Vehicle shock detection device

Abstract

To provide a shock determination device for a vehicle which can suppress erroneous determination where a shock caused by bad road travel is determined as a shock caused by engine start or engine stop.SOLUTION: An electronic control unit (shock determination device) 90 of a vehicle 10 at a start control period in accompany with switching power sources is given in which: (a) an engine starting shock is not determined to occur because acceleration Gx becomes a determination value Gx_jdg or more when a front-back direction acceleration Gx of the vehicle 10 becomes a determination value Gx_jdg or more and when an amount ΔNr of wheel speed change becomes a determination value ΔNr_jdg or more in a temporary no-determination period Tmsk_tmp started from the time when the acceleration Gx becomes the determination value Gx_jdg or more; (b) the engine starting shock is determined to occur because the acceleration Gx becomes the determination value Gx_jdg or more when the acceleration Gx becomes the determination value Gx_jdg or more and when the amount ΔNr of wheel speed change does not become the determination value ΔNr_jdg or more in the temporary no-determination period Tmsk_tmp.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a shock determination device for a vehicle equipped with an engine and an electric motor as power sources. [Background technology]

[0002] Among vehicles equipped with an engine and an electric motor as power sources, there are known vehicles that determine whether a shock occurs during automatic engine start control, such as the vehicle described in Patent Document 1. The vehicle described in Patent Document 1 is equipped with an idling stop system, for example, and determines whether or not a shock occurs when the engine is automatically started while the vehicle is stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-55943 Summary of the Invention [Problem to be solved by the invention]

[0004] In vehicles equipped with an engine and an electric motor as power sources, the engine may be automatically started or stopped while the vehicle is traveling. In this case, to accurately determine whether a shock is caused by engine start or engine stop, it is necessary to ensure that the shock is not caused by driving on a rough road. For example, a method can be considered in which a sudden change in wheel speed is detected to indicate that the vehicle is traveling on a rough road, and the shock generated during the rough road driving is not determined to be caused by engine start or other factors. However, although the occurrence of a shock caused by driving on a rough road and the change in wheel speed occur approximately simultaneously, depending on the road surface conditions, a change in wheel speed may occur after the shock occurs. Therefore, if the vehicle begins traveling on a rough road immediately after the automatic engine start control is initiated, a shock caused by driving on a rough road may be erroneously determined to be caused by engine start. In particular, a shock generated during a single rough road driving event, such as when the vehicle is going over a bump, is more likely to be erroneously determined than a continuous rough road driving event.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide a shock judgment device for a vehicle that can suppress erroneous judgment that a shock caused by driving on rough roads is a shock caused by engine start or engine stop. [Means for solving the problem]

[0006] The gist of the present invention is a shock judgment device for a vehicle that has an engine and an electric motor as power sources and is capable of switching between engine running, which uses at least the engine as a power source, and electric motor running, which uses only the electric motor as a power source, wherein during at least one of the engine start control period and stop control period associated with switching the power source from one of the electric motor running and the engine running to the other, (a) if the acceleration in the longitudinal direction of the vehicle becomes equal to or greater than a predetermined first judgment value and a wheel speed change amount, which is the amount of change in wheel speed, becomes equal to or greater than a predetermined second judgment value within a predetermined period from the point at which the acceleration becomes equal to or greater than the first judgment value, it is not judged that a start shock or a stop shock of the engine has occurred based on the acceleration becoming equal to or greater than the first judgment value, and (b) if the acceleration becomes equal to or greater than the first judgment value and the wheel speed change amount does not become equal to or greater than the second judgment value within the predetermined period, it is judged that a start shock or a stop shock of the engine has occurred based on the acceleration becoming equal to or greater than the first judgment value. [Effects of the Invention]

[0007] According to the shock determination device of the present invention, (a) if the acceleration in the longitudinal direction of the vehicle becomes equal to or greater than a predetermined first determination value and a wheel speed change amount, which is the amount of change in wheel speed, becomes equal to or greater than a predetermined second determination value within a predetermined period from the time the acceleration becomes equal to or greater than the first determination value, it is not determined that the engine start-up shock or engine stop-down shock has occurred based on the acceleration becoming equal to or greater than the first determination value, and (b) if the acceleration becomes equal to or greater than the first determination value and the wheel speed change amount does not become equal to or greater than the second determination value within the predetermined period, it is determined that the engine start-up shock or engine stop-down shock has occurred based on the acceleration becoming equal to or greater than the first determination value. Even when driving on a rough road where a change in wheel speed appears after the occurrence of a shock, erroneous determination that a shock caused by driving on a rough road is a shock caused by engine start-up or engine stop is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a diagram illustrating an example of a schematic configuration of a vehicle equipped with an electronic control device according to a first embodiment. [Figure 2] 2 is an example of a flowchart illustrating the control operation of the electronic control device shown in FIG. 1 during the engine start control period. [Figure 3] 3 is a time chart when the flowchart of FIG. 2 is executed, showing an example in which the wheel speed change detection signal is turned on after the shock detection signal is turned on. [Figure 4] 3 is a time chart when the flowchart of FIG. 2 is executed, showing an example of a case where the shock detection signal is turned on after the wheel speed change detection signal is turned on. [Figure 5] 10 is an example of a flowchart illustrating a control operation of an electronic control device according to a second embodiment during an engine stop control period. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Note that in each of the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is an example of a schematic configuration diagram of a vehicle 10 equipped with an electronic control device 90 according to a first embodiment.

[0011] The vehicle 10 is a hybrid vehicle equipped with an engine 12, a first electric motor MG1, and a second electric motor MG2, which function as power sources. In the vehicle 10, a power transmission path PT between the engine 12 and a pair of drive wheels 32 is connected, in order from the engine 12 side, to an engine connecting shaft 22, a differential unit 34, an automatic transmission input shaft 26, an automatic transmission 18, an automatic transmission output shaft 28, a differential 40, and a pair of axles 30, all of which are well-known components. The vehicle 10 also includes a hydraulic control circuit 50, an inverter 60, a battery 62, and an electronic control device 90.

[0012] The engine 12 is a well-known internal combustion engine. The first electric motor MG1 and the second electric motor MG2 are, for example, rotating electric machines having a motor function and a generator function, so-called motor generators. Note that the first electric motor MG1 and the second electric motor MG2 may be rotating electric machines without a generator function as long as they have a motor function.

[0013] The differential unit 34 is configured, for example, by a single-pinion planetary gear device, and the sun gear S0, carrier CA0, and ring gear R0 are connected to the first electric motor MG1, the engine 12 via the engine connecting shaft 22, and the AT input shaft 26 via the intermediate transmission shaft 36, respectively. The differential unit 34 is a power split mechanism that mechanically splits the power output from the engine 12 to the first electric motor MG1 and the intermediate transmission shaft 36. For example, the first electric motor MG1 generates electricity using the power of the engine 12 split by the first electric motor MG1, and the generated electrical energy is stored in a battery 62 via an inverter 60 or the electrical energy is used to rotationally drive the second electric motor MG2. The differential unit 34 functions as an electric differential unit (electric continuously variable transmission) in which the gear ratio γdif (= rotational speed [rpm] of the engine connecting shaft 22 / rotational speed [rpm] of the intermediate transmission shaft 36) is continuously changed by controlling the output torque of the first electric motor MG1. The second electric motor MG2 is connected to the intermediate transmission shaft 36 so as to be capable of transmitting power thereto.

[0014] The automatic transmission 18 is a well-known planetary gear automatic transmission that includes, for example, one or more planetary gear devices (not shown) and an engagement device CB. The engagement device CB includes, for example, a plurality of well-known hydraulic friction engagement devices. The automatic transmission 18 is a stepped transmission that forms one of a plurality of gear stages (also referred to as gear stages) with different speed ratios (also referred to as gear ratios) γat (=AT input shaft rotation speed Nin [rpm] / AT output shaft rotation speed Nout [rpm]) by engaging any of the engagement devices CB. The AT input shaft rotation speed Nin is the rotation speed of an AT input shaft 26, which is the input shaft of the automatic transmission 18, and the AT output shaft rotation speed Nout is the rotation speed of an AT output shaft 28, which is the output shaft of the automatic transmission 18.

[0015] The hydraulic control circuit 50 uses the hydraulic pressure of the hydraulic oil discharged from a mechanical oil pump or an electric oil pump (not shown) as the source pressure and supplies adjusted hydraulic pressure to the actuators that control the control state (engaged state, disengaged state) of the engagement devices CB of the automatic transmission 18. The hydraulic control circuit 50 also supplies hydraulic oil as lubricating oil to parts such as gears provided in the power transmission path PT.

[0016] The inverter 60 is a power supply circuit provided between the first electric motor MG1 and the second electric motor MG2 and the battery 62, and is controlled by the electronic control device 90 to convert DC to AC and AC to DC. The output torque of the first electric motor MG1, that is, MG1 output torque Tmg1 [Nm], and the output torque of the second electric motor MG2, that is, MG2 output torque Tmg2 [Nm], are each controlled by the inverter 60 controlled by the electronic control device 90.

[0017] The battery 62 is a rechargeable secondary battery such as a lithium ion battery or a nickel-metal hydride battery, etc. The battery 62 is mainly used to supply electric power to drive the first electric motor MG1 and the second electric motor MG2, which are the power sources, and to store electric power generated by the first electric motor MG1 and the second electric motor MG2 through regeneration.

[0018] The electronic control unit 90 is a controller including a control device that controls each part in the vehicle 10, and is configured to include, for example, a so-called microcomputer in which the CPU performs signal processing according to a program pre-stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control unit 90 corresponds to the "shock determination device" according to the present invention.

[0019] The electronic control device 90 receives various signals based on detected values from various sensors provided in the vehicle 10 (for example, an accelerator opening sensor 70, wheel speed sensors 72 provided for each of the front and rear wheels, an engine rotation speed sensor 74, an MG1 rotation speed sensor 76, an MG2 rotation speed sensor 78, an acceleration sensor 80, etc.) (for example, an accelerator opening θacc [%] which is the accelerator operation amount of the driver indicating the magnitude of the driver's acceleration operation, a wheel speed Nr [rpm] which is the rotation speed of each of the front and rear wheels, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, an MG1 rotation speed Nmg1 [rpm] which is the rotation speed of the first electric motor MG1, an MG2 rotation speed Nmg2 [rpm] which is the rotation speed of the second electric motor MG2, an acceleration Gx [m / sec] which is the acceleration in the longitudinal direction of the vehicle 10, etc.). 2 ], etc.) are input. The acceleration Gx is the amount of change per unit time in the longitudinal velocity [m / sec] of the vehicle 10, expressed as an absolute value. Therefore, the acceleration Gx also includes the deceleration (negative acceleration) of the vehicle 10 in the longitudinal direction, expressed as an absolute value. The acceleration Gx corresponds to the "acceleration" in the present invention.

[0020] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an MG1 control signal Smg1 and an MG2 control signal Smg2 for controlling the first electric motor MG1 and the second electric motor MG2, and a hydraulic control signal Sp for controlling the engagement and disengagement of the engagement device CB) to each device (e.g., the engine 12, the inverter 60, the hydraulic control circuit 50, etc.) provided in the vehicle 10.

[0021] The vehicle 10 can select either an electric motor driving mode or an engine driving mode. The electric motor driving mode is a driving mode in which the vehicle drives as a battery electric vehicle (BEV) using at least one of the first electric motor MG1 and the second electric motor MG2 as a power source while the engine 12, which is one of the power sources, is stopped. The engine driving mode is a driving mode in which the vehicle drives as a hybrid electric vehicle (HEV) using at least the engine 12 as a power source. When switching from the electric motor driving mode to the engine driving mode, engine start control is executed to automatically start the engine 12. When switching from the engine driving mode to the electric motor driving mode, engine stop control is executed to automatically stop the engine 12.

[0022] FIG. 2 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in FIG. 1 during a start control period of the engine 12. Hereinafter, the "start control period of the engine 12" will be simply referred to as the "start control period." The flowchart in FIG. 2 is repeatedly executed during electric motor running and during the start control period. FIG. 2 illustrates a case where the engine 12 is automatically started, for example, in an electric motor running mode in which only the second electric motor MG2 is used as a power source. In this case, the second electric motor MG2 corresponds to the "electric motor" in the present invention.

[0023] First, in step S10 (hereinafter, "step" will be omitted), it is determined whether or not the vehicle is in a start control period. If the determination in S10 is affirmative, it is determined in S20 whether or not the acceleration Gx is equal to or greater than a determination value Gx_jdg, i.e., whether or not a shock in the longitudinal direction of the vehicle 10 has occurred. The start control period is a period during which a shock resulting from the start of the engine 12 (hereinafter, referred to as "engine start shock") may occur, for example, a period during which engine start control is being executed (= the period from start point P1 to end point P2 of the engine start control shown in FIGS. 3 and 4). The determination value Gx_jdg is a determination value of the acceleration Gx that is determined in advance experimentally or by design in order to determine whether the shock that has occurred is outside the acceptable range for vehicle occupants, including the driver. The determination value Gx_jdg corresponds to the "predetermined first determination value" in the present invention.

[0024] If the determination in S20 is affirmative, in S30, a temporary non-determination period Tmsk_tmp [sec] is set from the time when the acceleration Gx becomes equal to or greater than the determination value Gx_jdg. The temporary non-determination period Tmsk_tmp is a grace period for determining whether or not the engine start shock is occurring. The temporary non-determination period Tmsk_tmp is the maximum delay time from the time when the acceleration Gx becomes equal to or greater than the determination value Gx_jdg due to rough road driving to the time when the wheel speed change amount ΔNr [rpm / sec] described below is detected as being equal to or greater than the determination value ΔNr_jdg, and is a period determined in advance experimentally or by design. Therefore, regardless of the road surface conditions of the rough road on which the vehicle 10 is traveling, the wheel speed change amount ΔNr will not be detected as being equal to or greater than the determination value ΔNr_jdg after the temporary non-determination period Tmsk_tmp has elapsed from the time when the acceleration Gx becomes equal to or greater than the determination value Gx_jdg. After S30 is executed, S40 determines whether the wheel speed change amount ΔNr is equal to or greater than a criterion value ΔNr_jdg within a temporary non-determination period Tmsk_tmp. The wheel speed change amount ΔNr is the amount of change in the wheel speed Nr per unit time, expressed as an absolute value. Preferably, the wheel speed change amount ΔNr is the largest amount of change per unit time among the amounts of change in the wheel speed Nr per unit time for the front and rear wheels. The criterion value ΔNr_jdg is a criterion value determined in advance through experimentation or design in order to determine whether the wheel speed change amount ΔNr caused by traveling on a rough road is due to traveling on a rough road. The criterion value ΔNr_jdg corresponds to the "predetermined second criterion value" in this invention. If the wheel speed change amount ΔNr is less than the criterion value ΔNr_jdg and no engine start shock occurs, the acceleration Gx is less than the criterion value Gx_jdg.

[0025] If the determination in S40 is affirmative, in S50, the temporary non-determination period Tmsk_tmp is set as a first non-determination period Tmsk1 [sec], which is the actual non-determination period, and the period from the time when it is determined in S40 that the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg to the end time P2 of the engine start control is set as a second non-determination period Tmsk2 [sec]. If the determination in S40 is affirmative, the shock detected in S20 may have been caused by traveling on a rough road. By setting the temporary non-determination period Tmsk_tmp as the first non-determination period Tmsk1 [sec], the shock detected in S20 is not determined to be an engine start shock. By setting the second non-determination period Tmsk2, it is not determined that an engine start shock has occurred even if the acceleration Gx becomes equal to or greater than the determination value Gx_jdg during this period.

[0026] If the determination in S40 is negative, the temporary non-determination period Tmsk_tmp is not set to the actual non-determination period in S60, and the shock detected in S20 is determined to be an engine start shock.

[0027] If the determination in S20 is negative, then in S70 it is determined whether the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg. If the determination in S70 is positive, then in S80 a second non-determining period Tmsk2 is set as the period from when it is determined in S70 that the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg to the end point P2 of the engine start control. By setting the second non-determining period Tmsk2, it is not determined that an engine start shock has occurred even if the acceleration Gx is equal to or greater than the determination value Gx_jdg during this period. If the determination in S10 is negative, after S50 is executed, after S60 is executed, if the determination in S70 is negative, or after S80 is executed, then the process returns.

[0028] For example, if S60 determines that the shock detected in S20 is an engine start shock, the control content is changed in the next engine start control so that the engine start shock is less likely to occur. For example, the cranking period is lengthened so that the engine rotation speed Ne approaches a rotation speed corresponding to the AT input shaft rotation speed Nin while the vehicle is running, thereby reducing the engine start shock by igniting the engine 12.

[0029] FIG. 3 is a time chart when the flowchart of FIG. 2 is executed, and shows an example of a case where the wheel speed change detection signal Snr goes into the ON state after the shock detection signal Ssh goes into the ON state.

[0030] The shock detection signal Ssh is a signal that detects a shock that has occurred in the vehicle 10, and specifically, is in the ON state while the acceleration Gx is equal to or greater than the judgment value Gx_jdg. In other words, the shock detection signal Ssh being in the ON state means that a shock that has occurred in the vehicle 10 has been detected. The wheel speed change detection signal Snr is a signal that detects a wheel speed change due to traveling on a rough road, and specifically, is in the ON state while the wheel speed change amount ΔNr is equal to or greater than the judgment value ΔNr_jdg. In other words, the wheel speed change detection signal Snr being in the ON state means that the wheel speed change amount ΔNr is equal to or greater than the judgment value ΔNr_jdg. The starting shock detection flag Fsh_eng is a flag signal that indicates that the shock detected by the shock detection signal Ssh is an engine starting shock. In other words, the starting shock detection flag Fsh_eng being in the ON state means that the shock detected by the shock detection signal Ssh has been determined to be an engine starting shock.

[0031] 3, the solid lines for the wheel speed change detection signal Snr, the second non-determination period setting signal Smsk2, and the starting shock detection flag Fsh_eng indicate an example in which the wheel speed change detection signal Snr is in the ON state during the temporary non-determination period Tmsk_tmp, whereas the dashed lines indicate an example in which the wheel speed change detection signal Snr is not in the ON state during the temporary non-determination period Tmsk_tmp but is in the ON state after the temporary non-determination period Tmsk_tmp has elapsed.

[0032] First, a case where the wheel speed change detection signal Snr is in the ON state (solid line) during the temporary non-determination period Tmsk_tmp will be described.

[0033] At the start point P1, engine start control is initiated. Due to the occurrence of front-rear shocks in the vehicle 10, the acceleration Gx becomes equal to or greater than the determination value Gx_jdg during the period from time point t1 to time point t2. As a result, the shock detection signal Ssh is in the ON state during the period from time point t1 to time point t2. Based on the change of the shock detection signal Ssh to the ON state at time point t1, a temporary no-determination period setting signal Smsk_tmp becomes in the ON state from time point t1. That is, the period from time point t1 to time point t5 is set as the temporary no-determination period Tmsk_tmp.

[0034] Within this temporary no-determination period Tmsk_tmp, during the period from time point t3 (t1 < t3 < t5) to time point t4, the wheel speed change detection signal Snr becomes in the ON state, that is, the wheel speed change amount ΔNr becomes equal to or greater than the determination value ΔNr_jdg. Based on the change of the wheel speed change detection signal Snr to the ON state at time point t3 within the temporary no-determination period Tmsk_tmp, a signal similar to the temporary no-determination period setting signal Smsk_tmp is output as the first no-determination period setting signal Smsk1. That is, the temporary no-determination period Tmsk_tmp is set as the actual no-determination period. Also, based on the change of the wheel speed change detection signal Snr to the ON state at time point t3, the second no-determination period setting signal Smsk2 is in the ON state for the period from time point t3 to the end point P2 of the engine start control. As a result, the period from time point t3 to the end point P2 is set as the second no-determination period Tmsk2. When the temporary no-determination period Tmsk_tmp is set as the first no-determination period Tmsk1, the shock detection signal Ssh detected during the period from time point t1 to time point t2 is within the actual no-determination period. As a result, for the period from time point t1 to time point t2, the start shock detection flag Fsh_eng is in the OFF state. That is, the shock detected by the shock detection signal Ssh during the period from time point t1 to time point t2 is not determined to be an engine start shock.

[0035] Next, a case where the wheel speed change detection signal Snr does not turn on during the temporary non-determination period Tmsk_tmp and the wheel speed change detection signal Snr turns on after the elapse of the temporary non-determination period Tmsk_tmp (the case of the dashed line) will be described.

[0036] The wheel speed change detection signal Snr turns on during the period from the time point t6 (t5 < t6) after the elapse of the temporary non-determination period Tmsk_tmp to the time point t7. Based on the change of the wheel speed change detection signal Snr to the on state at the time point t6 after the elapse of the temporary non-determination period Tmsk_tmp, the temporary non-determination period Tmsk_tmp is not set as the first non-determination period Tmsk1. That is, the temporary non-determination period Tmsk_tmp is not set as the actual non-determination period. Also, based on the change of the wheel speed change detection signal Snr to the on state at the time point t6, the second non-determination period setting signal Smsk2 is turned on for the period from the time point t6 to the end time point P2 of the engine start control. Thereby, the period from the time point t6 to the end time point P2 is set as the second non-determination period Tmsk2. Since the temporary non-determination period Tmsk_tmp is not set as the first non-determination period Tmsk1, the shock detection signal Ssh detected during the period from the time point t1 to the time point t2 is not regarded as non-determined, and the start shock detection flag Fsh_eng is turned on. That is, the shock detection signal Ssh detected during the period from the time point t1 to the time point t2 is determined to be an engine start shock after the elapse of the determination grace period set as the temporary non-determination period Tmsk_tmp.

[0037] FIG. 4 is a time chart when the flowchart of FIG. 2 is executed, and is an example in which the shock detection signal Ssh turns on after the wheel speed change detection signal Snr turns on. Since the time chart of FIG. 4 is substantially the same as the time chart of FIG. 3, the description will focus on the parts different from FIG. 3, and the substantially common parts will be denoted by the same reference numerals and the description will be omitted as appropriate.

[0038] Before the shock detection signal Ssh turns on at time point t1, the wheel speed change detection signal Snr turns on at time point t11 (t11 < t1). The wheel speed change detection signal Snr is on during the period from time point t11 to time point t12. Based on the change of the wheel speed change detection signal Snr to the on state at time point t11, the second non-determination period setting signal Smsk2 is set to the on state during the period from time point t11 to the end time point P2 of the engine start control. As a result, the period from time point t11 to the end time point P2 is set as the second non-determination period Tmsk2. When the second non-determination period Tmsk2 is set, the shock detection signal Ssh detected during the period from time point t1 to time point t2 is within the actual non-determination period. As a result, the start shock detection flag Fsh_eng is set to the off state during the period from time point t1 to time point t2. That is, the shock detected by the shock detection signal Ssh during the period from time point t1 to time point t2 is not determined to be an engine start shock.

[0039] According to the present embodiment, in the vehicle 10 including the engine 12 and the second motor MG2 as power sources, the electronic control device 90 of the vehicle 10 capable of switching between engine running using at least the engine 12 as a power source and motor running using only the second motor MG2 as a power source is configured such that, during the start control period accompanying the switching of the power source from motor running to engine running, (a) when the acceleration Gx of the vehicle 10 is equal to or greater than the determination value ΔNr_jdg and the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg within the temporary non-determination period Tmsk_tmp, it is not determined that an engine start shock has occurred based on the fact that the acceleration Gx is equal to or greater than the determination value ΔNr_jdg, and (b) when the acceleration Gx is equal to or greater than the determination value ΔNr_jdg and the wheel speed change amount ΔNr is not equal to or greater than the determination value ΔNr_jdg within the temporary non-determination period Tmsk_tmp, it is determined that an engine start shock has occurred based on the fact that the acceleration Gx is equal to or greater than the determination value ΔNr_jdg. Even in rough road driving where a change in the wheel speed Nr appears after the occurrence of a shock, misjudgment of the shock caused by rough road driving as an engine start shock is suppressed.

[0040] According to this embodiment, during the start control period, (a) if the acceleration Gx becomes equal to or greater than the reference value ΔNr_jdg, a predetermined period is set as a temporary non-determination period Tmsk_tmp during which it is not temporarily determined whether or not an engine start shock has occurred. (b) If the wheel speed change amount ΔNr becomes equal to or greater than the reference value ΔNr_jdg during the temporary non-determination period Tmsk_tmp, the temporary non-determination period Tmsk_tmp is set as the actual non-determination period. (b) If the wheel speed change amount ΔNr does not become equal to or greater than the reference value ΔNr_jdg during the temporary non-determination period Tmsk_tmp, the temporary non-determination period Tmsk_tmp is not set as the actual non-determination period. In this way, after the temporary non-determination period Tmsk_tmp is set, whether or not the temporary non-determination period Tmsk_tmp is set as the actual non-determination period is determined depending on whether the wheel speed change amount ΔNr becomes equal to or greater than the reference value ΔNr_jdg during the temporary non-determination period Tmsk_tmp. This allows the electronic control unit 90 to easily determine whether or not an engine start shock has occurred, with reduced erroneous determinations.

[0041] According to this embodiment, if the wheel speed change amount ΔNr becomes equal to or greater than the reference value ΔNr_jdg during the startup control period, it is not determined that an engine startup shock has occurred even if the acceleration Gx becomes equal to or greater than the reference value Gx_jdg during the second non-determination period Tmsk2 from the time when the wheel speed change amount ΔNr becomes equal to or greater than the reference value ΔNr_jdg (for example, time t3 or time t11) to the end time P2 of the startup control period. When the wheel speed change amount ΔNr becomes equal to or greater than the reference value ΔNr_jdg, erroneous determination that a shock caused by continuous rough road driving is an engine startup shock is suppressed. [Example]

[0042] FIG. 5 is an example of a flowchart illustrating the control operation of the electronic control device 90 according to the second embodiment during a stop control period of the engine 12. Hereinafter, the "stop control period of the engine 12" will be simply referred to as the "stop control period." This embodiment is substantially the same as the first embodiment, except that the control operation is performed during a start control period in the first embodiment, whereas the control operation is performed during a stop control period in the second embodiment. Therefore, the description will focus on the parts that are different from the first embodiment, and the same reference numerals will be used to denote substantially common parts, and the description will be omitted as appropriate. The flowchart of FIG. 5 is repeatedly executed during engine running and during the stop control period. FIG. 5 illustrates a case where the engine 12 is automatically stopped, for example, in an engine running mode in which both the engine 12 and the second electric motor MG2 are used as power sources. In this case, the second electric motor MG2 corresponds to the "electric motor" in the present invention.

[0043] First, in S110, it is determined whether or not the vehicle is in a stop control period. If the determination in S110 is positive, it is determined in S120 whether or not the acceleration Gx is equal to or greater than a determination value Gx_jdg, i.e., whether or not a shock has occurred in the longitudinal direction of the vehicle 10. The stop control period is a period during which a shock caused by stopping the engine 12 (hereinafter referred to as an "engine stop shock") may occur, for example, a period during which the engine stop control is being executed (= the period from the start to the end of the engine stop control).

[0044] If the determination in S120 is positive, in S130, a temporary non-determining period Tmsk_tmp is set from the time when the acceleration Gx becomes equal to or greater than the determination value Gx_jdg. After S130 is executed, in S140, it is determined whether the wheel speed change amount ΔNr becomes equal to or greater than the determination value ΔNr_jdg within the temporary non-determining period Tmsk_tmp.

[0045] If the determination in S140 is affirmative, in S150, the temporary non-determination period Tmsk_tmp is set as the actual non-determination period as a first non-determination period Tmsk1, and the period from the time when it is determined in S140 that the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg to the time when the engine stop control ends is set as a second non-determination period Tmsk2. If the determination in S140 is affirmative, the shock detected in S120 may have been caused by traveling on a rough road, and therefore the shock detected in S120 is not determined to be an engine stop shock. If the determination in S140 is negative, in S160, the temporary non-determination period Tmsk_tmp is not set as the actual non-determination period. As a result, the shock detected in S120 is determined to be an engine stop shock.

[0046] If the determination in S120 is negative, then in S170 it is determined whether the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg. If the determination in S170 is positive, then in S180 the period from when it is determined in S170 that the wheel speed change amount ΔNr is equal to or greater than the determination value ΔNr_jdg to when the engine stop control ends is set as a second non-determination period Tmsk2. If the determination in S110 is negative, after S150 is executed, after S160 is executed, if the determination in S170 is negative, or after S180 is executed, then the process returns.

[0047] For example, if it is determined in S160 that the shock detected in S120 is an engine stop shock, the control content is changed in the next engine stop control so that the engine stop shock is less likely to occur.

[0048] The only difference between this embodiment and the first embodiment is that the control is performed during the start control period, whereas the control is performed during the stop control period. Therefore, even when the vehicle is traveling on a rough road where a change in the wheel speed Nr occurs after a shock occurs, the same effects as those of the first embodiment can be achieved, such as suppressing erroneous determination that a shock caused by traveling on a rough road is an engine stop shock.

[0049] The above-described embodiments of the present invention are merely illustrative, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0050] In the first and second embodiments described above, the "motor-driven traveling" of the present invention uses only the second electric motor MG2 as a power source, but may also use, for example, only the first electric motor MG1 as a power source.

[0051] In the above-described first and second embodiments, a temporary non-determining period Tmsk_tmp is set from the point at which the shock detection signal Ssh changes to the on state, and if the wheel speed change amount ΔNr becomes equal to or greater than the determination value ΔNr_jdg within that temporary non-determining period Tmsk_tmp, it is not determined that a start-up shock or a stop-down shock of the engine 12 has occurred, but the present invention is not limited to this. For example, regardless of whether the wheel speed change amount ΔNr becomes equal to or greater than the judgment value ΔNr_jdg within the hypothetical non-judgment period Tmsk_tmp, the shock detected at S20 of the flowchart in Figure 2 or S120 of the flowchart in Figure 5 may not be judged to be an engine start shock in any of the following cases: (1) the friction coefficient μ of the road surface on which the vehicle 10 is traveling is equal to or less than a predetermined coefficient value μ_jdg, making it a low-μ road on which the drive wheels are likely to spin (slip); (2) either the accelerator or brake is operated during the start control period or the stop control period; (3) the oil temperature THoil [°C] of the hydraulic oil supplied from the hydraulic control circuit 50 is below a predetermined judgment temperature THoil_jdg; (4) engine start is canceled during the start control period of the engine 12; or (5) engine stop is canceled during the stop control period of the engine 12 and the engine 12 is restarted. The predetermined coefficient value μ_jdg is a coefficient value determined experimentally or by design as the upper limit of the friction coefficient range for a low μ road where a shock may occur in the vehicle 10. The predetermined judgment temperature TSoil_jdg is a judgment temperature determined experimentally or by design where a shock may occur in the vehicle 10 due to, for example, insufficient lubrication function of the hydraulic oil in the power transmission path PT. This is because a shock may occur even in the cases (1) to (5) above, without being caused by engine start or engine stop.

[0052] In the first and second embodiments, the second non-determination period Tmsk2 is set to the end point P2 of the engine start control or the end point of the engine stop control, but the present invention is not limited to this. For example, the second non-determination period Tmsk2 may be set to the maximum value of the delay time from the time when the wheel speed change amount ΔNr due to rough road driving is detected to the time when the acceleration Gx is detected to be equal to or greater than the determination value Gx_jdg, and may be set to a period determined in advance experimentally or by design. This reduces the non-determination period (= the period excluded from determination) for engine start shock or engine stop shock due to rough road driving, while suppressing erroneous determination that a shock caused by rough road driving is a shock caused by engine start or engine stop.

[0053] In the first and second embodiments described above, the vehicle 10 has an engine 12 and two electric motors (a first electric motor MG1 and a second electric motor MG2) as power sources, but the present invention is not limited to this. For example, the vehicle 10 to which the present invention is applied may have the engine 12 and one electric motor as power sources and an engagement device that connects and disconnects the power transmission between the engine 12 and the electric motor. In short, the present invention is applied to a vehicle 10 that has the engine 12 and an electric motor as power sources and is capable of switching between engine running and electric motor running. [Explanation of symbols]

[0054] 10: vehicle, 12: engine, 90: electronic control device (shock determination device), Gx: acceleration, Gx_jdg: determination value (predetermined first determination value), MG2: second electric motor (electric motor), Nr: wheel speed, Tmsk1: first non-determination period, Tmsk_tmp: temporary non-determination period ΔNr: wheel speed change amount, ΔNr_jdg: judgment value (predetermined second judgment value)

Claims

1. A shock determination device for a vehicle that has an engine and an electric motor as power sources and that can switch between engine running, in which at least the engine is used as a power source, and electric motor running, in which only the electric motor is used as a power source, comprising: During at least one of a start control period and a stop control period of the engine, which accompanies switching of the power source from one of the electric motor running mode and the engine running mode to the other, When the acceleration in the longitudinal direction of the vehicle becomes equal to or greater than a predetermined first determination value and a wheel speed change amount, which is the amount of change in wheel speed, becomes equal to or greater than a predetermined second determination value within a predetermined period from the time when the acceleration becomes equal to or greater than the first determination value, it is not determined that a start shock or a stop shock of the engine has occurred based on the acceleration becoming equal to or greater than the first determination value, When the acceleration becomes equal to or greater than the first determination value and the wheel speed change amount does not become equal to or greater than the second determination value within the predetermined period, it is determined that a start shock or a stop shock of the engine has occurred based on the acceleration becoming equal to or greater than the first determination value. A shock determination device for a vehicle.

2. When the acceleration becomes equal to or greater than the first determination value during at least one of a start control period and a stop control period of the engine, the predetermined period is set as a temporary non-determination period during which it is not temporarily determined whether a start shock or a stop shock of the engine has occurred, If the wheel speed change amount becomes equal to or greater than the second determination value during the provisional non-determination period, the provisional non-determination period is set as an actual non-determination period; If the wheel speed change amount does not become equal to or greater than the second determination value during the provisional non-determination period, the provisional non-determination period is not regarded as an actual non-determination period.

2. The shock determination device for a vehicle according to claim 1.

3. When the wheel speed change amount becomes equal to or greater than the second determination value during at least one of the engine start control period and the engine stop control period, it is not determined that a start shock or a stop shock of the engine has occurred even if the acceleration becomes equal to or greater than the first determination value during the period from when the wheel speed change amount becomes equal to or greater than the second determination value to the end of the engine start control period or the end of the engine stop control period.

3. The shock determination device for a vehicle according to claim 1 or 2.

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