Engine control device
The engine control device addresses vehicle vibrations by adjusting intake air amount and ignition timing to match target torque values, effectively managing compressor-driven changes in air conditioning load torque.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-10-24
- Publication Date
- 2026-05-12
AI Technical Summary
Existing engine control systems fail to effectively suppress vibrations in a running vehicle due to changes in the driving state of a compressor that compresses refrigerant for air conditioning.
An engine control device that performs air conditioning load torque correction control, including first torque correction control to adjust intake air amount and second torque correction control to adjust ignition timing, to compensate for changes in compressor operation.
This solution effectively suppresses vibrations in a moving vehicle by aligning actual engine torque with target torque values, ensuring smooth operation and reducing vibrations caused by compressor state changes.
Smart Images
Figure 2026076592000001_ABST
Abstract
Description
Technical Field
[0006] , , ,
[0001] The present invention relates to an engine control device.
Background Art
[0002] Conventionally, it is known to control the target rotational speed during engine idling operation in consideration of changes in engine load associated with driving a compressor that compresses refrigerant for air conditioning (see, for example, Patent Document 1). According to Patent Document 1, engine rotational fluctuations can be suitably suppressed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, Patent Document 1 is aimed at control during idling operation. Therefore, there is room for improvement in suppressing vibrations generated in a running vehicle due to driving of the compressor. <000G026>
[0005] An object of the present invention is to suppress vibrations that may occur in a running vehicle as the driving state of a compressor that compresses refrigerant for air conditioning changes.
Means for Solving the Problems
[0006] The above objective is achieved by an engine control device that includes an engine and a compressor that compresses a refrigerant for air conditioning driven by the engine, and in a vehicle in motion, performs air conditioning load torque correction control that reflects the change in air conditioning load torque due to a change in the driving state of the compressor in the required torque calculated based on the driver's operation, wherein the air conditioning load torque correction control includes a first torque correction control that increases the intake air amount to increase the actual air amount torque when the compressor transitions from a de-driven state to a driven state, and decreases the intake air amount to decrease the actual air amount torque when the compressor transitions from a driven state to a de-driven state, and a second torque correction control that retards the ignition timing to decrease the actual air amount torque and set a torque target value corresponding to the air conditioning load torque when the compressor transitions from a de-driven state to a driven state and when the compressor transitions from a driven state to a de-driven state. [Effects of the Invention]
[0007] This technology can suppress vibrations that may occur in a moving vehicle due to changes in the operating state of the compressor that compresses the refrigerant used for air conditioning. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is a schematic diagram of an engine to which the engine control device of the embodiment is applied. [Figure 2] Figure 2 is an example of a time chart showing the contents of the air conditioning load torque correction control performed by the engine control device of the embodiment. [Figure 3] Figure 3 is a block diagram showing the processing flow of the air conditioning load torque correction control implemented in this embodiment. [Figure 4] Figure 4 is a flowchart showing an example of air conditioning load torque correction control performed by the engine control device of the embodiment. [Figure 5]Figure 5A is an example of a time chart illustrating the control behavior when the compressor's operating state changes continuously. Figure 5B is an example of a time chart showing the control behavior when the compressor's operating state changes over a short period of time. [Modes for carrying out the invention]
[0009] (Embodiments) Embodiments will be described below with reference to the drawings.
[0010] [Engine Configuration] Referring to Figure 1, the schematic configuration of the engine 100 of this embodiment will be described. Various controls for the engine 100 are performed by the control device, the ECU (Electronic Control Unit) 50.
[0011] The engine 100 comprises multiple cylinders 2 within a cylinder block (only one cylinder 2 is shown in Figure 1). A piston 3 is slidably housed within each cylinder 2. The piston 3 forms a combustion chamber 2a between itself and the cylinder head located above the cylinder block. The piston 3 is connected to the crankshaft 5 via a connecting rod 4. The combustion chamber 2a is equipped with an injector 6 for injecting fuel into the cylinder and a spark plug 7. The fuel injected from the injector 6 becomes a fuel-air mixture in the combustion chamber 2a and is ignited by the spark plug 7. When the ignited fuel-air mixture burns and explodes, the piston 3 is pushed down. The pushed-down piston 3 transmits its explosive force to the crankshaft 5 via the connecting rod 4, causing the crankshaft 5 to rotate. The engine 100 is equipped with a crank angle sensor 15 for detecting the crank angle.
[0012] The engine 100 is equipped with an intake port 8 and an exhaust port 9, which are positioned to face the combustion chamber 2a. An intake pipe 10 is connected to the intake port 8. An exhaust pipe 11 is connected to the exhaust port 9.
[0013] The intake manifold 10 is equipped with an air cleaner 12, an air flow meter 13, a throttle valve 17, and an intake manifold 18, in that order from the upstream side of the intake airflow. The air flow meter 13 detects the amount of air flowing through the intake manifold 10. The throttle valve 17 adjusts the amount of air supplied to the combustion chamber 2a. The intake manifold 10 is branched by the intake manifold 18 and connected to the intake port 8 of each cylinder.
[0014] The exhaust pipe 11 is equipped with an exhaust manifold 20 and a catalytic converter 21, in that order from the upstream side of the exhaust flow. The catalytic converter 21 performs exhaust purification.
[0015] The engine 100 includes an intake valve 23 that opens and closes the intake port 8 and an exhaust valve 24 that opens and closes the exhaust port 9. The intake valve 23 is opened and closed by a valve train 25. The exhaust valve 24 is opened and closed by a valve train 26.
[0016] The engine 100 is connected to a compressor 31 that compresses the refrigerant used in the air conditioner (hereinafter simply referred to as AC) 30. The compressor 31 is connected to the crankshaft 5 via a clutch 31a. The drive state of the compressor 31 changes depending on the engagement state of the clutch 31a. In the following description, the torque corresponding to the drive load of the compressor 31 is referred to as the air conditioning load torque. The AC 30 includes a refrigerant pressure sensor 32a for measuring the refrigerant pressure and a refrigerant temperature sensor 32b for measuring the refrigerant temperature. The AC 30 also includes an air conditioning control unit 33. The AC 30 in this embodiment is a fixed-capacity AC.
[0017] The ECU50 comprises a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a storage device. The ECU50 controls the engine 100 by executing programs stored in the ROM and storage device. The storage device stores programs and maps used for control.
[0018] The ECU 50 functions as a required torque calculation unit 51 and an air conditioning load torque correction unit 52 by executing a program. The air conditioning load torque correction unit 52 includes a timing unit 53, an ignition timing control unit 54, and a throttle control unit 55. The ignition timing control unit 54 includes a difference calculation unit 56.
[0019] The ECU 50 is electrically connected to the air flow meter 13 and the crank angle sensor 15. The ECU 50 is electrically connected to an accelerator opening sensor 58 that measures the depression amount of the accelerator pedal 57. The ECU 50 is electrically connected to a shift position sensor 60 that detects the shift position in the shift device 59 and a vehicle speed sensor 61 that detects the speed of the vehicle 80. The ECU 50 includes a gear position information acquisition unit 62 that acquires the gear position in the transmission 81 provided in the vehicle 80. The ECU 50 selects the gear of the transmission 81 based on the driving state of the vehicle 80 and the depression amount of the driver's accelerator pedal 57, etc. The gear position information acquisition unit 62 acquires information on which gear is selected.
[0020] The required torque calculation unit 51 calculates the required torque required for the engine 100 based on the driver's operation. The required torque is calculated based on the engine speed acquired by the crank angle sensor 15, the vehicle speed acquired by the vehicle speed sensor 61, the accelerator depression amount acquired by the accelerator opening sensor 58, etc.
[0021] The air conditioning load torque correction unit 52 executes air conditioning load torque correction control. The air conditioning load torque correction control is control that reflects the change in the air conditioning load torque accompanying the change in the driving state of the compressor 31 in the required torque.
[0022] The timing unit 53 measures the period for ending the air conditioning load torque correction control. The end of the air conditioning load torque correction control will be described later. The ignition timing control unit 54 controls the ignition timing of the engine 100. The throttle control unit 55 controls the intake air amount by adjusting the opening of the throttle valve 17.
[0023] The throttle control unit 55 also adjusts the opening degree of the throttle valve 17 in various control operations of the engine 100 other than air conditioning load torque correction control. In air conditioning load torque control, the throttle control unit 55 performs a first torque correction control that changes the intake air amount. The first torque correction control adjusts the opening degree of the throttle valve so that the engine torque becomes a future torque target value. The future torque is the engine torque that can be obtained by adjusting the intake air amount within a responsive range. Since the future torque is derived from the intake air amount, there is a response delay. In the following description, the torque corresponding to the intake air amount controlled by the first torque correction control will be referred to as the actual air amount torque. The actual air amount torque can be determined based on the intake air amount detected by the air flow meter 13.
[0024] The ignition timing control unit 54 adjusts the ignition timing of the spark plug 7 in various control operations of the engine 100 other than the air conditioning load torque correction control. In the air conditioning load torque control, the ignition timing control unit 54 performs a second torque correction control that changes the ignition timing. The second torque correction control controls the ignition timing so that the engine torque becomes the immediate torque target value. The immediate torque is the engine torque that compensates for the discrepancy between the actual air volume torque, which is affected by the response delay of the intake air volume, and the air conditioning load torque by adjusting the ignition timing within an adjustable range. Since the immediate torque originates from the ignition timing, it is highly responsive and the target torque can be obtained instantaneously. The immediate torque decreases by retarding the ignition timing. In the following explanation, the torque corresponding to the ignition timing controlled by the second torque correction control will be referred to as the actual generated torque.
[0025] In this embodiment, first, the actual air volume torque is obtained by the first torque correction control. Then, by reducing the actual air volume torque with the second torque correction control, the actual generated torque is made to match the target air conditioning load torque. In this embodiment, the actual air volume torque is not actually output; instead, the actual generated torque, which is the actual air volume torque corrected, is output.
[0026] The difference calculation unit 56 calculates the difference between the actual air volume torque and the immediate torque target value in the second torque correction control. When this difference falls below a predetermined value, the second torque correction control is terminated. The termination of the second torque correction control will be explained later.
[0027] <Air Conditioning Load Torque Correction Control> Next, we will explain air conditioning load torque correction control with reference to Figures 2 to 4.
[0028] In this embodiment, the execution conditions for air conditioning load torque correction control are set (see step S1 in the flowchart shown in Figure 4). In this embodiment, the following three conditions are defined as prerequisites for executing air conditioning load torque correction control.
[0029] The first condition is that the shift device 59 has selected a shift position other than the stop position. Specifically, the shift device 59 has selected a position other than the P (Parking) position or the N (Neutral) position. This condition stipulates that the vehicle 80 is in a drivable state.
[0030] The second condition is that the transmission 81 has selected a low-speed gear position or a reverse gear position. For example, if the low gear and second gear are set as low-speed gears, then the low-speed gear position is selected when these gears are selected. This condition stipulates that the driver is in a state where they can easily perceive vibrations of the moving vehicle 80.
[0031] The third condition is that the amount the accelerator is pressed is below a preset threshold. For example, if the amount the accelerator is pressed is greater than the threshold, the driver will have difficulty perceiving vibrations caused by changes in the operating state of the compressor 31, in conjunction with the feeling of acceleration of the vehicle 80. The third condition also stipulates that the driver will have a good chance of perceiving vibrations of the vehicle 80 while it is in motion.
[0032] Next, an overview of the air conditioning load torque correction control will be explained. A detailed explanation based on the flowchart shown in Figure 4 will follow.
[0033] Air conditioning load torque correction control is performed when the driving state of AC30 changes. Specifically, it is performed when an ACON request is made at time t1 in Figure 2 and when an AC OFF request is made at time t3 in Figure 2. Figure 2 shows the future torque target value, the immediate torque target value, the actual air volume torque, and the actual generated torque. The future torque target value is drawn with a thick solid line. The immediate torque target value is drawn with a thin solid line. The actual air volume torque is drawn with a dotted line. The actual generated torque is drawn with a dashed line. The actual generated torque is obtained by performing ignition timing control so that the immediate torque target value is obtained. Because the responsiveness of the ignition timing control is good, the immediate target torque and the actual generated torque generally overlap.
[0034] The AC30's operating state changes under the control of the air conditioning control unit 33. After an ACON request is received at time t1, the clutch 31a of the AC30 engages at time t2. In other words, there is a delay period from time t1 to time t2 between the AC ON request and the engagement of the clutch 31a. Also, after an ACOFF request is received at time t3, the clutch 31a of the AC30 is released at time t4. In other words, there is a delay period from time t3 to time t4 between the AC OFF request and the release of the clutch 31a.
[0035] Referring to Figure 3, in order to set the target ignition timing and target throttle opening, the required torque based on the driver's operation is first calculated. The required torque is calculated based on the engine speed, vehicle speed, and accelerator pedal depression amount, which change based on the driver's operation. The required torque is obtained by controlling the intake air volume. The required torque is set as the future torque target value at this point. In the air conditioning load torque correction control, torque correction is performed on this future torque target value in accordance with the change in the driving state of the AC30. The control that sets the target throttle opening and changes the intake air volume corresponds to the first torque correction control. The control that changes the target ignition timing corresponds to the second torque correction control.
[0036] ≪First Torque Correction Control≫ The time chart shown in Figure 2 only depicts the torque change corresponding to the air conditioning load torque. In other words, Figure 2 does not include the required torque calculated based on the driver's operation. The torque required for engine 100 is the value obtained by adding the air conditioning load torque to the required torque.
[0037] First, let's explain what happens when an AC ON request is made at time t1. When an AC ON request is made, the future torque target value includes the steady-state air conditioning load torque and the inertia compensation torque.
[0038] The steady-state air conditioning load torque is the torque required to maintain the steady rotation state of the compressor 31. The inertia compensation torque is the torque used to compensate for the inertia of the compressor 31 when transitioning the compressor 31 to a steady rotation state. In air conditioning load torque correction, the steady-state air conditioning load torque and the inertia compensation torque are added to the future load torque target value. The value obtained by adding the steady-state air conditioning load torque and the inertia compensation torque is considered the future torque target value at this point in time. Here, the inertia compensation torque in the first torque correction control is estimated to be large enough to sufficiently compensate for the expected inertia.
[0039] In the first torque correction control, the steady-state air conditioning load torque and the inertia compensation torque are added together. These torque additions are obtained by increasing the intake air volume.
[0040] Therefore, the target air volume is calculated, and the corresponding target throttle opening is calculated. The target throttle opening is instructed to the throttle valve 17. There is a response delay in the torque obtained according to the intake air volume. The actual air volume torque is obtained when the throttle valve 17 reaches the target throttle opening. The effect on the engine 100 caused by the driving of AC30 appears after time t2 when the clutch 31a is engaged. In this embodiment, a delay period is provided from time t1 to time t2, so that the change in actual air volume torque appears approximately around time t2. In the example shown in Figure 2, the actual air volume torque begins to rise slightly earlier than time t2.
[0041] The inertia compensation torque is gradually changed in its rising and falling phases. As a result, the actual air volume torque changes slowly.
[0042] Next, we will explain the case when an AC OFF request is made at time t3. When an AC OFF request is made, it is not necessary to consider the inertia component. For this reason, the future torque target value when an AC OFF request is made is set to reduce the steady-state air conditioning load torque component at time t3.
[0043] When an AC OFF request is made, the engagement of clutch 31a is released, eliminating the need for air conditioning load torque. However, even if the requested torque, which is a reduction of the steady-state air conditioning load torque at time t3, is set as the future torque target value, there is a response delay in the actual air volume torque. In other words, even if the future torque target value is reduced in response to the AC OFF request, the actual air volume torque will remain higher than the requested torque for a while.
[0044] This first torque correction control is a feedforward control in which a future torque target value is preset in accordance with the characteristics of the AC30.
[0045] ≪Second Torque Correction Control≫ The second torque correction control retards the ignition timing. Retarding the ignition timing reduces the actual air volume torque. This reduced torque becomes the actual generated torque. Figure 2 shows the immediate torque target value, not the amount of ignition timing retardation. The immediate torque target value is the torque obtained as the output of the engine 100, reflecting the driving state of the compressor 31, that is, the engagement state of the clutch 31a.
[0046] Referring to Figure 3, the torque efficiency is calculated by considering the future torque target value and the immediate torque target value set in the air conditioning load torque correction. Based on this torque efficiency, the ignition retardation amount is calculated. Then, based on that ignition retardation amount and the optimal ignition timing at that time (MBT: Minimum advance for Best Torque), the target ignition timing is calculated.
[0047] First, let's explain the case when an AC ON request is made at time t1. The immediate torque target value when an AC ON request is made also includes the steady-state air conditioning load torque and the inertia compensation torque. The significance of the steady-state air conditioning load torque and the inertia compensation torque is the same as the significance of these torques in the future torque target value. However, the inertia compensation torque in the first torque correction control is estimated to be large enough to sufficiently compensate for the expected inertia. In contrast, the inertia compensation torque in the second torque correction control is smaller than the inertia compensation torque in the first torque correction control.
[0048] The immediate torque target value is set to rise at a timing that roughly coincides with the time t2 when the clutch 31a engages. Therefore, there is a period before time t2 when the actual air volume torque is greater than the immediate target torque. In the second torque correction control, the ignition timing is retarded during this period to bring the actual air volume torque closer to the immediate target torque.
[0049] Furthermore, even during the period when torque equivalent to the inertia compensation torque appears in the actual air volume torque, the ignition timing is retarded to bring the actual air volume torque closer to the immediate target torque.
[0050] This makes it possible to suppress vibrations caused by torque fluctuations resulting from the operation of the compressor 31.
[0051] Next, we will explain what happens when an AC OFF request is made at time t3. When an AC OFF request is made, it is unnecessary to consider the inertia component. For this reason, the immediate torque target value when an AC OFF request is made is set to decrease the steady-state air conditioning load torque component from time t3 onward. In this case, the immediate torque target value is gradually changed.
[0052] When an AC OFF request is made, the clutch 31a is disengaged at time t4, eliminating the need for air conditioning load torque. As described above, there is a period from time t3 onward where the actual air volume torque is higher than the requested torque. In the second torque correction control, the ignition timing is retarded, bringing the actual generated torque, which has been corrected by this actual air volume torque, closer to the requested torque.
[0053] This makes it possible to suppress vibrations caused by torque fluctuations resulting from the release of the compressor 31's drive.
[0054] Furthermore, the actual generated torque maintains a generally steady air conditioning load torque from time t3, when the AC OFF request is made, until around time t4, when the clutch 31a is disengaged. This prevents a decrease in the rotation speed of the engine 100 caused by the compressor 31 connected to the engine 100.
[0055] This second torque compensation control is a feedforward control in which a future torque target value is set in accordance with the characteristics of the AC30.
[0056] <<Control Example>> Here, with reference to the flowchart shown in Figure 4, an example of air conditioning load torque correction control performed by the ECU 50, including the air conditioning load torque correction unit 52, will be described.
[0057] In step S1, the ECU 50 determines whether the control preconditions are met. The control preconditions are the three conditions mentioned above for determining whether the vehicle 80 is in a driving state. If the determination in step S1 is Yes, the process proceeds to step S2. On the other hand, if the determination in step S1 is Negative (No), the ECU 50 terminates the process.
[0058] In step S2, the ECU 50 determines whether there has been a change in the ON and OFF requests for the AC 30. If the determination in step S2 is No, the ECU 50 terminates processing. If the determination in step S2 is Yes, the nature of the change in the request is further determined. Specifically, it is determined whether the change in the request is from OFF to ON or from ON to OFF. If the change in the request is from OFF to ON, processing proceeds to step S3. On the other hand, if the change in the request is from ON to OFF, processing proceeds to step S8. The ECU 50 obtains information regarding the change in the ON and OFF requests for the AC 30 from the air conditioning control unit 33. Also, in step S2, when there is a change in either request, the timing unit 53 starts counting.
[0059] In step S3, the ECU 50 calculates a future torque target value. The ECU 50 reflects the future torque target value calculated in step S3 into the requested torque calculated based on the driver's operation. Then, the throttle control unit 55 of the ECU 50 performs throttle control. After processing in step S3, the ECU 50 proceeds to step S4.
[0060] In step S4, the ECU 50 determines whether a predetermined time has elapsed since AC30 turned ON. Here, the predetermined time is the delay period in Figure 2. In other words, the ECU 50 determines whether time t2 has elapsed. If the determination in step S4 is Yes, the process proceeds to step S5. On the other hand, if the determination in step S4 is No, the process proceeds to step S7.
[0061] In step S5, the ECU 50 calculates the immediate torque target value. The ECU 50 also calculates the ignition timing corresponding to the immediate torque target value. The immediate torque target value includes the steady-state air conditioning load torque and the inertia compensation torque. The ECU 50 reflects the immediate torque target value calculated in step S5 into the requested torque calculated based on the driver's operation. The ignition timing control unit 54 controls the ignition timing to eliminate the discrepancy between the actual air volume torque and the immediate torque target value. When the actual air volume torque is greater than the immediate torque target value, the ignition timing is retarded. After processing in step S5, the ECU 50 proceeds to step S6.
[0062] In step S6, the ECU 50 determines whether the termination conditions for the air conditioning load torque correction control have been met. In this embodiment, three conditions are set as the termination conditions for the air conditioning load torque correction control. If any one of these three conditions is met, the air conditioning load torque correction control is terminated. The air conditioning load torque correction control is terminated by terminating the ignition timing control in the second torque correction control. The three conditions for terminating the air conditioning load torque correction control will be explained later.
[0063] If the result in step S6 is "Yes", the ECU 50 terminates the air conditioning load torque correction control process. On the other hand, if the result in step S6 is "No", the ECU 50 repeats the process from step S3.
[0064] Next, step S7 will be described. In step S7, the ECU 50 calculates the immediate torque target value. The ignition timing control unit 54 also calculates the ignition timing corresponding to the immediate torque target value. The ECU 50 reflects the immediate torque target value calculated in step S7 into the requested torque calculated based on the driver's operation. However, unlike in step S5, the immediate torque target value in step S7 is set to 0 Nm. Therefore, the immediate torque target value between time t1 and time t2 matches the requested torque calculated based on the driver's operation. The ignition timing control unit 54 controls the ignition timing to eliminate the discrepancy between the actual air volume torque and the immediate torque target value. However, there is a response delay in the rise of the actual air volume torque. Therefore, MBT is maintained until the actual air volume torque rises. After the actual air volume rises, the ignition timing is retarded. After processing in step S7, the ECU 50 repeats the processing from step S3.
[0065] Next, step S8 will be explained. The processing from step S8 onward is the processing that occurs when an ACOFF request is made. In step S8, the ECU 50 calculates a future torque target value. The ECU 50 reflects the future torque target value calculated in step S8 into the requested torque calculated based on the driver's operation. Then, the throttle control unit 55 of the ECU 50 executes throttle control. However, the future torque target value in step S8 is set to 0 Nm. This is because, based on the ACOFF request, the air conditioning load torque will no longer be needed in the future. For this reason, the future torque target value from time t3 onward matches the requested torque calculated based on the driver's operation. After processing in step S8, the ECU 50 proceeds to step S9.
[0066] In step S9, the ECU 50 determines whether a predetermined time has elapsed since AC30 changed to OFF. Here, the predetermined time is the delay period in Figure 2. In other words, the ECU 50 determines whether time t4 has elapsed. If the determination in step S9 is Yes, the process proceeds to step S10. On the other hand, if the determination in step S9 is No, the process proceeds to step S12.
[0067] In step S10, the ECU 50 calculates the immediate torque target value. The ECU 50 also calculates the ignition timing corresponding to the immediate torque target value. The ECU 50 reflects the immediate torque target value calculated in step S10 into the requested torque calculated based on the driver's operation. The ignition timing control unit 54 controls the ignition timing to eliminate the discrepancy between the actual air volume torque and the immediate torque target value. When the actual air volume torque is greater than the immediate torque target value, the ignition timing is retarded. After processing in step S10, the ECU 50 proceeds to step S11.
[0068] In step S11, the ECU 50 determines whether the termination condition for the air conditioning load torque correction control has been met. The process in step S11 is largely the same as the process in step S6. Therefore, a detailed explanation of step S11 is omitted here.
[0069] If the result in step S11 is "Yes", the ECU 50 terminates the air conditioning load torque correction control process. On the other hand, if the result in step S11 is "No", the ECU 50 repeats the process from step S8.
[0070] Here, we will explain how to set the immediate torque target value when the process from step S8 is repeated, thereby performing the process in step S10 again. In the first step S10, a value equivalent to the steady-state air conditioning load torque is set as the immediate torque target value. In the second and subsequent steps S10, a value obtained by subtracting a predetermined amount from the immediate torque target value set in the previous step S10 is set as the new immediate torque target value. In other words, the immediate torque target value decreases gradually. This smooths the change in the actual generated torque and effectively suppresses the occurrence of vibrations.
[0071] Next, step S12 will be described. In step S12, the ECU 50 calculates the immediate torque target value. The ignition timing control unit 54 also calculates the ignition timing corresponding to the immediate torque target value. The ECU 50 reflects the immediate torque target value calculated in step S12 into the requested torque calculated based on the driver's operation. After processing in step S12, the ECU 50 repeats the processing from step S8.
[0072] Here, we will explain how to set the immediate torque target value when the process from step S8 is repeated, resulting in the process of step S12 being performed again. In step S12, unlike step S10, the immediate torque target value set in the previous step S12 is maintained.
[0073] As shown in Figure 2, the immediate torque target value and the actual generated torque begin to decrease slightly earlier than time t4. The decrease in the immediate torque target value should ideally begin around time t4. As shown in Figure 2, by disengaging the clutch 31a after the actual generated torque has begun to decrease, the actual generated torque can be changed more smoothly, effectively suppressing the occurrence of vibrations.
[0074] Here, we will explain in detail the three conditions that serve as termination conditions for the air conditioning load torque correction control in steps S6 and S11.
[0075] The first termination condition is that the difference between the actual air volume torque and the immediate target torque value, which is the target torque value in the second torque correction control, is less than or equal to a predetermined value. The actual air volume torque can be calculated based on the value detected by the air flow meter 13. The difference between the actual air volume torque and the immediate target torque is calculated by the difference calculation unit 56. If the difference between the actual air volume torque and the immediate target torque value becomes small, vibrations caused by the air conditioning load torque are less likely to occur even if the retardation of the ignition timing is stopped. For this reason, a condition is set regarding the difference between the actual air volume torque and the immediate target torque value.
[0076] The second termination condition is that a predetermined time has elapsed since the instruction to change the drive state of the compressor 31. If the air conditioning load torque correction control continues, the ignition timing correction continues, and ignition does not occur in the MBT. If ignition does not occur in the MBT, the output and fuel efficiency of the engine 100 will be affected. Therefore, if the first condition is not met within the predetermined time, the ECU forcibly terminates the air conditioning load torque correction control.
[0077] The third termination condition is a change in the AC30 request during air conditioning load torque correction control. For example, if an AC OFF request is received while air conditioning load torque correction control based on an ACON request is being executed, the air conditioning load torque correction control based on the AC ON request will terminate. In this case, air conditioning load torque correction control based on the AC OFF request will be executed again. Similarly, if an AC ON request is received while air conditioning load torque correction control based on an AC OFF request is being executed, the air conditioning load torque correction control based on the AC OFF request will terminate. Then, air conditioning load torque correction control based on the AC ON request will be executed again.
[0078] For example, as shown in Figure 5A, suppose that air conditioning load torque correction control based on an ACON request at time t1 is being executed, and that an AC OFF request is received at time t3. In this case, at time t3, air conditioning load torque correction control based on an AC ON request is continuing. Thus, when an AC OFF request is received while the previously executed air conditioning load torque correction control is continuing, the air conditioning load torque correction control is terminated. Then, the process from step S1 is executed again. This example corresponds to the case where the AC30 request changes from ON to OFF in step S2. Therefore, the process proceeds to step S8, and air conditioning load torque correction control is executed anew. By continuously executing air conditioning load torque correction control in this way, vibration can be effectively suppressed. The same process is followed when the AC30 request changes from OFF to ON.
[0079] Furthermore, if the interval between switching AC30 ON and OFF is short, the previously executed air conditioning load torque correction control will terminate. Then, a new air conditioning load torque correction control will be executed. For example, as shown in Figure 6, consider a case where an ACON request is issued at time t1, and shortly thereafter, a time t3' when an AC OFF request is issued and a time t4' when the clutch 31a is disengaged arrive. Even in such a case, the previously executed air conditioning load torque correction control will terminate, and a new air conditioning load torque correction control will be executed.
[0080] In this embodiment, the air conditioning load torque correction control terminates when one of these three conditions is met.
[0081] [Effects] The control device of the embodiment reflects the change in air conditioning load torque associated with the change in the driving state of the compressor 31 in the required torque calculated based on the driver's operation when the vehicle 80 is in a predetermined driving state and the driving state of the compressor 31 changes. At this time, a first torque correction control that changes the intake air amount and a second torque correction control that changes the ignition timing in the engine 100 are executed. As a result, vibrations that may occur in the vehicle 80 while it is driving due to the operation of the compressor 31 can be suppressed.
[0082] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]
[0083] 1...Internal combustion engine, 7...Spark plug, 30...Air conditioning system (AC), 31...Compressor, 31a...Clutch, 33...Air conditioning control unit, 50...ECU, 51...Required torque calculation unit, 52...Air conditioning load torque correction unit, 53...Timer unit, 54...Ignition timing control unit, 55...Throttle control unit, 56...Difference calculation unit, 58...Accelerator opening sensor, 59...Shift device, 60...Shift position sensor, 61...Vehicle speed sensor, 62...Gear position information acquisition unit, 80...Vehicle, 81...Transmission, 100...Engine
Claims
1. An engine control device comprising an engine and a compressor that compresses a refrigerant for air conditioning driven by the engine, which performs air conditioning load torque correction control in a vehicle in motion, which reflects the change in air conditioning load torque due to a change in the driving state of the compressor in the required torque calculated based on the driver's operation, The aforementioned air conditioning load torque correction control is A first torque correction control that increases the intake air volume to increase the actual air volume torque when the compressor transitions from a deactivated state to a driven state, and decreases the intake air volume to decrease the actual air volume torque when the compressor transitions from a driven state to a deactivated state, The system includes a second torque correction control that retards the ignition timing to reduce the actual air volume torque when the compressor transitions from a de-drive state to a drive state and when the compressor transitions from a drive state to a de-drive state, thereby setting a torque target value corresponding to the air conditioning load torque. Engine control device.
2. The vehicle is equipped with a shift device and a transmission that can select at least a low-speed gear position, a high-speed gear position and a reverse gear position. The control device for an engine according to claim 1, wherein the control device determines that the vehicle is in a driving state when a shift position other than the stop position is selected by the shift device, a low-speed gear position or a reverse gear position is selected by the transmission, and the amount of accelerator pedal depression is less than or equal to a preset threshold.
3. The control device for an engine according to claim 1, wherein the control device terminates the second torque correction control when the difference between the actual air volume torque and the torque target value in the second torque correction control becomes less than or equal to a predetermined value set in advance.
4. The control device for an engine according to claim 1, wherein the control device terminates the second torque correction control when a predetermined time has elapsed after an instruction to change the driving state of the compressor.