JP2009180214A - Method for measuring rotation speed of plug ignition type internal combustion engine and device for measuring rotation speed of plug ignition type internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring rotation speed of a plug ignition type internal combustion engine and a device for measuring rotation speed of the plug ignition type internal combustion engine, can measuring accurate rotation speed by counting the number of waves of induction electromotive force generated during ignition by winding a coil around a cord supplying electricity to an ignition plug. <P>SOLUTION: This device is provided with an induction electromotive force generation means generating induction electromotive force in the coil as the coil 5 is wound around the cord 4 supplying electricity to the ignition plug 3 for each ignition, a waveform shaping means shaping ignition pulse waves generated by the induction electromotive force generation means into rectangular waves, and a rotation speed detection means detecting rotation speed of the engine by counting rectangular waves shaped by the waveform shaping means per unit time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotational speed measurement method for a plug ignition internal combustion engine and a rotational speed measurement device for a plug ignition internal combustion engine. More specifically, the present invention relates to a compact and space-saving method for measuring the rotational speed of a plug-ignited internal combustion engine and a rotational speed measurement device for a plug-ignited internal-combustion engine that are effective for a small engine.

  Conventionally, as a means for measuring the engine speed, for example, an engine tachometer that detects an ignition pulse of an ignition internal combustion engine has been proposed (see Patent Document 1). Specifically, as shown in FIG. 8, a pulse wave receiving circuit 102 connected to the antenna 101, an arithmetic circuit 103 connected to the pulse wave receiving circuit 102 for calculating the engine speed, and the calculation are obtained. A waveform shaping means in the pulse wave receiving circuit 102 for converting the pulse wave of the ignition pulse in the electromagnetic wave generated by the electromagnetic induction through the antenna 101 into a display device 104 such as a liquid crystal display for displaying the engine speed. The output signal corresponding to the value obtained by multiplying the number of waveform shaping output signals per unit time by a predetermined proportional constant is calculated in the arithmetic circuit 103, and the value corresponding to the calculation result is calculated as the engine speed. As shown in FIG.

Japanese Patent Laid-Open No. 11-83877 (Specification, FIG. 5)

  However, when the pulse wave of the ignition pulse in the electromagnetic wave generated by the engine is received through the antenna, it can be reliably received under the influence of environmental electromagnetic noise depending on the sensitivity of the antenna and the mounting position of the antenna. Therefore, there is a problem that an accurate rotational speed cannot be measured.

  Further, when a plurality of engines are operating close to each other, it is presumed that the pulse receiving circuit receives ignition pulse waves from the plurality of engines, thereby causing a large error in the rotation speed measurement.

  In addition, for example, in the case of control of a helicopter with a small unmanned gasoline engine, flight control is required while maintaining a constant engine speed. Therefore, installation of an engine speed measuring device that constantly measures the rotational speed of the engine is desired. Is the current situation. However, in the engine tachometer described in Patent Document 1, there is almost no space for installing an antenna and a pulse receiving circuit.

  The present invention has been devised in view of the above points, and a coil is wound around a cord that is energized to a spark plug, and an accurate rotational speed is obtained by counting the number of induced electromotive forces generated at the time of ignition. It is an object of the present invention to provide a plug ignition type internal combustion engine rotation speed measuring method and a plug ignition type internal combustion engine rotation speed measurement apparatus capable of measuring.

  In order to achieve the above object, a method for measuring the rotational speed of a plug ignition internal combustion engine according to the present invention includes a step of winding a coil around a cord energizing the ignition plug and generating an induced electromotive force in the coil at each ignition. And a waveform shaping step of shaping the ignition pulse wave generated by the induced electromotive force into a rectangular wave, and a rotation speed detection step of detecting the rotation speed of the engine by counting the rectangular wave.

  Here, by winding the coil around a cord that is energized to the spark plug, an induced electromotive force is generated in the coil every time the plug is ignited. The ignition pulse wave due to the induced electromotive force for each ignition is shaped into a rectangular wave by a waveform shaping circuit, and the number of times of ignition of the engine is detected by detecting the number of times of the rectangular wave per unit time with a counter board. The rotation speed can be measured.

  In order to achieve the above object, a rotational speed measuring device for a plug ignition internal combustion engine according to the present invention includes an induced electromotive force generating means in which a coil is wound around a cord that is energized to the spark plug for each ignition, Waveform shaping means for shaping the ignition pulse wave generated by the induced electromotive force generation means into a rectangular wave; and a rotation speed detection means for detecting the engine speed by counting the rectangular wave shaped by the waveform shaping means. Prepare.

  Here, when the engine is operated, a high voltage is instantaneously applied to the cord that energizes the spark plug at every ignition, and an electric current flows. Therefore, an induced electromotive force is generated in the coil wound around the cord, and this induction is generated. The ignition pulse wave generated by the electromotive force is shaped into a rectangular wave by a waveform shaping circuit, and the number of ignitions of the engine can be detected by detecting the number of times of the rectangular wave per unit time with a counter board.

  By detecting the number of ignitions of the engine, for example, in the case of a two-cycle engine, the detected number of ignitions becomes the engine speed, and in the case of a four-cycle engine, twice the detected number of ignitions is the engine speed. It becomes possible to detect the rotational speed of the engine reliably.

  According to the method and apparatus for measuring the rotation of a plug ignition internal combustion engine of the present invention, a coil is wound around a cord energized to a spark plug, and an induced electromotive force generated in the coil wound at the time of plug ignition is counted. Since the number of ignitions can be detected, the measurement accuracy is high, compact and light, and does not take up space, unlike a conventional measuring apparatus having an antenna or a pulse receiving circuit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings to provide an understanding of the present invention.
FIG. 1 is a principle explanatory view for explaining the outline of a method and apparatus for measuring the rotational speed of a plug ignition internal combustion engine to which the present invention is applied, and FIG. 2 is a rotational speed of the plug ignition internal combustion engine to which the present invention is applied. The circuit explanatory drawing for demonstrating an example of the waveform shaping circuit of the measuring method and its apparatus is shown.

  In the method and apparatus 1 for measuring the rotational speed of a plug ignition internal combustion engine shown here, an induction coil 5 is wound around a cord 4 of a spark plug 3 of a gasoline engine 2. A high voltage of usually 15,000 volts or more is instantaneously applied to the spark plug 3 through the cord 4 for every ignition, whereby an induced electromotive force is generated in the induction coil 5.

  An ignition detection circuit 7 is constituted by the induction coil 5, the diode 5A, and the resistor 5B. In the ignition detection circuit 7, when the engine is operated, a high voltage is instantaneously applied to the cord 4 of the spark plug for every ignition, and an induced electromotive force is generated in the induction coil 5. This induced electromotive force flows to the waveform shaping circuit 6 connected to the ignition detection circuit 7.

  The waveform of the induced electromotive force is shaped into a rectangular wave by the waveform shaping circuit 6, and the number of ignitions of the engine is detected by counting the pulse wave per unit time with a counter (CNT) board. For example, in the case of a two-cycle engine, the number of ignitions is the engine speed, and in the case of a four-cycle engine, twice the number of ignitions is the engine speed.

  For example, as shown in FIG. 2, the waveform shaping circuit 6 is configured so that the LM741CN and 74LS28N portions constitute a waveform shaping circuit, and the 74LS06P portion adjusts the waveform to match the input specifications of the CNT board. ing.

  A commercially available CNT board can be used. For example, in this example, CNT24-4 (PCI) manufactured by Contec was used. The response frequency of this CNT board is 7700 Hz or more at the TTL level input, and in the case of a two-cycle high-speed engine, for example, the pulse generated by ignition at 12000 rpm is 200 Hz. Can respond.

  Here, in the circuit shown in FIG. 2, a waveform of the induced electromotive force (engine speed is about 9300 rpm) generated by engine ignition using a power source of V1 = 10 (V) and V2 = 5 (V) is shown in FIG. Shown in

  Further, FIG. 4 shows the result of counting the device output signal corresponding to the waveform of the induced electromotive force generated by the ignition of the engine shown in FIG. 3 with the CNT board. It was confirmed from FIGS. 3 and 4 that the ignition of the engine was correctly counted by the CNT board.

  Further, as a result of experiments at low, medium and high speeds, it was confirmed that the engine speed was accurately counted in the method and apparatus for measuring the rotational speed of the plug ignition internal combustion engine of the present invention.

Hereinafter, the case where the rotational speed measuring method and apparatus for a plug ignition internal combustion engine to which the present invention is applied is applied to altitude control of a small unmanned helicopter will be described as an example.
FIG. 5 is an explanatory diagram for explaining an outline of a small unmanned helicopter experimental apparatus to which the rotational speed measurement method and apparatus for a plug ignition internal combustion engine to which the present invention is applied is applied.

  The Ergo 230R model made by JRPROPO was used as the helicopter body for this experiment. The specifications of this helicopter are as follows: total length: 1570 mm, height: 645 mm, main rotor diameter: 1770 mm, tail rotor diameter: 265 mm, total weight: 6.1 kg, loading capacity: 4 kg, equipped with a two-cycle gasoline engine Has been.

  Here, the experimental helicopter 10 is constrained to rotate back and forth, right and left, by a slide guide 12 inserted through the pedestal 11 and a slide guide ring 13A inserted through the yawing motion stop rod 13.

  The experimental helicopter 10 is connected by a wire 14 and a safety spring 15 for altitude measurement and safety ensuring, and the altitude is calculated using an angle detected from the potentiometer 16. Altitude control is performed by controlling the engine speed of the helicopter and the pitch angle of the main rotor. That is, the engine speed is kept constant (target speed) and the aircraft can fly at an altitude set by pitch angle control.

Therefore, an experiment was conducted in which the engine speed of the experimental helicopter 10 was measured and the engine speed was controlled so that the measured engine speed became the target speed.
FIG. 6 shows the results of altitude control when the experimental helicopter 10 has its target altitude changed alternately from 20 cm to 30 cm. From FIG. 6, it was confirmed that the experimental helicopter 10 was shifted from the target altitude within an error range of ± 1 cm.

  Here, the pitch angle of the main rotor changes in order to follow the change in the target altitude of the experimental helicopter 10, and the air resistance changes accordingly, thereby changing the engine load, so that the engine speed is maintained. It is necessary to change the engine output in response to the load fluctuation.

  FIG. 7 shows the results of speed control of the engine speed corresponding to FIG. 6 (35 rev / 200 ms (10500 rpm)) and the engine speed during the flight of the experimental helicopter. On the other hand, it was confirmed that the engine speed was maintained at the target speed.

  From the above results, it was confirmed that the reliability of the measurement, that is, sufficient measurement accuracy was obtained by using the method and apparatus for measuring the rotational speed of the plug ignition type internal combustion engine of the present invention for a small unmanned helicopter control experiment. Furthermore, by applying it to a small unmanned helicopter control experiment, we were able to confirm the usefulness of the measurement method and its apparatus and its ease of application to a control system.

  The method and apparatus for measuring the rotational speed of a plug ignition internal combustion engine according to the present invention can be effectively applied not only to small unmanned helicopter flight control but also to control of other mechanical systems with gasoline engines.

BRIEF DESCRIPTION OF THE DRAWINGS It is principle explanatory drawing which shows the outline | summary of the rotational speed measuring method and its apparatus of the plug ignition type internal combustion engine to which this invention is applied. It is circuit explanatory drawing which shows an example of the waveform shaping circuit of the rotational speed measuring method of the plug ignition type internal combustion engine to which this invention is applied, and its apparatus. It is a graph which shows the waveform of the induced electromotive force produced by the ignition of the engine in a small unmanned helicopter experimental device. It is graph explanatory drawing which shows the result of having counted the apparatus output signal corresponding to the waveform of the induced electromotive force produced by the ignition of the engine in a small unmanned helicopter experimental apparatus with the CNT board. It is explanatory drawing which shows an example of the outline of the small unmanned helicopter experimental apparatus to which the rotational speed measuring method of the plug ignition type internal combustion engine to which this invention is applied, and its apparatus are applied. It is graph explanatory drawing which shows the result of the altitude control when changing the target altitude of the experimental helicopter in the small unmanned helicopter experimental apparatus alternately from 20 cm to 30 cm. It is graph explanatory drawing which shows the result of the speed control of the engine speed at the time of experimental helicopter flight in the experimental helicopter engine target speed (35rev / 200ms (10500rpm)) in a small unmanned helicopter experimental device. It is explanatory drawing which shows an example of the measurement means of the conventional engine speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotational speed measuring method and apparatus of ignition type internal combustion engine 2 Gasoline engine 3 Spark plug 4 Code 5 Induction coil 5A Diode 5B Resistance 6 Waveform shaping circuit 10 Experimental helicopter 11 Base 12 Slide guide 13 Yawing motion stop rod part 13A Slide guide Ring 14 Wire 15 Safety spring 16 Potentiometer

Claims (2)

Winding a coil around a cord for energizing the spark plug and generating an induced electromotive force in the coil for each ignition;
A waveform shaping step for shaping the ignition pulse wave generated by the induced electromotive force into a rectangular wave;
And a rotational speed detection step of detecting the rotational speed of the engine by counting the rectangular waves. A method for measuring a rotational speed of a plug ignition type internal combustion engine. An induced electromotive force generating means in which a coil is wound around a cord energized to the spark plug for each ignition;
Waveform shaping means for shaping the ignition pulse wave generated by the induced electromotive force generation means into a rectangular wave;
A rotation speed device for a plug ignition type internal combustion engine, comprising: a rotation speed detection means for detecting the rotation speed of the engine by counting the rectangular waves shaped by the waveform shaping means.

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