ENGINE ROTATING METER

• US 20090165541A1
• Filed: 04/06/2006
• Published: 07/02/2009
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: Oppama Industry C., Ltd.
• Original Assignee: Oppama Industry Co., Ltd. (Yamabiko Corporation)
• Inventors: Iwata, Masao, Kawahara, Atsushi, Takano, Toshiyuki, Matsuda, Fumitake
• Granted Patent: US 7,913,547 B2
• Time in Patent Office: Days
• US Class Current: 73/114.250
• CPC Class Codes: G01P 3/48 by measuring frequency of generated current or voltage in general G01R23/00
• CPC Class Codes: G01P 3/4807 by using circuits for the detection of the pulses delivered by the ignition system of an internal combustion engine

Abstract

A level adjusting circuit which adjusts input pulses from an antenna to a level suitable for determining the number of engine revolutions, is connected in a circuit that connects the antenna with a determining circuit. An optimum adjustment of the determination level by manual operation allows the pulses inputted to the determining circuit to be precisely determined at all times.

Claims

1. An engine rotating meter comprising an antenna which induces and detects an electromagnetic wave generated in an ignition system of an engine, and a measurement processing circuit which measures an engine speed based on a pulse of the electromagnetic wave detected by the antenna, wherein a level adjusting circuit which adjusts the electromagnetic wave from the antenna to a level suitable for performing a measurement processing of the engine speed is connected to an intermediate point of a circuit which connects the antenna and the measurement processing circuit.

2. The engine rotating meter according to claim 1, wherein the level adjusting circuit is formed of a variable resistance connected to a point between the circuit which connects the antenna and the measurement processing circuit, and a ground.

3. The engine rotating meter according to claim 1, wherein the level adjusting circuit is formed of a variable capacitor connected to a point between the circuit which connects the antenna and the measurement processing circuit, and a ground.

4. The engine rotating meter according to claim 1, wherein the level adjusting circuit is formed of a variable resistance and a capacitor which are connected to a point between the circuit which connects the antenna and the measurement processing circuit, and a ground.

5. The engine rotating meter according to claim 1, wherein the antenna includes an electromagnetic wave receiving section with an electromagnetic wave receiving surface larger than that of other component so as to be moved adjacent to an engine ignition system, and an antenna lead having a leading end connected to the electromagnetic wave receiving section to lead a signal derived from an induction detection.

6. The engine rotating meter according to claim 5, wherein the electromagnetic wave receiving section is formed of a conductive plate attached to the leading end of the antenna lead.

7. The engine rotating meter according to claim 5, wherein the electromagnetic wave receiving section is formed by shaping the leading end of the antenna lead into a loop with a diameter substantially the same as that of an ignition coil for generating the electromagnetic wave.

8. The engine rotating meter according to claim 5, wherein the electromagnetic wave receiving section is attached to the leading end of the antenna lead such that an area of an electromagnetic wave receiving surface is adjustable.

9. The engine rotating meter according to claim 5, wherein the electromagnetic wave receiving section is attached to the leading end of the antenna lead such that an angle in a wave receiving direction is adjustable.

10. The engine rotating meter according to claim 5, wherein the electromagnetic wave receiving section is formed of a conductive suction cup attached to the leading end of the antenna lead.

11. The engine rotating meter according to claim 5, wherein an antenna jack connectable to a socket formed in a body of the engine rotating meter for inputting a signal at an end of the antenna lead opposite an end where the electromagnetic wave receiving section is provided.