JPS63109267A - Piston of internal combustion engine - Google Patents
Piston of internal combustion engineInfo
- Publication number
- JPS63109267A JPS63109267A JP61253948A JP25394886A JPS63109267A JP S63109267 A JPS63109267 A JP S63109267A JP 61253948 A JP61253948 A JP 61253948A JP 25394886 A JP25394886 A JP 25394886A JP S63109267 A JPS63109267 A JP S63109267A
- Authority
- JP
- Japan
- Prior art keywords
- ceramic
- piston
- cavity member
- molded body
- piston body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002485 combustion reaction Methods 0.000 title claims description 13
- 239000000919 ceramic Substances 0.000 claims abstract description 67
- 239000000835 fiber Substances 0.000 claims abstract description 43
- 229910010272 inorganic material Inorganic materials 0.000 claims abstract description 18
- 239000011147 inorganic material Substances 0.000 claims abstract description 18
- 238000009413 insulation Methods 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 230000007423 decrease Effects 0.000 abstract description 4
- 229910000838 Al alloy Inorganic materials 0.000 abstract description 3
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 238000000465 moulding Methods 0.000 abstract 1
- 239000011248 coating agent Substances 0.000 description 17
- 238000000576 coating method Methods 0.000 description 17
- 239000000463 material Substances 0.000 description 15
- 238000010438 heat treatment Methods 0.000 description 10
- 239000000843 powder Substances 0.000 description 9
- 238000002347 injection Methods 0.000 description 8
- 239000007924 injection Substances 0.000 description 8
- 238000005266 casting Methods 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000008119 colloidal silica Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F3/00—Pistons
- F02F3/0015—Multi-part pistons
- F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
- F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
- F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
- F02B23/0603—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
- F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
- F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
- F02B23/0675—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston the combustion space being substantially spherical, hemispherical, ellipsoid or parabolic
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
- F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
- F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
- F02B23/0603—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head
- F02B2023/0612—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head the material having a high temperature and pressure resistance, e.g. ceramic
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2201/00—Metals
- F05C2201/02—Light metals
- F05C2201/021—Aluminium
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、ピストン上部にセラミック製キャビティ部材
を設け、このセラミック製キャビティ部材の内部に燃焼
室を形成した内燃機関のピストンに関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a piston for an internal combustion engine in which a ceramic cavity member is provided in the upper part of the piston, and a combustion chamber is formed inside the ceramic cavity member.
従来、ディーゼルエンジンのピストンにおいて、その上
部にセラミック製キャビティ部材を鋳ぐるんだ構造のも
のが既に提案されている。ところで、燃焼室に燃料を直
接吹き込む直接噴射式ディーゼルエンジンは、間接噴射
式ディーゼルエンジンに比して燃費は優れているものの
、排ガス特性、騒音、始動性等の諸特性では間接噴射式
ディーゼルエンジンより劣っている。この場合、直接噴
射式ディーゼルエンジンのピストンにおける上記キャビ
ティ部材として、断熱性に優れたセラミック、例えば部
分安定化ジルコニアセラミックを使用すれば、上記の諸
特性を改善することができる。BACKGROUND ART Conventionally, a structure in which a ceramic cavity member is cast in the upper part of a piston of a diesel engine has already been proposed. By the way, direct injection diesel engines, which inject fuel directly into the combustion chamber, have better fuel efficiency than indirect injection diesel engines, but they are inferior to indirect injection diesel engines in various characteristics such as exhaust gas characteristics, noise, and startability. Inferior. In this case, the above characteristics can be improved by using a ceramic with excellent heat insulation properties, such as a partially stabilized zirconia ceramic, as the cavity member in the piston of the direct injection diesel engine.
ところが、キャビティ部材として断熱性の良いセラミッ
クを使用すれば、燃焼室に面したキャビティ部材の内表
面と、外表面との間の温度差が大きくなるので、上記外
表面近傍で大きな熱応力が生じてキャビティ部材にクラ
ンクを発生する虞れがある。特に、キャビティ部材にピ
ストン本体からの抜止め用フランジ部が設けられている
場合、抜止め用フランジ部では、その外周面とキャビテ
ィ部材の内表面との間の距離が大きくなるので、温度差
が極めて大きくなって、外周部でクランクが生じやすく
なる。However, if ceramic with good heat insulation properties is used as the cavity member, the temperature difference between the inner surface of the cavity member facing the combustion chamber and the outer surface will increase, resulting in large thermal stress near the outer surface. There is a risk that the cavity member will develop a crank. In particular, when the cavity member is provided with a flange to prevent it from coming off from the piston body, the distance between the outer peripheral surface of the flange and the inner surface of the cavity member is large, so the temperature difference is It becomes extremely large and tends to cause cranking at the outer periphery.
その対策として、キャビティ部材とピストン本体との間
に断熱用の空気層を設けたものが提案されている（実開
昭５７−１０７９３７号公報）。ところが、この場合、
空気層を介在させねばならないので、キャビティ部材を
ピストン本体に鋳ぐるむことができず、従って、ピスト
ン本体の鋳造後にピストン本体にキャビティ部材をねじ
等で組み付ける必要が生じて、工程が複雑になるという
問題を有していた。As a countermeasure against this, it has been proposed to provide a heat insulating air layer between the cavity member and the piston body (Japanese Utility Model Publication No. 57-107937). However, in this case,
Since an air layer must be provided, the cavity member cannot be cast into the piston body. Therefore, it becomes necessary to assemble the cavity member to the piston body with screws, etc. after the piston body is cast, which complicates the process. There was a problem.
〔発明の目的〕
本発明は、上記従来の問題点を考慮してなされたもので
あって、セラミック製キャビティ部材のクランクを減少
させることができるとともに、製造工程の単純化を図る
ことができる内燃機関のピストンの提供を目的とするも
のである。[Object of the Invention] The present invention has been made in consideration of the above-mentioned conventional problems, and is an internal combustion engine which can reduce the number of cranks of ceramic cavity members and can simplify the manufacturing process. The purpose is to provide pistons for engines.
本発明は上記の目的を達成するために、ピストン上部に
セラミック製キャビティ部材を有する内燃機関のピスト
ンにおいて、ピストン本体と、ピストン本体の上部に鋳
ぐるまれる上記セラミック製キャビティ部材と、セラミ
ックファイバーの成形体に無機材を塗布または含侵させ
てなり、上記セラミック製キャビティ部材の外表面を被
覆した状態でピストン本体に鋳ぐるまれる断熱層とを備
える。これにより、セラミック製キャビティ部材の外側
に配した断熱層によって、セラミック製キャビティ部材
の内表面と外表面との間の温度差を小さくして、セラミ
ック製キャビティ部材のクランクを減少させ、また、断
熱層を空気層ではなく、セラミックファイバー成形体に
より形成して、セラミック製キャビティ部材の外壁に断
熱層を装着した後に、これらをピストン本体に鋳ぐるむ
ことによりピストンを製造できるようにして、製造工程
の単純化を図るものである。また、セラミックファイバ
ー成形体に無機材を塗布または含侵させることにより、
セラミックファイバー成形体の少なくとも外表面近傍を
硬化させて、鋳ぐるみ時に、セラミックファイバー成形
体内に、ピストン本体を形成する溶湯が侵入するのを防
止して、セラミックファイバー成形体からなる断熱層の
断熱性の低下を阻止し、かつ上記無機材によりセラミッ
クファイバー成形体の少なくとも外表面近傍を硬化させ
ることにより、振動によるセラミックファイバー成形体
の崩れや、加熱に伴うセラミックファイバー成形体の収
縮を低減させることができるように構成したことを特徴
とするものである。In order to achieve the above object, the present invention provides a piston for an internal combustion engine having a ceramic cavity member in the upper part of the piston. The molded body is coated with or impregnated with an inorganic material, and includes a heat insulating layer that is cast into the piston body while covering the outer surface of the ceramic cavity member. As a result, the thermal insulation layer placed on the outside of the ceramic cavity member reduces the temperature difference between the inner and outer surfaces of the ceramic cavity member, reducing cranking of the ceramic cavity member, and also provides insulation. The layer is formed from a ceramic fiber molded body instead of an air layer, and after the insulation layer is attached to the outer wall of the ceramic cavity member, the piston can be manufactured by casting these layers into the piston body, and the manufacturing process is improved. The aim is to simplify the process. In addition, by coating or impregnating the ceramic fiber molded body with an inorganic material,
At least the vicinity of the outer surface of the ceramic fiber molded body is hardened to prevent the molten metal forming the piston body from penetrating into the ceramic fiber molded body during casting, thereby improving the heat insulation properties of the heat insulating layer made of the ceramic fiber molded body. By preventing the decrease in the temperature and hardening at least the vicinity of the outer surface of the ceramic fiber molded body using the above-mentioned inorganic material, it is possible to reduce the collapse of the ceramic fiber molded body due to vibration and the shrinkage of the ceramic fiber molded body due to heating. It is characterized by being configured so that it can be used.
［実施例〕
本発明の一実施例を第１図ないし第３図に基づいて説明
すれば、以下の通りである。第１図に示すように、直接
噴射式ディーゼルエンジンのピストンは、アルミニウム
合金または鋳鉄等からなるピストン本体１を備えている
。ピストン本体１の上部には、例えば部分安定化ジルコ
ニアセラミック等の断熱性の高いセラミックからなり、
その内表面が燃焼室としてのキャビティ２（穴）を形成
するとともに、その外表面にピストン本体１からの抜止
め用の環状フランジ部３を有するほぼカップ状のセラミ
ック製キャビティ部材４が同心に鋳ぐるまれでいる。こ
のセラミック製キャビティ部材４の外壁における抜止め
用の環状フランジ部３より下方の部位は、セラミックフ
ァイバーをほぼカップ状に成形したセラミックファイバ
ー成形体に、無機材を塗布してなる断熱層５で被覆され
、この断熱層５もピストン本体１内に鋳ぐるまれている
。尚、第１図では便宜上、セラミックファイバー成形体
と無機材とを一層で表している。[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. As shown in FIG. 1, the piston of a direct injection diesel engine includes a piston body 1 made of aluminum alloy, cast iron, or the like. The upper part of the piston body 1 is made of a highly insulating ceramic such as partially stabilized zirconia ceramic,
A substantially cup-shaped ceramic cavity member 4, whose inner surface forms a cavity 2 (hole) serving as a combustion chamber, and whose outer surface has an annular flange portion 3 for preventing removal from the piston body 1, is cast concentrically. Stay together. The portion of the outer wall of the ceramic cavity member 4 below the annular flange portion 3 for preventing removal is covered with a heat insulating layer 5 made of a ceramic fiber molded body formed from ceramic fiber into a substantially cup shape and coated with an inorganic material. This heat insulating layer 5 is also cast inside the piston body 1. In addition, in FIG. 1, the ceramic fiber molded body and the inorganic material are shown as one layer for convenience.
ピストン本体１には、３つの環状ピストンリング溝６・
７・８が形成され、上側の２つのピストンリング溝６・
７には図示しないコンプレッションリングが嵌合される
一方、最下方のピストンリング溝８には図示しないオイ
ルリングが嵌合される。また、ピストン本体１の下部に
は、図示しないピストンピンが嵌合するピストンボス９
が形成される。The piston body 1 has three annular piston ring grooves 6.
7 and 8 are formed, and the upper two piston ring grooves 6 and
A compression ring (not shown) is fitted into the piston ring 7, while an oil ring (not shown) is fitted into the lowermost piston ring groove 8. Further, a piston boss 9 into which a piston pin (not shown) fits is provided at the lower part of the piston body 1.
is formed.
なお、ピストン本体１によるセラミック製キャビティ部
材４および断熱層５の鋳ぐるみに際し、ピストン本体１
を形成するアルミニウム合金等の溶湯からセラミック製
キャビティ部材４に加わる熱衝撃を緩和させるためには
、セラミック製キャビティ部材４を上記溶湯との温度差
が３００℃以下となる程度まで予備加熱しておく必要が
ある。また、鋳ぐるみ後に熱処理を行う場合、熱処理に
伴ってセラミック製キャビティ部材４にクラックが発生
するのを防止するためには、鋳ぐるみに際して・セラミ
ック製キャビティ部材４のキャビティ２に装着した図示
しない中子を取り外すことなく熱処理を行うことが好ま
しい。In addition, when casting the ceramic cavity member 4 and the heat insulating layer 5 with the piston body 1, the piston body 1
In order to alleviate the thermal shock applied to the ceramic cavity member 4 from the molten metal such as aluminum alloy forming the ceramic cavity member 4, the ceramic cavity member 4 is preheated to such an extent that the temperature difference with the molten metal is 300°C or less. There is a need. In addition, when heat treatment is performed after casting, in order to prevent cracks from occurring in the ceramic cavity member 4 due to the heat treatment, during casting, Preferably, the heat treatment is performed without removing the child.
次に、断熱層５の好ましい材質等について詳述する。本
発明者は、セラミックファイバーとして、アルミナシリ
ケートファイバー（以下、ファイバーＡと称する）、ア
ルミナファイバー（以下、ファイバーＢと称する）の２
種類を使用し、一方、無機材を含むコーテイング材とし
て第１表に示す３種類を使用して、セラミックファイバ
ーの振動による崩れ、および加熱に伴う収縮につき実験
を行った。Next, preferred materials for the heat insulating layer 5 will be described in detail. The present inventor has developed two types of ceramic fibers: alumina silicate fiber (hereinafter referred to as fiber A) and alumina fiber (hereinafter referred to as fiber B).
On the other hand, using three types of inorganic-containing coating materials shown in Table 1, experiments were conducted to examine the collapse of ceramic fibers due to vibration and shrinkage due to heating.
上記の第１表から明らかなように、コーティング材Ｎｏ
、 １は、無機材としてのコロイダル（コロイド状）シ
リカのみで構成される。また、コーティング材Ｎｏ、２
は、コロイダルシリカにＭｇＯ粉その他の粉末を表中の
最右欄に示す割合で混合して混練したものであり、コー
テイング材Ｎ００３は、無機材としてのエチルシリケー
ト系シリカゾルにＭｇＯ粉その他の粉末を表中の最右欄
に示す割合で混合して混練したものである。実験には、
上記各ファイバーＡ−Ｂの成形体のみからなる試料（そ
れぞれ試料Ａ、試料Ｂとする）、ファイバーＡの成形体
の外表面に各コーテイング材Ｎｏ、１”Ｎｏ、３を塗布
して乾燥させてなる試料（それぞれ試料Ａ−１〜Ａ−３
とする）、およびファイバーＢの成形体の外表面に各コ
ーテイング材Ｎ００１〜Ｎ００３を塗布して乾燥させて
なる試料（それぞれ試料Ｂ−１〜Ｂ−３とする）の合計
８種類の試料を使用した。第１の実験では、各試料に１
２５０℃×３時間の熱処理を施し、この熱処理の前後に
おける寸法の変化量（収縮量）を測定した。この結果を
第２図に示す。また、第２の実験として、各試料に１０
００℃×３時間の熱処理を施した後に、ストローク１３
０ｃｍの往復動を毎分２３０回行わせる振動試験を実施
し、振動付加時間と試料の重量の減少量との関係を測定
した。この結果を第３図に示す。振動によりファイバー
成形体の重量が減少するのは、ファイバー成形体からフ
ァイバーが崩れ落ちるためである。As is clear from Table 1 above, coating material No.
, 1 is composed only of colloidal silica as an inorganic material. In addition, coating material No. 2
Coating material No. 003 is a mixture of colloidal silica and MgO powder and other powders in the ratio shown in the rightmost column of the table, and coating material No. 003 is a mixture of MgO powder and other powders with ethyl silicate-based silica sol as an inorganic material. These were mixed and kneaded in the proportions shown in the rightmost column in the table. The experiment included
Samples consisting only of molded bodies of each of the fibers A and B (referred to as sample A and sample B, respectively) were coated with coating materials No. 1, No. 3, and dried on the outer surface of the molded bodies of fiber A. samples (respectively samples A-1 to A-3)
A total of 8 types of samples were used: samples obtained by applying coating materials N001 to N003 on the outer surface of a molded body of fiber B and drying them (respectively referred to as samples B-1 to B-3). did. In the first experiment, each sample had 1
A heat treatment was performed at 250° C. for 3 hours, and the amount of change in dimensions (amount of shrinkage) before and after this heat treatment was measured. The results are shown in FIG. In addition, as a second experiment, 10
After heat treatment at 00℃ x 3 hours, stroke 13
A vibration test was conducted in which a reciprocating motion of 0 cm was performed 230 times per minute, and the relationship between the vibration application time and the amount of decrease in the weight of the sample was measured. The results are shown in FIG. The reason why the weight of the fiber molded body decreases due to vibration is that the fibers collapse from the fiber molded body.
上記の実験結果から、ファイバー成形体にコーティング
を施すことにより、耐収縮性、耐振性が向上することが
判明した。また、コーテイング材として優れているのは
、Ｎｏ、２、Ｎｏ、３、Ｎｏ、１の順であり、無機材の
みからなるコーテイング材よりも、ＭｇＯ等の粉末を添
加したコーテイング材の方が好ましいことが認められた
。また、このように粉末を添加することにより、セラミ
ックファイバー成形体の耐熱性、断熱性を向上させるこ
とができる。The above experimental results revealed that shrinkage resistance and vibration resistance were improved by applying a coating to the fiber molded body. In addition, the order of excellence as a coating material is No. 2, No. 3, No. 1, and a coating material containing powder such as MgO is preferable to a coating material made only of inorganic materials. This was recognized. Moreover, by adding powder in this way, the heat resistance and heat insulation properties of the ceramic fiber molded body can be improved.
なお、上記の実験で使用した各コーテイング材の組成は
単なる例示に過ぎず、コーテイング材の組成は前掲の表
中の好適な組成範囲の欄を目安として変更しうるもので
ある。また、セラミンクファイバー、無機材および添加
粉末として上述した以外のものを使用しても良いことは
勿論である。The composition of each coating material used in the above experiment is merely an example, and the composition of the coating material can be changed using the preferred composition range column in the table above as a guide. It goes without saying that ceramic fibers, inorganic materials, and additive powders other than those mentioned above may also be used.
さらに、上記実施例では、セラミックファイバー成形体
の外表面に無機材等からなるコーテイング材を塗布した
が、これに代えて、セラミックファイバー成形体に無機
材または無機材にＭｇＯ粉等の粉末を添加したものを含
侵させて断熱層を形成するようにしても良い。さらに、
上記実施例では、直接噴射式ディーゼルエンジンのピス
トンについて述べたが、本発明は間接噴射式ディーゼル
エンジンおよびガソリンエンジンのピストンにも適用で
きるものである。Furthermore, in the above example, a coating material made of an inorganic material was applied to the outer surface of the ceramic fiber molded body, but instead of this, an inorganic material or a powder such as MgO powder was added to the ceramic fiber molded body. The heat insulating layer may be formed by impregnating the material. moreover,
In the above embodiment, a piston of a direct injection diesel engine was described, but the present invention can also be applied to a piston of an indirect injection diesel engine and a gasoline engine.
本発明に係る内燃機関のピストンは、以上のように、ピ
ストン上部にセラミック製キャビティ部材を有する内燃
機関のピストンにおいて、ピストン本体と、ピストン本
体の上部に鋳ぐるまれる上記セラミック製キャビティ部
材と、セラミックファイバーの成形体に無機材を塗布ま
たは含侵させてなり、上記セラミック製キャビティ部材
の外表面を被覆した状態でピストン本体に鋳ぐるまれる
断熱層とを備えた構成である。As described above, the piston for an internal combustion engine according to the present invention includes a piston body, the ceramic cavity member cast in the upper part of the piston body, It is constructed by coating or impregnating a ceramic fiber molded body with an inorganic material, and includes a heat insulating layer that is cast into the piston body while covering the outer surface of the ceramic cavity member.
これにより、セラミック製キャビティ部材の外側に配し
た断熱層によって、セラミック製キャビティ部材の内表
面と外表面との間の温度差を小さくすることができるの
で、セラミック製キャビティ部材のクラックを減少させ
ることができる。また、断熱層を空気層ではなく、セラ
ミックファイバー成形体により形成したので、セラミッ
ク製キャビティ部材の外表面に断熱層を装着した後に、
これらをピストン本体内に鋳ぐるむことによりピストン
を製造でき、これにより、製造工程の単純化を図ること
ができる。さらに、セラミックファイバー成形体に無機
材を塗布または含侵させることにより、セラミックファ
イバー成形体の少なくとも外表面を硬化させたので、鋳
ぐるみ時に、セラミックファイバー成形体内に、ピスト
ン本体を形成する溶湯が侵入するのを防止でき、この結
果、セラミックファイバー成形体からなる断熱層の断熱
性を低下を阻止できる。また、上記無機材によりセラミ
ックファイバー成形体の少なくとも外表面を硬化させた
ので、振動によるセラミックファイバー成形体の崩れや
、加熱に伴うセラミックファイバー成形体の収縮を低減
させることができる等の効果を奏する。As a result, the temperature difference between the inner and outer surfaces of the ceramic cavity member can be reduced by the heat insulating layer placed on the outside of the ceramic cavity member, thereby reducing cracks in the ceramic cavity member. Can be done. In addition, since the heat insulating layer is formed from a ceramic fiber molded body instead of an air layer, after the heat insulating layer is attached to the outer surface of the ceramic cavity member,
The piston can be manufactured by casting these into the piston body, thereby simplifying the manufacturing process. Furthermore, by coating or impregnating the ceramic fiber molded body with an inorganic material, at least the outer surface of the ceramic fiber molded body is hardened, so that the molten metal forming the piston body enters into the ceramic fiber molded body during casting. As a result, the heat insulating properties of the heat insulating layer made of the ceramic fiber molded body can be prevented from deteriorating. Furthermore, since at least the outer surface of the ceramic fiber molded body is hardened with the above-mentioned inorganic material, it is possible to reduce the collapse of the ceramic fiber molded body due to vibration and the shrinkage of the ceramic fiber molded body due to heating. .
第１図ないし第３図は本発明の一実施例を示すものであ
って、第１図は直接噴射式ディーゼルエンジンのピスト
ンの縦断面図、第２図はセラミックファイバー成形体の
熱処理前後の寸法変化量を示すグラフ、第３図はセラミ
ックファイバー成形体に対する振動付加時間と重量減少
量との関係を示すグラフである。
■はピストン本体、４はセラミック製キャビティ部材、
５は断熱層である。
一４″−ｊFigures 1 to 3 show an embodiment of the present invention, in which Figure 1 is a longitudinal cross-sectional view of a piston of a direct injection diesel engine, and Figure 2 is a dimension of a ceramic fiber molded body before and after heat treatment. A graph showing the amount of change, and FIG. 3 is a graph showing the relationship between the vibration application time and the amount of weight reduction for the ceramic fiber molded body. ■ is the piston body, 4 is the ceramic cavity member,
5 is a heat insulating layer. 14″-j
Claims (1)
る内燃機関のピストンにおいて、ピストン本体と、ピス
トン本体の上部に鋳ぐるまれる上記セラミック製キャビ
ティ部材とを備え、セラミックファイバーの成形体に無
機材が付与されてなる断熱層を、上記セラミック製キャ
ビティ部材の外表面を被覆した状態でピストン本体に鋳
ぐるんで成る内燃機関のピストン。 ２、上記の断熱層は、セラミックファイバーの成形体に
無機材が塗布されたものである特許請求の範囲第１項記
載の内燃機関のピストン。 ３、上記の断熱層は、セラミックファイバーの成形体に
無機材が含浸されたものである特許請求の範囲第１項記
載の内燃機関のピストン。[Claims] 1. A piston for an internal combustion engine having a ceramic cavity member in the upper part of the piston, comprising a piston body and the above ceramic cavity member cast in the upper part of the piston body, and a molded body of ceramic fiber. A piston for an internal combustion engine, comprising a heat insulating layer formed by adding an inorganic material to the ceramic cavity member, which is cast into the piston body with the outer surface of the ceramic cavity member coated. 2. The piston for an internal combustion engine according to claim 1, wherein the heat insulating layer is a ceramic fiber molded body coated with an inorganic material. 3. The piston for an internal combustion engine according to claim 1, wherein the heat insulating layer is a ceramic fiber molded body impregnated with an inorganic material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61253948A JPS63109267A (en) | 1986-10-24 | 1986-10-24 | Piston of internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61253948A JPS63109267A (en) | 1986-10-24 | 1986-10-24 | Piston of internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63109267A true JPS63109267A (en) | 1988-05-13 |
Family
ID=17258210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61253948A Pending JPS63109267A (en) | 1986-10-24 | 1986-10-24 | Piston of internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63109267A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5645028A (en) * | 1995-11-21 | 1997-07-08 | Isuzu Motors Limited | Piston structure with a combustion chamber |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4245611A (en) * | 1978-09-05 | 1981-01-20 | General Motors Corporation | Ceramic insulated engine pistons |
-
1986
- 1986-10-24 JP JP61253948A patent/JPS63109267A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4245611A (en) * | 1978-09-05 | 1981-01-20 | General Motors Corporation | Ceramic insulated engine pistons |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5645028A (en) * | 1995-11-21 | 1997-07-08 | Isuzu Motors Limited | Piston structure with a combustion chamber |
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