JP2000088710A - Engine inspecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine inspecting method with high performance in detecting failures in engines in which repair is easy even in the case of the presence of failures in engines. SOLUTION: A plate is provided with both an air passage 14 which can be connected to the inside of a cylinder bore 15 of a cylinder block 16 and be opened and closed by a check valve 9 and a pressure sensor 10 capable of measuring the pressure in the cylinder bore 15. A crankshaft 11, a piston 12, and a connecting rod 13 are assembled to the cylinder block 16 in an engine 1. By this plate, the upper opening of the cylinder bore 15 of the engine 1 is blocked to rotate the crankshaft 11. By this, the piston 12 is vertically moved, and the pressure sensor 10 measures the pressure in the cylinder bore 15 at the time when the check valve 9 is opened and closed in response to the vertical movements of the piston 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an engine inspection method.

[0002]

2. Description of the Related Art Conventionally, in order to inspect an engine for a defect, a pressure sensor is mounted on an ignition plug mounting portion as disclosed in, for example, Japanese Patent Application Laid-Open No. 56-18739, and the compression pressure of each cylinder of the engine is measured. There is a known way. If the measured compression pressure does not show the proper value,
It is determined that there is an engine failure.

[0003]

However, in the conventional method, the compression pressure is measured after the engine has been assembled except for the spark plug. For this reason, when it is determined that the cylinder head is defective, the cylinder head must be removed, and much time is required for repair. In addition, one of the factors determined to be defective includes a variation in the volume of the cylinder head, so that the defect detection power is reduced. SUMMARY OF THE INVENTION An object of the present invention is to provide an engine inspection method that can be easily repaired even if an engine failure occurs and has a high engine failure detection power.

[0004]

The present invention to achieve the above object is as follows. A crankshaft, a piston, and a connecting rod are assembled to the cylinder block by a plate having an air passage that can communicate with the cylinder bore of the cylinder block and can be opened and closed by a check valve and a pressure sensor that can measure the pressure in the cylinder bore. By closing the upper opening of the cylinder bore of the engine and rotating the crankshaft,
An engine inspection method, wherein the piston is moved up and down, and the pressure in the cylinder bore when the check valve is opened and closed according to the up and down movement of the piston is measured by the pressure sensor.

[0005] In the above engine inspection method, the upper opening of the cylinder bore of the engine in a state where the crankshaft, the piston and the connecting rod are assembled to the cylinder block is closed by the plate, and the check valve is moved in accordance with the vertical movement of the piston. Since it is opened and closed, a state of the intake / compression process corresponding to a normal engine to which the cylinder head is attached is obtained. Then, by measuring the pressure in the cylinder bore when the check valve is opened and closed, it is possible to determine whether or not the engine is defective. Since the cylinder head is not attached, even if there is a defect in the engine, it is easy to make a correction, and the defect detection power is high because it does not include a defect due to a variation in the volume of the cylinder head.

[0006]

FIG. 1 shows an engine inspection method according to an embodiment of the present invention, and FIG. 2 shows compression pressure and crankshaft rotation in one cylinder measured by performing the engine inspection method according to the embodiment of the present invention. The angle relationship is shown.

The engine 1 to which the engine inspection method of the embodiment of the present invention is applied includes a cylinder block 16 having a crankshaft 11 and a plurality of pistons (for example, four pistons).
) And a plurality (the same number as the number of pistons) of connecting rods 13 are assembled. Therefore, it is in a state before the cylinder head is attached. A metal bearing (not shown) is used between the crankshaft 11 and each connecting rod 13.
A piston ring is mounted on the piston 12.

First, an apparatus for carrying out an engine inspection method according to an embodiment of the present invention will be described. As shown in FIG. 1, one plate 7 is used in the engine inspection method according to the embodiment of the present invention. The plate 7 has a plurality of air passages 1 each of which can be opened and closed by a check valve 9 and can communicate with each of the cylinder bores 15 of the cylinder block 16.
4 and a plurality of pressure sensors 10 for measuring the pressure in each cylinder bore 15. Pressure sensor 1
0 is buried in the plate 7 and the tip surface is
Is on the same plane as the lower surface of. A plurality of O-rings 8 are arranged on the lower surface side of the plate 7.

Further, a rotating device for rotating the crankshaft of the engine is used. The rotating device includes a drive shaft 4 detachable from the crankshaft 11, a drive shaft 4
, And a motor 5 for driving the drive shaft 4 to rotate. An encoder for measuring the rotation angle of the crankshaft 11 is attached to the drive shaft 4. The bearings 2 and 3 and the motor 5 are supported on a base 6.

Next, a description will be given of an engine inspection method according to an embodiment of the present invention, which is performed by using the above-described apparatus. First, the crankshaft 11, the piston 12, and the connecting rod 13 are assembled to the cylinder block 16, and the plate 7 is placed on the upper surface of the engine 1 supported by the base 6. Each air passage 14 of the plate 7 communicates with each cylinder bore 15 of the cylinder block 16, and each pressure sensor 10 of the plate 7 faces each other.

The plate 7 is pressed against a cylinder block 16 by a cylinder (not shown). By disposing the O-ring on the plate 7, the upper opening of the cylinder bore 15 is sealed by the plate 7.

Subsequently, the drive shaft 4 is connected to the crankshaft 11. At this time, the axis of the crankshaft 11 and the axis of the drive shaft 4 match. And the motor 5
As a result, the drive shaft 4 rotates, the crankshaft 11 rotates, and each piston 12 moves up and down. Piston 12
Rises, the pressure in the cylinder bore 15 increases, the check valve 9 closes, and the air passage 14 communicating with the cylinder bore 15 closes. When the piston 12 descends, the pressure in the cylinder bore 15 decreases, the check valve 9 opens, and the cylinder bore 15
The air passage 14 communicating with the inside is opened. Thereby, the cylinder head is attached and the crankshaft 1
A state corresponding to the normal intake / compression step of the engine, in which the valve opens in conjunction with the movement of 1, is realized by a simple method.

By measuring the pressure (compression pressure) in each cylinder bore 15 when the check valve 9 is opened and closed by the pressure sensor 10, the measurement waveform of the compression pressure in the cylinder bore 15 as shown in FIG.
Obtained separately for each cylinder. The maximum value is detected (measured) from the measured waveform for each cylinder.
Then, each maximum value is compared with a standard value indicated by the engine 1 when there is no defect. If the measured (detected) value is smaller than the lower limit of the standard value, the piston ring is not properly expanded, the piston ring is missing, the piston ring is broken, the cylinder bore diameter is large, the piston outer diameter is small, or the metal bearing is defective. It is determined that there is an engine failure such as. If the measured (detected) value is larger than the upper limit of the standard value, it is determined that there is an engine failure such as a small cylinder bore diameter or a large piston outer diameter.

In the embodiment of the present invention, since the engine 1 in which the cylinder head is not assembled is inspected, even if it is determined that there is a defect, it is compared with a normal engine in which the cylinder head is assembled. The time required for reworking is short. In addition, the cause of the failure does not include the variation in the volume on the cylinder head side, but only the variation on the cylinder block 16 side. Therefore, the variation in the compression pressure is small and the defect detection power is high.

[0015]

According to the engine inspection method of the present invention,
It measures the pressure in the cylinder bore of the engine before the cylinder head is assembled, and can detect engine failure, so it is necessary to repair the engine if it is defective compared to the engine with the cylinder head installed The time is short, and the defect detection power is high.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an engine inspection method of the present invention.

FIG. 2 is a graph showing a relationship between a crank rotation angle and a compression pressure obtained by an engine inspection method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 7 Plate 9 Check valve 10 Temperature sensor 11 Crankshaft 12 Piston 13 Connecting rod 14 Air passage 15 Cylinder bore 16 Cylinder block

Claims (1)

[Claims] 1. A cylinder rod having a crankshaft, a piston, and a connecting rod formed by a plate having an air passage which can communicate with a cylinder bore of a cylinder block and can be opened and closed by a check valve, and a pressure sensor capable of measuring a pressure in the cylinder bore. By closing an upper opening of a cylinder bore of an engine in which the piston is vertically moved by rotating the crankshaft, the cylinder bore when the check valve is opened and closed in accordance with the vertical movement of the piston. An engine inspection method, wherein the internal pressure is measured by the pressure sensor.