JP2000028458A - Pressure detector - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a compact and inexpensive pressure detecting device for engine control that is resource-saving and easy to use. SOLUTION: Two sensor chips (for intake pressure detection and atmospheric pressure detection) having the same characteristics are housed on the same side of one housing, each of which is separated from the pressure detection gas in a gas-tight manner, and on the opposite side. In addition, a common signal processing circuit board is arranged, and furthermore, a projection is provided on the intake pressure introducing pipe, so that it is resource-saving, easy to use, compact, easy to manufacture and inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for detecting pressure, and more particularly to a pressure detecting device used for controlling an engine of an automobile.

[0002]

2. Description of the Related Art As a conventional pressure detecting device, for example, there is a pressure sensor described in Japanese Patent Application No. 1-96872. FIG. 3 is a sectional view showing a sensor package structure disclosed in the above publication. Sensor chip case 41 containing pressure detection gauges 42 and 43 in sensor package 40
Are stored. The output of the sensor is connected to a lead pin terminal 45 connected to the sensor chip by a wire bonding wire 44 and a package terminal 46 and taken out to the outside. One sensor is housed in one housing. Since this sensor package is provided with mounting screws, it can be directly mounted on the intake pipe of the engine, and there is no need for piping.

[0003]

FIG. 2 shows an example of an engine control system using a pressure sensor. An intake pressure sensor 31, a throttle opening sensor 32, a temperature sensor 33, and an injector 34 for measuring intake pressure are attached to the intake pipe side. Apart from this, a control unit 35 equipped with an engine control microcomputer and the like is provided. In engine control, for the purpose of environmental protection, fuel saving, and the like, an optimum fuel is injected and supplied to the amount of intake air for combustion, so that it is necessary to accurately measure the amount of intake air. For this purpose, signals such as the intake pressure, throttle opening, intake temperature, engine speed, and atmospheric pressure are input to the control unit 35 to accurately calculate the intake air amount. An air-fuel ratio sensor 36 is mounted on the exhaust pipe side, and returns the result of the air-fuel ratio of the air-fuel mixture.

[0004] In the above system, two pressure signals of the suction pressure and the atmospheric pressure are indispensable, and conventionally, two sensors are separately used. Even though this does not cause any special problems, there are problems such as a high sensor cost and a large mounting volume.

SUMMARY OF THE INVENTION An object of the present invention is to store two pressure sensors for engine control in a single package to save resources, to improve usability, to reduce the size, and to reduce costs.

[0006]

In order to solve the above-mentioned problems, in a pressure detecting device according to the present invention, two sensor chips are housed in one housing in order to greatly reduce the number of parts, and furthermore, the sensor characteristics are improved. Is adjusted to one circuit board for signal processing, and signals from two sensor chips are input simultaneously. Furthermore, in order to facilitate output characteristic adjustment,
Since the suction pressure and the atmospheric pressure are substantially in the same pressure range, a sensor chip having the same detection characteristics and manufactured in the same specification and process is used.

[0007] Thus, the characteristics of the pressure-output of the sensor can be adjusted at the same time. Also, by using a common circuit board for processing the pressure detection signal of the sensor chip,
Atmospheric pressure and its differential pressure can be easily output. Further, by providing the pressure introduction chamber and the storage room for the signal processing circuit section separately at the top and bottom, the package can be made compact even if two sensor chips are stored.

When adjusting the output, pressure is applied to the sensor chip surface, and the output adjustment resistor provided on the signal processing circuit board is trimmed to a predetermined output value. Since the surface for applying pressure to the chip and the surface of the signal processing circuit board for pressure-output adjustment are separated into upper and lower surfaces and can be formed on opposite surfaces, the output adjustment work becomes easy. In addition, large and small projections are provided on the pressure introduction pipe to prevent errors during mounting piping.

[0009]

FIG. 1 is a sectional view of a pressure detecting device according to the present invention.

In this embodiment, sensor chip cases 1 and 2, sensor chips 3a and 3b, signal lead-out terminals 5a,
5b, bonding wires 4, 6, sensor output adjustment signal processing board 7, terminal 9, connection wire 8 between board circuit and terminal,
Sensor housing 10, pressure introduction chambers 11a and 11b, circuit board side chamber 12, intake pressure introduction protrusion 14, atmospheric pressure introduction hole 1
It consists of 5 mag. The sensor housing 10 has a partition 16 and divides the areas of the sensor chip cases 1 and 2. A sensor chip 3 for detecting pressure is adhered and fixed to the sensor chip case, and a signal extraction lead terminal 5 integrally molded with the chip case is connected to the chip with a wire 4. Fluorosilicone gel 17 is coated on the sensor chip to protect it from contaminants in the pressure measurement gas. The pressure introducing chambers 11a and 11b are airtightly separated by an adhesive 13.

A circuit board 7 on which a sensor signal processing circuit is formed
Are bonded and fixed to the back surface of the sensor chip case, and input a signal from the sensor chip to the processing circuit via the bonding wire 6. The sensor package terminal 9 changes according to the final output number. Since the GND and the power supply may be common, 2
The number of terminals is four at the time of output and five at the time of output, and the number of one or two terminals is reduced as compared with the case of using two sensors individually. The work of adjusting the output requires the application of pressure,
It is also advantageous in terms of adjustment that the pressure application surface and the front side of the signal processing circuit board including the circuit for performing adjustment are opposite surfaces. Further, the detection range of the intake pressure and the atmospheric pressure is 0.5 to 0.5.
Since the level is the same as about 1 atmosphere, the output adjustment of the two sensor chips can be performed simultaneously. Furthermore, by mounting and fixing the housing with the circuit board side as the top side, there is no accumulation of moisture in the measurement gas on the sensor chip surface, which is advantageous in reliability.

[0012]

By housing two sensors in one housing, the number of parts can be greatly reduced.
That is, the use of resources such as a housing, a cover, a signal processing circuit board, and terminals can be significantly reduced. Using a sensor chip having the same specifications and the same output characteristic specifications manufactured in the process, the pressure application surface for output adjustment and the surface of the signal processing circuit board for output adjustment are arranged to be opposite to each other. This facilitates the assembly adjustment work. Furthermore, by inputting the output signals from the two sensor chips to the same signal adjustment processing circuit board and adjusting them, it is possible to easily adjust the output form of the desired sensor.

Accordingly, by adopting such a configuration, it is possible to supply a compact and inexpensive engine control sensor which saves resources, is easy to use, and has good usability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure detecting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an engine control system.

FIG. 3 is a sectional view showing a conventional sensor.

[Explanation of symbols]

1,2 ... Sensor chip case, 3 ... Sensor chip, 4 ...
Bonding wire, 5 ... Lead terminal, 6 ... Bonding wire, 7 ... Signal processing circuit board, 8 ... Wire, 9
... package terminal, 10 ... housing, 11 ... measurement pressure introduction chamber, 12 ... circuit board side chamber, 13 ... adhesive, 14 ... pressure introduction protrusion, 15 ... pressure introduction hole, 16 ... partition, 17
... Fluorosilicone gel, 18 ... Cover.

Continued on the front page (72) Inventor Satoshi Shimada 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. In the Automotive Equipment Division of Hitachi, Ltd. (72) Inventor Keiji Hanzawa 2477 Takaba, Hitachinaka-shi, Ibaraki Prefecture Inside Hitachi Car Engineering Co., Ltd. (72) Seiji Kuryu 2477 Takaba, Hitachinaka-shi, Ibaraki Hitachi, Ltd. Inside Car Engineering (72) Inventor Junichi Horie 2520 No. Odaiba, Hitachinaka-shi, Ibaraki F-term (Reference) 2F055 AA01 AA22 BB05 CC60 DD20 EE40 FF43 GG11

Claims (3)

[Claims] In a pressure detecting device, one package is provided with an atmospheric pressure and intake pressure detecting sensor, and the two sensors have the same characteristics, and respective signals are processed by a circuit provided on the same substrate. A pressure detecting device having a structure provided on the opposite side of the substrate. 2. The pressure detecting device according to claim 1, wherein
A pressure detection device characterized in that only the intake pressure introduction pipe is provided with a projection out of the atmospheric pressure introduction pipe and the intake pressure introduction pipe. 3. The pressure detecting device according to claim 1, wherein
A pressure detecting device, wherein a signal processing circuit of the sensor outputs two or three of atmospheric pressure, intake pressure, and a differential pressure between atmospheric pressure and intake pressure.