Vehicle control device

Abstract

To provide a vehicle control device that can suppress power applied to a vehicle from increasing later than increase in required power, when the required power increases so that an internal combustion engine is required to be started.SOLUTION: When required power increases and reaches a threshold for an engine starting determination, a vehicle control device 10 rotates an internal combustion engine 20 by power outputted from a motor generator 32 without starting the internal combustion engine, and then executes engine-starting control of starting the internal combustion engine at a time point when a predetermined delay time has elapsed. The vehicle control device sets the predetermined delay time, on the basis of at least either of a temperature of the internal combustion engine or a target rotation speed of the internal combustion engine, during running of a vehicle 100, and sets the threshold for an engine starting determination to a small value so that the required power can reach the threshold for an engine starting determination earlier by the set predetermined delay time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A vehicle control device is known that, when starting an internal combustion engine of a vehicle, rotates the internal combustion engine using a starter motor without starting the internal combustion engine, thereby processing fuel that has leaked from a fuel injection valve while the internal combustion engine is stopped, and then starts the internal combustion engine (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-88672 Summary of the Invention

[0004] In a vehicle called a hybrid vehicle, the required power may increase while the vehicle is running, requiring the start of the internal combustion engine. In this case, if the internal combustion engine is started after being rotated by a starter motor or the like, as in the conventional vehicle control device described above, the increase in power applied to the vehicle will be delayed relative to the increase in the required power.

[0005] An object of the present invention is to provide a vehicle control device that can suppress a delay in the increase in power applied to a vehicle relative to the increase in required power when the required power increases and the start of an internal combustion engine is requested.

[0006] A vehicle control device according to the present invention is applied to a vehicle equipped with an internal combustion engine and a motor generator, and driven by power output from the internal combustion engine and the motor generator. The vehicle control device according to the present invention is configured to stop operation of the internal combustion engine and drive the vehicle solely on power output from the motor generator when required power is less than an engine start determination threshold, and to drive the vehicle solely on power output from the internal combustion engine and the motor generator when the required power is equal to or greater than the engine start determination threshold. The vehicle control device according to the present invention is further configured to execute engine start control, which, when the required power increases and reaches the engine start determination threshold, rotates the internal combustion engine using power output from the motor generator without starting the internal combustion engine, and then starts the internal combustion engine after a predetermined delay time has elapsed. The vehicle control device according to the present invention is further configured to set the predetermined delay time based on at least one of a temperature of the internal combustion engine and a target rotational speed of the internal combustion engine while the vehicle is running, and to set the engine start determination threshold to a small value so that the required power reaches the engine start determination threshold earlier by the set predetermined delay time.

[0007] According to the vehicle control device of the present invention, engine start control is usually initiated before the required power reaches the engine start determination threshold, which makes it possible to prevent a delay in the increase in power applied to the vehicle relative to the increase in required power when the required power increases and start of the internal combustion engine is requested.

[0008] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, features, and attendant advantages of the present invention will be easily understood from the description of the embodiments of the present invention. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a vehicle control device according to an embodiment of the present invention. [Figure 2]FIG. 2 is a flowchart showing a routine executed by the vehicle control device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a vehicle control device according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a vehicle control device 10 according to an embodiment of the present invention. The vehicle control device 10 is mounted on a vehicle 100. As shown in Fig. 1, the vehicle control device 10 includes an ECU (electronic control unit) 90 as a control device.

[0011] The vehicle 100 is also equipped with an internal combustion engine 20, a first motor generator 31, a second motor generator 32, an inverter 33, a battery , a power distribution device 40, and a water temperature sensor .

[0012] The internal combustion engine 20 has a plurality of (four in this example) cylinders 21. The internal combustion engine 20 is also provided with a plurality of (four in this example) fuel injection valves 22 attached to each cylinder 21. These fuel injection valves 22 are electrically connected to the ECU 90. The vehicle control device 10 can control the amount of fuel supplied to each cylinder 21 by controlling the operation of the fuel injection valves 22.

[0013] The inverter 33 is electrically connected to the first motor generator 31, the second motor generator 32, and the battery 34. The inverter 33 controls the transmission of power between the first motor generator 31, the second motor generator 32, and the battery 34. Furthermore, the inverter 33 is electrically connected to the ECU 90. By controlling the operation of the inverter 33, the vehicle control device 10 controls the transmission of power between the first motor generator 31, the second motor generator 32, and the battery 34, and thereby can control the operation of the first motor generator 31 and the second motor generator 32.

[0014] The first motor generator 31 and the second motor generator 32 each function as an electric motor (motor) that receives a supply of electric power from the battery 34 to generate power, and as a generator that receives a supply of power from the internal combustion engine 20 or the like to generate power. In this example, the first motor generator 31 mainly functions as a generator that generates power using the power output from the internal combustion engine 20, and the second motor generator 32 mainly functions as an electric motor that generates power to run the vehicle 100.

[0015] The power distribution device 40 is a device including a known planetary gear mechanism, for example, as described in Japanese Patent Application Laid-Open No. 2017-159722. The power distribution device 40 is connected to the internal combustion engine 20, a first motor generator 31, a second motor generator 32, and a drive shaft 120. Power output from the internal combustion engine 20 is applied to drive wheels 140 of the vehicle 100 via the power distribution device 40 and the drive shaft 120 as driving force for propelling the vehicle 100. Depending on the situation, power output from the internal combustion engine 20 is applied to the first motor generator 31 via the power distribution device 40 as power for generating electric power. Power output from the second motor generator 32 is applied to the drive wheels 140 via the power distribution device 40 and the drive shaft 120 as driving force for propelling the vehicle 100.

[0016] The water temperature sensor 50 is electrically connected to the ECU 90. The vehicle control device 10 acquires the temperature of the coolant that cools the internal combustion engine 20 as the engine water temperature Tw using the water temperature sensor 50. In this example, the engine water temperature Tw is used as a parameter that indicates the temperature of the internal combustion engine 20.

[0017] <Vehicle control device operation> Next, a description will be given of the operation of the vehicle control device 10. The vehicle control device 10 is configured to stop operation of the internal combustion engine 20 and run the vehicle 100 using only the power output from the second motor generator 32 when the required power Preq is smaller than the engine start determination threshold Pth, and to run the vehicle 100 using the power output from the internal combustion engine 20 and the second motor generator 32 when the required power Preq is equal to or greater than the engine start determination threshold Pth.

[0018] The required power Preq is a power that is required to be applied to the vehicle 100 based on the amount of accelerator pedal operation of the vehicle 100 by the driver, the traveling speed of the vehicle 100, and the like.

[0019] Furthermore, the vehicle control device 10 executes the routine shown in Fig. 2 at predetermined time intervals, and when predetermined conditions are met, starts engine start control. The engine start control is control for starting the internal combustion engine 20.

[0020] At a predetermined timing, the vehicle control device 10 starts processing from step S200 of the routine shown in FIG. 2, and proceeds to step S205 to determine whether the operation of the internal combustion engine 20 is currently stopped.

[0021] If the vehicle control device 10 determines "No" in step S205, the process proceeds directly to step S295, and the process of this routine is temporarily ended.

[0022] On the other hand, if the vehicle control device 10 determines "Yes" in step S205, the process proceeds to step S210, where it determines whether the vehicle 100 is currently in a traveling state.

[0023] If the vehicle control device 10 determines "Yes" in step S210, the process proceeds to step S215, where the vehicle control device 10 acquires the engine water temperature Tw. Next, the vehicle control device 10 proceeds to step S220, where the vehicle control device 10 acquires the target engine rotation speed NEtgt. The target engine rotation speed NEtgt is a target value for the engine rotation speed NE of the internal combustion engine 20 when the internal combustion engine 20 is started.

[0024] Next, the vehicle control device 10 proceeds to step S225, where it acquires a delay time Tdly based on the engine water temperature Tw acquired in step S215 and the target engine rotation speed NEtgt acquired in step S220. The delay time Tdly is the time from when the engine start control is started in step S250 (described later) until the internal combustion engine 20 is started (i.e., the time until fuel injection from the fuel injection valve 22 is started).

[0025] In this example, the vehicle control device 10 pre-stores a map for acquiring the delay time Tdly using the engine water temperature Tw and the target engine rotation speed NEtgt as arguments, and when the process proceeds to step S225, the delay time Tdly is acquired by applying the engine water temperature Tw and the target engine rotation speed NEtgt to the map. Furthermore, the delay time Tdly acquired in step S225 is shorter when the engine water temperature Tw is high than when the engine water temperature Tw is low. Furthermore, the delay time Tdly acquired in step S225 is shorter when the target engine rotation speed NEtgt is high than when the target engine rotation speed NEtgt is low.

[0026] Next, the vehicle control device 10 advances the process to step S230, and sets the engine start determination threshold value Pth based on the delay time Tdly calculated in step S225. Next, the vehicle control device 10 advances the process to step S245.

[0027] The engine start determination threshold value Pth is set to a value smaller than the reference threshold value Pbase as the delay time Tdly becomes longer. More specifically, the engine start determination threshold value Pth is set to a value at which the required power Preq reaches the engine start determination threshold value Pth at a time point the delay time Tdly before the time point at which the required power Preq increases and reaches the reference threshold value Pbase (in other words, the time point at which the required power Preq is predicted to reach the reference threshold value Pbase).

[0028] The reference threshold value Pbase is a threshold value that serves as a reference for determining whether or not to start the internal combustion engine 20, and is set in advance and stored in the vehicle control device .

[0029] On the other hand, if the vehicle control device 10 determines "No" in step S210, the process proceeds to step S235, where the reference delay time Tdly_base is set as the delay time Tdly. The reference delay time Tdly_base is a time that serves as a reference for the delay time Tdly. Next, the vehicle control device 10 proceeds to step S240, where the reference threshold value Pbase is set as the engine start determination threshold value Pth. Next, the vehicle control device 10 proceeds to step S245.

[0030] When the process proceeds to step S245, the vehicle control device 10 determines whether the required power Preq has become equal to or greater than the engine start determination threshold value Pth. At this time, if the process proceeds to step S245 via step S230, it determines whether the required power Preq has become equal to or greater than the engine start determination threshold value Pth set in step S230. On the other hand, if the process proceeds to step S245 via step S240, it determines whether the required power Preq has become equal to or greater than the engine start determination threshold value Pth set in step S240.

[0031] If the vehicle control device 10 determines "No" in step S245, the process proceeds directly to step S295, and the process of this routine ends for the time being.

[0032] On the other hand, if the vehicle control device 10 determines "Yes" in step S245, the process proceeds to step S250, where the vehicle control device 10 starts engine starting control. Next, the vehicle control device 10 proceeds to step S295, where the process of this routine ends.

[0033] When the vehicle control device 10 starts engine start control, first, the vehicle control device 10 rotates the internal combustion engine 20 using the power output from the first motor generator 31 without starting the internal combustion engine 20 (i.e., without injecting fuel from the fuel injection valve 22). Then, when the time (elapsed time Te) that has elapsed since the internal combustion engine 20 started to be rotated using the power output from the first motor generator 31 reaches the delay time Tdly, the vehicle control device 10 stops the rotation of the internal combustion engine 20 using the power output from the first motor generator 31, starts fuel injection from the fuel injection valve 22, and starts combustion in the cylinders 21 of the internal combustion engine 20, thereby starting the internal combustion engine 20.

[0034] In this way, when the required power Preq increases and reaches the engine start determination threshold Pth, the vehicle control device 10 is configured to execute engine start control to rotate the internal combustion engine 20 using the power output from the first motor generator 31 without starting the internal combustion engine 20, and then start the internal combustion engine 20 after a predetermined delay time (delay time Tdly) has elapsed.

[0035] The delay time Tdly used at this time is the delay time Tdly calculated in step S225 if the process proceeds to step S250 via step S225, and is the delay time Tdly set in step S235 if the process proceeds to step S250 via step S235.

[0036] Furthermore, when the elapsed time Te reaches the delay time Tdly and fuel injection from the fuel injection valve 22 begins, and the power applied to the vehicle 100 via the power distribution device 40 does not meet the required power Preq, the vehicle control device 10 may be configured to control the operation of the second motor generator 32, for example, by temporarily increasing the power output from the second motor generator 32 so that the power applied to the vehicle 100 becomes the required power Preq.

[0037] The above is the operation of the vehicle control device 10. In this way, the vehicle control device 10 is configured to set the predetermined delay time (delay time Tdly) based on at least one of the temperature of the internal combustion engine 20 (engine water temperature Tw) and the target value of the rotation speed of the internal combustion engine 20 (target engine rotation speed NEtgt) while the vehicle 100 is traveling, and to set the engine start determination threshold value Pth to a small value so that the required power Preq reaches the engine start determination threshold value Pth earlier by the set predetermined delay time.

[0038] According to this, engine start control is usually initiated before the required power Preq reaches the engine start determination threshold Pth, and therefore, when the required power Preq increases and a start of the internal combustion engine 20 is requested, a delay in the increase in power applied to the vehicle 100 relative to the increase in the required power Preq can be suppressed.

[0039] The present invention is applicable to vehicles that can be driven by manual operation and automatic driving control, vehicles that can be driven only by manual operation, and vehicles that can be driven only by automatic driving control.Furthermore, the present invention is also applicable to vehicles that can be driven by remote operation.

[0040] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention. [Explanation of symbols]

[0041] 10...vehicle control device, 20...internal combustion engine, 31...first motor generator, 32...second motor generator, 90...ECU, 100...vehicle

Claims

[Claim 1] A vehicle control device applied to a vehicle that is equipped with an internal combustion engine and a motor generator and is driven by power output from the internal combustion engine and the motor generator, When the required power is smaller than an engine start determination threshold, the operation of the internal combustion engine is stopped and the vehicle is run only by the power output from the motor generator, and when the required power is equal to or greater than the engine start determination threshold, the vehicle is run by the power output from the internal combustion engine and the motor generator, a vehicle control device configured to execute engine start control in which, when the required power increases and reaches the engine start determination threshold, the internal combustion engine is rotated by power output from the motor generator without being started, and then the internal combustion engine is started when a predetermined delay time has elapsed; while the vehicle is running, the predetermined delay time is set based on at least one of a temperature of the internal combustion engine and a target value of a rotation speed of the internal combustion engine; setting the engine start determination threshold to a small value so that the required power reaches the engine start determination threshold earlier by the set predetermined delay time; A vehicle control device configured as follows.

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