JP2809983B2 - Engine exhaust valve test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust valve testing device for an engine, and more particularly, to a situation similar to a case where an exhaust valve is installed in an actual engine by using an L head type single cylinder engine for testing. The present invention relates to an engine exhaust valve testing device that can be tested under:

[0002]

2. Description of the Related Art Various engine parts have been tested to improve the performance and durability of a spark ignition internal combustion engine for an automobile. Among such engine parts, an exhaust valve device is characterized in that high-temperature and high-pressure exhaust gas flows between a valve and a valve seat at a high speed, for example, a sonic speed (7.
(As high as 00 m / s), and its performance and durability tests are very important.

A conventional engine exhaust valve test apparatus is
Attach the exhaust valve alone and the valve spring to the tester, open and close the valve with respect to the valve seat while maintaining the desired stroke and valve pressing pressure, and simultaneously heat the head of the valve with a burner flame to remove the hot exhaust gas. A test is conducted between the valve and the valve seat, such as durability.

[0004]

However, the conventional exhaust valve test apparatus for an engine is a test under a condition that is significantly different from a case where the valve is actually mounted on the engine, and thus has a problem of lack of reliability. is there.

In detail, the conventional exhaust valve testing apparatus for an engine simply heats the head of the valve with a burner flame and sucks and discharges the combustion gas through a valve with a blower. Cannot apply a pressure of about 0.4 to 5 MPa to the head of the valve, and the gas flow flowing between the valve and the valve seat also has a limited period of time, as in an actual engine. I can't keep it. In particular, if the gas velocity is much lower than in the actual case, the heat transfer from the gas to the valves and valve seats and the heat transfer from the gas to the exhaust water jacket will be significantly lower than in the actual case, and Reliability is greatly impaired.

In order to solve such a problem, it is conceivable that a valve is actually mounted on a multi-cylinder engine to perform a test. However, such tests require a large amount of fuel, require a full-scale test bench for continuous durability tests, and require a great deal of labor to perform the test work for an extremely long time. In addition, problems such as noise occur. Therefore, an object of the present invention is to enable a test of an exhaust valve to be performed under conditions close to actual use conditions without requiring a large amount of fuel consumption, and to significantly reduce the test time. An engine exhaust valve testing device is provided.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides a single cylinder engine, a crankshaft rotationally driven by the engine, an opening / closing cam for opening / closing an exhaust valve of the engine, and an opening / closing cam. A camshaft for driving a cam, a transmission mechanism for transmitting rotation of the crankshaft to the camshaft such that a rotation phase of the camshaft has a predetermined relationship with a rotation phase of the crankshaft; Adjusting means for adjusting the transmission mechanism during a stop to change the predetermined relationship, the adjusting means being integrally rotatable together with the camshaft after the adjustment, and the exhaust valve being provided on a wall of a combustion chamber of the engine. And a light-transmitting window disposed opposite to the radiation thermometer for measuring the temperature of the exhaust valve through the window,
It is characterized by having.

[0008]

When the single cylinder engine is started, the crankshaft is rotated by this, and the rotation of the crankshaft is transmitted to the camshaft via the transmission mechanism. Thus, the camshaft drives the valve opening / closing cam to open / close the exhaust valve. Since the transmission mechanism transmits the rotation of the crankshaft to the camshaft such that the rotation phase of the camshaft has a predetermined relationship with the rotation phase of the crankshaft, the exhaust valve is opened and closed according to the cycle of the single cylinder engine. . In this manner, a predetermined test is performed on the exhaust valve under a condition in which the fluctuating high-temperature and high-pressure gas due to combustion is applied to the exhaust valve and flows between the exhaust valve and the valve seat at a high speed.

When the adjusting means adjusts the transmission mechanism during stoppage of the engine to change the relationship between the rotational phase of the camshaft and the rotational phase of the crankshaft so that the opening timing of the exhaust valve is advanced, when the exhaust valve is opened. Gas temperature and gas pressure are significantly higher and higher than before the change. As a result, the operating conditions become severer than usual, and the test time can be shortened. As described above, since the test is performed with the exhaust valve mounted on the L-head type single cylinder engine, the test can be performed under conditions very close to actual use conditions. The fuel consumption is low and the test time can be reduced by operating the adjusting means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine exhaust valve testing apparatus according to the present invention will be described below with reference to FIGS. 1 and 2, an L head type single cylinder engine 1
The crankshaft 4 is connected to the piston 2 via a connecting rod 3. The crankshaft 4 has a pair of crank arms 4 a and 4 b and is rotatably supported by a pair of crank shaft bearings 5 a and 5 b. Have been. An exhaust valve seat 8 and an intake valve seat 9 are attached to a cylinder block upper end surface 6a of the engine 1.
An exhaust valve 10 is seated on the exhaust valve seat 8,
An intake valve 11 is seated on the intake valve seat 9.

The exhaust valve 10 includes an exhaust valve guide 12
And driven by an exhaust valve spring 14 attached to the exhaust valve spring seat 13 and an exhaust valve opening / closing cam 15. Similarly, the intake valve 11 is guided by an intake valve guide 16 and is driven to open and close by an intake valve spring 18 and an intake valve opening / closing cam 19 attached to an intake valve spring seat 17.

The opening / closing cam 15 for the exhaust valve and the opening / closing cam 19 for the intake valve are both attached to one end of a camshaft 20, and the other end of the camshaft 20 connects the inside of a coaxial hollow outer shaft 21. Penetrate. A worm wheel 22 is fixed to the other end of the camshaft 20 that penetrates the outer shaft 21. A wheel 23 is fixed to the outer shaft 21. A feed screw for rotating the worm wheel 22 is fixed to the wheel 23. 24 are fixed. The camshaft 20 and the outer shaft 21 are rotatably supported by cam opening bearings 25 and 26. A large gear 27 is fixed to the outer shaft 21, and a small gear 28 meshes with the large gear 27, and the small gear 28 is fixed to one end of the crankshaft 4. The small gear 28 and the large gear 27 reduce the rotation of the crankshaft 4 by １ ／ and transmit the rotation to the camshaft.

A flywheel 29 and a coupling 30 are fixed to the other end of the crankshaft 4. The coupling 30 has a motoring and power absorbing mechanism via a timing gear 31 for measuring the crank position and the engine speed. Three-phase AC motor 32 is connected. A pulse counter 33 is disposed opposite to the timing gear 31, and the pulse counter 33 measures the number of rotations of the timing gear 31. In the case of an air-cooled engine, the flywheel 29 also serves as a cooling blower. The above-described outer shaft 21, worm wheel 22, wheel 23, feed screw 24, large gear 27, and small gear 28 are arranged so that the rotational phase of the camshaft 20 has a predetermined relationship with the rotational phase of the crankshaft 4. A transmission mechanism for transmitting the rotation of the crankshaft 4 to the camshaft 20 is configured. The worm wheel 22, the wheel 23 and the feed screw 24 are connected to the camshaft 20.
The relationship between the rotational phase of the crankshaft 4 and the rotational phase of the crankshaft 4 is changed to constitute an adjusting means for making the exhaust valve opening crank angle earlier than the normal crank angle.

Further, as shown in FIG.
Above 0, a window 34 of a fused quartz plate is arranged, and this fused quartz plate window 34 is fixed to a window holder 36 by a set screw 35 for fastening the window. A radiation thermometer 37 is disposed above the molten quartz plate window 34, and measures the temperature of the head of the exhaust valve 10 via the fused quartz plate window 34. As shown in FIG. 2, the ignition plug 7 and the pressure indicator 38 are arranged on the cylinder head 6b. In addition to the radiation thermometer 37 and the pressure indicator 38 described above, a gas thermometer or the like is installed in the combustion chamber or the like as needed. Further, a display device such as a cathode ray tube for displaying a measurement result is provided.

Next, the operation of this embodiment will be described. When the L-head type single cylinder engine 1 is started, the piston 2 rotates the crankshaft 4, and the rotation of the crankshaft 4 rotates the outer shaft 21 via the small gear 28 and the large gear 27. The rotation of the outer shaft 21 is performed by the wheel 23 and the feed screw 2
4 and the worm wheel 22 through the camshaft 20
Is transmitted to Accordingly, the camshaft 20 drives the opening and closing cam 15 for the exhaust valve and the opening and closing cam 19 for the intake valve to open and close the exhaust valve 10 and the intake valve 11. The outer shaft 21, the worm wheel 22, the wheel 23, the feed screw 24, the large gear 27, and the small gear 28 are arranged such that the rotational phase of the camshaft 20 has a predetermined relationship with the rotational phase of the crankshaft 4. Since the rotation of No. 4 is transmitted to the camshaft 20, the exhaust valve 10 and the intake valve 11 are opened and closed at a predetermined timing according to the cycle of the L-head type single cylinder engine.

Thus, the fluctuating high-temperature and high-pressure gas due to combustion is applied to the head of the exhaust valve 10 and
A predetermined test is performed on the exhaust valve 10 under a state where the high-temperature combustion gas flows at a high speed between the exhaust valve 10 and the valve seat 8. A predetermined test is similarly performed on the intake valve 11. Assuming that Δθ is a change in the crank angle θ, when the worm wheel 22 is advanced by Δθ / 2 by rotating the feed screw 24 while the engine is stopped, the camshaft 20 is advanced by Δθ / 2.
The opening and closing angles of the exhaust valve 10 and the intake valve 11 are advanced by Δθ. Thereby, for example, the exhaust valve 10
3 shows the normal operation state (E. 0.) of the engine, in which the entire valve opening / closing timing is shown by a solid line as shown in FIG.
C. ), (E.C.), (S.O.), advanced by .DELTA..theta., And indicated by dotted lines (E.O.) ', (S.C.).
', (EC)', and (SO) '. In this case, if Δθ = 30 ° to 50 °, the exhaust pressure and the exhaust temperature by early opening of the exhaust valve 10 can be increased to desired values without significantly affecting the engine body performance. FIG. 4 is a graph in which the horizontal axis indicates the crank angle and the vertical axis indicates the gas temperature in the cylinder. In the normal operation state (EO), the exhaust valve 10 is opened at the temperature t _E ,
For a while, the air is adiabatically expanded and exhausted at a sonic speed between the exhaust valve seat 8 and the exhaust valve 10. Exhaust valve 10
Is advanced from the normal operation state (EO) by Δθ and becomes (EO) ′, the gas temperature in the cylinder is changed from t _E to t as indicated by the dotted line. _E ′, the sound speed period becomes longer, and the exhaust gas temperature becomes higher.

As a result, the operating conditions become harsher than usual, and the desired exhaust temperature can be maintained, and the test time can be shortened.

FIG. 5 shows a modification of the adjusting means of the camshaft transmission mechanism for opening the exhaust valve at an early stage in the above embodiment. A disk 39 is fixed to the outer shaft 21 instead of the wheel 23. A worm wheel 22 on the camshaft 20
Instead, a disk 40 is fixed. Elongated holes 41 extending in the circumferential direction are formed in the disk 40 at equal angular intervals. The bolt 42 is provided in the hole of the disc 39 and the slot 4 of the disc 40.
1 and the disk 39 and the disk 40 together with the nut 43 are fixed to each other. Adjustment of the opening / closing timing of the exhaust valve 10 and the like is performed by loosening the nut 43 and rotating the disk 40 relative to the disk 39, and then tightening the nut 43 again. The present invention can be applied to a test of a piston or a piston ring as well as an exhaust valve, an intake valve, and a valve guide.

[0019]

As is apparent from the above description, according to the present invention, a single-cylinder engine, a crankshaft rotationally driven by the engine, an opening / closing cam for opening / closing an exhaust valve of the engine, and the opening / closing cam , A transmission mechanism for transmitting the rotation of the crankshaft to the camshaft such that the rotation phase of the camshaft has a predetermined relationship with the rotation phase of the crankshaft, and a stop of the engine. Adjusting means for adjusting the transmission mechanism during the change of the predetermined relationship, the adjusting means being integrally rotatable together with the camshaft after the adjustment,
A light-transmitting window disposed on the wall of the combustion chamber of the engine so as to face the exhaust valve; and a radiation thermometer for measuring the temperature of the exhaust valve through the window. Since the test is performed with the exhaust valve attached to the single cylinder engine, it is possible to perform the test under conditions very close to the actual use conditions, and the use of a single cylinder engine consumes less fuel, and By operating the adjusting means and advancing the exhaust valve opening crank angle, the gas pressure and the gas temperature when the exhaust valve is opened are increased, and the gas flow passing between the valve and the valve seat is maintained at the sonic speed, thereby greatly reducing the test time. You can also.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a partial cross section of an embodiment of an exhaust valve testing apparatus for an engine according to the present invention.

FIG. 2 is a front view schematically showing the embodiment in a partial cross section.

FIG. 3 is a diagram showing opening / closing timing of an exhaust valve according to the embodiment.

FIG. 4 shows the influence of the early opening of the exhaust valve by taking the crank angle on the horizontal axis and the gas temperature in the cylinder on the vertical axis.

FIG. 5 is a front view and a side view showing a modification of the valve timing adjusting means of the embodiment in a partial cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 L-head type single cylinder engine 4 Crankshaft 10 Exhaust valve 11 Intake valve 12 Exhaust valve guide 15 Opening / closing cam for exhaust valve 20 Camshaft 21 Outer shaft 22 Worm wheel 23 Wheel 24 Feed screw 25, 26 Cam bearing 27 Large gear 28 Small gear 29 Flywheel 30 Coupling 21, 22, 23, 24, 27, 28 Transmission mechanism 22, 23, 24 Valve opening / closing standby adjusting means

Claims (1)

(57) [Claims] A single-cylinder engine, a crankshaft rotationally driven by the engine, an opening / closing cam for opening and closing an exhaust valve of the engine, a camshaft for driving the opening / closing cam, and a rotation phase of the camshaft. A transmission mechanism that transmits the rotation of the crankshaft to the camshaft so as to have a predetermined relationship with the rotation phase of the crankshaft; and adjusting the transmission mechanism while the engine is stopped to adjust the predetermined relationship. Adjusting means for changing, the adjusting means being integrally rotatable together with the camshaft after adjustment, and a light-transmissive window disposed on a wall of a combustion chamber of the engine so as to face the exhaust valve. An exhaust valve testing device for an engine, comprising: a radiation thermometer for measuring the temperature of the exhaust valve through the window.