JP2724942B2 - Engine valve timing measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing measuring device for measuring the opening and closing timing of intake and exhaust valves of an engine.

[0002]

2. Description of the Related Art Conventionally, according to Japanese Patent Publication No. 2-55738, compressed air from an air source is supplied to a port formed in a cylinder head of an engine, and a crankshaft is forcibly rotated from the outside in this state. There is a known valve that opens and closes a valve, and detects a pressure change in the port due to the opening and closing with a pressure sensor to measure the opening and closing timing of the valve.
In this device, a seal plate is attached to a port opening surface of a cylinder head, and an air supply pipe connected to an air source is directly connected to an air supply hole formed in the seal plate to supply compressed air to the port.

[0003]

In the above prior art, the air supply hole is formed to have a small diameter so that the pressure in the port drops sharply when the valve is opened, and the response of the pressure change in the port due to the opening and closing of the valve. Is increasing the character. According to this, the measurement accuracy of the valve timing of a normal engine with one port and one valve can be ensured, but in a multi-valve engine having a plurality of valves in one port, the opening and closing timings of the plurality of valves are different from each other. In such a case, the pressure in the port drops sharply when the valve in the opening order is opened, so that the pressure drop width when the valve in the rear position is opened is small, and the valve in the rear position is opened. Timing cannot be measured accurately. In view of the above, it is an object of the present invention to provide an apparatus capable of accurately measuring the opening / closing timing of each of a plurality of valves of a multi-valve engine.

[0004]

In order to achieve the above object,
In the present invention, one port has different opening / closing timings.
A forcibly rotating a crankshaft of a multi-valve engine having a plurality of valves from the outside to measure the opening / closing timing of these valves, comprising: an air supply means for supplying a pressurized gas to the port; in those and detection means for detecting a change in pressure in the port <br/> over preparative accompanying the opening and closing, and a variable throttle means for varying the supply passage area to said port to said air supply means, a variable throttle means Control
To measure the opening / closing timing of the valve with the leading position.
In this case, make the air supply passage area relatively small, and
Air supply passage when measuring the opening / closing timing of
A control means for making the area relatively large is provided.

[0005]

When measuring the valve timing of a valve of a multi-valve engine having a leading valve opening order, the air supply passage area is reduced to a relatively small value, and the responsiveness of the pressure change in the port accompanying the opening and closing of the valve is enhanced. On the other hand, when measuring the valve timing of the valve of the multi-valve engine whose valve opening order is later, the supply passage area is made relatively large. According to this, the pressure drop in the port at the time of opening the valve of the preceding valve becomes relatively gentle due to the supply of the pressurized gas through the air supply passage, and when the valve of the succeeding valve is opened. Is larger than when the air supply passage area is reduced, so that the valve timing of the downstream valve can be accurately measured from the pressure change in the port.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, two intake and exhaust valves are provided for one cylinder.
The present invention is applied to measurement of valve timing of a multi-valve engine provided individually, and the drawing shows the intake side of the engine. As shown in FIGS. 1 and 2, an intake port 3 formed in the cylinder head 1 of the engine corresponding to each cylinder 2 has two branches connected to two _first and second intake valves 4 ₁ and 4 ₂ on the way. It branches into passages 3a and 3a. Figure 3 shows the opening change of the valve, a valve opening characteristic, b line of the second intake valve 4 ₂ opening characteristics of the drawing a line first intake valve 4 _1, the first intake valve 4 ₁ is the second intake valve 4 ₂
The valve opens early and closes late.

An air supply head 10 is mounted on the port opening surface of the cylinder head 1 so as to close the open end of the intake port 3. The air supply head 10 has a chamber 12 connected to an air source 11. The compressed air from the air source 11 is supplied to the intake port 3 through the chamber 12, and the detection passage 1 formed in the air supply head 10 is further formed.
3, a pressure sensor 14 connected to the intake port 3 via the pressure sensor 3 is provided.
4 to enable detection.

The air supply head 10 has an intake port 3
Is provided with a variable throttle means 15 for varying the area of the air supply passage with respect to. In the present embodiment, the variable aperture means 15
Are two orifice holes 16 ₁ and 16 _2, which are provided at the distal end of the air supply head 10 and communicate with the chamber 12 via the air supply passage 16 a, respectively, and a first orifice hole 16 having a relatively large diameter. ₁ and a shut-off valve 17 which is opened and closed by a cylinder 17a. The closing of the valve 17 reduces the size of the air supply passage area by the second orifice hole 16 ₂ having a relatively small diameter. The area of the valve 17
By opening the valve, the area of the air supply passage is enlarged to a relatively large area including the first and second orifice holes 16 ₁ and 16 ₂ .

Referring to FIG. 1, reference numeral 18 denotes a controller comprising a microcomputer. The controller 18 controls a motor (not shown) for rotating an engine crankshaft and a cylinder 17a for the shut-off valve 17, and A signal from the pressure sensor 14 and a signal from a crank angle sensor 19 for detecting a rotation angle (crank angle) of a crankshaft are input to the controller 18, and the first
And the opening / closing timing of the _second intake valves 4 ₁ and 4 ₂ are measured as described later.

Hereinafter, a procedure for measuring the valve timing will be described. First, the compressed air from the air source 11 is supplied to the intake port 3 via the air supply head 10 and the shutoff valve 17 is closed to reduce the area of the air supply passage, and the crankshaft is rotated at a low speed by the motor in this state. and opening and closing both the first and second intake valves 4 _1, 4 ₂ and. At this time, the pressure P in the intake port 3 is rapidly changed as shown in FIG. 4 (a) by the opening and closing of the first intake valve 4 _1, open from the change in detected pressure of the first intake valve 4 _first pressure sensor 14 to determine the valve when O ₁ and closing time C ₁ clearly measures a crank angle at the opening time O ₁ and closing time C ₁ as the first opening timing and closing timing of the intake valve 4 _1. However, appear sudden pressure change, the second intake valve 4 _second opening before and two valve only the first intake valve 4 ₁ even after closing is open 4 _1, 4 ₂ total opening a small area of the can not be clearly determine the second intake valve 4 _second opening time O ₂ and closing time C ₂ of the pressure change.

[0011] Therefore, after the measurement of the first intake valve 4 ₁ closing timing, to expand the supply passage area open shut-off valve 17, the second intake valve 4 is rotated again by the motor crankshaft in this state Measure the opening and closing timing of ₂ . The pressure change in the intake port 3 in this case is shown in FIG.
Becomes as shown in, the pressure change in a small region of the second intake valve 4 both valves 4 _{1 2} of the valve opening before and after closing, 4 ₂ total opening degree becomes moderate, the second intake valve 4 ₂ Abrupt pressure change occurs in a region where the total opening degree is large after the valve is opened or before the valve is closed. Therefore, to be able to determine the opening time O ₂ and closing time C ₂ of the pressure change in the second intake valve from the change point of regulation 4 ₂ detected by the pressure sensor 14, the opening time O ₂ and closed measuring the crank angle of the valve when C ₂ as the second opening timing and closing timing of the intake valve 4 _2.

Although the measurement of the valve timing on the intake side has been described above, the valve timing on the exhaust side can be similarly measured. In the above embodiment, the variable throttle means 15 is constituted by the pair of orifice holes 16 ₁ , 16 ₂ and the shut-off valve 17 closing _one of the orifice holes 16 ₁ , 16 _2. The variable throttle means may be constituted by a throttle valve having a variable area.

[0013]

As is apparent from the above description, according to the present invention, the opening / closing timing of each of a plurality of valves of a multi-valve engine can be accurately measured. Is sufficient, and the structure is simplified and an inexpensive device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of an example of the device of the present invention.

FIG. 2 is a plan view cut along the line II-II of FIG. 1;

FIG. 3 is a diagram showing operating characteristics of a valve;

4A and 4B are diagrams showing a pressure change in a port, where FIG. 4A shows a case where the air supply passage area is small, and FIG. 4B shows a case where the air supply passage area is large.

[Explanation of symbols]

3 intake port 4 ₁ , 4 ₂ intake valve 10 air supply head 11 air source 14 pressure sensor 15 variable throttle means

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuyuki Iwata 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References JP-A-61-182548 (JP, A)

Claims (1)

(57) [Claims] 1. The opening / closing timing of one port is mutually
By forcibly rotating the crankshaft of a multi-valve engine having a plurality of different valve from the outside there is provided an apparatus for measuring the open-close timing of these valves, the air supply means for supplying pressurized gas to the port, the valve Before opening and closing
Control in what and detection means for detecting a pressure change in the serial port, and a variable throttle means for varying the supply passage area to said port to said air supply means, a variable throttle means
To measure the opening / closing timing of the valve with the leading valve opening order
In this case, make the air supply passage area relatively small
When measuring the opening / closing timing of the rear valve, supply air
An engine valve timing measuring device, further comprising control means for relatively increasing a road area .