodiment. The operation realized by the processing group S200 will be described with reference to FIG. The processing group S200 realizes a motor generator torque determination method that cooperates with knock control.

If the engine torque decrease occurs while the "ignition timing control logic" implemented by another flowchart different from that of FIG. 3 is performing knock control, the motor generator torque is increased accordingly. This makes it possible to compensate for the decrease in engine torque.

In the time chart of the ignition timing in FIG. 6, the “retard phase” and the “advance phase” are respectively described.

The retard phase immediately after knocking will be described. The electronic control unit 50 calculates the engine torque decrease margin ΔTQ _d based on the engine speed NE, the charging efficiency KL, and the ignition timing retard amount SA _ret .

The electronic control unit 50 sets the motor generator torque target value TQ _MGt according to the following formula.
TQ _MGt = TQ _MGbase + ΔTQ _d

The advance phase after avoiding knock will be described. The electronic control unit 50 calculates the engine torque recovery margin ΔTQ _i based on the engine rotation speed NE, the charging efficiency KL, and a predetermined ignition advance amount.

The electronic control unit 50 sets the motor generator torque target value TQ _MGt according to the following formula.
TQ _MGt = TQ _MGt -ΔTQ _i

As can be seen from the time chart at the bottom of FIG. 6, it is preferable that the total TQ _MGt +TQ _e of the motor generator torque TQ _MGt and the engine torque TQe be constant.

1 Engine 2 First motor generator (generator)
3 Transmission 4 Clutch 5 Second Motor Generator (Drive Motor)
6 Second Motor Generator Reduction Mechanism 7 Differential Gear 8 Tire 10 Vehicle System 50 Electronic Control Unit TQ _MGt Motor Generator Torque Target Value ΔTQ _d Engine Torque Reduction Amount (Engine Torque Reduction Allowance)
ΔTQ _i Engine torque increase amount (engine torque recovery allowance)

Claims (1)

A surge determining means for determining whether or not a surge occurs in a hybrid vehicle equipped with an internal combustion engine and a motor,
Knock detection means for detecting the knock generated in the internal combustion engine,
Ignition timing adjustment means for adjusting the ignition timing based on the detection of the knock by the knock detection means,
When the surge determining unit determines that the surge is generated and the knock detecting unit detects the knock, the engine torque fluctuation according to the ignition timing adjusting unit adjusting the ignition timing. Motor output correction means for correcting the output target value of the motor so as to suppress
And a control device for a hybrid system for a vehicle.

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