JPH04287739A - Electromagnetic pickup - Google Patents

Abstract

PURPOSE:To reduce the number of wires of a wire harness by incorporating a signal wave-form shaping/processing circuit and a constant-voltage power source for the wave-form shaping/processing circuit in an electromagnetic pickup detecting the engine rotating speed and timing for controlling an engine. CONSTITUTION:A coil 6 detecting the movement of the teeth 5 of the rotor 1 of an engine control system, a wave-form shaping circuit 7 shaping the signal wave-form outputted from the coil 6 into the desired wave-form, and its power source 10 are incorporated in an electromagnetic pickup 2, and they are connected to an engine control device 3 with a wire harness 4. A wire harness for feeding power to the electromagnetic pickup 2 from the power source 9 of the engine control device 3 is not required.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic pickup for a system that detects the rotational speed and timing of an engine using an electromagnetic pickup and controls the engine based on the detected rotational speed.

0002

[Prior Art] In recent years, as in the invention described in Japanese Unexamined Patent Publication No. 64-63814, the state of the engine is detected by various sensors in order to perform electronic control of the engine, and air-fuel ratio control, ignition timing control, etc. It is carried out. Of these,
A rotation speed sensor that detects engine speed, a crank angle sensor that detects crank angle, and a cam angle sensor that detects cam angle are installed close to the shaft directly connected to the engine, such as the crankshaft, camshaft, or distributor shaft. An electromagnetic pickup is used.

[0003] This electromagnetic pickup has a coil installed opposite to a toothed rotor (signal disk plate) attached to a crankshaft or the like, and as the engine rotates, the teeth of the rotor connect with the electromagnetic pickup body. When passing near the coil, the magnetic flux in the coil changes and a signal waveform is output. Based on this output, the engine control device detects engine speed, crank angle, cylinder discrimination, cam angle, etc.

FIG. 3 shows a schematic diagram of a conventional engine control system using an electromagnetic pickup. This engine control system includes a rotor 11 connected to a crankshaft 21 of an engine body 20, an electromagnetic pickup 12 disposed opposite to the rotor 11, and an electromagnetic pickup 12.
an engine control device 13 that controls the engine based on signals from the electromagnetic pickup 12 and the engine control device 1;
3 and a wire harness 14 that connects the two.

FIG. 2 shows the configuration of the conventional engine control system described above. Rotor 11 of this engine control system
Teeth 15 are provided on the outer periphery of. Further, the electromagnetic pickup 12 has a built-in coil 16 that detects engine rotation and a waveform shaping processing circuit 17 that processes the signal waveform output by the coil 16.
3 includes a microcomputer 18 and a microcomputer 18 for detecting engine speed, crank angle, cylinder discrimination, cam angle, etc. from the signal waveform processed by the waveform shaping processing circuit 17; A constant voltage power supply 19 for driving is built-in.

[0006] The signal waveform of this coil 16 provides an output exceeding 100V when the engine is rotating at high speed.
At low speed rotation, only an output of about several tens of mV can be obtained. On the other hand, ignition noise for engine ignition is present in the engine room where the electromagnetic pickup 12 and the engine control device 13 are housed. Therefore, the weak voltage from the coil 16 during low speed rotation is buried in the ignition noise and is difficult to detect. Therefore, as a measure against ignition noise, a shielded wire is used in the wire harness 14 that connects the electromagnetic pickup and the engine control device, but since this shielded wire is expensive, it is possible to take measures against noise without using this shielded wire. The realization of an engine control system is desired.

To this end, the present inventors proposed that in the invention described in the patent application filed at the same time as this application, the waveform shaping processing circuit 17 is disposed within the electromagnetic pickup 12 instead of within the engine control device 13. We are proposing a distinctive invention. However, in order to operate the waveform shaping processing circuit 17 built into the electromagnetic pickup 12, it is necessary to supply a driving constant voltage of about 5V. To do this, it is necessary to add one power line to the wire harness connecting the engine control device 13 and the electromagnetic pickup 12.
This not only increases the number of pins of the connector of the engine control device 13, but also increases the capacity of the constant voltage power supply 19 built into the engine control device 13.

The present invention solves the above-mentioned problem, without adding a power line to the wire harness connecting the engine control device and the electromagnetic pickup, increasing the number of connector pins of the engine control device and increasing the load on the constant voltage power supply for the engine control device. The objective is to obtain an electromagnetic pickup that does not require

[0009]

[Means for Solving the Problems] In order to solve the above problems, the present invention incorporates a constant voltage power supply for a waveform shaping processing circuit into an electromagnetic pickup.
A rotor that is connected to a shaft that is directly connected to the engine and has teeth on its outer periphery, an electromagnetic pickup that is placed opposite to the rotor and has a built-in coil, and an engine control that controls the engine based on signals from the electromagnetic pickup. and a wire harness connecting the electromagnetic pickup and the engine control device, the electromagnetic pickup is used in an engine control system, the electromagnetic pickup having a signal waveform detected by the coil as a desired signal. To provide an invention in which an electromagnetic pickup is characterized in that it has a built-in waveform shaping processing circuit for shaping a waveform and a constant voltage power supply for the waveform shaping processing circuit.

0010

[Operation] In the electromagnetic pickup according to the present invention, the power source for the waveform shaping processing device is built into the electromagnetic pickup together with the waveform shaping processing device, so that the power source for driving the waveform shaping processing device is routed through the wire harness of the engine control device. supplied directly without

[0011]

Embodiment Next, an embodiment of an engine control system using an electromagnetic pickup according to the present invention will be described with reference to FIG. The outline of this engine control system is basically the same as the conventional engine control system shown in FIG. It consists of an electromagnetic pickup 2, an engine control device 3 that controls the engine based on signals from the electromagnetic pickup 2, and a wire harness 4 that connects the electromagnetic pickup 2 and the engine control device 3.

Teeth 5 are provided on the outer periphery of the rotor 1. The electromagnetic pickup 2 includes a coil 6 for detecting the movement of the teeth 5, a waveform shaping processing circuit 7 for shaping the signal waveform detected by the coil 6 into a desired waveform, and a constant voltage power supply 10 for the waveform shaping processing circuit. Built-in. The engine control device 3 also includes a microcomputer 8 that detects engine speed, crank angle, cylinder discrimination, cam angle, etc. based on signals transmitted from the electromagnetic pickup 2.
A constant voltage power supply 9 for driving the microcomputer 8 is built-in.

[0013]

As explained above, since the electromagnetic pickup of the present invention incorporates a waveform shaping processing circuit and a constant voltage power supply for the waveform shaping processing circuit, it is possible to reduce the number of wires of the wire harness of the engine control device and the pins of the connector. The number can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an engine control system using an electromagnetic pickup of the present invention.

FIG. 2 is an explanatory diagram of an engine control system using a conventional electromagnetic pickup.

FIG. 3 is a schematic diagram of a conventional example of an engine control system using an electromagnetic pickup.

[Explanation of symbols]

1 Rotor 2 Electromagnetic pickup 3 Engine control device 4 Wire harness 5 Teeth 6 Coil 7 Waveform shaping processing circuit 8. Microcomputer

Claims (1)

[Claims] 1. A rotor that is connected to a shaft that is directly connected to the engine and has teeth on its outer periphery; an electromagnetic pickup that is disposed opposite to the rotor and has a built-in coil; An electromagnetic pickup used in an engine control system including an engine control device that controls the electromagnetic pickup and a wire harness that connects the electromagnetic pickup and the engine control device, the electromagnetic pickup having a signal waveform detected by the coil. An electromagnetic pickup characterized by having a built-in waveform shaping processing circuit that shapes the signal into a desired signal waveform, and a constant voltage power supply for the waveform shaping processing circuit.