CN112031947A

CN112031947A - Novel ignition type engine piston

Info

Publication number: CN112031947A
Application number: CN202010685350.1A
Authority: CN
Inventors: 李伟; 吴学成
Original assignee: AVL List Technical Center Shanghai Co Ltd
Current assignee: AVL List Technical Center Shanghai Co Ltd
Priority date: 2020-07-16
Filing date: 2020-07-16
Publication date: 2020-12-04

Abstract

The invention discloses a novel ignition type engine piston which comprises a piston body, a combustion chamber molded surface, a piston inner cavity molded surface and an external piston cooling nozzle, wherein a cylinder hole is formed in the middle of the piston body, the combustion chamber molded surface is of a regular rotating body structure, the combustion chamber molded surface consists of an edge plane part I, a central bulge part III and a middle annular pit part II, the edge plane part I, the central bulge part III and the middle annular pit part II are in smooth transition and integrated forming, and the fillet radius of smooth transition among the edge plane part I, the central bulge part III and the middle annular pit part II is based on the fillet radius of a larger value. According to the invention, the piston top structure is designed into a convex cylindrical structure, so that the downward movement of the piston enhances the vortex in the cylinder, the upward movement of the piston maintains the vortex flow velocity in the cylinder, the flow velocity of the mixed gas in the cylinder under the low-rotation-speed working condition of the engine is improved, the flame propagation speed is increased, the ignition duration is shortened, and the thermal efficiency is improved.

Description

Novel ignition type engine piston

Technical Field

The invention relates to the technical field of ignition type high-heat-efficiency engines, in particular to a piston combustion chamber structure and a piston cooling structure of an engine.

Background

The fuel consumption rate is an important index for examining an automobile engine, and in the process of organizing the airflow in an engine cylinder, the airflow in a combustion chamber can be organized to flow by optimizing a piston combustion chamber, so that the intake vortex is increased to fully mix fuel and air, and the condition of complete combustion of mixed gas is met as far as possible so as to achieve higher thermal efficiency. Meanwhile, the piston operates under the working condition of high speed and high heat load, and new requirements are put on the cooling of the piston along with the increase of the power density of the engine. For this reason, corresponding technical solutions need to be researched and solved.

Disclosure of Invention

The invention aims to provide a spark ignition type engine piston matched with vortex gas inlet, wherein the top structure of the piston is designed into a convex cylindrical structure, so that the downward movement of the piston enhances the vortex flow in a cylinder, the upward movement of the piston maintains the vortex flow velocity in the cylinder, the flow velocity of mixed gas in the cylinder under the working condition of low rotating speed of the engine is improved, the flame propagation speed after ignition is increased, the ignition duration is shortened, and the heat efficiency is improved.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the utility model provides a novel ignition type engine piston, includes the piston body, is located combustion chamber profile, piston inner chamber profile and the outside piston cooling nozzle of piston top surface, the cylinder hole has been seted up at piston body middle part, the combustion chamber profile is regular revolution solid structure, the combustion chamber profile comprises border plane part I, central bulge III and middle annular pit part II, border plane part I, central bulge III and middle annular pit part II set up for smooth transition integrated into one piece, just along plane part I, central bulge III and middle annular pit part II smooth transition's fillet radius is with getting the great value fillet radius as the standard each other.

As an improvement of the technical scheme, the height of the central bulge part III from the plane of the top surface of the piston is 0.1-0.3 times of the diameter size of the cylinder hole, and the fillet radius of the central bulge part III is equal to the edge radius of the bulge cylinder.

As an improvement of the technical scheme, the depth of the middle annular concave pit part II is 0.03-0.05 times of the diameter size of the cylinder hole.

As an improvement of the technical scheme, the molded surface of the inner cavity of the piston is designed along with the molded surface structure of the top combustion chamber, and the top of the piston adopts a sphere-like molded surface structure.

As an improvement of the technical scheme, the angle of the transition plane on the lower side of the sphere-like surface of the inner cavity of the piston is the same as the angle of the oil beam direction of the piston cooling nozzle, so that the oil beam is sprayed into the sphere-like surface along the inner cavity of the piston to achieve the effect of fully cooling the piston.

Compared with the prior art, the invention has the following implementation effects:

the piston top structure is of a convex cylindrical structure or a conical structure, the strength of a downward vortex of the piston is enhanced during an intake stroke, the strength of the upward vortex of the piston is maintained during a compression stroke, the flow speed of mixed gas in a cylinder under the working condition of low rotating speed of the engine is further improved, the piston combustion chamber is simple in structure and good in manufacturability, a middle convex part of the piston is of a hollow structure, the structure has a guiding effect on engine oil sprayed out from a piston cooling nozzle, the cooling function of the piston is improved, an inner cooling oil duct which is complex and high in cost and can replace a traditional engine can be used, and the piston is more reliable in the operating environment with high heat, high speed and high strength.

Different from the technology of Chinese patent CN 207018102U, the piston combustion chamber of the invention has no valve avoiding pit, and the top of the piston is designed into a convex structure; different from the technology of Chinese patent CN 206190419U, the top edge of the piston is designed in a plane without a valve avoiding pit; the combustion chamber of the invention is obviously different from the typical omega-shaped combustion chamber of the diesel engine in Chinese patent CN 208518762U, CN 209892324U, CN 201820347056.8; different from the piston cooling structure adopting the internal cooling oil passage for cooling in Chinese patent CN 110513182A, CN 109869239A and the like, the piston cooling structure adopting the structure without the internal cooling oil passage of the piston and having a larger heat exchange area meets the cooling requirement of the piston.

Drawings

FIG. 1 is an isometric view of a piston of the present invention;

FIG. 2 is a front cross-sectional view of a piston according to the present invention and a schematic flow of the cooling nozzle oil jet.

Detailed Description

The present invention will be described with reference to specific examples.

As shown in fig. 1 and 2: a novel spark-ignition engine piston, comprising: piston body 1, be located the combustion chamber profile 2 of piston top surface, piston inner chamber profile 3 and outside piston cooling nozzle 4, combustion chamber profile 2 is regular revolution solid structure, no air valve keeps away the valve pit, combustion chamber profile 2 is by border plane part I, central bulge III and middle annular pit part II are constituteed, border plane part I, central bulge III and middle annular pit part II set up for smooth transition integrated into one piece, and border plane part I, central bulge III and middle annular pit part II smooth transition's fillet radius is with getting bigger value fillet radius as the standard each other, avoid forming stress concentration or closed angle focus.

Further improved, as shown in fig. 2: the height of the central convex part III from the plane of the top surface of the piston is 0.1-0.3 times of the diameter of the cylinder hole 5, and the fillet of the central convex part III is equal to the radius of the edge of the convex cylinder; the depth of the middle annular recess portion II is 0.03 to 0.05 times the diameter dimension of the cylinder bore.

Specifically, the molded surface 3 of the inner cavity of the piston is structurally designed along with the molded surface 2 of the top combustion chamber, and the top of the molded surface adopts a ball-like molded surface structure so as to increase the cooling area of the piston; the angle of the transition plane at the lower side of the class spherical surface of the molded surface 3 of the inner cavity of the piston is the same as the angle of the oil beam direction of the piston cooling nozzle 4, so that the oil beam is sprayed into the class spherical surface along with the molded surface 3 of the inner cavity of the piston to achieve the effect of fully cooling the piston.

More specifically, this example uses the cylinder bore diameter to be Φ 73.2mm, middle protruding part height is 15.5mm, the pit depth is 3mm, wherein I, II, III three part profile transition fillet radius is all not less than R10mm, guarantee that the profile does not have the stress concentration or the existence hotspot that sharp-pointed transition department arouses, the piston inner chamber top is SR7 mm's sphere design, and match piston cooling nozzle oil beam injection angle, the transition profile of rational design inner chamber, make the oil beam paste the piston inner chamber and flow in, fully with top inner chamber profile contact, greatly increased cooling efficiency.

The foregoing is a detailed description of the invention with reference to specific embodiments, and the practice of the invention is not to be construed as limited thereto. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A novel ignition type engine piston is characterized in that: including piston body (1), be located combustion chamber profile (2), piston inner chamber profile (3) and outside piston cooling nozzle (4) of piston top surface, combustion chamber profile (2) are regular revolution structure, combustion chamber profile (2) comprises border plane part I, central bulge III and middle annular pit part II, border plane part I, central bulge III and middle annular pit part II set up for smooth transition integrated into one piece, just along plane part I, central bulge III and middle annular pit part II smooth transition's fillet radius is with getting bigger value fillet radius as the standard each other.

2. A novel spark ignition engine piston as claimed in claim 1, wherein: the height of the central bulge part III from the plane of the top surface of the piston is 0.1-0.3 times of the diameter size of the cylinder hole, and the fillet at the top of the central bulge part III is approximately equal to the radius of the edge of the bulge cylinder.

3. A novel spark ignition engine piston as claimed in claim 1, wherein: the depth of the middle annular concave pit part II is 0.03-0.05 times the diameter size of the cylinder hole.

4. A novel spark ignition engine piston as claimed in claim 1, wherein: the molded surface (3) of the inner cavity of the piston is structurally designed along with the molded surface (2) of the top combustion chamber, and the top of the piston adopts a sphere-like molded surface structure.

5. The novel spark-ignition engine piston of claim 4, wherein: the transition plane angle of the lower side of the sphere-like surface of the inner cavity molded surface (3) of the piston is the same as the oil beam direction angle of the piston cooling nozzle (4), so that the oil beam is sprayed into the sphere-like surface along with the molded surface (3) of the inner cavity of the piston to achieve the effect of fully cooling the piston.