JP2016142203A - Collision avoidance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a collision avoidance device which can enhance a speed reduction effect by a discharge brake when avoiding a collision between a vehicle and an obstacle by automatically operating the discharge brake, in the vehicle which uses an engine with a supercharger as a drive force source.SOLUTION: A collision avoidance device comprises: an engine having a supercharger which drives an own vehicle; an exhaust brake which can generate a brake force at the own vehicle by enhancing the discharge pressure of the engine; an obstacle detection unit which detects an obstacle located in front of the own vehicle; a collision time calculation unit which calculates a collision time up to a collision of the own vehicle with the obstacle; an exhaust brake operation unit which automatically operates the discharge brake when the collision time reaches a prescribed first threshold; and an exhaust brake preparation unit which lowers a rotation number of the supercharger when the collision time reaches a second threshold which is larger than the first threshold.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a collision avoidance device for avoiding a collision with an obstacle in front of a vehicle.

  Conventionally, in order to avoid collision between the host vehicle and surrounding obstacles, the service brake (hydraulic brake) and the retarder brake (exhaust brake) are automatically activated according to the estimated time until the vehicle collides with the obstacle. A brake control system is known (for example, Patent Document 1).

JP 2011-218885 A

  However, in a vehicle using a supercharged engine as a driving force source, even if the exhaust pressure is increased and the exhaust brake is operated, in the state where the supercharger is rotating to some extent, due to the supercharging effect on the intake side, There is a possibility that the deceleration effect by the exhaust brake may be reduced.

  Therefore, in view of the above problems, in a vehicle using a supercharged engine as a driving force source, when the collision between the vehicle and an obstacle is avoided by automatically operating the exhaust brake, the deceleration effect by the exhaust brake is enhanced. It is an object of the present invention to provide a collision avoidance device that can perform the above operation.

In order to achieve the above object, in one embodiment, a collision avoidance device comprises:
An engine having a supercharger for driving the vehicle;
An exhaust brake capable of generating a braking force on the host vehicle by increasing an exhaust pressure of the engine;
An obstacle detection unit for detecting an obstacle located in front of the host vehicle;
A collision time calculation unit for calculating a collision time until the host vehicle collides with the obstacle;
An exhaust brake operating section that automatically operates the exhaust brake when the collision time is equal to or less than a predetermined first threshold;
When the collision time becomes equal to or less than a second threshold value that is greater than the first threshold value, an exhaust brake preparation unit that reduces the rotational speed of the supercharger is provided.

  According to this embodiment, in a vehicle using a supercharged engine as a driving force source, when the collision between the vehicle and an obstacle is avoided by automatically operating the exhaust brake, the deceleration effect by the exhaust brake is reduced. A collision avoidance device that can be enhanced can be provided.

It is a block diagram which shows an example of a structure of the own vehicle containing a collision avoidance apparatus. It is a flowchart which shows notionally an example of the main automatic braking control processing by a collision avoidance apparatus (PCS-ECU). It is a flowchart which shows notionally an example of the auxiliary | assistant automatic braking control process by a collision avoidance apparatus (PCS-ECU). It is a figure which shows the structure of a turbocharger typically. It is a flowchart which shows notionally an example of the exhaust-brake preparation control process by a collision avoidance apparatus (PCS-ECU). It is a control block diagram which shows an example of WGV and throttle cooperation control by a collision avoidance apparatus (PCS-ECU).

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating an example of a configuration of a host vehicle 100 including a collision avoidance device 1 according to the present embodiment.

  The collision avoidance device 1 according to the present embodiment automatically operates a main brake (hydraulic brake system) in order to avoid collision between the host vehicle 100 and an obstacle. In addition, the collision avoidance device 1 avoids a collision between the host vehicle 100 and an obstacle, and, in addition to the main brake, an auxiliary control by the action of the intake brake system 2 and the exhaust brake system 3 that increases the braking force by the engine brake. Power is also generated.

  The collision avoidance device 1 includes an obstacle detection unit 10, a PCS-ECU 20, a brake ECU 30, a brake actuator 40, an engine ECU 50, an engine 60, and the like.

  The obstacle detection unit 10 is an obstacle detection unit that detects an obstacle (a preceding vehicle, a pedestrian, a fixed object on the road, etc.) located in front of the host vehicle 100. The obstacle detection unit 10 may detect (calculate) the relative position (distance to the host vehicle, direction seen from the host vehicle), relative speed, size (width in the left-right direction), and the like of the detected obstacle. it can. The obstacle detection unit 10 is, for example, a known radar sensor that detects an obstacle by transmitting a detection wave (radio wave, laser, etc.) in front of the host vehicle 100 and receiving a reflected wave corresponding to the detection wave. (Millimeter wave radar, laser radar, etc.). The obstacle detection unit 10 captures an obstacle by imaging the front of the host vehicle 100 using an imaging device such as a CCD (Charge Coupled Device) and performing known image processing on the captured image. It may be a known camera sensor to detect. The obstacle detection unit 10 may include a radar sensor and a camera sensor.

  The obstacle detection unit 10 transmits information (obstacle information) on the obstacle including the relative position (distance, azimuth, etc.), relative speed, size (width), etc. of the obstacle to the PCS-ECU 20.

  The obstacle detection unit 10 is communicably connected to the PCS-ECU 20 through a one-to-one communication line (direct line), an in-vehicle LAN, or the like. Further, when there are a plurality of obstacles, the obstacle detection unit 10 may transmit obstacle information regarding all the obstacles, or an obstacle with the closest distance to the host vehicle 100 (that is, collision avoidance). Obstacle information regarding the obstacle with the highest degree of urgency as a target of driving assistance may be transmitted.

  Further, some of the functions in the obstacle detection unit 10 may be executed by the outside of the obstacle detection unit 10 (for example, the PCS-ECU 20). For example, the obstacle detection unit 10 executes only detection of an object (transmission of a detection wave by a radar sensor and reception of a reflected wave, imaging of the front of the host vehicle 100 by a camera sensor, etc.), and detection of the relative position of the obstacle, etc. Processing functions such as (calculation) may be executed by the PCS-ECU 20.

  The PCS-ECU 20 is an electronic control unit that executes main control processing in the collision avoidance device 1. The PCS-ECU 20 is configured by, for example, a microcomputer and executes various control processes by executing various programs stored in the ROM on the CPU.

  Note that the PCS-ECU 20 is communicably connected to the brake ECU 30 and the engine ECU 50 through an in-vehicle LAN or the like.

  When an obstacle ahead of the host vehicle 100 is detected by the obstacle detection unit 10, the PCS-ECU 20 calculates a TTC (Time To Collision) that is a predicted time until the host vehicle 100 collides with the obstacle. calculate. For example, the PCS-ECU 20 calculates TTC (= D / V) based on the obstacle information received from the obstacle detection unit 10 (distance D to the obstacle, relative speed V of the obstacle).

  In addition, the PCS-ECU 20 automatically generates braking force of the host vehicle 100 based on the calculated TTC in order to avoid a collision between the obstacle detected by the obstacle detection unit 10 and the host vehicle 100. Execute the process. Specifically, a hydraulic brake system that is a main brake (so-called service brake) of the host vehicle 100, an intake brake system 2 that is an auxiliary brake (so-called retarder brake) of the host vehicle, and an exhaust brake system are used automatically. To generate braking force.

  The intake brake system 2 includes an engine ECU 50, a throttle body 61 (throttle valve 61a), which will be described later, and the like, and the throttle valve 61a is fully closed based on a control command from the engine ECU 50. Thereby, since the intake resistance of the engine 60 is increased, the braking force by the engine brake is increased. The exhaust brake system 3 includes an engine ECU 50, a turbocharger 62 (Waistgate Valve: WGV) 62a, which will be described later, and the like, and the WGV 62a is fully closed based on a control command from the engine ECU 50. As a result, the exhaust resistance increases, so that the braking force by the engine brake is increased. Hereinafter, the intake and exhaust brakes may be collectively referred to as “intake and exhaust brakes”.

  Here, a control process for automatically generating a braking force (automatic braking) by the collision avoidance device according to the present embodiment will be described with reference to FIGS.

  FIG. 2 is a flowchart conceptually showing an example of automatic braking (main automatic braking) control processing using the main brake (hydraulic brake system) by the collision avoidance apparatus 1 (PCS-ECU 20) according to the present embodiment. FIG. 3 is a flowchart conceptually showing an example of automatic braking (auxiliary automatic braking) control processing using an auxiliary brake (intake and exhaust brake) by the collision avoidance device 1 (PCS-ECU 20) according to the present embodiment.

  2 and 3 are started when an obstacle is detected by the obstacle detection unit 10, and are repeatedly executed while the detection of the obstacle continues.

  First, referring to FIG. 2, in step S101, the PCS-ECU 20 calculates TTC.

  In step S102, the PCS-ECU 20 determines whether TTC is equal to or less than a predetermined threshold value Ton_th1. The PCS-ECU 20 proceeds to step S103 when the TTC is equal to or smaller than the predetermined threshold value Ton_th1, and returns to step S101 when the TTC is not equal to or smaller than the predetermined threshold value Ton_th1, and repeats the processes of steps S101 to S102.

  In step S103, the PCS-ECU 20 automatically activates the main brake (starts main automatic braking). Specifically, by transmitting an automatic braking request to the brake ECU 30, the brake ECU 30 operates the brake actuator 40 in response to the automatic braking request. As a result, the main brake (hydraulic brake system) is automatically activated, and a braking force is generated in the host vehicle 100.

  In step S104, PCS-ECU 20 calculates TTC.

  In step S105, the PCS-ECU 20 determines whether or not TTC is equal to or less than a predetermined threshold value Toff_th1 (≧ Ton_th1). The PCS-ECU 20 proceeds to step S106 when the TTC is equal to or smaller than the predetermined threshold value Toff_th1, and proceeds to step S107 when not equal to or smaller than the predetermined threshold value Toff_th1.

  In step S106, the PCS-ECU 20 determines whether the host vehicle 100 has stopped based on a detection signal from a vehicle speed sensor (not shown). If the host vehicle 100 is stopped, the PCS-ECU 20 proceeds to step S107. If the host vehicle 100 is not stopped, the PCS-ECU 20 returns to step S104 and repeats the processes of steps S104 to S106.

  In step S107, the PCS-ECU 20 automatically releases the state in which the main brake is operated (releases the main automatic braking). Specifically, by transmitting an automatic braking release request to the brake ECU 30, the brake ECU 30 releases the operation of the brake actuator 40 in response to the automatic braking release request.

  Subsequently, referring to FIG. 3, in step S201, the PCS-ECU 20 calculates TTC.

  In step S202, the PCS-ECU 20 determines whether or not TTC is equal to or less than a predetermined threshold value Ton_th2 that is equal to or greater than the predetermined threshold value Ton_th1. When the TTC is equal to or smaller than the predetermined threshold value Ton_th2, the PCS-ECU 20 proceeds to step S203. When the TTC is equal to or smaller than the predetermined threshold value Ton_th2, the PCS-ECU 20 returns to step S201 and repeats the processes of steps S201 to S202.

  In step S203, the PCS-ECU 20 automatically activates the auxiliary brake (intake and exhaust brake) (starts auxiliary automatic braking). Specifically, by transmitting an automatic braking request to the engine ECU 50, the engine ECU 50 operates (fully closes) the throttle valve 61a and the WGV 62a in response to the automatic braking request. As a result, the auxiliary brake (intake and exhaust brake) is automatically activated, and a braking force is generated in the host vehicle 100.

  In step S204, PCS-ECU 20 calculates TTC.

  In step S205, the PCS-ECU 20 determines whether or not TTC is equal to or less than a predetermined threshold value Toff_th2 (≧ Ton_th2). The PCS-ECU 20 proceeds to step S206 when the TTC is equal to or smaller than the predetermined threshold value Toff_th2, and proceeds to step S207 when not smaller than the predetermined threshold value Toff_th2.

  In step S206, the PCS-ECU 20 determines whether or not the host vehicle 100 has stopped based on a detection signal from a vehicle speed sensor (not shown). If the host vehicle 100 is stopped, the PCS-ECU 20 proceeds to step S207. If the host vehicle 100 is not stopped, the PCS-ECU 20 returns to step S204 and repeats the processes of steps S204 to S206.

  In step S207, the PCS-ECU 20 automatically releases the state of operating the auxiliary brake (releases auxiliary automatic braking). Specifically, by transmitting an automatic braking release request to the engine ECU 50, the engine ECU 50 releases the operation of the throttle valve 61a and the WGV 62a in response to the automatic braking release request.

  Thus, in addition to the main brake, it is possible to further enhance the deceleration effect by performing automatic braking with an auxiliary brake (intake and exhaust brake). Further, since the burden on the main brake is reduced, for example, it is possible to suppress wear of the brake pad, and the reliability and maintainability of the main brake can be improved.

  Returning to FIG. 1, the brake ECU 30 is an electronic control unit that controls the operating state of the main brake (hydraulic brake system) of the host vehicle 100. The brake ECU 30 controls, for example, the brake actuator 40 that operates a hydraulic brake system disposed on each wheel of the host vehicle 100. The brake ECU 30 may be configured by, for example, a microcomputer and executes various control processes by executing various programs stored in the ROM on the CPU.

  The brake ECU 30 is communicably connected to the brake actuator 40 through a solid line or the like.

  The brake ECU 30 automatically generates the braking force of the host vehicle 100 in response to the automatic braking request received from the PCS-ECU 20 regardless of the driver's braking operation. For example, the brake ECU 30 controls the brake actuator 40 to generate a predetermined hydraulic pressure regardless of the master cylinder pressure, and to output the hydraulic pressure or a hydraulic pressure obtained by adding the hydraulic pressure to the master cylinder pressure as the wheel cylinder pressure. . Specifically, by controlling various valves and pumps included in a brake actuator 40 described later, a predetermined hydraulic pressure is generated, and the hydraulic pressure or a hydraulic pressure obtained by adding the hydraulic pressure to the master cylinder pressure is used as the wheel cylinder pressure. Output. Also, the brake ECU 30 releases the operation of the brake actuator 40 corresponding to the automatic braking request in response to the automatic braking release request received from the PCS-ECU 20.

  The brake actuator 40 generates an output for operating the main brake (hydraulic brake system) of the host vehicle 100. The brake actuator 40 may include, for example, a pump that generates high hydraulic pressure (including a motor that drives the pump), various valves, a hydraulic circuit, and the like, and increases output (e.g., foil without regard to brake operation by the driver). Any configuration may be used as long as cylinder pressure can be increased.

  The engine ECU 50 is an electronic control unit that controls the operating state of the engine 60. The engine ECU 50 may be constituted by, for example, a microcomputer and executes various control processes by executing various programs stored in the ROM on the CPU.

  The engine ECU 50 automatically generates the braking force of the host vehicle 100 (braking force by the engine brake) in response to the automatic braking request received from the PCS-ECU 20. The engine ECU 50 controls the engine 60 (throttle valves 61a and WGV 62a included therein) to increase intake resistance and exhaust resistance, that is, generate braking force by intake and exhaust brakes (increase braking force by engine brakes). .

  The engine 60 is an internal combustion engine as a driving force source that drives the host vehicle 100. The engine 60 includes a throttle body 61, a turbocharger 62, and the like.

  The throttle body 61 is a device that adjusts the amount of intake air to the engine 60. The throttle body 61 is provided between the outside air inlet and the turbocharger 62 (compressor), and the amount of intake air can be adjusted by changing the opening (throttle opening) of the throttle valve 61a. Throttle body 61 includes a throttle sensor 61b that detects the opening of the throttle body, and throttle sensor 61b outputs a detection signal corresponding to the throttle opening to engine ECU 50.

  The engine ECU 50 performs feedback control or the like so that the detection signal received from the throttle sensor 61b matches the opening required for the throttle valve 61a (requested opening).

  The turbocharger 62 is an example of a supercharger (a device that increases charging efficiency by compressing intake air with a compressor). As shown in FIG. 4 (a diagram schematically showing the structure of the turbocharger 62), the turbocharger 62 rotates the exhaust turbine by introducing the exhaust of the engine 60 into the exhaust turbine. As a result, a compressor coaxial with the exhaust turbine rotates, and the intake air introduced through the throttle body 61 is compressed. The compressed air that has been increased to a supercharging pressure higher than the atmosphere is introduced into the engine 60. Further, the turbocharger 62 has a WGV 62a for bypassing exhaust from the engine 60 without introducing it into the exhaust turbine in order to prevent an excessive supercharging pressure or excessive rotation of the exhaust turbine. The WGV 62a operates in response to a control command from the engine ECU 50.

  Next, characteristic processing by the collision avoidance device 1 according to the present embodiment, that is, preparation processing (exhaust brake preparation processing) for maximizing the braking force by the exhaust brake will be described.

  FIG. 5 is a flowchart conceptually showing an example of the exhaust brake preparation process by the collision avoidance apparatus 1 (PCS-ECU 20) according to the present embodiment.

  The processing flow is started when an obstacle is detected by the obstacle detection unit 10 and is repeatedly executed while the detection of the obstacle continues. The preparation flag is set to “0” at the start of the flowchart.

  In step S301, the PCS-ECU 20 calculates TTC.

  In step S302, the PCS-ECU 20 determines whether or not the preparation flag is “0”. When the preparation flag is “0”, the process proceeds to step S303, and when it is not “0” (when it is “1”), the process proceeds to step S307.

  In step S303, the PCS-ECU 20 determines whether or not TTC is equal to or less than a predetermined threshold value Ton_th3 that is greater than the predetermined threshold value Ton_th2 and greater than the predetermined threshold value Ton_th2. If the condition is satisfied, the PCS-ECU 20 proceeds to step S304. If the condition is not satisfied, the PCS-ECU 20 ends the current process.

  In step S304, the PCS-ECU 20 determines whether or not the WGV 62a is fully closed. The PCS-ECU 20 proceeds to step S306 when the WGV 62a is not fully closed, and proceeds to step S305 when the WGV 62a is fully closed.

  Note that the PCS-ECU 20 can determine whether or not the WGV 62a is fully closed by acquiring information regarding the operating state of the WGV 62a from the engine ECU 50.

  In step S305, the PCS-ECU 20 fully opens the WGV 62a. Specifically, by sending a WGV full-open request to engine ECU 50, engine ECU 50 sends a control signal to WGV 62a in response to the WGV full-open request to make it fully open (WGV full-open control). The PCS-ECU 20 performs coordinated control of the throttle opening (WGV / throttle coordinated control) in conjunction with fully opening the WGV 62a. That is, when the WGV 62a is fully opened, the number of revolutions of the turbocharger 62 (exhaust turbine) decreases, so the torque of the engine 60 decreases and the drivability of the host vehicle 100 may deteriorate due to torque fluctuations. Therefore, cooperative control for correcting the throttle opening is performed so as to compensate for the torque reduction caused by fully opening the WGV 62a. Details will be described later.

  The process started in step S305 is continued until the process of step S308 described later is executed or no obstacle is detected.

  In step S306, the PCS-ECU 20 sets the preparation flag to “1” and ends the current process.

  On the other hand, in step S307, the PCS-ECU 20 determines whether or not TTC is equal to or smaller than a predetermined threshold value Toff_th3 (≧ Ton_th3) and larger than the predetermined threshold value Ton_th2. The PCS-ECU 20 proceeds to step S304 when the condition is satisfied, and proceeds to step S308 when the condition is not satisfied.

  In step S308, the PCS-ECU 20 cancels the execution of the WGV fully open control and the WGV / throttle cooperative control.

  In step S309, the PCS-ECU 20 sets the preparation flag to “0” and ends the current process.

  As described above, in the present embodiment, the WGV 62a is fully opened at an earlier timing (when TTC becomes equal to or less than the predetermined threshold value Ton_th3, which is greater than the predetermined threshold value Ton_th2). As a result, the flow rate of the exhaust gas flowing through the exhaust turbine is reduced, and the rotational speed of the exhaust turbine can be lowered. Therefore, it is possible to keep the rotational speed of the exhaust turbine relatively low when the exhaust brake is actuated (when the WGV 62a is fully closed) (when TTC becomes equal to or less than the predetermined threshold value Ton_th2). That is, it is possible to suppress a situation in which the deceleration effect due to the exhaust brake is reduced due to the supercharging effect on the intake side of the engine 60 by the turbocharger 62.

  Next, WGV / throttle cooperative control executed in conjunction with WGV full-open control will be described.

  The required value of throttle opening (required opening) usually depends on the amount of accelerator operation by the driver (accelerator opening), the degree of external load on the engine 60 (alternator operating state, air conditioning compressor operating state), etc. Accordingly, it is determined by engine ECU 50. Hereinafter, this required opening is referred to as a pre-correction required opening. On the other hand, in the WGV / throttle control, in order to suppress the influence of the torque fluctuation (torque reduction) of the engine 60 due to the exhaust brake preparation control (WGV 62a fully opened), the opening degree that compensates for the torque fluctuation (torque reduction) A correction amount is calculated, and a value obtained by adding the opening correction amount to the required opening before correction is newly set as the required opening. Hereinafter, this required opening is referred to as a corrected required opening. As a result, even if the WGV 62a is fully opened by the exhaust brake preparation control, the torque decrease due to the full opening of the WGV 62a is absorbed by the correction of the throttle opening by the WGV / throttle cooperative control, thereby suppressing deterioration in drivability due to torque fluctuations. can do.

  In response to a request from the PCS-ECU 20, the engine ECU 50 estimates a torque fluctuation amount of the engine 60 caused by fully opening the WGV 62a, and calculates an opening correction amount corresponding to the estimated torque fluctuation amount. Hereinafter, the WGV / throttle cooperative control will be described in detail with a focus on a method for estimating the torque fluctuation.

  FIG. 6 is a control block diagram showing an example of WGV / throttle cooperative control by the collision avoidance apparatus 1 (engine ECU 50) according to the present embodiment.

  In the present embodiment, the torque fluctuation amount is estimated from the behavior change of the host vehicle 100. Specifically, the jerk (jerk acceleration) of the host vehicle 100 is calculated from the acceleration of the host vehicle 100 (detected value by a G sensor (not shown)), and the torque variation is estimated from the jerk calculation value to determine the opening correction amount. To do.

  The engine ECU 50 executes WGV / throttle cooperative control by the throttle opening control block 51, the filter processing & differentiation calculation block 52, the actuator amount conversion block 53, and the like.

  The throttle opening control block 51 receives various requests (pre-correction required opening) and an opening correction amount corresponding to the level of the operation by the driver and the external load on the engine 60, and the requested opening (post-correction requested opening). Output). As a result, even if torque fluctuation occurs due to the WGV 62a being fully opened, the torque fluctuation is compensated by the opening correction amount, so that deterioration in drivability can be suppressed.

  The filter processing & differentiation calculation block 52 receives the G sensor detection value (detection value of the acceleration of the host vehicle 100), performs filter processing using a Kalman filter or the like, and then performs a differentiation calculation to determine the jerk (jerk calculation value of the host vehicle 100). ) Is output.

  The actuator amount conversion block 53 receives the jerk calculation value as input, estimates the torque fluctuation amount, converts the estimated torque fluctuation amount into an operation amount (opening correction amount) in the actuator (throttle valve 61a), and outputs it. .

  Note that the method for estimating the torque fluctuation due to the fully opening of the WGV 62a is not limited to that according to the present embodiment. For example, when a sensor capable of monitoring the rotational speed and angular velocity of the exhaust turbine is provided, the torque fluctuation may be estimated (directly calculated) from the amount of change in the rotational speed and angular velocity of the exhaust turbine. Further, the amount of torque fluctuation may be estimated based on the amount of change in parameters (engine speed, vehicle speed, etc.) correlated with the output of the engine 60. Further, a torque fluctuation amount with respect to an elapsed time after the WGV 62a is fully opened may be mapped based on experiments or simulations in advance and stored in an internal memory or the like, and the torque fluctuation amount may be estimated based on the map. Further, the torque fluctuation amount may be estimated based on the change in the passage flow rate estimated from the model (formula) representing the relationship between the open / closed state of the WGV 62a and the exhaust turbine passage flow rate.

  As described above, in this embodiment, the WGV / throttle cooperative control for correcting the throttle opening is executed in conjunction with the fully opening of the WGV 62a. As a result, torque fluctuations of the engine 60 when the WGV 62a is fully opened in preparation for the operation of the exhaust brake can be suppressed, so that deterioration in drivability can be suppressed.

  Further, in the present embodiment, excessive supercharging can be cut by fully opening the WGV 62a, which can contribute to improvement in fuel consumption.

  In addition, since the collision avoidance technology according to the present embodiment (automatic braking by the intake and exhaust brakes, WGV 62a fully open control for preparing the operation of the exhaust brakes, etc.) can be dealt with only by changing the software using the existing hardware configuration, This can be realized without increasing the cost.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

  For example, in the above-described embodiment, the rotational speed of the turbocharger 62 (exhaust turbine) is reduced by fully opening the WGV 62a, but the configuration is not limited thereto. For example, a brake shoe may be provided on a shaft portion or the like of the exhaust turbine, and the brake shoe may be configured to be pressed against the shaft using exhaust pressure or the like, thereby reducing the rotational speed of the exhaust turbine. Further, by providing an electric motor coaxially with the exhaust turbine, energy regeneration may be performed while reducing the rotational speed of the exhaust turbine by causing the electric motor to act as a regenerative brake.

  In the above-described embodiment, the WGV / throttle cooperative control is executed while the WGV 62a is fully opened, thereby achieving both suppression of the exhaust turbine speed and suppression of drivability deterioration. However, the present invention is not limited to this configuration. . For example, by performing gradual change control that gradually changes the WGV 62a and finally fully opens, it is possible to achieve both suppression of the rotational speed of the exhaust turbine and suppression of drivability deterioration.

  In addition to or instead of the turbocharger 62, a supercharger (mechanical supercharger) may be employed. For example, in the case of a supercharger, the rotational speed of the supercharger can be suppressed by turning off an electromagnetic clutch provided on a path for transmitting the power of the engine 60 to the supercharger. The exhaust brake can be realized, for example, by providing a shutter valve or the like in the exhaust manifold of the engine 60 and fully closing the shutter valve. Therefore, even in such a case, the same effect as the above-described embodiment can be obtained.

1 Collision avoidance device 2 Intake brake system 3 Exhaust brake system (exhaust brake)
10 obstacle detection unit 20 PCS-ECU (collision time calculation unit, exhaust brake operation unit, exhaust brake preparation unit)
30 Brake ECU
40 Brake actuator 50 Engine ECU
60 Engine 61 Throttle body 61a Throttle valve 61b Throttle sensor 62 Turbocharger 62a Wastegate valve 100 Own vehicle

Claims (1)

An engine having a supercharger for driving the vehicle;
An exhaust brake capable of generating a braking force on the host vehicle by increasing an exhaust pressure of the engine;
An obstacle detection unit for detecting an obstacle located in front of the host vehicle;
A collision time calculation unit for calculating a collision time until the host vehicle collides with the obstacle;
An exhaust brake operating section that automatically operates the exhaust brake when the collision time is equal to or less than a predetermined first threshold;
An exhaust brake preparation unit that reduces the rotational speed of the supercharger when the collision time is equal to or less than a second threshold value that is greater than the first threshold value;
Collision avoidance device.

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