Vehicle Controls

Abstract

The present invention provides a vehicle control device capable of appropriately stopping an engine during driving, regardless of whether there is traction or not. A vehicle having an engine (10) driving wheels via a power transmission device (100) is controlled, the vehicle control device comprising: a traction state detection unit (270) for detecting the traction state of the vehicle; and an engine control unit (200) for stopping the engine when a predetermined engine stop condition is satisfied during driving of the vehicle, and when the traction state detection unit detects the traction state, the engine control unit changes the engine stop condition in a manner that reduces the driving area in which the engine is stopped, compared to when the traction state is not detected.

Description

Technical Field

[0001] The present invention relates to a vehicle control device for controlling a vehicle having a function of stopping an engine during driving. Background Art

[0002] In vehicles such as automobiles, various trailers (towed vehicles) such as trailers for loading cargo and / or trailer homes may be towed (towing).

[0003] In addition, it has been proposed to control the driving and other aspects of the vehicle differently from the normal state when the vehicle is towing.

[0004] As a prior art related to control during vehicle towing, for example, Patent Document 1 describes the following scheme: in an automatic transmission having an engaging clutch element and a releasing clutch element, when a towing state determination unit determines that the vehicle is in a towing state, based on an increase in the running load, at least one of the engaging hydraulic pressure and the releasing hydraulic pressure immediately before a rotational change of the input shaft occurs is increased.

[0005] Patent Document 2 discloses a system for controlling a towing vehicle that increases the output of an engine and an automatic transmission after the towing vehicle is connected and corrects the control gains of ABS control, ACS control, and 4WS control to values ​​suitable for the towing state.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-155825

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 6-219348 Summary of the invention

[0010] Technical issues

[0011] In recent years, in order to improve the fuel efficiency of a vehicle, it has been proposed to stop the engine and perform coasting even when the vehicle is running when a predetermined condition is satisfied.

[0012] When the engine is stopped during driving and the vehicle is allowed to coast, the braking force is reduced due to the reduction in the engine's brake assist function using intake pipe negative pressure, or there is no driving force applied to the wheels. The handling stability when avoiding danger is different from that when the engine is running. Therefore, for example, when the inter-vehicle distance to other vehicles ahead is short, it is preferable to not stop the engine for safety reasons.

[0013] In addition, when the vehicle is towing, there is a concern that the inertial force caused by the mass of the trailer itself and / or the disturbed behavior of the trailer during emergency braking may further reduce the braking performance and / or crisis avoidance performance compared to the case where towing is not performed.

[0014] Therefore, in a vehicle that coasts with the engine stopped, it is required to ensure the safety of the vehicle even during towing.

[0015] In order to enable safe inertial driving even when the braking performance during towing is reduced, a plan is also being considered to strictly set the conditions for stopping the engine (in the direction of reducing the driving area for stopping the engine), such as increasing the minimum inter-vehicle distance allowing the engine to stop.

[0016] However, in this case, if towing is not performed, the engine is not stopped even in a driving range where the engine can be stopped (coasting), and a sufficient fuel efficiency improvement effect cannot be obtained.

[0017] In view of the above-mentioned problems, an object of the present invention is to provide a vehicle control device capable of appropriately stopping an engine during traveling regardless of whether or not the vehicle is towing.

[0018] Technical Solution

[0019] The present invention solves the above-mentioned problems by the following solutions.

[0020] The vehicle control device of the invention of technical solution 1 is characterized in that a vehicle having an engine that drives wheels via a power transmission device is controlled, and the vehicle control device comprises: a traction state detection unit that detects the traction state of the vehicle; and an engine control unit that stops the engine when a predetermined engine stop condition is satisfied during driving of the vehicle, and when the traction state detection unit detects the traction state, the engine control unit changes the engine stop condition in a manner that reduces the driving area in which the engine is stopped, compared to a case in which the traction state is not detected.

[0021] Accordingly, when the vehicle is towing, the driving area where the engine is stopped is reduced during driving, so that even if the braking performance and / or crisis avoidance performance is reduced due to towing, the engine can be safely stopped only in the area where the engine can be stopped, thereby improving safety during towing.

[0022] On the other hand, when towing is not performed, the condition for stopping the engine during traveling can be optimized to a non-towing state, and the driving range in which the engine is stopped can be expanded, thereby further improving the fuel efficiency of the vehicle.

[0023] The vehicle control device of the invention of Technical Solution 2 is characterized in that, according to the vehicle control device described in Technical Solution 1, it comprises: a vehicle distance detection unit, which detects the vehicle distance between the above-mentioned vehicle and other vehicles traveling directly in front of the above-mentioned vehicle; and a vehicle speed detection unit, which detects the driving speed of the above-mentioned vehicle, and when the above-mentioned vehicle distance is greater than a threshold value, the above-mentioned engine stop condition is satisfied, and when the above-mentioned traction state detection unit detects the above-mentioned traction state, the above-mentioned engine control unit reduces the driving area where the above-mentioned engine is stopped by increasing the above-mentioned threshold value compared to a case where the above-mentioned traction state is not detected.

[0024] According to this, when the braking capacity is reduced due to the towing state, the engine is stopped during traveling only when a larger inter-vehicle distance than normal is ensured, thereby ensuring safety and improving the fuel efficiency of the vehicle.

[0025] Effects of the Invention

[0026] As described above, according to the present invention, it is possible to provide a vehicle control device that can appropriately stop the engine during traveling regardless of whether or not the vehicle is towing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a block diagram schematically showing the configuration of a vehicle including an embodiment of a vehicle control device to which the present invention is applied.

[0028] Figure 2 This is a flowchart showing the engine stop control during traveling in the vehicle control device according to the embodiment.

[0029] Figure 3 The flowchart shows the setting of the threshold value of the inter-vehicle distance in the engine stop control during traveling in the vehicle control device according to the embodiment.

[0030] Explanation of symbols

[0031] 10: Engine

[0032] 110: Torque converter

[0033] 120: forward and backward switching mechanism

[0034] 130: Transmission

[0035] 140: Final reduction gear

[0036] 200: Engine control unit

[0037] 210: Accelerator pedal sensor

[0038] 220: Vehicle speed sensor

[0039] 230: Steering angle sensor

[0040] 240: Accelerometer

[0041] 250: Brake control unit

[0042] 260: Environmental Identification Unit

[0043] 270: Traction detection unit DETAILED DESCRIPTION

[0044] Hereinafter, an embodiment of a vehicle control device to which the present invention is applied will be described.

[0045] The vehicle control device according to the embodiment is mounted on, for example, an automobile such as a passenger car that uses an engine such as a gasoline engine as a driving power source.

[0046] Figure 1 It is a block diagram schematically showing the configuration of a vehicle including the vehicle control device according to the embodiment.

[0047] The engine 10 is a power source for driving the vehicle, and a gasoline engine is used, for example.

[0048] The power transmission device 100 that transmits the output of the engine 10 to wheels (not shown) is configured to include a torque converter 110 , a forward / reverse travel switching mechanism 120 , a transmission 130 , a final reduction gear 140 , and the like.

[0049] Torque converter 110 is a fluid coupling to which the output shaft of engine 10 is connected, and functions as a starting device capable of starting the vehicle from a state where the vehicle speed is zero.

[0050] Torque converter 110 includes a stator connected to an input shaft, a turbine connected to an output shaft, and a stator provided between them and fixed to a transmission.

[0051] Torque converter 110 includes a lock-up clutch that restricts relative rotation between an impeller and a turbine in a predetermined driving state.

[0052] The connection force of the lock-up clutch is controlled by the transmission control unit 300 .

[0053] An output shaft of the torque converter 110 is connected to a forward / reverse travel switching mechanism 120 .

[0054] The forward / reverse switching mechanism 120 is a mechanism capable of switching between a forward state in which the rotation of the output shaft of the engine 10 is directly transmitted and a reverse state in which the rotation of the output shaft of the engine 10 is reversed and transmitted.

[0055] The forward / reverse switching mechanism 120 is configured to include a planetary gear mechanism, a forward clutch, a reverse clutch, and the like.

[0056] The forward / reverse switching mechanism 120 is connected to the crankshaft of the engine 10 via the torque converter 110 .

[0057] The forward / reverse switching mechanism 120 can block the transmission of torque between the torque converter 110 and the transmission 130 by disengaging the forward clutch when the vehicle is moving forward.

[0058] The transmission 130 is provided on the output side of the forward / reverse travel switching mechanism 120 , and is a speed change mechanism portion that changes the rotation speed of the output shaft of the engine 10 .

[0059] The transmission 130 is configured to include a primary pulley, a secondary pulley, a chain, an output shaft, and the like.

[0060] The primary pulley and the secondary pulley are rotatable around rotation center axes arranged in parallel.

[0061] The primary pulley and the secondary pulley respectively have a fixed pulley and a movable pulley for clamping the chain.

[0062] The chain 133 is a member that is wound between the primary pulley and the secondary pulley and transmits power therebetween.

[0063] The chain is formed into a flexible loop by connecting a plurality of lock pins clamped between pulleys via link plates.

[0064] The primary pulley and the secondary pulley can steplessly change the interval between the fixed pulley and the movable pulley according to the control of the transmission control unit 300, thereby changing the effective diameter around which the chain is wound to perform speed change.

[0065] Final reduction gear 140 reduces the speed of rotation of the output shaft of transmission 130 and transmits the rotation to wheels.

[0066] Final reduction gear 140 includes, for example, a reduction gear train such as a hypoid gear and / or a differential mechanism that transmits driving force to the left and right wheels and absorbs a difference in rotation speed between the left and right wheels caused by turning or the like.

[0067] In addition, the vehicle includes an engine control unit 200 and a transmission control unit 300 .

[0068] The engine control unit 200 and the transmission control unit 300 are configured as electronic control devices including, for example, an information processing unit such as a CPU, a storage unit such as a RAM and / or a ROM, an input / output interface, and a bus connecting them.

[0069] The engine control unit 200 and the transmission control unit 300 can perform cooperative control of the engine 10 and the power transmission device 100 by communicating via an in-vehicle LAN such as a CAN communication system or directly communicating.

[0070] The engine control unit 200 is an engine control unit that comprehensively controls the engine 10 and its auxiliary equipment.

[0071] An accelerator pedal sensor 210 , a vehicle speed sensor 220 , a steering angle sensor 230 , an acceleration sensor 240 , a brake control unit 250 , an environment recognition unit 260 , a traction detection unit 270 , and the like are connected to the engine control unit 200 .

[0072] The engine control unit 200 cooperates with these components to constitute the vehicle control device of the present invention.

[0073] The accelerator pedal sensor 210 includes a position encoder that detects the operation amount (depression amount) of the accelerator pedal input by the driver for acceleration operation.

[0074] The engine control unit 200 sets the driver's required torque based on the output of the accelerator pedal sensor 210, etc., and controls the throttle valve, fuel injection amount, fuel injection timing, ignition timing, valve timing, state of the swirl control valve, EGR rate, boost pressure, etc. in a manner that makes the actual output torque of the engine 10 consistent with the driver's required torque.

[0075] The vehicle speed sensor 220 detects the running speed of the vehicle.

[0076] The vehicle speed sensor 220 is provided on a wheel hub, for example, and is configured to output a signal (so-called vehicle speed pulse signal) whose voltage changes periodically at a frequency proportional to the rotation speed of the wheel.

[0077] The engine control unit 200 can calculate the vehicle speed based on the output signal of the vehicle speed sensor 220 .

[0078] The steering angle sensor 230 includes a rotary encoder provided in a power steering device of a vehicle and detects a steering angle (rotation angle of a steering shaft=operation angle of a steering wheel) in the steering device.

[0079] The steering angle sensor 230 may be configured to communicate with the engine control unit 200 via a power steering control unit (not shown).

[0080] The acceleration sensor 240 has acceleration receivers that detect accelerations acting on the vehicle body in the front-rear direction and the vehicle width direction.

[0081] The brake control unit 250 controls a hydraulic control unit having a function of individually controlling the wheel cylinder hydraulic pressure of each wheel in the hydraulic service brake of the vehicle.

[0082] The brake control unit 250 can detect the hydraulic pressure of each wheel cylinder.

[0083] The brake control unit 250 has functions such as: anti-lock braking control for periodically decompressing the wheel cylinder to restore rotation when wheel W is locked; vehicle behavior control for generating a braking force difference between the left and right wheels and generating a yaw moment in the direction of suppressing the behavior when understeer or oversteer occurs; torque vector control for applying braking force to the inner wheel side when turning to improve turning performance, etc.

[0084] The environment recognition unit 260 uses various sensors such as stereo cameras, monocular cameras, millimeter-wave radars, lidars, laser scanners, and / or a vehicle positioning device and a navigation device with map data, road-to-vehicle communication, vehicle-to-vehicle communication, etc. to obtain information related to the environment around the vehicle and perform environment recognition.

[0085] The environment recognition unit 260 detects a preceding vehicle traveling in the same direction in front of the host vehicle, and can detect the inter-vehicle distance, relative speed, etc. between the preceding vehicle and the host vehicle.

[0086] The towing detection unit 270 detects whether the host vehicle is in a towing state of towing another towed vehicle (trailer).

[0087] The towing detection unit 270 may be configured to detect the towing state by detecting, for example, the connection state of a connector that supplies power for operating lights, etc. from the host vehicle to the towed vehicle.

[0088] The transmission control unit 300 comprehensively controls the power transmission device 100 and its auxiliary devices.

[0089] The transmission control unit 300 has functions of controlling the connection force of the lockup clutch in the torque converter 110, the state of the forward / reverse switching mechanism 120, the speed ratio in the transmission 130, the clamping force of the chain, etc., according to the running state of the vehicle.

[0090] Figure 2 This is a flowchart showing the engine stop control during traveling in the vehicle control device according to the embodiment.

[0091] Below, each step is described in order.

[0092] <Step S01: Determining the driver's required torque>

[0093] The engine control unit 200 determines whether the driver's requested torque set based on the output of the accelerator pedal sensor 210 is zero.

[0094] For example, when the accelerator pedal sensor 210 detects that the accelerator pedal is not depressed, it can be determined that the driver requested torque is zero.

[0095] When the driver's requested torque is 0, the process proceeds to step S02 , and otherwise, the process proceeds to step S08 .

[0096] <Step S02: Determine vehicle speed>

[0097] The engine control unit 100 determines whether the current running speed (vehicle speed) of the host vehicle calculated based on the output of the vehicle speed sensor 220 is within a predetermined range (below an upper limit value and above a lower limit value) that is set in advance.

[0098] When the vehicle speed is within the predetermined range, the process proceeds to step S03 , and otherwise, the process proceeds to step S08 .

[0099] <Step S03: Determine steering angle>

[0100] The engine control unit 100 determines whether the current steering angle of the steering system detected by the steering angle sensor 230 is equal to or less than a preset threshold value (whether the vehicle is traveling on a straight road or a slightly curved road).

[0101] When the steering angle is equal to or smaller than the threshold, the process proceeds to step S04 , and otherwise, the process proceeds to step S08 .

[0102] <Step S04: Determining vehicle acceleration>

[0103] The engine control unit 200 determines whether the vehicle acceleration in the front-rear direction and the lateral direction detected by the acceleration sensor 240 is equal to or less than a preset threshold value.

[0104] When the accelerations in the front-rear direction and the lateral direction are both below the threshold, the process proceeds to step S05 ; otherwise, the process proceeds to step S08 .

[0105] <Step S05: Determine the braking state>

[0106] The engine control unit 200 determines whether the braking force is generated in the on state or the off state based on the information on the wheel cylinder fluid pressure of the vehicle service brake transmitted from the brake control unit 250.

[0107] When the service brake is in the OFF state, the process proceeds to step S06 , and otherwise, the process proceeds to step S08 .

[0108] <Step S06: Determine the inter-vehicle distance>

[0109] The environment recognition unit 260 recognizes the presence of a preceding vehicle traveling in the same lane in front of the host vehicle, and the inter-vehicle distance and relative speed of the preceding vehicle to the host vehicle if there is a preceding vehicle, and transmits the recognition result to the engine control unit 200 .

[0110] The engine control unit 200 determines that the risk of rear-end collision is low and proceeds to step S07 when the inter-vehicle distance is greater than or equal to a predetermined inter-vehicle distance threshold and the preceding vehicle is not approaching the host vehicle at a relative speed greater than or equal to a predetermined speed. Otherwise, the engine control unit 200 proceeds to step S08 .

[0111] It should be noted that the setting of the vehicle distance threshold will be described in detail later.

[0112] <Step S07: Executing the engine stop control during driving>

[0113] When it is determined that the predetermined running engine stop condition is sufficient, the engine control unit 200 executes the running engine stop control for stopping the fuel injection and ignition of the engine 10 and stopping the engine 10 while the vehicle is running.

[0114] It should be noted that, when at least one of the above-mentioned conditions is insufficient, the engine 10 stopped in this way will automatically restart. In addition, in order to prevent automatic stop and restart from being repeated frequently, conditions (threshold values, etc.) can be different when stopping and restarting and delay can be set.

[0115] At this time, if the forward clutch of the forward-reverse switching mechanism 120 is released through coordinated control with the transmission control unit 300, and the torque transmitted to the torque converter 110 side is blocked, the friction loss, pump loss and other frictions of the engine 10 will not become a load, and the distance that can be traveled using inertia when the engine 10 is stopped can be extended.

[0116] Thereafter, a series of processing is terminated.

[0117] <Step S08: Normal engine operation>

[0118] The engine control unit 200 prohibits execution of the above-mentioned running engine stop control, and the engine 10 is maintained in a normal driving state.

[0119] Thereafter, a series of processing is terminated.

[0120] In the present embodiment, as described below, the threshold value of the inter-vehicle distance in the above-mentioned control (see step S06 ) is made different depending on whether the traction state is detected.

[0121] Figure 3 The flowchart shows the setting of the threshold value of the inter-vehicle distance in the engine stop control during traveling in the vehicle control device according to the embodiment.

[0122] Below, each step is described in order.

[0123] <Step S11: Detecting vehicle speed>

[0124] The engine control unit 100 detects the current vehicle speed of the host vehicle based on the output of the vehicle speed sensor 220 .

[0125] After the vehicle speed is detected, the process proceeds to step S12.

[0126] <Step S12: Determine the pulling state>

[0127] The towing detection unit 270 determines whether the host vehicle is currently in a towing state of towing another towed vehicle (trailer).

[0128] If the system is not in the traction state, the process proceeds to step S13 , and if the system is in the traction state, the process proceeds to step S14 .

[0129] <Step S13: Determining the inter-vehicle distance threshold using the non-traction map>

[0130] The engine control unit 100 uses a non-traction map prepared in advance to determine the inter-vehicle distance threshold used in the above-mentioned step S06.

[0131] The non-traction state map is a map configured to read out the corresponding inter-vehicle distance threshold value according to the running speed (vehicle speed) of the host vehicle, for example.

[0132] The inter-vehicle distance threshold is set in consideration of the inter-vehicle distance at which the vehicle ahead can stop safely without colliding with the vehicle ahead if any abnormality occurs.

[0133] The inter-vehicle distance threshold is set so that it becomes larger (the inter-vehicle distance becomes longer) as the vehicle speed increases.

[0134] Such an inter-vehicle distance threshold value may be configured to be corrected according to weather and / or an estimated friction coefficient of the road surface.

[0135] Thereafter, a series of processing is terminated.

[0136] <Step S14: Determining the inter-vehicle distance threshold using the towing map>

[0137] The engine control unit 100 determines the inter-vehicle distance threshold used in the above-mentioned step S06 using a towing map prepared in advance separately from the non-towing map.

[0138] The configuration of the towing map is similar to that of the non-towing map described above, but the inter-vehicle distance threshold value for the same vehicle speed is set to be relatively larger than the value of the non-towing map.

[0139] The amount of increase of the inter-vehicle distance threshold value in the towing map at the same vehicle speed and the inter-vehicle distance threshold value in the non-towing map is set in consideration of reductions in the braking capability and danger avoidance capability of the towing vehicle.

[0140] Thereafter, a series of processing is terminated.

[0141] As described above, according to this embodiment, the following effects can be obtained.

[0142] (1) When the vehicle is towing, the driving area where the engine 10 is stopped is reduced during driving. Therefore, even if the braking performance and / or crisis avoidance performance is reduced due to towing, the engine 10 can be safely stopped only in the area where the engine 10 can be stopped, thereby improving safety during towing.

[0143] On the other hand, when towing is not performed, the conditions for stopping the engine during driving can be optimized for the non-towing state, and the driving range in which the engine is stopped can be expanded to further improve the fuel efficiency of the vehicle.

[0144] (2) When the braking capacity decreases due to the traction state, the engine 10 is stopped during traveling only when the inter-vehicle distance is larger than normal, thereby ensuring safety and improving the fuel efficiency of the vehicle.

[0145] (Variation Example)

[0146] The present invention is not limited to the above-described embodiments, and various modifications and / or changes may be made, which are also within the technical scope of the present invention.

[0147] (1) The configurations of the vehicle control device and the vehicle provided with the vehicle control device are not limited to the above-described embodiments, and may be modified as appropriate.

[0148] For example, the engine is not limited to a gasoline engine, but may be a diesel engine and / or other internal combustion engine, and there is no particular limitation on the number of cylinders, cylinder layout, presence or absence of a supercharger, fuel injection method, ignition method, etc. In addition, the configuration of the power transmission device in the embodiment is also an example, and for example, a CVT other than a chain type such as a belt type or a ring type and / or a step-type AT, AMT, DCT, etc. may be used.

[0149] (2) The condition for stopping the engine during traveling in the embodiment is an example, but the present invention is not limited thereto, and other conditions may be added or some conditions may be omitted.

[0150] In the embodiment, the engine is stopped during driving only when the driver's required torque is zero, that is, when the accelerator pedal is fully released. However, the engine may be stopped during driving when the vehicle acceleration decreases even when the accelerator pedal is lightly depressed.

[0151] (3) In the embodiment, when the traction state is detected, the threshold of the inter-vehicle distance when the engine is stopped during driving is increased, but the present invention is not limited to this, and other conditions and / or thresholds may be changed depending on whether the traction state is detected.

[0152] For example, when a traction state is detected, thresholds related to the acceleration of the vehicle body and / or the steering angle, the vehicle speed, etc. may also be changed.

[0153] (4) The specific configuration of the traction detection unit and / or the method of detecting the traction state are not limited to the above-mentioned embodiments, and may be appropriately modified. For example, in the embodiments, the traction state is detected based on the connection state of the connector that supplies power to the towed vehicle, but the invention is not limited thereto. For example, a configuration may be adopted in which the traction state is detected based on the correlation between the estimated driving force of the vehicle (calculated based on the estimated torque of the engine and the reduction ratio, etc.) and the acceleration of the vehicle.

Claims

1. A vehicle control device, characterized in that: A vehicle control device is provided for controlling a vehicle having an engine that drives wheels via a power transmission device, the vehicle control device comprising: a traction state detection unit for detecting a traction state of the vehicle towing other towed vehicles; an inter-vehicle distance detection unit configured to detect an inter-vehicle distance between the vehicle and another vehicle traveling directly in front of the vehicle; a vehicle speed detection unit for detecting a running speed of the vehicle; and an engine control unit, wherein when the vehicle is able to continuously travel, if the driver's required torque is zero, the steering angle is less than a first predetermined value, the vehicle body acceleration is less than a second predetermined value, the brake is off, the vehicle speed is less than an upper limit value and greater than a lower limit value, the inter-vehicle distance is greater than a threshold value, and a preceding vehicle is not approaching the vehicle at a relative speed greater than a predetermined value, the engine control unit stops the engine and continues to travel by inertia, and continuously determines the engine stop condition during inertia travel, and as long as the engine stop condition is satisfied, the vehicle continues to travel by inertia by stopping the engine regardless of other conditions except the engine stop condition, until the engine stop condition is not satisfied, and if the engine stop condition is not satisfied, the vehicle continues to travel by starting the engine and stopping inertia regardless of other conditions except the engine stop condition, The vehicle control device sets a delay so that the threshold value is different when the engine is stopped and when the engine is restarted, When the traction state detection unit detects the traction state, the engine control unit changes the engine stop condition so as to reduce the driving region in which the engine is stopped, compared to when the traction state is not detected.

2. The vehicle control device according to claim 1, characterized in that: When the traction state detection unit detects the traction state, the engine control unit reduces the driving region in which the engine is stopped by increasing the threshold value compared to a case in which the traction state is not detected.

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