JPS5817334A - Measuring device for suction pressure of internal combustion engine - Google Patents

Abstract

PURPOSE:To enable to perform an equal measurement of a suction pressure of each cylinder, by mounting suction pressure sensors at an equal distance from each suction valve. CONSTITUTION:Ends of 4 pressure feed pipes 20-23 are collected at one spot, and a suction pressure sensor 17 is coupled to said collecting spot. A signal, corresponding to a crank angle of an internal combustion engine, is generated by a crank sensor 24. The signal from the suction pressure sensor 17 is detected by a computing circuit 25 at a time when a crank is brought to a crank angle at which a suction valve of each cylinder opens to a full capacity. This permits measuring of a suction pressure produced at a time when the suction valve opens to its full capacity so that it most accurately corresponds to a suction air amount.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a device for measuring the pancreatic force of a multi-cylinder internal combustion engine with a throttle valve.

The intake pressure (intake negative pressure) of an internal combustion engine is an operating parameter that indicates the amount of load on the internal combustion engine. has also been put into practical use.

Therefore, when measuring intake pressure, it is necessary that the measured value accurately match the state of the cylinder during the intake stroke at that time, but with conventional devices, accurate measured values are not always possible. It's not something you can get.

FIG. 1 is an example of a conventional intake pressure measuring device.

In FIG. 1, 1 is an air cleaner, 2 is an intake manifold, 6 is a throttle valve, and 4 to 7 are intake boats.

8 to 11 are cylinders (combustion chambers), and 12 to 15 are intake valves 16 which are IE pressure introduction pipes. Reference numeral 17 denotes an intake UE sensor, which is composed of, for example, a diaphragm and a semiconductor strain sensor. 18 is a trigger signal generator installed in the distributor, which allows the distributor to rotate 180°.
A trigger signal S2 is output every time the motor rotates (560" in crank angle). Reference numeral 19 denotes an arithmetic circuit, which is composed of, for example, a microcomputer.

In the device shown in FIG. 1, intake air is sent from an air cleaner 1 to each intake port 4 to 7 via an intake manifold 2, and is then sent to each cylinder in the intake stroke, that is, the intake valve 1.
It is drawn into open cylinders 2 to 15 (cylinder 8 in FIG. 1).

The intake pressure at this time is sent to the intake pressure sensor 17 via the pressure introduction pipe 16, and the intake pressure sensor 17 outputs an intake pressure signal S1 corresponding to the intake pressure.

On the other hand, the arithmetic circuit 19 reads the intake pressure signal S1 every time the trigger signal S2 is given, calculates the basic injection amount according to that value and a rotational speed signal (not shown), and further performs correction based on temperature, etc. The injection amount is determined, and the fuel injection valve is controlled according to the determination result to perform fuel injection.

As mentioned above, in the conventional system, the intake manifold 2
The intake pressure is drawn out from the air by the pressure introduction pipe 16. However, since the length, shape, and angle of the intake port at which it is attached to the intake manifold are different for each cylinder, the pressure is not transmitted to the intake manifold depending on the cylinder. Because of the difference in intake manifold pressure, it is difficult to accurately measure the intake pressure of each cylinder by measuring the intake manifold pressure.

The timing for reading the output of the intake pressure sensor was also determined regardless of the opening of the intake valve, so there was a problem that an error occurred between the read value and the actual load amount (intake air amount). In addition, as mentioned above, in the conventional system, the positive 6W for each cylinder is
Therefore, the difference in air-fuel ratio between cylinders becomes large, which causes inconsistencies such as a decrease in torque, the occurrence of knocking, and a decrease in exhaust purification performance.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an intake pressure measuring device that can accurately measure intake pressure for each cylinder.

In order to achieve the above object, the present invention has the following features.

The structure is such that the intake pressure is measured when the intake valve is fully open, which corresponds most accurately to the intake air amount. In addition, an intake pressure sensor is provided at an equal distance from each intake valve, so that the intake pressure of each cylinder can be measured equally.

The present invention will be described in detail below based on the drawings.

FIG. 2 is a diagram showing one embodiment of the present invention, and FIG. 6 is a time chart of the operation of the apparatus shown in FIG.

In FIG. 2, four pressure introduction pipes 20 to 26 are connected to each of the intake ports 4 to 7, one each, and the lengths of all four are set to be the same.

One ends of the four pressure introduction pipes mentioned above are gathered into one, and the intake pressure sensor 17 is connected to the gathering portion.

On the other hand, the crank angle sensor 24 is built into the distributor, for example, and detects the crank angle of 720° and 18°.
0” and 2° (660°, 90° of distributor
720° signal S3, 180° signal S4 and 2° signal S5 are output for each angle (equivalent to 1° and 1°), respectively.

The 720° signal S is a signal for cylinder discrimination, and is output at the top dead center of the intake stroke of a specific cylinder, for example, the first cylinder.

In addition, the 180° signal S4 indicates the top dead center of each cylinder's intake stroke (
It is output at the point marked Δ in Fig. 6).

Therefore, by counting the number of 180° signals S4 after the 720° signal S3 is input, it is possible to determine which cylinder is in the intake stroke.

The 2° signal S5 is a signal for detecting the i↑ measurement point of the intake pressure, that is, the full opening timing of the intake valve.

As can be seen from the stroke diagram in Figure 6, in the intake stroke, the intake valve generally begins to open before the top dead center and fully opens after the bottom dead center, but the crank angle at which the intake valve fully opens is (indicated by an arrow in Figure 6).

In one engine, Q and V are constant. Therefore, from the time when the 180° signal S4 is input, the 2° signal S is measured, and when the integrated value is 1-, which corresponds to the fully open position, the intake pressure sensor It is sufficient to read the intake pressure signal S1 from No. 17.

The arithmetic circuit 25 performs the above-mentioned arithmetic operations.

FIG. 4 is a flowchart showing the calculation process of the calculation circuit 25.

The calculation shown in FIG. 4 is repeated every time the 720° signal S3 is input.

First, in P, NS4 and NS5 are set to 1. As shown in FIG. 6, NS4 and NS5 are the numbers s4 and 85, and are counted by a counter (not shown). Note that the value of NS4 is cleared every time s3 is input, and 9=! The value of NS5 is cleared every time s4 is input.

Next, it is determined whether N54=1 at P.

When P2 is YIkoS, that is, when l'Js4==1, it indicates that the first cylinder is in the ignition stroke.

At P3, it is determined whether NSλ-In or not.

Note that m is a constant, and when NS = In, the intake valve is fully open.

Therefore, P2 and P5 are repeated in the trench where the value of NS5 counted by the counter becomes In, and when P3 becomes YES, the value of the intake pressure signal S is measured in P4, and the value of the intake pressure signal S is measured in P5. is stored as the intake pressure.

Thereafter, in the same manner, the intake pressures when the intake valves are fully open are measured and stored in the order of the 6th cylinder, the 4th cylinder, and the 2nd cylinder.

As described above, in the present invention, it is possible to measure the intake pressure when the intake valve is fully open, which corresponds most accurately to the intake air amount, and also to determine which cylinder is in the intake stroke at that time, and to determine the intake pressure of that cylinder. can be accurately measured by pressure introduction tubes connected to each intake port. Therefore, since it is possible to inject fuel in an amount that accurately corresponds to the amount of intake air in each cylinder, it is possible to make the air-fuel ratio of each cylinder the same, which improves engine output, prevents knocking,
Effects such as improved exhaust purification performance can be obtained.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional device, Fig. 2 shows an example of the present invention, Fig. 3 shows a time chart of the device shown in Fig. 12, and Fig. 4 shows the calculation process of the device shown in Fig. 2. It is a flowchart. Explanation of symbols To air cleaner 2... Intake machine = Holt 6...
- Throttle valve 4-7... Intake port 8-11 - Cylinder 12-15... Intake valve 16 - Pressure introduction pipe 1
7.Intake pressure sensor 18...Trigger signal generator 19.Arithmetic circuit 20-25...Pressure introduction pipe 24 Crank angle sensor 25.Arithmetic circuit Patent attorney Junnosuke Nakamura 1 Figure

Claims (1)

[Claims] 1. In a multi-cylinder internal combustion engine having a throttle valve. An intake pressure sensor is installed at a position equidistant from the intake valve of each cylinder in the pressure system, and a crank angle sensor that generates a signal corresponding to the crank angle of the internal combustion engine is input. and an arithmetic circuit that detects the signal of the intake pressure sensor when the crank angle is such that the intake valve is fully open, and the internal combustion engine is characterized in that the intake pressure is measured when the intake valve of each cylinder is fully open. Intake pressure measuring device. 2 Connect equal length pressure introduction pipes to the intake ports of each cylinder,
An apparatus for measuring intake force for an internal combustion engine according to claim 1, characterized in that one ends of these pressure introduction pipes are gathered together and an intake pressure sensor is attached to the gathering part.