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Symmetrical intake and exhaust cam of three-cylinder gasoline engine

A gasoline engine, symmetrical technology, applied in the direction of valve details, valve driving devices, etc., can solve the problems of high material consumption, low lift curve full coefficient, affecting the stability of the valve mechanism, etc., to achieve a stable valve mechanism and save materials Effect

Inactive Publication Date: 2008-02-27
TIANJIN FAW XIALI AUTOMOBILE
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Problems solved by technology

The disadvantage is that it is not easy to maintain the continuity of the derivative above the third order at the connection of each section, which affects the stability of the valve train.
[0005] 3. High-degree polynomial (high-square equation): Its advantage is that the acceleration curve is smooth, and the stability of the valve train is easy to ensure. The disadvantage is that the lift curve fullness coefficient is relatively low

Method used

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  • Symmetrical intake and exhaust cam of three-cylinder gasoline engine

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Embodiment Construction

[0028] The present invention will be described in detail below with reference to the drawings and examples.

[0029] The invention lies in that the cam profile designed with a group of optimized parameters can not only meet the requirements of the engine charging performance, but also ensure the stability of the gas distribution mechanism.

[0030] The cam profile of the present invention is mainly applied to a 1.0L three-cylinder gasoline engine adopting a four-valve cylinder head.

[0031] Fig. 1 is the cam profile of the intake and exhaust cam profile design of the three-cylinder gasoline engine of the present invention; Fig. 2 is an enlarged view of part A.

[0032] As shown in Fig. 1 and Fig. 2, the cam profile of the present invention consists of base circle, buffer section (θ 1 , θ 2 The arc segment corresponding to θ) and the working segment (the arc segment corresponding to θ) are composed of three segments.

[0033] Its working section adopts multiple dynamic equa...

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Abstract

The symmetrical admission and exhaust cam for three cylinder gasoline engine has profile line with the work section equation of h=(hmax-hr)(1+c2A2+c4A4+cpAp+cqAq+crAr+csAs), where, h is the lift of the cam work section, hmax is the maximum lift and equals to 7.3-7.5 mm, hr is the lift of cam buffer section and equals to 0.3-0.35 mm, A is cam angle, p, q, r and s are indexes, c4=0.1, p=14, q=28, r=42, and s=56. The cam has base circle diameter of 33 mm, contact width to the jib of 10 mm, total contact angle of 167-172 deg, work section angle of 121 deg, and buffer section angle of 46-52 deg. The symmetrical admission and exhaust cam has the advantages of capacity of reaching excellent dynamic characteristic of gasoline engine and smooth running of the valve mechanism, and small thickness.

Description

technical field [0001] The invention belongs to the valve mechanism components of automobile engines, and in particular relates to a symmetrical type of three-cylinder gasoline engine whose cam profile designed with a group of optimized parameters can not only meet the requirements of engine charging performance, but also ensure the stability of the valve mechanism. Intake and exhaust cams. Background technique [0002] The cam profile is a parameter that has an important influence on the performance of the engine. At present, the design methods that are widely used in the field of gasoline engines have the following forms: [0003] 1. Sinusoidal parabolic type: Its advantage is that the shortening of the positive acceleration section can make the lift curve plump, but the disadvantage is that the maximum positive acceleration increases sharply, which causes the vibration and noise of the valve mechanism to increase. [0004] 2. Combined polynomial type: It is characterized...

Claims

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Application Information

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IPC IPC(8): F01L1/08
Inventor 张群魏罡居钰生俞培泳李明杰
Owner TIANJIN FAW XIALI AUTOMOBILE
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