JPH09119326A - Valve operating device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote vaporization of fuel in cooling of engine by constituting a valve operating device in an internal combustion engine so that an intake valve may be opened in the compression or combustion stroke. SOLUTION: In cooling of an engine, intake and exhaust valves 1, 2 are made to perform the intake and exhaust actions as normal, and the intake valve 1 is slightly lifted by a very small cam lobe of a cam nose 11 in the expansion stroke in which cylinder pressure is high. High-temperature combustion gas is forcibly allowed to flow back, the temperature of the intake valve 1 is rapidly raised, fuel to be supplied from the fuel injection valve to an intake port 15 before the intake valve 1 is opened is heated by the contact of the intake valve 1 with a shade part 1a, and vaporization of fuel is promoted. Since the valve clearance is increased more than the cam lobe height of the cam nose 11 by thermal expansion of an engine head 16 after the engine is warmed up, the valve lift by the very small cam lobe is restrained, and forcible flowback of combustion gas is restrained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a valve operating device for an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional valve actuating device for an internal combustion engine, there is, for example, one disclosed in Japanese Patent Laid-Open No. 59-103907. However, in the conventional valve actuating device for an internal combustion engine, since the intake valve is not sufficiently heated at the time of cold start, the vaporization of the fuel is not sufficient, and most of the fuel supplied from the injector remains liquid in the combustion chamber. Since it enters, the HC in the exhaust gas increases rapidly, and there is a risk that the exhaust gas will deteriorate.

[0003]

The present invention focuses on the temperature rise of the intake valve for promoting the vaporization of fuel, and forcibly blows it back by opening the intake valve during compression and combustion strokes. The purpose is to solve the above-mentioned problems by raising the temperature of the intake valve quickly.

[0004]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that, in a valve operating device in an internal combustion engine, an intake valve is opened during a compression or combustion stroke. In the valve operating device for an internal combustion engine as described in claim 2, a hydraulic crush adjuster may be used as the valve operating component. Further, as described in claim 3, in the valve operating device for the internal combustion engine according to claim 1, the intake valve may be closed before the main combustion engine starts with respect to the intake valve timing.

[0005]

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the present invention. First, the structure will be described. A crankshaft (not shown) for extracting the rotational force of the engine, an intake valve 1 and an exhaust valve 2
(Not shown) for transmitting the rotational force of the intake / exhaust camshafts 5, 6 to the intake / exhaust camshafts 5, 6 for driving the intake / exhaust camshafts to open / close against the valve springs 3, 4. With. 2 shows the relationship between the cam profile of the intake camshaft 5 and the in-cylinder pressure.

The cam 7 formed integrally with the intake camshaft 5 includes a cam nose 9 for opening and closing the intake valve 1 in response to the intake stroke, and an intake valve 1 corresponding to the expansion stroke.
Cam nose 1 to open and close the valve with a small amount of lift
1 is formed. FIG. 1 shows a state in which the engine is warmed up, in which the base circle 12 of the cam 7 and the shim 14 loaded on the valve lifter 13 are in contact with each other.

Next, the operation will be described. When the engine is cold, the intake / exhaust valves 1 and 2 perform normal intake and exhaust operations, and in addition, the intake valve 1 slightly lifts due to the minute cam peaks of the cam nose 11 during the expansion stroke in which the cylinder pressure is high. Therefore, the high temperature combustion gas is forcibly blown back, and the temperature of the intake valve 1 rapidly rises. Therefore, the fuel supplied from the fuel injection valve (not shown) to the intake port 15 before the intake valve 1 is opened is heated by the contact with the umbrella portion 1a of the intake valve 1, and the vaporization of the fuel is promoted.

After the engine is warmed up, the engine head 16 made of aluminum expands more than the intake valve 1 made of heat-resistant steel due to thermal expansion, and the valve clearance (clearance between the base circle 12 and the shim 14) is increased. Since the height of the cam peak of the cam nose 11 is larger than that of the cam nose 11, the valve does not lift at the minute cam peak, and compulsory blowback of the combustion gas disappears. See FIG.

FIG. 4 shows another embodiment. This is an example of using a hydraulic lash adjuster. The hydraulic lash adjuster has the characteristics that the rigidity increases due to the hardening of the internal oil when it is cold, and leakage occurs due to the leakage of internal oil after warming up, and it slightly sinks when the valve is lifted. Therefore, the effect is added to the effect of thermal expansion of the schilling head described above, and the minute lift amount by the cam nose 22a of the intake cam 22 can be increased and the blowback amount can be increased. In the drawing, 1 is a cylinder head, 2 is an intake port, 3 is an exhaust port, 7 is a valve spring, 11 is a rocker arm, and 1 is a rocker arm.
2 is an intake valve, 13 is an exhaust valve, 15 is an intake camshaft,
Reference numeral 16 is an exhaust cam shaft, and 23 is an exhaust cam.

FIG. 5 shows another embodiment. This is an example in which the position of the minute lift by the cam nose is defined. Here, the position of the minute lift is from the end of the compression stroke to immediately before the fuel combustion stroke. By doing so, the HC and the like are not blown back as compared with the case of the small lift during the expansion stroke, so that the generation of the intake valve deposit and the like can be eliminated.

[0011]

As described above, according to the present invention, it is possible to obtain the effect that the vaporization of the fuel when the engine is cold can be promoted by setting the forced blowback cam in the intake cam.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment.

FIG. 2 is a diagram showing a relationship between a camshaft profile and an in-cylinder pressure.

FIG. 3 is a cross-sectional view showing a case where the engine head is thermally expanded.

FIG. 4 is a cross-sectional view showing another embodiment.

FIG. 5 is a diagram showing a profile of a camshaft according to another embodiment.

[Explanation of symbols]

 1 intake valve 5 cam 11 cam nose

Front Page Continuation (72) Inventor Yasuyuki Ito 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (3)

[Claims] 1. A valve actuator for an internal combustion engine, comprising:
A valve actuating device for an internal combustion engine, wherein an intake valve is opened during a compression or combustion stroke. 2. The valve actuating device for an internal combustion engine according to claim 1, wherein a hydraulic lash adjuster is used as a valve actuating component. 3. The valve operating system for an internal combustion engine according to claim 1, wherein the intake valve is closed before the main combustion engine starts with respect to the intake valve timing.