Engine control device

Abstract

To provide an engine control device capable of suppressing the occurrence of a jump-out feeling in starting caused by idle stabilization control.SOLUTION: A vehicle speed determination unit configured to determine whether or not a vehicle speed of the vehicle is less than a speed threshold value, an acceleration intention determination unit configured to calculate a drive required engine torque from an accelerator opening degree of the vehicle and determine whether or not a difference between the drive required engine torque and an actual engine torque of the engine is less than an acceleration intention threshold value, and an engine control unit configured to perform the idle stabilization control when a load of an auxiliary machine of the engine is large, the engine control unit does not perform the idle stabilization control when it is not determined that the vehicle speed of the vehicle is less than the speed threshold value or when it is not determined that the difference between the drive required engine torque and the actual engine torque is less than the acceleration intention threshold value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an engine control device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2005-232992 is a known technical document relating to an engine control device. This publication describes a system that, when an accessory load changes from a non-loaded state to a loaded state based on a signal from an air conditioning switch while a vehicle engine is idling, increases the engine throttle opening and the intake valve duration and lift amount by an amount sufficient to counteract the increased accessory load. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-232992 Summary of the Invention [Problem to be solved by the invention]

[0004] It is known that vehicle speed is used to determine whether the engine is idling. However, when the vehicle is moving at extremely low speeds, accurate determination of whether the vehicle is stopped cannot be made based on vehicle speed alone. Therefore, when idle stabilization control is performed, engine operation becomes unstable when the vehicle starts moving, and the driver may feel a sudden sensation of jumping out due to sudden acceleration. [Means for solving the problem]

[0005] One aspect of the present invention is an engine control device that performs idle stabilization control of a vehicle engine, and includes a vehicle speed determination unit that determines whether the vehicle speed is less than a microspeed threshold, an acceleration intention determination unit that calculates a drive request engine torque from the vehicle's accelerator opening and determines whether the difference between the drive request engine torque and the engine's actual engine torque is less than an acceleration intention threshold, and an engine control unit that performs idle stabilization control when the load on the engine accessories is heavy, and the engine control unit does not perform idle stabilization control if it is determined that the vehicle speed is not less than the microspeed threshold or if it is determined that the difference between the drive request engine torque and the actual engine torque is less than the acceleration intention threshold. [Effects of the Invention]

[0006] According to one aspect of the present invention, it is possible to suppress the occurrence of a sudden start feeling at start caused by idle stabilization control. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram illustrating an engine control device according to an embodiment. [Figure 2] 4 is a flowchart showing an example of an idle stabilization process of the engine control device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a block diagram showing an engine control device 100 according to one embodiment. The engine control device 100 shown in FIG. 1 is a device for performing idle stabilization control of a vehicle engine. The vehicle is, for example, a hybrid vehicle (HEV: Hybrid Electric Vehicle). As a hybrid vehicle, the vehicle is equipped with one motor and an engine 6. The motor and engine 6 are connected via a planetary gear mechanism. The engine 6 is a turbocharged engine.

[0010] The engine control device 100 includes an ECU 10 (Electronic Control Unit) that performs overall control of the device. The ECU 10 is an electronic control unit having a CPU (Central Processing Unit) and a storage unit. The storage unit is configured, for example, with a ROM (Read Only Memory), a RAM (Random Access Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), etc. The ECU 10 realizes various functions by, for example, causing the CPU to execute programs stored in the storage unit. The ECU 10 may also function as an HV-ECU. The ECU 10 is connected to a plurality of sensors for controlling the operation of the engine 6.

[0011] The engine control device 100 includes an auxiliary device-related sensor 1, a crank angle sensor 2, an atmospheric pressure sensor 3, a vehicle speed sensor 4, and an accelerator pedal sensor 5. The engine control device 100 may be configured as a device including an engine 6.

[0012] The auxiliary sensor 1 is a sensor for monitoring the operating state of the auxiliary and is used to determine the load of the auxiliary. Since determining the load of the auxiliary is a well-known technique, a detailed description thereof will be omitted.

[0013] The crank angle sensor 2 detects the rotational position and rotational speed of the engine crankshaft and is used to accurately measure the engine rotation speed. The atmospheric pressure sensor 3 measures the surrounding atmospheric pressure and is used to control the engine according to environmental conditions such as high altitude.

[0014] The vehicle speed sensor 4 is a detector that detects the speed of the vehicle. The vehicle speed sensor 4 transmits the detected vehicle speed information to the ECU 10. The accelerator pedal sensor 5 is a sensor that detects the amount of accelerator pedal operation by the driver, and is used to calculate a drive request engine torque, which will be described later.

[0015] Next, a description will be given of the functional configuration of the ECU 10. The ECU 10 includes an auxiliary load determination unit 11, a target rotation speed calculation unit 12, a rotation speed convergence determination unit 13, a vehicle speed determination unit 14, a drive torque requirement calculation unit 15, an acceleration intention determination unit 16, and an engine control unit 17.

[0016] The auxiliary load determination unit 11 receives data from the auxiliary-related sensor 1 and determines the load of the auxiliary. If the load of the auxiliary is equal to or greater than a load determination threshold, it issues an instruction to the engine control unit 17 to perform idle stabilization control. The idle stabilization control will be described later.

[0017] Target rotation speed calculation unit 12 calculates a target rotation speed of engine 6. This target rotation speed is set to maintain optimal operation of engine 6 and is dynamically changed according to the load and operating conditions of engine 6. Target rotation speed calculation unit 12 calculates the target rotation speed using a well-known method according to the operating status of electrical equipment such as the air conditioner, the charging status of the battery, data from accelerator pedal sensor 5, etc.

[0018] The rotation speed convergence determination unit 13 determines whether the engine rotation speed has converged to the target rotation speed calculated by the target rotation speed calculation unit 12. The rotation speed convergence determination unit 13 detects the engine rotation speed of the engine 6 based on data from the crank angle sensor 2. The rotation speed convergence determination unit 13 determines that the engine rotation speed has converged to the target rotation speed, for example, when the maximum value of the difference between the engine rotation speed and the target rotation speed over a certain period of time is less than a predetermined threshold value. When the engine rotation speed has not converged to the target rotation speed, the rotation speed convergence determination unit 13 prohibits idle stabilization control.

[0019] The vehicle speed determination unit 14 determines whether the vehicle speed detected by the vehicle speed sensor 4 is less than a very low speed threshold. The very low speed threshold may be, for example, 3 km / h. The very low speed threshold is not particularly limited. If the vehicle speed is less than the very low speed threshold, the vehicle speed determination unit 14 permits idle stabilization control. If the vehicle speed is equal to or greater than the very low speed threshold, the vehicle speed determination unit 14 determines that the vehicle is not stopped and prohibits idle stabilization control.

[0020] The driving demand torque calculation unit 15 receives data from the accelerator pedal sensor 5 and calculates the driving demand engine torque based on the accelerator opening. This driving demand engine torque is used as an index showing how much acceleration the driver is demanding.

[0021] Acceleration intention determination unit 16 determines whether the driver intends to accelerate by comparing the difference between the drive request engine torque and the actual engine torque. If the difference between the drive request engine torque and the actual engine torque is less than the acceleration intention threshold, acceleration intention determination unit 16 determines that the driver does not intend to accelerate and permits idle stabilization control. If the difference between the drive request engine torque and the actual engine torque is equal to or greater than the acceleration intention threshold, acceleration intention determination unit 16 determines that the driver intends to accelerate and prohibits idle stabilization control.

[0022] The engine control unit 17 executes engine idle stabilization control based on the above-mentioned determination results. Idle stabilization control is a control for stabilizing the rotation speed and operation of the engine 6 when the engine 6 is idling (when the vehicle is stopped but the engine 6 is operating). In idle stabilization control, the opening and closing timing of the engine's intake valve (IN: Intake Valve) and exhaust valve (EX: Exhaust Valve) are appropriately controlled. In idle stabilization control, a request is made to close the wastegate valve as necessary. Furthermore, if the battery needs to be charged while idling, the engine 6 is operated appropriately to charge the battery. Well-known control methods can be used for idle stabilization control.

[0023] Based on data from the atmospheric pressure sensor 3, the engine control unit 17 may additionally perform control to close the wastegate valve and increase the boost pressure of the turbocharger when the atmospheric pressure is low, such as when the vehicle is at high altitude.

[0024] Next, the idle stabilization process of the engine control device 100 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a flowchart showing an example of the idle stabilization process of the engine control device 100.

[0025] 2, in step S10, the ECU 10 of the engine control device 100 determines whether the load of the auxiliary equipment is equal to or greater than the load determination threshold using the auxiliary equipment load determination unit 11. If the load of the auxiliary equipment is equal to or greater than the load determination threshold (S10: YES), the process proceeds to the next step S11. If the load of the auxiliary equipment is not equal to or greater than the load determination threshold (S10: NO), the process ends without performing idle stabilization control.

[0026] In step S11, the ECU 10 determines whether the engine speed has converged to the target speed using the speed convergence determination unit 13. If the engine speed has converged to the target speed (S11: YES), the ECU 10 proceeds to the next step S12. If the engine speed has not converged to the target speed (S11: NO), the ECU 10 ends the current process without performing idle stabilization control.

[0027] In step S12, the ECU 10 determines whether the vehicle speed is less than the slow speed threshold using the vehicle speed determination unit 14. If the vehicle speed is less than the slow speed threshold (S12: YES), the ECU 10 proceeds to the next step S13. If the vehicle speed is not less than the slow speed threshold (S12: NO), the ECU 10 ends the current process without performing idle stabilization control.

[0028] In step S13, the ECU 10 determines whether the difference between the drive request engine torque and the actual engine torque is less than the acceleration intention threshold using the acceleration intention determination unit 16. If the difference between the drive request engine torque and the actual engine torque is less than the acceleration intention threshold (S13: YES), the ECU 10 proceeds to the next step S14. If the difference between the drive request engine torque and the actual engine torque is not less than the acceleration intention threshold (S13: NO), the ECU 10 determines that the driver intends to accelerate, and ends this processing without performing idle stabilization control.

[0029] In step S14, the ECU 10 determines whether the atmospheric pressure is less than the low atmospheric pressure threshold value using the engine control unit 17. If the atmospheric pressure is less than the low atmospheric pressure threshold value (S14: YES), the process proceeds to S15. If the atmospheric pressure is not less than the low atmospheric pressure threshold value (S14: NO), the process proceeds to S16.

[0030] In step S15, the ECU 10 executes VVT advance control and boost pressure increase control as idle stabilization control by the engine control unit 17. The VVT ​​advance control is a control that improves intake efficiency by, for example, advancing the opening and closing timing of the intake valve, and improves exhaust efficiency by advancing the opening and closing timing of the exhaust valve. The boost pressure increase control is a control that increases the boost pressure of the turbocharger by, for example, controlling the wastegate valve to close. Then, the ECU 10 ends this processing.

[0031] In step S16, the ECU 10 executes VVT advance control as idle stabilization control by the engine control unit 17. After that, the ECU 10 ends this processing.

[0032] According to the engine control device 100 of this embodiment described above, idle stabilization control is not performed while the engine speed has not converged to the target speed, thereby preventing hunting of the wastegate valve closing request during idling and suppressing deterioration of NV (Noise and Vibration). Furthermore, according to the engine control device 100, the difference between the drive request engine torque and the actual engine torque is compared, and idle stabilization control is not performed if the driver intends to accelerate. Therefore, compared to the conventional technology in which idle stabilization control is erroneously started only based on a stop determination when the driver intends to accelerate, the occurrence of a sudden feeling of suddenness at start-off caused by idle stabilization control can be suppressed.

[0033] When determining the driver's intention to accelerate, if the brake signal is used, there is a problem that it cannot be determined while driving if the brakes are not fully released. This is particularly true on uphill roads. Furthermore, if an idle state determination flag is used, there is a problem that it cannot be determined because the idle state is OFF and the flag is not established when a charge / discharge request for the HV is being made. If the accelerator opening is used directly, there is a problem that it cannot be determined at low speeds, such as those below the very low speed threshold, because the cruise control request is not reflected.

[0034] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. The present invention can be embodied in various forms, including the above-described embodiments, with various modifications and improvements made based on the knowledge of those skilled in the art.

[0035] The vehicle does not necessarily have to be a hybrid vehicle, but may be a vehicle equipped with an engine. The vehicle does not necessarily have to be equipped with a turbocharger. In this case, control related to the turbocharger is not required. [Explanation of symbols]

[0036] 1...auxiliary equipment related sensor, 2...crank angle sensor, 3...atmospheric pressure sensor, 4...vehicle speed sensor, 5...accelerator pedal sensor, 6...engine, 10...ECU, 11...auxiliary equipment load determination unit, 12...target rotation speed calculation unit, 13...rotation speed convergence determination unit, 14...vehicle speed determination unit, 15...driving request torque calculation unit, 16...acceleration intention determination unit, 17...engine control unit, 100...engine control device

Claims

[Claim 1] An engine control device that performs idle stabilization control of a vehicle engine, a vehicle speed determination unit that determines whether the vehicle speed is less than a very low speed threshold; an acceleration intention determination unit that calculates a drive request engine torque from an accelerator opening of the vehicle and determines whether a difference between the drive request engine torque and an actual engine torque of the engine is less than an acceleration intention threshold; an engine control unit that performs the idle stabilization control when a load on an accessory of the engine is large; Equipped with The engine control device does not perform the idle stabilization control when it is determined that the vehicle speed of the vehicle is not less than the very low speed threshold, or when it is determined that the difference between the drive request engine torque and the actual engine torque is less than the acceleration intention threshold.

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