Vehicle control system

Abstract

To provide a vehicle control device that can suppress the occurrence of pre-ignition without reducing acceleration performance. [Solution] When pre-ignition occurs in the engine (S1), target rotational speed increase control is performed to control the engine so that the rotational speed becomes a target rotational speed higher than a predetermined pre-ignition occurrence range, and transmission rate reduction control is performed to control the clutch so as to reduce the power transmission rate between the engine and the transmission (S2).

Description

Technical Field

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[0001] The present invention relates to a control device for a vehicle.

Background Art

[0002] Conventionally, in an internal combustion engine that ignites and burns a mixture of fuel and air by the spark of a spark plug, abnormal combustion due to self-ignition of the mixture (hereinafter, also referred to as "pre-ignition" or "pre-ignition") may occur, as described in Patent Document 1. Patent Document 1 proposes a control device for an internal combustion engine that suppresses the occurrence of pre-ignition.

[0003] The control device for an internal combustion engine proposed in Patent Document 1 includes a rich spike execution means for executing a rich spike that temporarily controls the air-fuel ratio to the rich side from stoichiometry when the occurrence of pre-ignition is detected, a target air-fuel ratio calculation means for calculating a target air-fuel ratio during the execution of the rich spike based on the NOx storage amount of the NOx catalyst when the occurrence of pre-ignition is detected, and an air amount control means for reducing the amount of air inhaled into a plurality of cylinders during the execution of the rich spike to a predetermined amount.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the conventional technology as described above has a problem that the acceleration performance deteriorates because the amount of air inhaled into a plurality of cylinders is reduced during the execution of the rich spike.

[0006] The present invention was made to solve the above-mentioned problems, and aims to provide a vehicle control device that can suppress the occurrence of pre-ignition without reducing acceleration performance. [Means for solving the problem]

[0007] The vehicle control device according to the present invention is a vehicle control device for controlling a vehicle equipped with an engine, a transmission, and a power transmission mechanism for adjusting the power transmission rate between the engine and the transmission, and is characterized by comprising a control unit that, when a pre-ignition occurs in the engine, controls the engine so that the rotational speed becomes a target rotational speed higher than a predetermined pre-ignition occurrence range, and controls the power transmission mechanism to reduce the power transmission rate between the engine and the transmission. [Effects of the Invention]

[0008] The present invention provides a vehicle control device that can suppress the occurrence of pre-ignition without reducing acceleration performance. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of a vehicle equipped with a vehicle control device according to one embodiment of the present invention. [Figure 2] Figure 2 is a conceptual diagram illustrating the target rotational speed of a vehicle equipped with a vehicle control device according to one embodiment of the present invention. [Figure 3] Figure 3 is a flowchart showing the pre-ignition suppression operation of a vehicle control device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] A vehicle control device according to one embodiment of the present invention is a vehicle control device for controlling a vehicle equipped with an engine, a transmission, and a power transmission mechanism for adjusting the power transmission rate between the engine and the transmission, and is characterized by comprising a control unit that controls the engine so that the rotational speed becomes a target rotational speed higher than a predetermined pre-ignition occurrence range when pre-ignition occurs in the engine, and controls the power transmission mechanism to reduce the power transmission rate between the engine and the transmission. As a result, the vehicle control device according to one embodiment of the present invention can suppress the occurrence of pre-ignition without reducing acceleration performance. [Examples]

[0011] Hereinafter, a vehicle equipped with a vehicle control device according to one embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1, the vehicle 1 is composed of an engine 2, a transmission 3, a clutch 4, drive wheels 5, and an ECU (Electronic Control Unit) 6.

[0012] Engine 2 has multiple cylinders. In this embodiment, engine 2 generates power by performing a series of four strokes for each cylinder, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0013] The transmission 3 transmits power between the engine 2 and the drive wheels 5. In this embodiment, the transmission 3 is configured as a normally meshing AMT (Automated Manual Transmission) consisting of a parallel shaft gear mechanism.

[0014] The clutch 4 is provided in the power transmission path between the engine 2 and the transmission 3. The clutch 4 adjusts the power transmission rate between the engine 2 and the transmission 3 by adjusting the engagement state between a fully engaged state, which completely connects the power transmission path from the engine 2 to the transmission 3, and a disengaged state, which disconnects the power transmission path from the engine 2 to the transmission 3. The clutch 4 constitutes the power transmission mechanism in the present invention.

[0015] The ECU6 is a computer unit that includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, input ports, and output ports.

[0016] The ROM of this computer unit stores various constants and maps, along with a program that allows the computer unit to function as an ECU6. In other words, the CPU executes the program stored in the ROM using RAM as a working area, thereby enabling this computer unit to function as an ECU6 in this embodiment.

[0017] Various sensors are connected to the input port of the ECU6, including a vehicle speed sensor 11 for detecting vehicle speed, an engine speed sensor 12 for detecting the rotational speed of the engine 2, and a pre-ignition sensor 13 for detecting the pre-ignition of the engine 2. In this embodiment, the pre-ignition sensor 13 is composed of a knock sensor or an in-cylinder pressure sensor.

[0018] The output port of the ECU6 is connected to various control devices, including an injector 21 that injects fuel into the engine 2, a spark plug 22 that ignites in the combustion chamber of the engine 2, a throttle valve actuator 23 that adjusts the opening of the throttle valve that adjusts the amount of intake air for the engine 2, a gear actuator 24 that changes the gear position formed by the transmission 3, and a clutch actuator 25 that changes the engagement state of the clutch 4. The ECU6 controls the various control devices connected to the output port based on information obtained from various sensors connected to the input port.

[0019] When pre-ignition occurs in the engine 2, the ECU 6 functions as a control unit 30 that controls the engine 2 so that the rotational speed becomes a target rotational speed Na higher than a predetermined pre-ignition occurrence range, and controls the clutch 4 so as to reduce the power transmission rate transmitted between the engine 2 and the transmission 3. The ECU 6 determines whether or not pre-ignition has occurred in the engine 2 based on the detection result of the pre-ignition sensor 13.

[0020] As shown in FIG. 2, pre-ignition has a higher occurrence frequency when the engine 2 is operating at a low rotational speed and high load. Therefore, when pre-ignition occurs in the engine 2, the ECU 6 controls the engine 2 to operate while avoiding the operation region 40 where the occurrence frequency of pre-ignition is high.

[0021] In this embodiment, when pre-ignition occurs in the engine 2, the ECU 6 executes target rotational speed increase control for controlling the engine 2 so that the rotational speed becomes a target rotational speed Na higher than the pre-ignition occurrence region 41 corresponding to the operation region 40.

[0022] In FIG. 1, the ECU 6 that executes the target rotational speed increase control adjusts the injection amount of fuel injected by the injector 21, the ignition timing of the ignition plug 22, and the intake air amount adjusted by the throttle valve actuator 23 so that the rotational speed detected by the engine rotational speed sensor 12 becomes the target rotational speed Na.

[0023] When the rotational speed of the engine 2 is controlled to become the target rotational speed Na, the torque output from the engine 2 becomes higher than the required torque required for the engine 2. Therefore, when pre-ignition occurs in the engine 2, the ECU 6 executes transmission rate reduction control for controlling the clutch 4 via the clutch actuator 25 so as to reduce the power transmission rate transmitted between the engine 2 and the transmission 3.

[0024] The ECU 6, which performs the transmission rate reduction control, controls the clutch 4 so that the required torque requested by the engine 2 is output from the clutch 4 to the transmission 3. In other words, when the ECU 6 controls the clutch 4 to reduce the power transmission rate between the engine 2 and the transmission 3 due to pre-ignition occurring in the engine 2, it controls the clutch 4 so that the required torque requested by the engine 2 is output from the clutch 4 to the transmission 3.

[0025] The ECU6 calculates the target vehicle speed Va based on the reduction ratio Gr between the engine speed 2 and the vehicle speed when the clutch 4 is fully engaged, and the target rotational speed Na. The ROM of the ECU6 stores the reduction ratio Gr for each gear stage formed in the transmission 3. The ECU6 calculates the target vehicle speed Va from the product of the reduction ratio Gr corresponding to the gear stage formed in the transmission 3 and the target rotational speed Na.

[0026] When the vehicle speed V detected by the vehicle speed sensor 11 (hereinafter also simply referred to as "actual vehicle speed") becomes equal to or greater than the target vehicle speed Va, the ECU 6 terminates the transmission rate reduction control and the target rotational speed increase control. In other words, when the actual vehicle speed V becomes equal to or greater than the target vehicle speed Va, the ECU 6 controls the clutch 4 to be fully engaged and controls the engine 2 to output the required torque.

[0027] The pre-ignition suppression operation by the ECU6 configured as described above will be explained with reference to Figure 3. Note that the pre-ignition suppression operation described below is repeatedly performed throughout the period that the ECU6 is operating.

[0028] First, in S1, the ECU6 determines whether or not a pre-ignition has occurred in engine 2. If it determines in S1 that a pre-ignition has occurred in engine 2, the ECU6 executes the process in S2. If it determines in S1 that a pre-ignition has not occurred in engine 2, the ECU6 terminates the pre-ignition suppression operation.

[0029] In S2, ECU6 performs target rotational speed increase control and transmission rate decrease control. After performing the process in S2, ECU6 performs the process in S3. In S3, ECU6 calculates the target vehicle speed Va. After performing the process in S3, ECU6 performs the process in S4.

[0030] In S4, the ECU6 determines whether the actual vehicle speed V is equal to or greater than the target vehicle speed Va. If the ECU6 determines in S4 that the actual vehicle speed V is equal to or greater than the target vehicle speed Va, it executes the process in S5. If the ECU6 determines in S4 that the actual vehicle speed V is not equal to or greater than the target vehicle speed Va, it executes the process in S2.

[0031] In S5, the ECU 6 terminates the transmission rate reduction control and the target rotational speed increase control. That is, in S5, the ECU 6 controls the clutch 4 to be fully engaged and controls the engine 2 to output the required torque. After executing the process in S5, the ECU 6 terminates the pre-ignition suppression operation.

[0032] As described above, the vehicle control device according to this embodiment controls the engine 2 so that the rotational speed becomes a target rotational speed Na that is higher than a predetermined pre-ignition occurrence range 41 when a pre-ignition occurs in the engine 2, and controls the clutch 4 to reduce the power transmission rate between the engine 2 and the transmission 3, thereby operating the engine 2 while avoiding the operating range 40 in which pre-ignition occurs frequently.

[0033] Therefore, the vehicle control device according to this embodiment can suppress the occurrence of pre-ignition without performing rich spikes, thus suppressing the occurrence of pre-ignition without reducing acceleration performance.

[0034] Furthermore, in the vehicle control device according to this embodiment, when the ECU 6 controls the clutch 4 to reduce the power transmission rate between the engine 2 and the transmission 3 due to pre-ignition occurring in the engine 2, it controls the clutch 4 so that the required torque required by the engine 2 is output from the clutch 4 to the transmission 3. Therefore, the occurrence of pre-ignition can be suppressed without affecting the operability of the vehicle.

[0035] In this embodiment, an example was described in which the ECU 6 performs target rotational speed increase control and transmission efficiency decrease control when a pre-ignition occurs in the engine 2. Alternatively, the ECU 6 may perform target rotational speed increase control and transmission efficiency decrease control when a pre-ignition occurs in the engine 2 a predetermined number of times or more within a certain period of time.

[0036] Furthermore, although this embodiment describes an example in which the transmission 3 is configured using an AMT, the transmission 3 may be configured using other automatic transmissions that require a clutch, such as DCTs (Dual-Clutch Transmissions).

[0037] Although embodiments of the present invention have been disclosed above, it is clear that modifications can be made to these embodiments without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the premise that equivalents with such modifications are included in the invention described in the claims. [Explanation of Symbols]

[0038] 1 vehicle 2 engines 3. Transmission 4. Clutch (power transmission mechanism) 30 Control Unit

Claims

1. The engine and The transmission and A vehicle control device for controlling a vehicle equipped with a power transmission mechanism that adjusts the power transmission rate between the engine and the transmission, A vehicle control device characterized by comprising a control unit that controls the engine so that, when a pre-ignition occurs in the engine, the rotational speed becomes a target rotational speed higher than a predetermined pre-ignition range, and controls the power transmission mechanism to reduce the power transmission rate between the engine and the transmission.

2. The control device for a vehicle according to claim 1, characterized in that when the control unit controls the power transmission mechanism to reduce the power transmission rate between the engine and the transmission due to a pre-ignition occurring in the engine, it controls the power transmission mechanism so that the required torque required by the engine is output from the power transmission mechanism to the transmission.

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