CN201083134Y - Symmetrical gas charging and discharging cam for three-cylinder gasoline engine - Google Patents

Abstract

The utility model relates to a symmetrical air inlet and outlet cam of a three-cylinder gasoline engine, wherein the equation of a cam molded line working section is as follows: h=(hmax-hr)(1+c2 alpha<2>+c4 alpha<4>+cp alpha<p>+ cq alpha<q>+cr alpha<r>+cs alpha<s>), wherein h is the lift of the cam working section; hmax is maximum cam lift; hr is the lift of a cam buffering section; alpha is a cam angle; p, q, r and s are exponents; moreover, according to the equation, h max ranges between 7.3 mm and 7.5 mm; hr ranges between 0.3 mm and 0.35 mm; c4 is equal to 0.1; p is equal to 14; q is equal to 28; r is equal to 42 and s is equal to 56. The base diameter (phi) of the cam is 33 mm; the contact width with a tappet is 10 mm; the total angle of contact ranges between 167 degrees and 172 degrees; the working section angle theta is 121 degrees; moreover, the buffering section angle theta1+theta2 ranges between 46 degrees and 52 degrees. The utility model has the advantages of excellent dynamic property of a gasoline engine, smooth operation of a valve mechanism and a thin cam.

Description

The symmetric form intake and exhaust cam of three-cylinder gasoline engine

Technical field

The utility model belongs to the distribution device parts of motor car engine, the cam profile that particularly relates to one group of optimum parameters design of a kind of usefulness both can satisfy the requirement of motor inflation performance, can guarantee the symmetric form intake and exhaust cam of the three-cylinder gasoline engine of distribution device stationarity again.

Background technique

Cam profile is the parameter that engine performance is had material impact, uses more design method that following several form is arranged at present in the petrol engine field:

1. sinusoidal parabolic shape: its advantage is that the shortening of positive acceleration section can make lifting curve plentiful, and shortcoming is that maximum positive acceleration increases severely, and causes that valve mechanism vibrations and noise increase.

2. combination polynomial type: be characterized in being easy to keep big advantage of uniform acceleration cam time-section and positive negative acceleration transition light to slide, can coordinate motor inflation property and the requirement of distribution device stationarity preferably.Its shortcoming is that each section joint is difficult for keeping the continuity of three rank with upper derivate, influences the stationarity of distribution device work.

3. high-order moment (high side's equation): its advantage is acceleration diagram smooth degree height, and the distribution device stationarity is easy to guarantee that shortcoming is that the lifting curve fullness coefficient is relatively low.Be that cam in 91212657.4 " high-speed enhanced petrol engine special-purpose no impact cam " designs with high-order moment as the patent No..

Cam thickness in 91212657.4 patents is 18mm, and is thicker.High material consumption.

Summary of the invention

The utility model provides the cam profile of one group of optimum parameters design of a kind of usefulness both can satisfy the requirement of motor inflation performance for solving the technical problem that exists in the known technology, can guarantee the symmetric form intake and exhaust cam of the three-cylinder gasoline engine of distribution device stationarity again.

The technological scheme that the utility model is taked for the technical problem that exists in the solution known technology is:

The symmetric form intake and exhaust cam of three-cylinder gasoline engine of the present utility model, its cam profile active section adopts multinomial dynamic equation, and its equation is:

h＝(h _max-h _r)(1+c ₂α ²+c ₄α ⁴+c _pα ^p+c _qα ^q+c _rα ^r+c _sα ^s)

Wherein: h is a cam work section lift, h _MaxBe the cam maximum lift,

h _rBe cam breeze way lift, α is a cam angle degree,

P, q, r, s are index;

It is characterized in that: in the aforesaid equation:

hmax＝7.3～7.5mm hr＝0.3～0.35mm c ₄＝0.1

c ₂＝-1.2 c _p＝8 c _q＝-16 c _r＝9.5 c _s＝-1.38

p＝14， q＝28， r＝42， s＝56，

Cam base circle diameter ￠=33mm, with the tappet contact width be 10mm,

Total cornerite is 167 °～172 °,

Active section angle θ is 121 °, breeze way angle θ ₁+ θ ₂=46 °～52 °

Advantage and the good effect that the utlity model has are:

The symmetric form intake and exhaust cam of three-cylinder gasoline engine of the present utility model, adopt the volumetric efficiency of the motor of the utility model cam profile can reach 0.58, be generally 0.55, adopting the maximum engine torque of this molded lines at present is 89Nm/3600rpm, peak output is 48KW/6000rpm, and level is in a leading position in uniform machines.Advantage mainly contains:

1. the cam profile acceleration diagram is comparatively smooth, and distribution device is comparatively steady, adopts less spring force can guarantee the smooth running of valve mechanism.

2 adopt the contact stress that can guarantee cam and tappet than thin cam thickness within the material allowable stress requires, and this cam thickness is 10mm only, thereby has saved material, realizes compact design.And passed through the country endurance test requirement in 400 hours.

3. adopt under the situation of less total cornerite (167 °～172 °), active section angle (θ in the accompanying drawing) promptly reaches 121 °.The parameter that mainly is employing is comparatively reasonable, with short breeze way (θ in the accompanying drawing ₁And θ ₂) dynamics requirement in the time of can satisfying engine valve and open and close.

Description of drawings

Fig. 1 is the cam profile figure of the intake and exhaust cam molded lines design of the utility model three-cylinder gasoline engine;

Fig. 2 is an A portion enlarged view.

Embodiment

Followingly the utility model is described in detail with reference to drawings and Examples.

The utility model is both can satisfy the requirement of motor inflation performance with the cam profile of one group of optimum parameters design, can guarantee the requirement of distribution device stationarity again.

Cam profile of the present utility model is mainly used in adopting on the 1.0L three-cylinder gasoline engine of four-valve cylinder head.

Fig. 1 is the cam profile figure of the intake and exhaust cam molded lines design of the utility model three-cylinder gasoline engine; Fig. 2 is an A portion enlarged view.

As shown in Figure 1 and Figure 2, cam profile of the present utility model is by basic circle, breeze way (θ ₁, θ ₂Pairing arc section), three sections compositions of active section (the pairing arc section of θ).

Its active section adopts multinomial dynamic equation, and its equation is:

h＝(h _max-h _r)(1+c ₂α ²+c ₄α ⁴+c _pα ^p+c _qα ^q+c _rα ^r+c _sα ^s)

Wherein: h is a cam work section lift, h _MaxBe the cam maximum lift,

h _rBe cam breeze way lift, α is a cam angle degree,

P, q, r, s are index;

Outstanding feature of the present utility model is in the aforesaid equation:

hmax＝7.3～7.5mm?hr＝0.3～0.35mm c ₄＝0.1

c ₂＝-1.2 c _p＝8 c _q＝-16 c _r＝9.5 c _s＝-1.38

p＝14， q＝28， r＝42， s＝56，

Cam base circle diameter ￠=33mm, with the tappet contact width be 10mm.

Total cornerite is 167 °～172 °.

Active section angle θ is 121 °, breeze way angle θ ₁+ θ ₂=46 °～52 °.

Total cornerite=active section angle θ+breeze way angle θ ₁+ θ ₂

Adopt the thread cam profile symmetry of cam type of the present utility model.

Claims (1)

1. the symmetric form intake and exhaust cam of a three-cylinder gasoline engine, its cam profile active section adopts multinomial dynamic equation, and its equation is:

h＝(h _max-h _r)(1+c ₂α ²+c ₄α ⁴+c _pα ^p+c _qα ^q+c _rα ^r+c _sα ^s)

Wherein: h is a cam work section lift, h _MaxBe the cam maximum lift,

h _rBe cam breeze way lift, α is a cam angle degree,

P, q, r, s are index;

It is characterized in that: in the aforesaid equation:

hmax＝7.3～7.5mm hr＝0.3～0.35mm c ₄＝0.1

c ₂＝-1.2 c _p＝8 c _q＝-16 c _r＝9.5 c _s＝-1.38

p＝14， q＝28， r＝42， s＝56，

The cam base circle diameter is ￠ 33mm, with the tappet contact width be 10mm,

Total cornerite is 167 °～172 °,

Active section angle θ is 121 °, breeze way angle θ ₁+ θ ₂=46 °～52 °

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