JP5187596B2 - Alcohol detector - Google Patents

Description

  The present invention relates to an alcohol detection device for detecting the alcohol concentration in exhaled breath discharged from a user.

  This specification demonstrates the alcohol detection apparatus mounted in a vehicle (for example, motor vehicle). In recent years, drunk driving of vehicles has become a serious social problem, and it is strictly forbidden for a driver to drive a vehicle in a drunk state. In order to secure this, inventions of various types of vehicle alcohol detection devices have been filed.

  Various techniques have been disclosed as alcohol detection devices (see, for example, Patent Document 1). However, in the case of this alcohol detection device, a good detection result can be obtained when the driver blows weak exhalation, but when the user blows strong exhalation, when the exhalation passes through the sensor part The flow rate becomes large and it becomes difficult to obtain a stable measurement result.

  In particular, when using multiple sensors, the response of each sensor differs, so if exhaled air with a large flow rate is sent to the sensor part by a fan, a detection error may occur depending on the sensor, making it difficult to detect alcohol with high accuracy. There is a risk.

JP 2009-300199 A

  In view of the above-described problems, an object of the present invention is to enable each sensor to reliably detect expiration in an apparatus that detects alcohol concentration in expiration by using a plurality of sensors.

The present invention for solving the above problems is as follows.
A case body provided with an exhalation entrance for introducing exhalation exhaled by the user;
A fan that is disposed on the downstream side of the exhalation inlet in the case body so as to oppose the exhalation inlet, and further sends the exhalation of the user that has flowed in through the exhalation inlet to the downstream side;
A plurality of sensors arranged on the downstream side of the fan in the case body and detecting elements in the user's exhalation sent by the fan;
It is characterized in that the rotation speed of the fan is adjusted by using any one of the sensors as detecting a change in the element during expiration. The adjustment of the rotation speed of the fan is to decelerate or stop the rotation for a predetermined time.

  The alcohol detection device according to the present invention is configured as described above, and is provided with a plurality of sensors for detecting changes in elements (for example, oxygen concentration and alcohol concentration) in the user's breath. Since these sensors have a difference in their responsiveness, there are cases in which the elements of exhalation passing as an exhalation aggregate having a flow rate above a certain level cannot be accurately detected. However, in the alcohol detection device according to the present invention, the rotation speed of the fan is adjusted (decelerated or stopped) triggered by any sensor (for example, the sensor having the best response) detecting a change in the element of expiration. ) As a result, the flow rate of the exhalation assembly passing through the sensor part (the part where each sensor is arranged) is reduced, so that all sensors reliably detect changes in the elements of the exhalation assembly, and the accuracy of alcohol detection Becomes higher.

The sensor includes an oxygen sensor that detects at least a change in oxygen concentration in the breath,
The predetermined time may be from when the oxygen sensor detects that the oxygen concentration in the exhaled breath has become equal to or lower than a set value until it detects that the oxygen sensor has recovered to a set value or higher.

  A sensor serving as a trigger for adjusting the rotational speed of the fan is a temperature sensor, and this temperature sensor detects that the oxygen concentration of the exhalation aggregate has become a set value (for example, 20%) or less and then recovers from the fan. The rotation can be decelerated or stopped. The sensor serving as the trigger may be other than the oxygen sensor.

The driving means of the fan is a DC motor,
A PWM controller connected to the oxygen sensor and converting an oxygen concentration signal output from the oxygen sensor into a pulse signal;
The rotation speed of the fan can be adjusted by the PWM control device.

  A space portion may be provided between an exhalation inlet provided in the case body and the fan. In addition, a baffle plate may be provided between the fan and the sensor for reducing the flow rate by applying exhaled air sent to the downstream side by the fan.

  By taking these measures, the flow rate of the exhaled breath can be further reduced without complicating the configuration of the alcohol detection device, and the element change detection by each sensor becomes more reliable.

It is the schematic of the driver's seat in which the alcohol detection apparatus 101 which concerns on this invention is mounted. 1 is an overall perspective view of an alcohol detection device 101 according to a first embodiment. It is an exploded perspective view similarly. 2 is a perspective view of an alcohol detection sensor 16. FIG. (A) is a cross-sectional schematic diagram of the alcohol detection apparatus 101 of 1st Example, (b) is a cross-sectional schematic diagram of the alcohol detection apparatus 100 of a comparative example. 2 is a schematic diagram of a PWM control circuit 200. FIG. (A)-(d) is a time chart which shows the detection result of the element by each sensor 14-16. It is a cross-sectional schematic diagram of the alcohol detection apparatus 102 of 2nd Example.

  Hereinafter, embodiments of the present invention will be described in detail. In this specification, an alcohol detection device mounted on a vehicle will be described.

  FIG. 1 is a schematic diagram of a driver seat on which an alcohol detection device 101 according to the present invention is mounted, FIG. 2 is an overall perspective view of the alcohol detection device 101 of the first embodiment, FIG. 3 is an exploded perspective view, and FIG. FIG. 5A is a schematic cross-sectional view of the alcohol detection device 101 of the first embodiment, and FIG. 5B is a schematic cross-sectional view of the alcohol detection device 100 of the comparative example.

  As shown in FIG. 1, an alcohol detection device 101 according to the embodiment is attached to a driver's seat of a vehicle (automobile). For example, the alcohol detection device 101 is detachably connected to the instrument panel 1 of the driver's seat with a cable 2. When the driver M (user) seated in the driver's seat tries to start the engine of the vehicle, the driver M blows the breath on the alcohol detection device 101. If the alcohol concentration in the exhalation is equal to or lower than a predetermined value, the device ECU (not shown) determines that the driver M is not in a drunk state and permits the engine to start. If the alcohol concentration in the exhalation exceeds a predetermined value, the device ECU determines that the driver M is in a drunk state and does not allow the engine to start. This prevents drunk driving.

  As shown in FIGS. 2 and 3, the alcohol detection device 101 of the first embodiment is a composite gas sensor in which a plurality of types of sensors (described later) are mounted on a case body 5 including a front panel 3 and a rear panel 4. As a form. A frame member 6 is internally provided in the case body 5, and a fan 7 and a sensor support member 8 are attached to the frame member 6. The sensor support member 8 has a fixed plate portion 9 for fixing the fan 7, a first support portion 11 having a tapered cylindrical shape for flowing exhalation smoothly, and a straight cylindrical shape for fixing each sensor. And a second support portion 12. Each sensor (temperature sensor 14, humidity sensor 15, alcohol detection sensor 16, and oxygen sensor 17) mounted on the substrate 13 is supported on the second support portion 12 of the sensor support member 8.

  The case body 5 formed integrally with the front panel 3 and the rear panel 4 has a size that can be easily gripped by the driver M (see FIG. 1). 3a and 4a are continuously thinned. And in the front part of the front panel 3, an inhalation hole 18 (exhalation inlet) for passing the exhaled air blown by the driver M is provided. In the case of the alcohol detection device 101 of the first embodiment, a large number of small-diameter intake holes 18 are provided.

  The fan 7 fixed to the fixing plate portion 9 of the sensor support member 8 is assembled to the frame member 6 so as to face the intake hole 18 of the front panel 3. The fan 7 is, for example, an outer rotor type brushless DC motor, and includes a frame portion 19, a rotating shaft portion 21 that is rotatably supported by the frame portion 19, and a plurality of sheets (first plates) that protrude radially from the outer peripheral surface thereof. In the case of one embodiment, eight blade portions 22 are provided. The frame member 6 is attached with a substrate 24 on which a speaker 23 is attached, a switch substrate 27 on which a liquid crystal panel 25 and a switch 26 are attached. The liquid crystal panel 25 displays the detection result of the alcohol concentration of the driver M as characters and is visible to the driver M from the display window 28 of the front panel 3. The switch 26 energizes the fan 7, the sensors 14 to 17, the speaker 23 and the liquid crystal panel 25 to enable the alcohol detection device 101 to operate. The switch 26 is disposed in a window portion 29 provided on the side wall portion of the front panel 3 and is operated by pressing a knob 31. In FIG. 3, 32 is a bush for protecting the cable 2 of the alcohol detection device 101, and 33 is an exhaust hole provided in the rear panel 4.

  The exhaled air blown to the intake hole 18 of the front panel 3 by the driver M passes through the intake hole 18 and is sent out to the sensor support member 8 by the fan 7. At this time, exhaled air is agitated by the fan 7, and exhaled air and outside air (air flowing in simultaneously with exhaled air and air existing in the sensor support member 7 in advance) are mixed. Then, after the alcohol concentration of the breath is detected by contacting each of the sensors 14 to 17, the air is exhausted from the exhaust hole 33 of the rear panel 4 to the outside (inside the vehicle).

  Next, each sensor 14-17 is demonstrated. The temperature sensor 14 is called a “thermistor”, for example, and is a ceramic semiconductor made of an oxide such as nickel, cobalt, or manganese. The temperature of the exhalation changes depending on the method of blowing the exhalation by the driver M. For example, when the exhaled breath blown by the driver M is generated from the body (lung), the temperature is high and it is easy to determine whether or not it contains alcohol. However, when it originates in the mouth or is sprayed by unauthorized means, the temperature is low. It also changes depending on the outside temperature. For this reason, the temperature sensor 14 detects the temperature of the exhalation to determine whether or not it is the exhalation from the lungs of the driver M.

  The humidity sensor 15 is a sensor (for example, a capacitance change type humidity sensor) that measures the humidity of the air when the electrical conductivity or capacitance of the sensor element changes due to a change in the amount of moisture in the air. Here, the alcohol detection sensor 16 may also react to humidity in the outside air. Further, since the breath of the driver M contains alcohol even if the driver M is not drunk, the alcohol detection sensor 16 detects the alcohol in the breath in the normal state (the state that is not drunk). May end up. For this reason, by monitoring the humidity detected by the humidity sensor 15, even if the alcohol detection sensor 16 detects the humidity of the outside air or alcohol in the normal state of expiration, those detected values can be prevented from being adopted. .

  As shown in FIG. 4, the alcohol detection sensor 16 is a semiconductor type gas sensor, and the electric conductivity (electric resistance) due to adsorption of gas (alcohol in breath) on the surface of a metal oxide (for example, tin oxide) semiconductor. ) Is measured. A gas sensitive element 35 (metal oxide semiconductor) is installed on the upper surface of the base member 34, and the periphery thereof is covered with a metal cap 36. A window 36 a is provided on the upper surface of the cap 36, and the window 36 a is covered with a mesh 37 having a double wire mesh structure. The mesh 37 reduces the influence of the detected exhalation flow rate.

  The oxygen sensor 17 detects the oxygen concentration of exhaled breath that is diluted by being mixed with outside air, and may be, for example, one using a zirconia solid electrolyte. Here, the oxygen concentration in the outside air in the passenger compartment is almost constant even when the weather and the number of passengers change. However, the oxygen concentration of exhaled air (in other words, the dilution rate of exhaled air) is lower than the oxygen concentration of outside air even when diluted with outside air. That is, by monitoring changes in the oxygen concentration detected by the oxygen sensor 17, it is possible to determine whether or not the air in the sensor support member 8 contains exhaled air.

  The alcohol detection device 101 of the first embodiment will be described in more detail. 5A is a schematic cross-sectional view of the alcohol detection device 101 according to the embodiment of the present invention, and FIG. 5B is an alcohol that is assumed to be designed in a normal state (a state in which the above-described problems are not assumed). In the cross-sectional schematic diagram of the detection apparatus 100, it shows as a comparative example for clarifying the difference with this invention. In the following drawings, only the alcohol detection sensor 16 and the oxygen sensor 17 are illustrated as sensors.

  When the alcohol detection device 101 of the first embodiment shown in FIG. 5A is compared with the alcohol detection device 100 of the comparative example shown in FIG. 5B, the alcohol detection device 101 of the first embodiment is as follows. The gap e between the front panel 3 and the rotary shaft portion 21 of the fan 7 is longer than the gap e ′ in the alcohol detection device 101 of the comparative example. That is, if the gap e ′ in the alcohol detection device 101 is 1 to 2 mm, the gap e of the alcohol detection device 101 of the first embodiment is about 5 mm, and a large space is formed between the front panel 3 and the fan 7. Q1 is formed.

  Further, the alcohol detection device 101 according to the first embodiment has a ring-shaped obstacle at the connection portion between the first support portion 11 and the second support portion 12 between the fan 7 and the sensors 16 and 17 in the sensor support member 8. A plate 38 is provided. Moreover, the inclination of the first support portion 11 of the sensor support member 8 in the alcohol detection device 101 of the first embodiment is gentler than the inclination of the first support portion 11 of the sensor support member 8 in the alcohol detection device 100 of the comparative example. ing. For this reason, the distance L from the fan 7 to the baffle plate 38 is slightly larger than the same distance L ′ in the alcohol detection device 100 of the comparative example, and a space portion Q2 is formed between the fan 7 and the baffle plate 38. .

  A vent hole 38 a through which exhaled air A passes is provided at the axial center portion of the baffle plate 38. The diameter d1 of the vent hole 38a of the baffle plate 38 is smaller than the outer diameter D of the rotating shaft portion 21 of the fan 7. Of the strong exhalation A blown by the driver M, even if there is something that has passed through the gap of the blade portion 22 of the fan 7, it strikes against the baffle plate 38, hits the rotating shaft portion 21 of the fan 7, and reduces its flow rate; After temporarily stopping in the space part Q2, it is sent to the sensor part (the part where each sensor 14-17 is arrange | positioned) through the ventilation hole 38a of the hole diameter d1 smaller than the outer diameter D of the rotating shaft part 21. FIG. Accordingly, even when the driver M blows in the exhalation A strongly or weakly, the flow rate when the exhalation A passes through the sensor portion is small and constant, so that it is always stable. Measurement results can be obtained. The distance e (the size of the space Q1) can be, for example, not less than half the protrusion length H in the radial direction from the rotating shaft 21 of the blade portion 22 of the fan 7 and not more than the protrusion length H. The distance L from the fan 7 to the baffle plate 38 (the size of the space portion Q2) can be, for example, about the same as or longer than the protruding length H of the blade portion 22 of the fan 7.

In the case of the alcohol detection device 101 of the first embodiment, the motor 7a for driving the fan 7 is a DC motor having a rotational speed of 4000 min ⁻¹ (rpm), for example, at 5 V, and the rotational speed is a device ECU (not shown). ) Can be adjusted by a PWM control circuit 200 (Pulse Width Modulation) incorporated in (). The principle of the PWM control circuit 200 will be described. As shown in FIG. 6, the PWM control circuit 200 controls the duty ratio of the PWM wave generated by the PWM generator 39 with an analog input voltage (variable voltage 41), and switches the transistor 42 with this PWM wave to switch the motor. The rotational speed of 7a is increased or decreased. Here, the oxygen sensor 17 and the PWM generator 39 are connected to each other, and the PWM generator 39 is operated by an oxygen concentration signal output from the oxygen sensor 17. In FIG. 6, reference numeral 43 denotes a flywheel diode for protecting the motor 7a.

In FIG. 7, the time chart when each sensor 14-17 in the alcohol detection apparatus 101 of 1st Example detects is shown. 7A is a time chart of the temperature sensor 14, FIG. 7B is a time chart of the humidity sensor 15, FIG. 7C is a time chart of the oxygen sensor 17, and FIG. 7D is a time chart of the alcohol sensor 16. In the chart, the horizontal axis indicates time, and the vertical axis indicates the temperature (° C.), humidity (%), oxygen concentration (%), and alcohol concentration (ppm) of exhaled air A in order. Further, a straight line (horizontal line) provided in the time chart of the oxygen sensor 17 indicates a state where the oxygen concentration of the exhaled breath A detected by the oxygen sensor 17 is 20%. In the case of the alcohol detection device 101 of the first embodiment, the rotational speed of the motor 7a of the fan 7 is adjusted by the oxygen concentration of the exhaled breath A. That is, when the oxygen concentration of exhalation A is 20% or more by normally rotating the motor 7a in 4000 min ^-1, to reduce the rotational speed of the motor 7a if the oxygen concentration is lower than 20% for example 1000min ^-1, oxygen When the concentration is restored to 20%, the rotational speed of the motor 7a is returned to the normal rotation of 4000 min ⁻¹ .

  Next, the operation of the alcohol detection device 101 of the first embodiment will be described with reference to FIG. When the driver M blows strong exhalation A into the intake holes 18 of the alcohol detection devices 101 and 100, in the case of the alcohol detection device 100 of the comparative example, the exhalation A is immediately agitated by the fan 7 and sent downstream. The Depending on the expiration A, as indicated by an arrow 44 in FIG. 5B, the sensor portion (the sensors 14 to 17 are arranged in the sensor support member 8 by passing through the gap of the blade portion 22 of the fan 7 and at a large flow velocity. Some parts are sent to a portion that is a part (that is, the second support part 12). Then, it becomes difficult to obtain a stable measurement result.

  On the other hand, in the case of the alcohol detection device 101 of the first embodiment, as shown in FIG. 5A, the exhalation A that the driver M of the vehicle blows into the intake hole 18 of the alcohol detection device 101 gathers. After temporarily stopping in a large space portion Q1 formed between the front panel 3 of the case body 5 and the rotating shaft portion 21 of the fan 7, the exhalation aggregate in this state is indicated by reference symbol A ′. ), Sucked into the fan 7 and sent to the downstream side while being stirred. And it stops in the space part Q2, or hits the baffle plate 38 and flows backward. As a result, the flow rate of the expiratory aggregate A ′ further decreases, so that the expiratory aggregate A ′ becomes close to a laminar flow and passes through the passage hole 38a of the baffle plate 38 to become the expiratory aggregate A ″ further downstream. Is sent to the sensor portion on the side (second support portion 12 of the sensor support portion 8).

  Here, there is a difference (sensitivity level) in sensitivity characteristics when each sensor 14 to 17 detects an element (in this case, oxygen concentration, alcohol concentration, temperature and humidity) in the breath assembly A ″. As shown in FIG. 7, the time t1 when the oxygen sensor 17 detects the peak value and the time t2 when the humidity sensor 15 detects the peak value are different, and a reaction delay time Δt occurs between them. For this reason, when the flow rate of the exhalation aggregate A ″ is equal to or higher than a predetermined speed, it may be difficult to detect elements or cause a detection error.

In the case of the alcohol detection device 101 of the first embodiment, among the sensors 14 to 17, the responsiveness of the oxygen sensor 17 to the exhalation assembly A ″ is the best. The oxygen concentration of the body A ″ is detected. The fan 7 is triggered by the fact that the oxygen concentration in the exhalation assembly A ″ has become a predetermined value (for example, 20%) or less (this means that the exhalation assembly A ″ has approached the sensor portion). Adjust the rotation speed. That is, a command is sent from the oxygen sensor 17 to the PWM generator 39, an average current proportional to the duty ratio of the PWM wave corresponding to the command flows from the PWM generator to the motor 7a, and the rotational speed of the fan 7 decreases. If alcohol detection device 101 of the first embodiment, reducing the rotational speed of the fan 7 from 4000 min ^-1, for example, in 1000min ^-1.

  As a result, the flow rate of the exhalation assembly A ″ decreases, and the exhalation assembly A ″ passes through the sensor portion at a low speed. As a result, each of the sensors 14 to 16 other than the oxygen sensor 17 reliably detects the element of the exhalation aggregate A ″. Then, the exhalation aggregate A ″ passes through the sensor portion, so that the oxygen concentration becomes a predetermined value. (For example, 20%), the rotational speed of the fan 7 is returned to the original level again, and the expiratory assembly A ″ is quickly exhausted. As a result, the sensitivity is lower than that of the oxygen sensor 17. The sensors 14, 15, and 17 are prevented from causing detection errors of the respective elements, and it becomes possible to always detect the elements with high accuracy.

  The alcohol detection device 101 of the first embodiment is for reducing the rotational speed of the fan 7 in a predetermined case, and when the detection of the elements of the exhalation aggregate A ″ by the sensors 14 to 17 is completed, the exhalation is performed. There is an advantage that the aggregate A ″ can be exhausted quickly. However, the rotation of the fan 7 may be stopped in a predetermined case.

  In the alcohol detection device 101 of the first embodiment, the front panel 3 is provided with a number of intake holes 18. However, the number of intake holes 45 may be one as in the alcohol detection device 102 of the second embodiment shown in FIG. At this time, it is desirable that the hole diameter d <b> 2 of the intake hole 45 be smaller than the outer diameter D of the rotating shaft portion 21 of the fan 7. As a result, the exhaled air A blown by the driver M hits the rotating shaft portion 21 of the fan 7 and is sent downstream after the flow rate is reduced.

  Further, in the case of the alcohol detection devices 101 and 102 of the above embodiments, the sensitivity of the oxygen sensor 17 is the best. Although the rotation speed of the fan 7 is adjusted using the above as a trigger, the fact that the other sensors 14 to 16 have detected the elements may be used as the trigger.

  In the alcohol detection devices 101 and 102 of the above embodiments, the alcohol detection sensor 16 and the oxygen sensor 17 are arranged on the same circumference with respect to the delivery direction of the exhalation aggregate A ″. It may be arranged in series along the delivery direction of A. As a result of the experiment by the applicant, even if the arrangement of the sensors 14 to 17 is different, a significant difference in detection accuracy is recognized. There wasn't.

  In this specification, the case where the alcohol detection devices 101 and 102 of each embodiment are mounted on a vehicle has been described. However, you may use this alcohol detection apparatus 101 for uses other than being mounted in a vehicle.

  The present invention can be used for an alcohol detection device of a vehicle (for example, an automobile).

101, 102 Alcohol detection device 200 PWM control circuit (PWM control device)
5 Case body 7 Fan 7a Motor (DC motor)
14 Temperature sensor (sensor)
15 Humidity sensor (sensor)
16 Alcohol detection sensor (sensor)
17 Oxygen sensor (sensor)
18, 45 Inhalation hole (exhalation inlet)
38 Baffle A, exhalation A ', A "exhalation assembly (exhalation)
M Driver (user)
Q1 space

Claims (7)

A case body provided with an exhalation entrance for introducing exhalation exhaled by the user;
A fan that is disposed on the downstream side of the exhalation inlet in the case body so as to oppose the exhalation inlet, and further sends the exhalation of the user that has flowed in through the exhalation inlet to the downstream side;
A plurality of sensors arranged on the downstream side of the fan in the case body and detecting elements in the user's exhalation sent by the fan;
An alcohol detection device characterized in that the number of rotations of the fan is adjusted by using any one of the sensors as detecting a change in an element during expiration.   The alcohol detection device according to claim 1, wherein the rotation speed of the fan is adjusted by decelerating or stopping the rotation for a predetermined time. The sensor includes an oxygen sensor that detects at least a change in oxygen concentration in the breath,
The predetermined time is from when the oxygen sensor detects that the oxygen concentration in the exhaled breath that has been blown is below a set value to when it is detected that the oxygen sensor has recovered to a set value or more. Item 3. The alcohol detection device according to Item 2. The driving means of the fan is a DC motor,
A PWM controller connected to the oxygen sensor and converting an oxygen concentration signal output from the oxygen sensor into a pulse signal;
The alcohol detection device according to claim 1, wherein the rotation speed of the fan is adjusted by the PWM control device.   The alcohol detection device according to any one of claims 1 to 4, wherein a space is provided between an exhalation inlet provided in the case body and the fan.   6. A baffle plate is provided between the fan and the sensor for applying an exhalation sent downstream by the fan to reduce the flow rate thereof. The alcohol detection device according to item.   The alcohol detection device according to any one of claims 1 to 6, wherein the alcohol detection device is mounted on a vehicle, and a user blows in exhalation while bringing an exhalation entrance of the case body close to his / her mouth.

Images