JPS59122915A - Gas flow rate measuring device for vehicle engine - Google Patents

Abstract

PURPOSE:To omit an occupying space for a detecting circuit, by constituting a local flow rate sensor and the detecting circuit as different bodies, attaching the local flow rate sensor to a throttle body, and attaching the detecting circuit to a body mounting member. CONSTITUTION:An HW sensor 5 as a local flow rate sensor is located at the upstream side of a throttle valve 3 and also in the vicinity of the throttle valve 3. When the throttle valve 3 is rotated in the direction of an arrow A with respect to a central axis 0-0 of an intake air path 2, the throttle valve 3 is moved farther from the sensor. The sensor is deviated upward from the central axis 0-0. Said HW sensor 5 is fixed to a throttle body 1 through a fixing tool 7 made of Bakelite and the like. The fixing tool 7 prevents the intrusion of external air through the gap between the HW sensor 5 and the throttle body 1. The detecting circuit is electrically connected to the HW sensor 5 through a lead wire 8. The detecting circuit 6 is attached to a body 9 and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the flow rate of gas, such as the amount of intake air, in an engine mounted on a vehicle.

For example, Niresin, which uses an electronic fuel injection device installed in a vehicle, automatically controls the amount of fuel injection according to the amount of intake air. Requires quantity measuring equipment. As this type of constant device, a local flow rate measuring device is employed because measuring the total amount of intake air would require a large and complicated device. This device measures the flow rate or flow velocity of a part of the intake passage using a local flow rate sensor, calculates the local flow rate data measured by the sensor into a total flow rate using a detection circuit, and outputs a signal as the total flow rate from the detection circuit. is sent to the engine control converter (ECU). Local flow measuring devices of this type therefore include a local flow sensor and a detection circuit.

Note that a hot wire current meter (hereinafter referred to as HW sensor) is known as a representative example of the local flow rate sensor.

By the way, the above-mentioned local flow rate measuring device has conventionally been installed as shown in FIG. In other words, 1 is a throttle body, 2 is an intake passage in the throttle body 1, 3 is a throttle valve, 4 is a throttle shaft, 5 is a HW sensor, and 6 is a throttle body.
is the detection circuit. The amount of intake air in the intake passage 2, which is controlled by the opening degree of the throttle valve 30, is measured as a local flow rate by the HW sensor 5, and the HW sensor 5 sends an electrical signal corresponding to this local flow rate to the detection circuit 6. . This detection circuit 6
The system receives the electrical signal of the local flow rate, converts it to the overall flow rate, and generates an electrical signal commensurate with the overall flow rate.

By the way, since the HW unit 5 faces into the intake passage 2, it is attached to the throttle body 1, but in the past, the detection circuit 6 was also attached to the throttle body 1, as can be seen from FIG. When the detection circuit 6 is attached to the throttle D1, the detection circuit 6 occupies a large space, so the connection space for the intake pipe connected to the air cleaner side becomes extremely small, making it difficult to perform piping connection work. Furthermore, since the detection circuit 6 occupies a large space, the mounting position of the HW sensor 5 is also restricted, making it impossible to expect highly accurate measurements. Furthermore, since the throttle body 1 is subjected to engine vibrations, the detection circuit 6 is also vibrated, which causes problems such as early wiring failures and deterioration of circuit components.

The present invention was developed based on the above circumstances, and it is possible to secure sufficient connection space for other piping, increase the degree of freedom in mounting the local flow rate sensor (HW SEFT, etc.), and furthermore, the detection circuit is designed to prevent engine vibrations. It is an object of the present invention to provide a gas flow measuring device for an engine in a vehicle that is difficult to absorb and has increased durability.

That is, the present invention is characterized in that the local flow rate sensor is installed in the throttle body, but the detection circuit is installed in the vehicle body or a member mounted on the vehicle body other than the engine.

An embodiment of the present invention will be described below based on the drawings from FIG. 2 onwards.

The intake passage 2 of the throttle body 1 shown in FIGS. 2 and 3 is opened and closed by a throttle valve 3 attached to the throttle body 1 via a throttle shaft 4, as in the conventional case shown in FIG. be. H as local flow rate
The W sensor 15 is located on the upstream side of the throttle valve 3, close to the throttle valve 3, and located at the center axis 0-0 of the intake passage 2.
The throttle valve 3 is preferably provided at a position where the throttle valve 3 moves away when the throttle valve 3 is rotated in the direction of the arrow, that is, deviated upward from 0-0 in FIG. This HW sensor 5 is attached to the throttle body 1 via a fixture 7 made of Bakelite, for example, and this fixture 7 prevents outside air from entering through the gap between the HW sensor 5 and the throttle body 1. It also has a sealing effect. The detection circuit 6 is electrically connected to the KW sensor 5 via a lead wire 8, and is attached to a vehicle body 9, for example. The vehicle body 9 is fixed together with an engine control computer (ECU) 11 below the passenger seat in a vehicle interior 10 shown in FIG. In FIG. 4, 12 is an engine, 13 is an air cleaner, 14 is an intake pipe, 15 is an air chamber, 16 is a circuit Orzoni/Grillay, 17 is a main relay, and 18 is a fuel pump.

In the embodiment with such a configuration, when the throttle valve 3 is rotated in the direction of the arrow in conjunction with the operation of an accelerator pedal (not shown), the opening degree of the intake passage 2 increases, so that the air cleaner 13, the intake pipe 14. Air is drawn into the engine 12 through the intake passage 2 and the air chamber 15. In the intake passage 2, a HW sensor 5 locally detects the amount of intake air. Since the HW sensor 5 is provided close to the throttle valve 3, it is easy to detect changes in the amount of intake air that is controlled according to the opening degree of the throttle valve 3, and has good throttle response. Moreover, the HW sensor 5 is provided offset above the center line O-0 in FIG. 2, and this position is opposite to the side from which the throttle valve 3 moves away when the throttle valve 3 is opened. Therefore, it is difficult to be affected by turbulence generated on the upstream side of the throttle valve 3, and therefore, highly accurate flow rate detection is possible.

Overwrite i! The local flow rate detected by the HW sensor 5 is transmitted as an electrical signal according to the local flow rate, and the lead wire 8
The signal is transmitted to the detection circuit 6 via. The detection circuit 6 calculates the total flow rate in the intake passage 2 based on the local flow rate signal. Then, an electrical signal corresponding to this total flow rate, such as a voltage signal, is sent to the ECU 11. As shown in FIG. 5, the ECU 11 also inputs other factors depending on the operating status of the engine 12, such as engine speed N, load Q, engine temperature T, and other data from each sensor, and uses these data. The data is compared and calculated to determine the fuel injection amount. The ECU 11 then sends a signal corresponding to the calculated fuel injection amount to an electromagnetic injection valve (not shown) to supply each cylinder with a fuel amount corresponding to the operating condition.

According to this embodiment, since the detection circuit 6 is attached to the vehicle body 9 side, the space in the throttle body 1 is increased. Therefore, the degree of freedom in the mounting position of the HW sensor 5 is increased, and as described above, the HW sensor 5 can be placed as close to the throttle valve 3 as possible on the upstream side of the throttle valve 3, and responsiveness can be improved. Further, the intake pipe 14 connected to the air cleaner 13 can be easily connected.

On the other hand, since the detection circuit 6 is attached to the vehicle body 9 side, it is not directly affected by the vibrations of the engine 12, increasing durability and eliminating the need to worry about a vibration-resistant structure.

Note that the present invention is not limited to the above embodiments.

For example, instead of attaching the detection circuit 6 to the vehicle body 9, the detection circuit 6 may be attached to the ECU 11 or the circuit opening relay 16, and may be attached to a mounting member other than the engine 12 in the engine room, such as an air cleaner 13. It may also be installed on parts with low vibration, such as.

Further, the local flow rate sensor is not limited to the HW sensor 5, but may be any sensor that detects the entire flow rate in a part of the ventilation passage and converts it into an electrical signal.

Furthermore, the present invention is not limited to measuring the intake air amount of the engine, but may also measure the exhaust amount and other ventilation amounts.

According to the present invention as described above, the local flow rate sensor and the detection circuit are configured separately, and the local flow rate sensor is attached to the throttle body, and the detection circuit is attached to the vehicle body or a member mounted on the vehicle body other than the engine. , the space occupied by the detection circuit in the throttle body is no longer required.

Therefore, the degree of freedom in mounting the local flow rate sensor is increased, and the space for connecting the throttle body to the intake pipe is also increased, making the connection work easier. Moreover, since the detection circuit is not directly affected by engine vibration, it has the advantage of increased surface durability and the ability to simplify the vibration-resistant structure.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view for explaining a conventional structure, Fig. 2 and the following show an embodiment of the present invention, Fig. 2 is a partially sectional side view, and Fig. FIG. 4 is an illustration of the arrangement in an automobile, and FIG. 5 is an illustration of the operation of the ECU. l...throttle body, 2...intake passage, 3...
- Throttle valve, 5... HW sensor (local flow rate sensor), 6... detection circuit, 8... lead wire, 9... vehicle body, 11... ECU, 12... engine.

Claims (1)

[Claims] The airflow inside the throttle body, which is controlled to open and close by the throttle valve, is measured by a local flow rate sensor that measures the local flow rate and converts it into an electrical signal, and the local flow rate signal sent from the local flow rate sensor is sent to a detection circuit. In the gas flow measuring device that calculates the total flow rate of the throttle body and generates an electrical signal corresponding to the total flow rate from the detection circuit, the local flow rate sensor and the detection circuit are configured separately, and the local flow rate sensor is A gas flow rate measuring device for an engine in a vehicle, characterized in that the detection circuit is attached to a throttle body and a detection circuit is attached to a vehicle body or a member mounted on the vehicle other than the engine.