JP2009073492A - Tip-over detection device for motor vehicle, and motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tip-over detection device for a motor vehicle, detecting the tip-over without prolonging the detection time and without any erroneous determination while eliminating fluctuation of the tip-over detection angle owing to a vehicle body vibration or the like. <P>SOLUTION: This tip-over detection device has a tip-over sensor for detecting the tip-over based on the inclination angles of an ECU for drivingly controlling an engine and a vehicle body. The tip-over sensor is formed of an acceleration sensor, and the acceleration sensor is incorporated in the ECU. The acceleration sensor has: a longitudinally arranged sensor for detecting the acceleration in the first detecting direction which is vertical to the ground when the vehicle body is in the non-inclined state; and a transversely arranged sensor for detecting the acceleration in the second detecting direction orthogonal to the first detecting direction. The acceleration sensor determines the tip-over based on the ratio of (the output of the transversely arranged sensor)/(the output of the longitudinally arranged sensor). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motorcycle fall detection device using an acceleration sensor and a motorcycle equipped with the fall detection device.

  In a motorcycle, an ECU (engine control unit) is provided for fuel injection control and ignition timing control. This ECU drives and controls the injector and ignition coil in accordance with a preset map and control program based on engine speed detection data, throttle opening detection data, intake pipe negative pressure detection data, and the like. Such an ECU includes a semiconductor circuit such as a storage circuit storing a map and a program and an arithmetic circuit for performing data processing on a printed circuit board, and is attached to the vehicle body as a single component. .

  In addition, a fall sensor is provided in the motorcycle, and when the fall of the vehicle body is detected, fuel injection and ignition are stopped, and the fuel supply electromagnetic pump is stopped to prevent fuel from flowing out when the engine is stopped.

  A conventional fall sensor has a mechanical structure that uses a weight or pendulum that moves according to the inclination of the vehicle body, and the weight or pendulum switches on when the vehicle falls. The fall sensor having such a mechanical structure is attached to the vehicle body as a separate body from the ECU, and the fall detection data is sent to the ECU, and the ECU controls the engine at the fall based on the detection data.

  However, the conventional mechanical fall sensor has insufficient aspects in terms of detection accuracy and reliability. Therefore, in order to improve this and improve the accuracy and reliability, it is necessary to prevent the contact failure of the switch and to smoothly operate the weight and the pendulum. For this reason, it is necessary to perform a plating process or a structure without a step, which makes the manufacturing process cumbersome and increases costs. In addition, the size and weight are large, which is a space constraint on other parts.

  Further, in the conventional ECU mounting structure, since the ECU and the fall sensor are separate bodies, there is a large space restriction when used for a small scooter or the like in which the space around the engine is narrow. In addition, the conventional body tipping sensor uses a mechanical pendulum structure, so it is large and complicated in configuration, and it is vertical to the ground and in the longitudinal direction so that the pendulum can move smoothly in the lateral direction of the body. It had to be installed vertically, the layout was complicated, and the installation was troublesome.

  On the other hand, an acceleration sensor using a semiconductor element is known. This acceleration sensor detects a magnitude of acceleration by forming a capacitor between electrodes and changing the capacitance according to the acceleration. This acceleration sensor does not have a large mechanical configuration other than the electrodes, and can obtain highly accurate acceleration detection data in the form of a semiconductor element. Therefore, if gravity acceleration is detected by this acceleration sensor, the inclination of the sensor can be detected.

  Therefore, it has been proposed by the present inventor to use this acceleration sensor as a fall sensor and to integrate it into the ECU (see, for example, Patent Document 1).

  The acceleration sensor has a detection direction for detecting acceleration, the one-axis sensor detects acceleration in one direction, the two-axis sensor detects acceleration in two orthogonal directions, and the three-axis sensor has three orthogonal directions The acceleration is detected for each. When this acceleration sensor is incorporated in the ECU as a fall sensor and this ECU is mounted on the vehicle body, the acceleration sensor detection direction for one axis is in a vertical arrangement or in the vehicle body in the vertical direction (perpendicular to the ground) with respect to the vehicle body On the other hand, it is considered that the acceleration when the vehicle body is tilted can be detected efficiently by adopting any one of the horizontal placements in the left-right direction (vehicle width direction).

  Such an acceleration sensor outputs an analog voltage as a detection voltage according to the inclination of the vehicle body. This analog detection voltage is A / D converted and input as a digital signal to a control circuit (CPU) in the ECU to determine the fall state.

JP 2002-71703 A

  However, when an acceleration sensor is used as a fall sensor and a fall is determined from the detection signal, a conversion error based on the A / D conversion width occurs when the detection signal is A / D converted to make a fall decision. Therefore, this conversion error causes a fall angle detection error, which may cause an erroneous determination.

  The present invention takes the above-described conventional technology into consideration, and includes a fall detection device for a motorcycle that reduces the A / D conversion error of the fall sensor composed of an acceleration sensor and improves the accuracy of the fall judgment, and the fall detection device. The purpose is to provide a motorcycle.

  In order to achieve this object, a motorcycle fall detection device according to the present invention includes an ECU for driving and controlling an engine and a fall sensor for detecting a fall based on an inclination angle of a vehicle body. The fall sensor is detected by an acceleration sensor. In the motorcycle overturn detection device configured and incorporating the acceleration sensor in the ECU, the acceleration sensor detects an acceleration in a first detection direction which is a direction perpendicular to the ground when the vehicle body is in a non-tilt state. A vertical sensor to detect and a horizontal sensor to detect acceleration in a second detection direction that is perpendicular to the first detection direction, (horizontal sensor output) ÷ (vertical sensor output) The fall is determined based on the above.

  According to a second aspect of the present invention, there is provided a motorcycle overturn detection device according to the first aspect of the present invention, wherein the overturn angle at which the vehicle body is regarded as overturned is α, and the (horizontal sensor output) ÷ (vertical sensor output). ) Is smaller than 1 g · tan (−α) and when the value is larger than 1 g · tan (−α), it is determined that the vehicle has fallen when one of them continues for a predetermined time or more.

  The overturn detection device for a motorcycle according to claim 3 is the invention according to claim 2, wherein the determination of the overturn is based on the detection output of the vertical sensor, wherein the inclination angle of the vehicle body is within 90 °. This is performed when it is determined.

  According to a fourth aspect of the present invention, the fall detection device for a motorcycle changes the fall angle based on the mounting angle of the acceleration sensor.

  A motorcycle according to a fifth aspect is equipped with the fall detection device according to any one of the first to fourth aspects.

In the present invention, an acceleration sensor is used as a fall sensor, which is incorporated into an ECU and integrated into a single unit, thereby improving fall detection accuracy and simplifying the configuration, and is narrow without restricting the arrangement of other components. Efficient layout in space. At the same time, because the fall detection is based on (horizontal sensor output) ÷ (vertical sensor output), even if each sensor generates noise, the fluctuations of the vertical sensor and horizontal sensor cancel each other, The fall can be determined at the set detection angle, and the accuracy of the fall determination can be improved and the reliability can be improved.
For this reason, according to this invention, the fall detection apparatus for motorcycles which raised the precision of fall determination can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
First, the technology and the reference technology which are the premise of the present invention will be described with reference to FIGS.
FIG. 1 is an explanatory diagram of sensor output when a uniaxial acceleration sensor is placed horizontally. (A) is an output waveform, (B) is an explanatory view of a state in which the vehicle body is tilted to the right by an angle θ.

The acceleration sensor 101 shown in FIG. 1 is attached to the vehicle body in a horizontal arrangement in which the detection direction ab is horizontally arranged in a non-tilt state (neutral position) where the vehicle body is straight. Therefore, the sensor output is an output voltage V = g · sin θ with respect to the inclination angle θ of the vehicle body, and the output voltage characteristic draws a sine curve as shown in FIG. The motorcycle is considered to fall over when the vehicle body is tilted beyond the bank angle (about 65 to 70 °). Therefore, if the sensor output at 70 ° as the discrimination reference is the discrimination output Vc,
Vc = g · sin 70 ° = 0.94 g.

Here, when the A / D conversion error is ± 10 mV (± 0.03 g), the angle error is
(0.94-0.03) g ≒ g · sin65 °
(0.94 + 0.03) g ≒ g · sin75 °
It becomes. Therefore, the angle error based on A / D conversion is 70 ± 5 °.

FIG. 2 is an explanatory diagram of sensor output when the uniaxial acceleration sensor is vertically arranged. (A) is an output waveform, (B) is an explanatory view of a state in which the vehicle body is tilted to the left by an angle θ.

The acceleration sensor 101 shown in FIG. 2 is attached to the vehicle body in a vertical arrangement in which the detection direction ab is arranged perpendicular to the ground in a non-tilted state (neutral position) where the vehicle body is straight. Therefore, the sensor output becomes the output voltage V = g · cos θ with respect to the vehicle body inclination angle θ, and the output voltage characteristic draws a cosine curve as shown in FIG. The motorcycle is considered to fall over when the vehicle body is tilted beyond the bank angle (about 65 to 70 °). Therefore, if the sensor output at 70 ° as the discrimination reference is the discrimination output Vc,
Vc = g · cos 70 ° = 0.34 g.

Here, when the A / D conversion error is ± 10 mV (± 0.03 g), the angle error is
(0.34-0.03) g≈g · cos 72 °
(0.34 + 0.03) g ≒ g · cos68 °
It becomes. Therefore, the angle error based on A / D conversion is 70 ± 2 °.

  That is, the angle error based on the A / D conversion in the case of the vertical installation shown in FIG. 2 is smaller than that in the case of the horizontal installation shown in FIG. Therefore, by obtaining the inclination angle of the vehicle body using the acceleration sensor arranged vertically (Z direction), the A / D conversion error can be reduced and the detection accuracy can be increased. When a 2-axis (Y, Z direction) or 3-axis (X, Y, Z direction) acceleration sensor is used, one detection direction (first detection direction) is always set vertically (Z direction) The second detection direction is the horizontal vehicle width direction (Y direction) or the front-rear direction (X direction).

  When a 2-axis or 3-axis acceleration sensor is used, if a tilt greater than the fall angle is detected by a sensor in the Z direction, and if the sensor in the X or Y direction does not detect the tilt, the wheelie travel or the steep hill travel Therefore, the vehicle continues to run with normal control without performing the processing (stopping the fuel pump, stopping fuel injection, stopping ignition, etc.) at the time of falling.

  The detection direction of the biaxial acceleration sensor is set to the Z and X directions, and when the detection output in the X direction changes (when a tilt in the front-rear direction is detected), it is possible to determine that the slope is a steep slope or a wheelie and not consider it a fall. is there.

FIG. 3 is a flowchart showing an example of a technique that serves as a reference of the present invention.
In this reference example, the fall determination is performed only by detecting the sensor of one axis (Z-axis direction).
Step a1: The output voltage is detected from a fall sensor in which a 1-axis acceleration sensor is vertically arranged, or from a sensor in the Z-axis direction, which is the first detection direction of a vertically arranged 2-axis or 3-axis acceleration sensor.

  Step a2: It is determined whether or not the vehicle falls due to the detection output voltage of the Z-axis direction sensor. That is, it is determined whether or not the cosine curve in FIG. 2A is smaller than the output voltage value (g · cos (± 70 °)) corresponding to ± 70 ° that is the fall determination reference angle. If this state continues for 2 seconds or more, it is determined that the vehicle has fallen. The requirement that it last for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.

  Step a3: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, it is desirable to gradually reduce the engine output. For example, the application of the drive pulse signal to the ignition coil in the ignition cycle by the normal control is stopped at an appropriate interval to control the thinning of the ignition, and the output is reduced by reducing the number of times of ignition by the normal control. At this time, the thinning interval at which ignition is stopped is initially cut at a long interval, and thinned out to gradually shorten the interval. This prevents the vehicle body from becoming unstable due to a rapid output drop in the case of malfunction or the like. Instead of or in combination with such ignition control, thinning out of fuel injection may be performed in the same manner. In this case, the output is lowered by gradually reducing the application of the drive pulse signal to the solenoid of the injector. In the case of a vehicle equipped with an electronic throttle, the output may be reduced by controlling the electronic throttle.

FIG. 4 is a flowchart of a control example of the overturn control device as a reference technique of the present invention.
This reference example uses the output from the detection sensor of two axes (Y-axis direction and Z-axis direction), and in addition to the fall determination based only on the Z-axis sensor in the reference example of FIG. 3, the fall based on the Y-axis sensor A judgment condition is added. Thereby, the inclination of the vehicle body by wheelie driving or steep slope driving can be distinguished from falling.
Step b1: A biaxial acceleration sensor is placed vertically, and the detection direction is set as a Z axis (vertical direction) and a Y axis (horizontal direction). The output voltage of the acceleration sensor is detected in the Z-axis and Y-axis directions.

  Step b2: It is determined whether or not the vehicle falls due to the detection output voltage of the Z-axis direction sensor. That is, it is determined whether or not the cosine curve in FIG. 2A is smaller than the output voltage value (g · cos (± 70 °)) corresponding to ± 70 ° that is the fall determination reference angle. If this state continues for 2 seconds or more, it is determined that the vehicle has fallen. Note that, as described above, the requirement to continue for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.

  Step b3: If it is determined in the step b2 that the sensor is overturned by the Z-axis direction sensor, it is further determined whether or not the system is overturned based on the detected output voltage of the Y-axis direction sensor. That is, in the above-described sine curve of FIG. 1A, the output voltage value (g · sin (70 °)) corresponding to ± 70 ° that is the fall determination reference angle is greater than (g · sin (−70 °)). )) Determine if the state is smaller. If this state continues for 2 seconds or more, it is determined that the vehicle has fallen.

  If it is determined in step b2 that the vehicle has fallen, but the Y-axis sensor detects that the vehicle is not tilted in the left-right direction, the vehicle body is tilted in the front-rear direction due to a wheelie or the like. repeat.

  Step b4 :: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, as described above, it is desirable to gradually reduce the engine output.

FIG. 5 is a block diagram of the reference technique of the present invention.
In this reference example, when a two-axis or three-axis acceleration sensor is used, the input to the CPU for determining the fall is divided into two systems of DC input and AC input.

  As shown in the figure, the Z-axis output from the Z-axis sensor of the two-axis acceleration sensor 102 is input to the A / D converter 104 via the noise removal filter 103, where it is A / D converted and the CPU 107 in the ECU. And the fall state is determined by arithmetic processing. This system is a DC input system.

  On the other hand, the Y-axis output from the Y-axis sensor of the 2-axis acceleration sensor 102 is input to the A / D converter 104 via the smoothing capacitor 105 and the filter 106, where it is A / D-converted to be stored in the ECU. Input to the CPU 107, and the fall state is determined by arithmetic processing. This system is an AC input system.

  The Y-axis sensor is an auxiliary sensor for performing a wheelie determination as described above to prevent malfunction. Therefore, it is sufficient to determine whether the vehicle body is tilted from a straight state during traveling. Therefore, an input from the Y-axis sensor to the CPU is an AC input, and a wheelie or the like is discriminated based on an output voltage change amount. This eliminates the need to obtain the difference between the output voltage and the first reference value, and eliminates the need for correcting the offset error of the reference value.

FIG. 6 is a flowchart showing the operation of the fall detection device of FIG.
Step c1: A biaxial acceleration sensor is placed vertically, and the detection directions are a Z axis (vertical direction) and a Y axis (horizontal direction). The output voltage of the acceleration sensor is detected in the Z-axis and Y-axis directions.

  Step c2: It is determined whether or not the vehicle falls due to the detected output voltage of the Z-axis direction sensor. That is, it is determined whether or not the cosine curve in FIG. 2A is smaller than the output voltage value (g · cos (± 70 °)) corresponding to ± 70 ° that is the fall determination reference angle. If this state continues for 2 seconds or more, it is determined that the vehicle has fallen. Note that, as described above, the requirement to continue for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.

  Step c3: If it is determined in the step c2 that the sensor in the Z-axis direction has fallen, it is further determined whether or not the vehicle has fallen based on the detected output voltage of the Y-axis sensor. In this case, it is determined whether or not the output voltage of the horizontal Y-axis sensor has changed by a predetermined value (for example, 200 mV) in the sine curve of FIG. 1A described above, and the difference from the neutral position is not obtained. If there is no change in the inclination in the lateral direction (left and right of the vehicle body) (if 200 mV or less), the fall detection in step c2 is the inclination of the vehicle body in the front-rear direction due to a wheelie or the like, and the overturn process is not performed. Repeat the normal control routine.

  Step c4 :: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, as described above, it is desirable to gradually reduce the engine output.

FIG. 7 is an explanatory diagram of still another reference technique of the present invention.
In this reference example, the threshold of the detection voltage of the acceleration sensor is changed to prevent the detection accuracy from being lowered due to the attachment error of the acceleration sensor.

  In this method, first, the mounting error angle of the acceleration sensor is measured, and based on this, the threshold value is changed by that angle. For the installation error angle, in the case of a horizontal sensor, the sensor output is measured at three points of −90 °, 0 °, and + 90 °, and the attachment error angle is obtained from the measurement result by calculation processing. In the case of a vertical sensor, the sensor output is measured at three points of 0 °, 90 °, and 180 °, and the mounting error angle is obtained from the measurement result by calculation processing.

Arithmetic processing will be described using horizontal placement as an example.
When −90 °: Y = a + Xsin (−90 + b) = a−Xcos (b)
When 0 °: Y ′ = a + Xsin (b)
When + 90 °: Y ″ = a + Xsin (90 + b) = a + Xcos (b)
However, Y, Y ′, Y ″ are output voltages, a is an offset voltage, X is sensitivity, and b is sensor inclination (attachment error accuracy).

Here, a = (Y−Y ″) / 2 from Y + Y ″ = 2a.
From Y ″ −Y = 2X cos (b), X = (Y ″ −Y) / 2 cos (b)
From Y′−a = Xsin (b) = (Y ″ −Y) / {2cos (b) * sin (b)} 2cos (b) * sin (b) = sin (2b) = (Y ″ −Y) / (Y'-a)
Therefore, b = 1/2 * sin−1 {(Y ″ −Y) / (Y′−a)}.

Based on the inclination angle b obtained in this way, the threshold value for the fall determination is changed.
In the example of FIG. 7, the threshold value is changed from ± 70 ° to −65 ° and + 75 ° when b is tilted by + 5 ° in the horizontal sensor. In the case of a vertical sensor (in the case of a vertical sensor (Z-axis sensor) of a two-axis acceleration sensor), it is possible to determine the left / right tilt direction from the Y-axis sensor and change the threshold value according to the left / right direction .

FIG. 8 is an explanatory diagram of still another reference technique of the present invention.
In this reference example, when the mounting position of the acceleration sensor 110 on the printed circuit board 111 is checked, markings 108 and 109 made of silk are applied to the sensor mounting position of the printed circuit board 111 in advance so that visual or automatic check can be easily performed. It is a thing. The markings 108 and 109 are formed at positions that serve as a guide for the allowable tilt range and the mounting angle of the acceleration sensor 110. The marking shape is not limited to (A) and (B) in the figure, and may be any shape as long as the angle can be roughly identified.

  By applying such marking, an error in attaching the acceleration sensor to the printed circuit board is identified, and it is possible to correct the fall determination based on the error, and to easily determine the defective product.

  Thus, the printed circuit board which comprises an acceleration sensor and comprises CPU is accommodated in the case of ECU. In this case, a guide is provided in the ECU case, and the printed circuit board is slid along the guide, inserted into the case, positioned, and filled with resin or the like to fix the printed circuit board at the predetermined position in the case. It is desirable to hold. Thereby, the detection error due to the mounting error of the printed circuit board with respect to the ECU is reduced.

  When an ECU incorporating a fall sensor is mounted on a vehicle body, if the ECU is away from the center of gravity of the vehicle body, vibrations of the vehicle body will affect the fall sensor, leading to a decrease in detection accuracy and causing a false determination.

  Therefore, in order to improve detection accuracy, it is desirable that the ECU is attached as close to the center of gravity of the vehicle body as possible. Thereby, the noise factor by the influence of the vibration of the vehicle body and the front and rear pitch can be reduced, and the detection system can be enhanced.

FIG. 9 is a flowchart of still another reference technique of the present invention.
This reference example corrects the fall sensor by using a speed sensor to deal with the problems that the detection accuracy has fallen due to variations in offset of the fall sensor, changes over time, temperature characteristics, etc., which has been a problem in the past. Thus, the detection accuracy is improved.

  Step d1: The vehicle speed is detected by the speed sensor, and the inclination of the vehicle body is detected by the fall sensor (acceleration sensor).

  Step d2: Determine whether or not the state in which the detected value of the speed sensor exceeds a predetermined value (30 km / h in this example) and the change in the output voltage of the fall sensor is less than the predetermined value (10 mV in this example) continues for 10 seconds or more. To do. When this state continues for 10 seconds or more, it is determined that the vehicle is traveling in a straight posture.

  Step d3: When it is determined in step d3 that the vehicle body is running in a straight posture, the fall sensor output or its average value is updated as the center value (the output voltage value at the neutral position in FIGS. 1 and 2). save.

  Step d4: A change from the center value is detected to determine whether the vehicle falls over (inclination is 70 ° or more). As a result, it is possible to detect a fall with high accuracy regardless of offset variations or changes with time due to temperature characteristics of the sensor or mounting errors.

  Step d5 :: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, as described above, it is desirable to gradually reduce the engine output.

FIG. 10 is a flowchart of still another reference technique of the present invention.
This reference example further enhances the reliability of the vehicle body tilt determination other than the falling of the wheelie or the like in the reference example of FIG. 4 described above. That is, in the reference example of FIG. 4, when the vehicle body is turned upside down or turned over 90 °, it may not be determined to fall. This reference example reliably discriminates such an upside-down fall.

  More specifically, when the vehicle body falls 180 °, the output of the vertical Z-axis sensor is 1 g Cos (180 °) = − 1 g as shown in FIG. Show. On the other hand, as shown in FIG. 1 described above, the output of the horizontal Y-axis sensor is 1 gSin (180 °) = 0 g, which is erroneously determined as not falling.

  In this reference example, such erroneous determination is prevented, and when a tilt of ± 90 ° or more is detected by the Z-axis sensor, the fall is determined regardless of the Y-axis sensor.

  Step e1: A biaxial acceleration sensor is placed vertically, and the detection directions are a Z axis (vertical direction) and a Y axis (horizontal direction). The output voltage of the acceleration sensor is detected in the Z-axis and Y-axis directions.

Step e2: It is discriminated whether it is upside down (over 90 ° or more) based on the detected output voltage of the Z-axis direction sensor. That is, in the above-described cosine curve of FIG. 2A, it is determined whether or not the overturn determination angle is ± 90 ° and is less than the corresponding output voltage value (g · cos (± 90 °)). If this state continues for more than 2 seconds, it is determined that the person has fallen upside down. Note that, as described above, the requirement to continue for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.
If it is determined that the vehicle is toppled upside down, the process immediately proceeds to step e4 to perform overturning control such as stopping the fuel pump.

  Step e3: If it is determined in the step e2 that the sensor in the Z-axis direction does not fall upside down (inclined by more than ± 90 °), it will further fall according to the detection output voltage of the Z-axis sensor and Y-axis direction sensor. It is determined whether or not (falling within ± 90 °).

  That is, first, it is determined whether or not the vehicle falls due to the detected output voltage of the Z-axis direction sensor. As described above, in the cosine curve in FIG. 2A, it is determined whether or not the output voltage value (g · cos (± 70 °)) corresponding to ± 70 °, which is the fall determination reference angle, is smaller. . If this state continues for 2 seconds or more, it is determined that the vehicle has fallen. Note that, as described above, the requirement to continue for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.

  Further, in order to confirm that the fall determination by the Z-axis sensor is not a wheelie or a steep slope, it is determined whether or not the Y-axis sensor is tilted, and the fall is determined only when the Y-axis sensor is also determined to be tilted. . In this case, the fall determination reference angle is set to ± 50 °. As a result, as can be seen from the graph of FIG. 1 described above, the detection accuracy of the laterally placed Y-axis sensor is higher than when the determination angle is ± 70 °.

  That is, the Y-axis overturn determination is performed by setting the reference angle for overturn determination to ± 50 ° in the sine curve of FIG. ) Greater than or less than (g · sin (−50 °)). If this state continues for 2 seconds or more, it is determined that the vehicle has fallen.

  Even if it is determined that the Z-axis sensor has fallen, if the Y-axis sensor detects that the vehicle is not tilted in the left-right direction, the vehicle body is tilted in the front-rear direction due to a wheelie or the like. repeat.

  Step e4 :: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, as described above, it is desirable to gradually reduce the engine output.

Next, an embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 11 is a flowchart showing an embodiment of the present invention. FIG. 12 is a graph of tan (tangent) output data used in this embodiment.

  When an acceleration sensor is provided in a motorcycle, noise is included in the sensor output due to engine vibration, road surface unevenness, and the like. For this reason, when a logic is set to determine that a certain threshold has been exceeded for a certain period of time, it will be larger or smaller than the threshold due to vibration, and at a set angle. It cannot be detected. In this case, for example, if a low-pass filter such as a CR filter is provided to eliminate the vibration component, it can be detected at the set threshold fall angle. However, in this case, there is a problem that it takes a long response time and the detection time becomes long.

  Therefore, in this embodiment, the tangent of the output of the vertical sensor and the output of the horizontal sensor is obtained, and by judging the fall by this tangent output, even if each sensor picks up vibration and generates noise, the vertical sensor The change of the horizontal sensor cancels each other, so that the fall can be detected at the set detection angle.

  Step f1: A biaxial acceleration sensor is placed vertically, and the detection directions are a Z axis (vertical direction) and a Y axis (horizontal direction). The output voltage of the acceleration sensor is detected in the Z-axis and Y-axis directions.

  Step f2: It is discriminated whether it is upside down (over 90 ° or more) based on the detection output voltage of the Z-axis direction sensor. That is, in the above-described cosine curve of FIG. 2A, it is determined whether or not the overturn determination angle is ± 90 ° and is less than the corresponding output voltage value (g · cos (± 90 °)). If this state continues for more than 2 seconds, it is determined that the person has fallen upside down. Note that, as described above, the requirement to continue for 2 seconds or more is to increase the reliability of the fall determination by voltage detection.

  If it is determined that the vehicle has been turned upside down, the process immediately proceeds to step f4 to perform the overturn control such as stopping the fuel pump.

  Step f3: If it is determined in the step f2 that the sensor in the Z-axis direction is not upside-down (inclined by more than ± 90 °), it is further overturned by the detection output voltage of the Z-axis sensor and the Y-axis direction sensor. It is determined whether or not (falling within ± 90 °).

  That is, first, the output voltage of the horizontal Y-axis sensor in FIG. 1 (A) and the output voltage of the vertical Z-axis sensor in FIG. 2 (A) are detected, and the tangent (tan) = (Y-axis output). Voltage) / (Z-axis output voltage) is obtained by calculation. It is determined whether the tan output value is smaller than 1 g · tan (−α) or larger than 1 g · tan α when the fall angle is α. If any one of the conditions is satisfied continuously for 2 seconds or more, it is determined that the vehicle falls. The requirement to continue for 2 seconds or more is to increase the reliability of the fall determination based on the tangent output value. If both are not satisfied, it is judged that the person has not fallen.

  Explaining in the graph, the tangent curve output obtained from the sine curve output from the horizontal Y-axis sensor in FIG. 1A and the cosine curve output from the vertical Z-axis sensor in FIG. Represented. In FIG. 12, the vehicle body angle is in the range of −90 ° to + 90 ° because it is determined in step f2 that the vehicle does not fall upside down. Within this range, it is determined whether the falling angle α has been exceeded on the left side (−side) or the right side (+ side) of the vehicle body.

  The overturning angle α is set in consideration of the vehicle type of the scooter type or the normal motorcycle type, the body size, the displacement or the like. This α may be rewritable on the program according to the vehicle type or the like.

  In this way, by using a biaxial sensor that includes a vertical position to determine the fall by the tangent of both sensor outputs, noise is canceled out, so even if the sensor output fluctuates due to vibration or the like, the fall is reliably determined. Can do.

  Step f4 :: When it is determined that the vehicle has fallen, the fuel pump is stopped, fuel injection and ignition are stopped, and the engine is stopped. At this time, as described above, it is desirable to gradually reduce the engine output.

  As described above, the motorcycle overturn detection device according to this embodiment includes the vertical sensor (Z-axis sensor) and the horizontal sensor (Y-axis sensor), and (horizontal sensor output) / ( It is characterized by a fall determination based on the vertical sensor output.

  According to this configuration, even if the output value of the fall detection fluctuates due to the vibration of the vehicle body or the like, it is possible to perform the fall detection with high reliability and no erroneous determination in a short time without using a noise removal filter or the like.

  In other words, when an acceleration sensor is used as a fall sensor for a motorcycle, the fall detection angle that serves as a fall judgment threshold may change due to vibration of the vehicle body or the like. In response to this, the fall detection angle can be kept constant by providing a filter in the control circuit to remove the vibration component. However, if a filter is provided, it takes a long response time, and there is a possibility that the detection time becomes long and the countermeasure against the fall is delayed.

  Therefore, there is a need for a fall sensor capable of detecting a fall without any erroneous determination by eliminating fluctuations in the fall detection angle due to vehicle body vibration or the like without increasing the detection time. The present invention satisfies such a requirement.

Next, a structure for mounting the ECU incorporating the fall sensor on the vehicle body will be described.
FIG. 13 is an external view of a small motorcycle to which the present invention is applied.

  The vehicle body 1 has a handle 2 at the front, and the handle 2 is connected to a front wheel 5 via a steering shaft 4 through which a head pipe 3 is inserted. A body frame 6 is coupled to the head pipe 3. The body frame 6 forms a frame structure of the entire vehicle body. The front part of the vehicle body is covered with a cowling 7. The vehicle body 1 is covered with a vehicle body cover 8 from the outside of the vehicle body frame 6. A seat 9 is provided at the center of the vehicle body, a fuel tank 10 is provided on the lower side, and a helmet box (case) 11 is provided on the rear side. The fuel tank 10 supplies fuel to an injector (not shown) via a fuel hose (not shown). One end of the breather hose 12 is connected to the upper portion of the fuel tank 10, and the other end is connected to the canister 13. The canister 13 is connected to an intake system (for example, a throttle body) via a purge hose 14. A throttle wire 15 is attached to a throttle grip (or lever) of a right handle portion (not shown) and is connected to a throttle valve of an intake system. Similarly, a brake cable 16 is attached to a brake lever (not shown) of the handle portion and is connected to a brake cam shaft 18 of the rear wheel 17.

  An engine unit 19 is attached to the vehicle body frame 6 at the center of the vehicle body. The engine unit 19 includes an engine (not shown) and a speed reducer 24 integrally coupled to a crankcase (not shown). The engine unit 19 is suspended via an engine bracket 20 so as to be rotatable around a pivot 22 with respect to a lower body frame member 21 constituting a part of the body frame 6. The rear wheel 17 is connected to the rear portion of the engine unit 19 and the lower end of the damper 23 is pivoted. The upper end of the damper 23 is pivotally attached to a rear body frame (not shown) constituting a part of the body frame 6. As a result, the engine unit 19 can swing around the pivot 22 together with the rear wheel 17 to form a swing unit type engine.

  An air cleaner 25 is provided above the speed reducer 24. An outside air intake opening 25 a is opened at the front of the air cleaner 25, and a dustproof cover 26 made of rubber or resin is provided inside the vehicle body cover 8 so as to cover the opening. Reference numeral 27 denotes a stand, and 28 denotes a kick lever.

  FIGS. 14 and 15 are a side view and a plan view, respectively, showing a main part of the motorcycle equipped with the fuel injection engine according to the present invention. FIG. 16 is an enlarged view of the intake system portion.

  An engine 29 is provided below the fuel tank 10. The engine 29 is a four-cycle single cylinder engine having a fuel injection injector. A crankcase (not shown) of the engine 29 is integrally coupled with a speed reducer 24 composed of, for example, a V-belt type continuously variable speed reduction mechanism, and constitutes an engine unit 19 of a swing unit engine type as a whole. A duct 30 is connected to the front portion of the speed reducer 24, and outside air is sucked from the open end 30a and supplied to the speed reducer 5 to cool the inside. A rear output shaft (not shown) of the speed reducer 24 is connected to the axle of the rear wheel 17.

  An engine bracket 20 is integrally coupled to a front portion of the engine unit 19 of the swing unit engine type. A link plate 32 is pivotally attached to the engine bracket 20 via a shaft 31. The link plate 32 is rotatably attached to the lower body frame member 21 via the pivot 22.

  A damper (shock absorber) 23 is provided at the rear of the engine unit 19. The upper end 33 of the damper 23 is pivotally attached to the rear body frame member 34, and the lower end 35 is pivotally attached to a bracket 36 at the rear end portion of the engine unit 19. As a result, the engine unit 19 is mounted so as to be swingable with respect to the vehicle body frame around the pivot 22 on the front side. As shown in FIG. 16, the cylinder 37 of the engine 29 is tilted forward almost to the horizontal. The crankshaft 38 swings around the pivot 22 as shown by the arrow D together with the shaft 31 of the engine bracket 20 (FIG. 14).

  An intake manifold 39 communicating with an intake port (not shown) of the cylinder head and an intake pipe 40 (FIGS. 15 and 16) connected thereto are provided on the intake side of the engine 29, and an exhaust pipe 41 (FIG. 15) is provided on the exhaust side. ) Is connected. The intake pipe 40 is a bent elbow-shaped intake pipe. As shown in FIG. 16, the flange 43 is abutted against each other via a resin heat insulating material 42 and fixed by two bolts 44. Reference numeral 45 denotes a valve cam maintenance cover. The engine 29 is provided with a water temperature sensor 46 (FIGS. 15 and 16). The detection output signal of the water temperature sensor 46 is sent to the engine control unit 47 (FIG. 15) via the water temperature signal cable 89 (FIG. 15) and the wire harness 72. Further, a detection signal cable (not shown) of an intake air temperature sensor and an intake pressure sensor, which will be described later, is connected to the engine control unit 47 via a wire harness 72, and the throttle valve (not shown) is controlled to open and close based on these detection data. To do.

  A throttle body 48 is connected to the intake manifold 39 via the bent elbow-shaped intake pipe 40 described above. The throttle body 48 is connected to the air cleaner 25 via a joint 49. An injector 50 is attached to the intake pipe 40.

  A throttle valve (not shown) is mounted in the throttle body 48, and a diaphragm type suction piston 51 is mounted on the upstream side thereof. As will be described later, the suction piston 51 has a diaphragm chamber 52 provided on the upper side of the throttle body 48, and an air inlet (atmosphere open end) 54 of an air passage 53 for introducing the air into the diaphragm chamber 52 is a throttle. Provided on the lower side of the body 48. A throttle wire 15 connected to a throttle lever (not shown) or a throttle grip is connected to a valve shaft of the throttle valve via a link 55.

  The air intake opening 25a at the front of the air cleaner 25 is covered with a dust-proof cover 26 (dotted line in FIG. 13) made of rubber or resin. A vehicle body cover is further attached to the outside of the dust cover 26. The air intake 54 of the suction piston 51 opens inside the dust cover 26.

  Adjacent to the suction piston 51, the throttle body 48 is provided with a heater-type wax type auto choke 56 and an intake pressure sensor 57 (FIG. 15). The auto choke 56 opens and closes a bypass pipe (not shown) that communicates the upstream side and the downstream side of the throttle valve. The intake pressure sensor 57 communicates with the intake manifold 39 or the intake pipe 40 via a negative pressure hose 58 (FIG. 16). An intake air temperature sensor 59 (FIG. 15) is provided in the air cleaner 25.

  The intake pressure sensor 57 may be provided in the vicinity of the intake manifold. Further, a throttle position sensor (not shown) may be provided on the valve shaft of the throttle valve opposite to the link 55. In this case, the auto choke 56 is provided upstream of the throttle valve so as not to interfere with the throttle position sensor.

  The front lower portion of the fuel tank 10 is fixed to the left and right vehicle body frame members 61 via the bracket 60. A fuel hose 62 is pulled out from the rear of the fuel tank 10 to supply fuel to the injector 50. The fuel hose 62 is fixed to the rear body frame member 34 via a stay 63 (FIGS. 14 and 16). Reference numeral 64 (FIG. 14) denotes an overflow pipe. Reference numeral 65 (FIG. 15) denotes a battery, and 66 (FIG. 15) denotes a cooling water recovery tank. As shown in FIG. 15, a secondary air introduction system 86 for purifying exhaust gas is provided on the right side of the center of the vehicle body. The secondary air introduction system 86 communicates with the intake manifold via a negative pressure hose 87, and supplies outside air to a catalyst (not shown) via an air hose 88 in accordance with the intake negative pressure to reburn the exhaust gas.

  As shown in FIG. 14, a blow-by gas hose 90 is connected to the air cleaner 25. The blow-by gas hose 90 communicates with a cam chain chamber (not shown) that leads to a crankcase (not shown) of the engine 29, and prevents oil seal drop and loss horsepower due to a pressure increase in the crankcase of the engine. This blow-by gas hose 90 is connected to the clean side after passing through the element in the air cleaner, and the blow-by gas is again introduced into the combustion chamber.

  The fuel tank 10 communicates with the canister 13 via the breather hose 12 as shown in FIG. A rollover valve 124 is provided in the middle of the breather hose 12. The rollover valve 124 is closed at the time of falling to prevent the fuel from flowing out from the fuel tank 10.

17A and 17B are a front side view and a left side view, respectively, of a mounting portion of the engine control unit.
In this arrangement example, the engine control unit (ECU) 47 has a substantially rectangular body shape in which the thickness of the lower portion 47b protruding to the front side is thicker than that of the upper portion 47a and the rear surface side forms a rectangular flat mounting surface 47c. The ear pieces 158 are provided on the left and right of the same surface as the mounting surface 47c. Each ear piece 158 is fixed to a stay 160 that is welded and fixed to the inner surface side of the bracket 60 for supporting the fuel tank by a bolt 159. A wire harness 72 is connected to the lower part of the ECU 47 via a coupler 161.

  The bracket 60 is joined on a vehicle body frame member 61 joined to the left and right rear vehicle body frame members 34. The left and right rear body frame members 34 are joined to the front body frame members 140 via elbow frames 145, respectively. The aforementioned lower body frame member 21 is joined to the elbow frame 145, and a pivot 22 is provided on the lower body frame member 21 so as to swingably support the engine unit 19 (FIGS. 13 and 14). 162 is a tandem rider's footrest pipe frame, and 163 is a side stand.

  The fuel tank (not shown) is supported and disposed on a support member (not shown) provided between the upper parts of the left and right brackets 60 and a stay 63 provided on the upper part of the rear body frame member 34.

  A circuit board (not shown) arranged in parallel with the mounting surface 47c is accommodated in the ECU 47, and a two-dimensional (two-axis) acceleration sensor (not shown) is placed on this circuit board with its detection surface parallel to the board plane. Has been implemented. Therefore, the fall sensor composed of the two-dimensional acceleration sensor is mounted at a position protected by the brackets 60 on both the left and right sides at the center of the vehicle body in the left-right direction with the detection surface being substantially perpendicular to the vehicle body front-rear direction.

18A and 18B are a rear side front view and a left side view, respectively, of an ECU mounting structure according to another embodiment of the present invention.
In this example, two upper pipe frames 165 and two lower pipe frames 166 are fixed by welding to the rear of the head pipe 164 constituting the front part of the vehicle body frame, and are surrounded by these four pipe frames 165 and 166. The ECU 47 is attached to the position. In the ECU 47, the ear piece 158 is fixed to the bracket 167 with a bolt 159 with the mounting surface 47 c as the front surface. The bracket 167 has a bifurcated lower part fixed to the left and right lower pipe frames 166 with bolts 168. The bracket 167 may be welded and fixed to the lower pipe frame 166 at appropriate portions such as both side edges.

  Reference numeral 169 denotes a fuel supply electromagnetic pump. Reference numeral 170 denotes a filter provided in the middle of a fuel hose (not shown) between the electromagnetic pump 169 and a fuel tank (not shown).

  In this embodiment as well, the ECU 47 has a mounting surface 47c parallel to the detection surface of a fall sensor (not shown) formed of an internal two-dimensional acceleration sensor substantially perpendicular to the longitudinal direction of the vehicle body, and substantially in the center of the lateral direction of the vehicle body. It is attached to a position protected by the pipe frames 165 and 166.

Explanatory drawing of the output voltage of the acceleration sensor of the horizontal placement which concerns on this invention. Explanatory drawing of the output voltage of the acceleration sensor of the vertical placement which concerns on this invention. It is a flowchart which shows an example of the technique used as the reference of this invention. The flowchart of the fall discrimination | determination control by the biaxial acceleration sensor used as the reference technique of this invention. The block block diagram of another reference technique of this invention. The flowchart of the operation | movement of the reference example of FIG. The output voltage explanatory drawing of another reference technique of this invention. The structure explanatory view of another reference technique of the present invention. The flowchart of operation | movement of another reference technique of this invention. The flowchart of operation | movement of another reference technique of this invention. The flowchart of operation | movement of embodiment of this invention. FIG. 12 is a graph of sensor output of the embodiment of FIG. 1 is an external view of a small motorcycle according to the present invention. FIG. 14 is a side view of the main part of the motorcycle shown in FIG. 13. Fig. 14 is a plan view of a main part of the motorcycle shown in Fig. 13. FIG. 14 is a configuration diagram of an engine portion of the motorcycle of FIG. 13. Structure explanatory drawing of ECU attachment structure. Structure explanatory drawing of ECU attachment structure.

Explanation of symbols

1: body, 2: handle, 3: head pipe, 4: steering shaft,
5: Front wheel, 6: Body frame, 7: Cowling, 8: Body cover,
9: Seat, 10: Fuel tank, 11: Helmet box,
12: Breather hose, 13: Canister, 14: Purge hose,
15: throttle wire, 16: brake cable, 17: rear wheel,
18: Brake camshaft, 19: Engine unit,
20: engine bracket, 21: lower body frame member, 22: pivot,
23: Damper, 24: Reducer, 25: Air cleaner l,
25a: Air intake opening, 26: Dust cover, 27: Stand,
28: kick lever, 29: engine, 30: duct, 30a: open end,
31: shaft, 32: link plate, 33: upper end, 33a: damper mounting hole,
34: Rear body frame member, 35: Lower end, 36: Bracket,
37: cylinder, 38: crankshaft, 39: intake manifold, 40: intake pipe,
41: exhaust pipe, 42: heat insulating material, 43: flange, 44: bolt,
45: Cover for maintenance, 46: Water temperature sensor, 47: Engine control unit,
47a: upper part, 47b: lower part, 47c: mounting surface,
48: throttle body, 49: joint, 49a: joint end,
50: Injector, 51: Suction piston, 52: Diaphragm chamber,
53: Air passage, 54: Air intake, 55: Link, 56: Auto choke,
57: Intake pressure sensor, 58: Negative pressure hose, 59: Intake temperature sensor,
60: bracket, 61: body frame member, 62: fuel hose,
62a: fixed hose part, 62b: swinging hose part, 63: stay,
64: overflow pipe, 65: battery,
66: Recovery tank, 72: Wire harness, 74: Throttle valve,
86: Secondary air introduction system, 87: Negative pressure hose, 88: Air hose,
89: Water temperature signal cable, 90: Blow-by gas hose,
101: Acceleration sensor, 102: Two-axis acceleration sensor, 103: Filter,
104: A / D converter, 105: capacitor, 106: filter,
107: CPU, 108, 109: marking, 110: acceleration sensor,
111: Printed circuit board, 124: Rollover valve,
140: front body frame member, 145: elbow frame,
158: Ear piece, 159: Bolt, 160: Stay, 161: Coupler,
162: A pedestal pipe frame for tandem riders,
163: Side stand, 164: Head pipe,
165: Upper pipe frame, 166: Lower pipe frame,
167: Bracket, 168: Bolt, 169: Electromagnetic pump,
170: Filter.

Claims (5)

An ECU that controls the engine and a fall sensor that detects the fall based on the tilt angle of the vehicle body,
The fall sensor is composed of an acceleration sensor,
In the motorcycle overturn detection device incorporating the acceleration sensor in the ECU,
The acceleration sensor is a vertical sensor that detects acceleration in a first detection direction that is a direction perpendicular to the ground when the vehicle body is in a non-tilt state;
A lateral sensor that detects acceleration in a second detection direction that is perpendicular to the first detection direction;
A fall detection device for a motorcycle, wherein the fall is determined based on (horizontal sensor output) ÷ (vertical sensor output).   The fall detection device for a motorcycle according to claim 1, wherein the fall angle at which the vehicle body is assumed to fall is α, and the value of (horizontal sensor output) ÷ (vertical sensor output) is 1 g · tan (−α ) And when the value is larger than 1 g · tan α, it is determined that the vehicle has fallen when one of them continues for a predetermined time or more.   3. The motorcycle overturn detection device according to claim 2, wherein the overturn determination is performed when it is determined that the inclination angle of the vehicle body is within 90 degrees based on the detection output of the vertical sensor. A motorcycle fall detection device.   The motorcycle overturn detection device according to claim 2, wherein the overturn angle is changed based on an attachment angle of the acceleration sensor.   A motorcycle equipped with the fall detection device according to any one of claims 1 to 4.

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