JP2008095576A - Structure of combustion chamber for internal combustion engine - Google Patents

Structure of combustion chamber for internal combustion engine Download PDF

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JP2008095576A
JP2008095576A JP2006276521A JP2006276521A JP2008095576A JP 2008095576 A JP2008095576 A JP 2008095576A JP 2006276521 A JP2006276521 A JP 2006276521A JP 2006276521 A JP2006276521 A JP 2006276521A JP 2008095576 A JP2008095576 A JP 2008095576A
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cylinder head
combustion chamber
peripheral wall
cylinder block
cylinder
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Kazuyuki Maeda
一之 前田
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Nissan Motor Co Ltd
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    • 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

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  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To improve engine output while increasing an end gas cooling rate only in an intake side to suppress knocking. <P>SOLUTION: A cylinder head 1 is made of an aluminum material having a higher thermal conductivity than that of a cylinder block 2 made of a steel material. A jointing surface between the cylinder head 1 and the cylinder block 2 is inclined in a direction approaching a crankshaft, from an exhaust valve 6 side to an intake valve 5 side. Near a top dead center, the circumferential wall of the top of a piston 3 is opposed to the circumferential wall of the cylinder head 1 on an intake side, and opposed to the circumferential wall of the cylinder block 2 on an exhaust side. The circumferential wall of the cylinder head on the intake side, which is opposed to the circumferential wall of the top of the piston 3, is outwardly expanded from the circumferential wall of the cylinder head 2 on the exhaust side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、内燃機関の燃焼室構造に関し、特に、ノッキングを防止するための技術に関する。   The present invention relates to a combustion chamber structure of an internal combustion engine, and more particularly to a technique for preventing knocking.

特許文献１には、シリンダヘッド底壁に設けた凹部に吸気バルブ、点火プラグを設置し、排気側の燃焼室下面に沿ってスキッシュを形成し、前記凹部のコンパクトな燃焼室にエンドガスを押し込み、吸・排気バルブのオーバーラップ時に、燃焼室内の混合気が排気側に抜けることを抑制する技術が開示されている。
特開平４−３２１７１４号 In Patent Document 1, an intake valve and a spark plug are installed in a recess provided in the bottom wall of the cylinder head, a squish is formed along the lower surface of the combustion chamber on the exhaust side, and an end gas is pushed into the compact combustion chamber of the recess, A technique is disclosed that suppresses the air-fuel mixture in the combustion chamber from escaping to the exhaust side when the intake and exhaust valves overlap.
JP-A-4-321714

特許文献１のものは、燃焼室内の燃料／空気の混合や乱流強化に着目しているが、温度上からノッキング防止を手当てするものではない。このため、ノッキングは、火炎伝播の遅い吸気側で発生し、かつ、燃焼室温度の影響が大きいが、特許文献１等のように温度対策を施していないものでは、燃焼室が高温になるため、ノッキングを十分抑制できるものではなかった。   Although the thing of the patent document 1 pays attention to the fuel / air mixing in a combustion chamber, and turbulent flow reinforcement | strengthening, it does not treat knocking prevention from temperature. For this reason, knocking occurs on the intake side where flame propagation is slow and the influence of the temperature of the combustion chamber is large. However, in the case where temperature countermeasures are not taken as in Patent Document 1, the combustion chamber becomes hot. , Knocking could not be sufficiently suppressed.

このため、本発明は、
シリンダヘッドを、シリンダブロックより熱伝導率が高い材料で形成すると共に、
前記シリンダヘッド及びシリンダブロックを、上死点付近でピストン頂部周壁が、吸気側でシリンダヘッド周壁に対向し、排気側でシリンダブロック周壁に対向するように形成したことを特徴とする。 For this reason, the present invention
The cylinder head is made of a material having a higher thermal conductivity than the cylinder block,
The cylinder head and the cylinder block are formed so that the piston top peripheral wall faces the cylinder head peripheral wall on the intake side and the cylinder block peripheral wall on the exhaust side near top dead center.

吸気側は排気側より低温であるため火炎伝播速度が遅いため、吸気側のエンドガス中を火炎が通過する時間が長引き、その間に自発火してノッキングを発生する傾向が大きい。
本発明では、上死点付近で吸気側のピストン頂部周壁とシリンダヘッド周壁との間に溜まるエンドガスから熱伝導率が高い材料で形成されたシリンダヘッドへの放熱量を大きくすることができるので、該エンドガスが効率よく冷却されて、ノッキングの発生を抑制することができる。 Since the intake side has a lower temperature than the exhaust side and the flame propagation speed is slow, the time for the flame to pass through the end gas on the intake side is prolonged, and it tends to spontaneously ignite during that time to cause knocking.
In the present invention, the amount of heat released from the end gas accumulated between the piston top peripheral wall and the cylinder head peripheral wall near the top dead center to the cylinder head formed of a material having high thermal conductivity can be increased. The end gas is efficiently cooled, and the occurrence of knocking can be suppressed.

一方、ノッキングが発生しにくい排気側のピストン頂部周壁とシリンダヘッド周壁との間に溜まるエンドガスは、シリンダヘッドより熱伝導率が低い材料で形成されたシリンダブロックへの放熱を抑制できるので、必要以上の放熱冷却を抑制して熱効率の低下を最小限に留めることができる。
これにより、上記ノッキング抑制機能の向上とあいまって機関の最高出力を高めることができる。 On the other hand, the end gas that accumulates between the piston top peripheral wall on the exhaust side and the cylinder head peripheral wall, where knocking is unlikely to occur, can suppress heat dissipation to the cylinder block made of a material with lower thermal conductivity than the cylinder head, so it is more than necessary Therefore, it is possible to suppress a decrease in thermal efficiency by suppressing heat radiation cooling.
Accordingly, the maximum output of the engine can be increased together with the improvement of the knocking suppression function.

以下、図面に基づき、本発明の実施形態について説明する。
図１は、本発明に係る火花点火式内燃機関の全体システムを示す。
内燃機関は、シリンダヘッド１、シリンダブロック２、及びピストン３から画成される燃焼室４を有し、吸気バルブ５を介して吸気ポート７から新気を導入する。
燃焼室４は、シリンダヘッド１に形成される頂壁が円錐状をなす、いわゆるペントルーフ型に形成される。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall system of a spark ignition type internal combustion engine according to the present invention.
The internal combustion engine has a combustion chamber 4 defined by a cylinder head 1, a cylinder block 2, and a piston 3, and introduces fresh air from an intake port 7 via an intake valve 5.
The combustion chamber 4 is formed in a so-called pent roof type in which the top wall formed in the cylinder head 1 has a conical shape.

吸気ポート７には、燃料噴射弁９が燃焼室４を臨んで配置され、噴射された燃料は新気と混合しながら燃焼室４内に吸入され、燃焼に適した可燃混合気を形成する。そして、燃焼室４内に形成された混合気は、点火プラグ１０により点火・燃焼され、排気バルブ６を介して排気ポート８から排出される。
内燃機関の運転状態は、エンジンコントロールユニット（以下「ＥＣＵ」と称する）１１によって統合的に制御される。ＥＣＵ１１には、アクセル開度センサ１２、水温センサ１３、及びクランク角センサ１４等から各種信号が入力され、これらの信号に基づいてＥＣＵ１１の内部で必要な処理・演算を行い、燃料噴射弁９、点火プラグ１０等を制御する。 A fuel injection valve 9 is disposed at the intake port 7 so as to face the combustion chamber 4, and the injected fuel is sucked into the combustion chamber 4 while mixing with fresh air to form a combustible mixture suitable for combustion. The air-fuel mixture formed in the combustion chamber 4 is ignited and burned by the spark plug 10 and is discharged from the exhaust port 8 via the exhaust valve 6.
The operating state of the internal combustion engine is integrally controlled by an engine control unit (hereinafter referred to as “ECU”) 11. Various signals are input to the ECU 11 from the accelerator opening sensor 12, the water temperature sensor 13, the crank angle sensor 14, and the like, and based on these signals, necessary processing / calculation is performed inside the ECU 11, and the fuel injection valve 9, The spark plug 10 and the like are controlled.

図２は、本発明に係る燃焼室構造の詳細を示す。
前記シリンダヘッド１は、アルミ系材料（アルミ合金）で形成され、シリンダブロック２は、スティール系材料で形成されている。なお、周知のようにアルミ系材料は、スティール系材料と比較して、熱伝導率が高い。
また、シリンダヘッド１とシリンダブロック２の接合面が、排気バルブ６側から吸気バルブ５側に向かって、クランクシャフトに近づく方向に傾斜して形成されている。 FIG. 2 shows the details of the combustion chamber structure according to the present invention.
The cylinder head 1 is made of an aluminum material (aluminum alloy), and the cylinder block 2 is made of a steel material. As is well known, aluminum-based materials have higher thermal conductivity than steel-based materials.
Further, the joint surface between the cylinder head 1 and the cylinder block 2 is formed so as to be inclined in a direction approaching the crankshaft from the exhaust valve 6 side toward the intake valve 5 side.

そして、上記接合面の傾斜により、吸気バルブ側のシリンダヘッド１周壁は、排気側より下方に延びて形成され、上死点付近でピストン３の頂部周壁に対向し、排気側のシリンダヘッド１周壁は、上死点でも略ピストン３の頂面より上方にあって、上死点付近で排気側のピストン３の周壁は、シリンダブロック２の周壁に対向する。
また、上記吸気バルブ側のシリンダヘッド周壁を、排気バルブ側のシリンダヘッド周壁より外側に膨らませて形成する。 Due to the inclination of the joint surface, the peripheral wall of the cylinder head on the intake valve side is formed to extend downward from the exhaust side, opposes the top peripheral wall of the piston 3 near the top dead center, and the peripheral wall of the cylinder head on the exhaust side. Is approximately above the top surface of the piston 3 even at the top dead center, and the peripheral wall of the piston 3 on the exhaust side faces the peripheral wall of the cylinder block 2 near the top dead center.
Further, the cylinder head peripheral wall on the intake valve side is formed to bulge outward from the cylinder head peripheral wall on the exhaust valve side.

具体的には、図（Ｂ）に示すように、上死点付近においてシリンダヘッド１、シリンダブロック２及びピストン３で画成される燃焼室４のシリンダ中心軸と直交する断面が、排気側の径より吸気側の径が大きい卵形をなすように形成する。
次に、上記構造を有する燃焼室の作用を説明する。
上述したように、吸気側は排気側より低温のため火炎伝播速度が遅く、エンドガス中を火炎が通過する時間が長引き、その間に自発火してノッキングを発生する傾向が大きい。 Specifically, as shown in FIG. (B), a cross section perpendicular to the cylinder central axis of the combustion chamber 4 defined by the cylinder head 1, the cylinder block 2, and the piston 3 near the top dead center is on the exhaust side. It is formed so as to form an oval shape whose diameter on the intake side is larger than the diameter.
Next, the operation of the combustion chamber having the above structure will be described.
As described above, since the intake side has a lower temperature than the exhaust side, the flame propagation speed is slow, the time for the flame to pass through the end gas is prolonged, and during this time, there is a greater tendency to ignite and knock.

しかし、吸気側のエンドガスは、ピストン３の頂部周壁とシリンダヘッド１の周壁との間に溜まるため、排気側に比較して熱伝導率が高いアルミ系材料で形成されたシリンダヘッド１周壁からの放熱量を大きくすることができ、エンドガスを効率よく冷却することができるので、ノッキングの発生を抑制できる。
一方、ノッキングが発生しにくい排気側では、ピストン３の頂部周壁とシリンダヘッド１の周壁との間に溜まるエンドガスは、シリンダヘッド１より熱伝導率が低いスティール系材料で形成されたシリンダブロック２への放熱・冷却を抑制できるので、熱効率の低下を最小限に留めることができる。 However, since the end gas on the intake side accumulates between the top peripheral wall of the piston 3 and the peripheral wall of the cylinder head 1, the end gas from the cylinder head 1 peripheral wall formed of an aluminum-based material having a higher thermal conductivity than the exhaust side. Since the amount of heat radiation can be increased and the end gas can be efficiently cooled, the occurrence of knocking can be suppressed.
On the other hand, on the exhaust side where knocking is unlikely to occur, the end gas accumulated between the top peripheral wall of the piston 3 and the peripheral wall of the cylinder head 1 is directed to the cylinder block 2 formed of a steel material having a lower thermal conductivity than the cylinder head 1. Therefore, it is possible to suppress the decrease in thermal efficiency.

そして、このように、必要最小限の放熱・冷却によってノッキング抑制機能を高めることにより、ノッキング制御時における点火時期進角限界を最大限拡張して機関の最高出力を高めることができる。
また、吸気側では、ピストン頂部周壁がシリンダブロックとシリンダヘッドの接合面を跨ぐことになるが、本実施形態のように一般的なペントルーフ型の燃焼室４においては、シリンダヘッドのシリンダブロックへの組み付け位置の接合面に沿ったバラツキにより、ピストン頂壁エッジ部分が燃焼室頂壁と接触ないし極接近する可能性があり、その場合、機関運転時にピストンの首振りモーションによってピストンとシリンダヘッドとが干渉して、かじりを発生してしまう。 Thus, by increasing the knocking suppression function by the minimum necessary heat dissipation and cooling, the ignition timing advance limit at the time of knocking control can be extended to the maximum, and the maximum output of the engine can be increased.
On the intake side, the piston top peripheral wall straddles the joint surface between the cylinder block and the cylinder head. However, in the general pent roof type combustion chamber 4 as in the present embodiment, the cylinder head is connected to the cylinder block. Due to variations along the joint surface at the assembly position, there is a possibility that the edge portion of the piston top wall contacts or comes close to the combustion chamber top wall.In this case, the piston and cylinder head are moved by the swing motion of the piston during engine operation. Interference will cause galling.

そこで、本実施形態では、ピストン３の頂部周壁と対向する吸気側のシリンダヘッド１周壁を排気側のシリンダブロック１周壁より外側に膨らませて形成している。
これにより、組み付けバラツキがあっても、ピストン３頂壁エッジ部分と燃焼室４頂壁との間に十分な隙間が与えられるので、ピストン３の首振りモーションによるピストン３とシリンダヘッド１の干渉を回避でき、かじりの発生を防止できる。 Therefore, in the present embodiment, the intake-side cylinder head 1 peripheral wall facing the top peripheral wall of the piston 3 is formed to bulge outward from the exhaust-side cylinder block 1 peripheral wall.
Thereby, even if there is a variation in assembly, a sufficient gap is provided between the top wall edge portion of the piston 3 and the top wall of the combustion chamber 4, so that the piston 3 and the cylinder head 1 are not interfered by the swing motion of the piston 3. It can be avoided and the occurrence of galling can be prevented.

実施形態に係る火花点火式内燃機関の全体システムの構成図1 is a configuration diagram of an overall system of a spark ignition type internal combustion engine according to an embodiment. 実施形態の燃焼室構造の詳細及び燃焼室の横断面形状を示す図The figure which shows the detail of the combustion chamber structure of embodiment, and the cross-sectional shape of a combustion chamber

符号の説明Explanation of symbols

１ シリンダヘッド
２ シリンダブロック
３ ピストン
４ 燃焼室
５ 吸気バルブ
６ 排気バルブ
９ 燃料噴射弁
１０ 点火プラグ DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Cylinder block 3 Piston 4 Combustion chamber 5 Intake valve 6 Exhaust valve 9 Fuel injection valve 10 Spark plug

Claims (5)

シリンダヘッドを、シリンダブロックより熱伝導率が高い材料で形成すると共に、
前記シリンダヘッド及びシリンダブロックを、上死点付近でピストン頂部周壁が、吸気側でシリンダヘッド周壁に対向し、排気側でシリンダブロック周壁に対向するように形成したことを特徴とする内燃機関の燃焼室構造。 The cylinder head is made of a material having a higher thermal conductivity than the cylinder block,
Combustion of an internal combustion engine, characterized in that the cylinder head and the cylinder block are formed so that the piston top peripheral wall faces the cylinder head peripheral wall on the intake side and the cylinder block peripheral wall on the exhaust side near top dead center Chamber structure. シリンダヘッドに形成される燃焼室頂壁が円錐状であり、前記ピストン頂部周壁と対向する吸気側のシリンダヘッド周壁を排気側のシリンダブロック周壁より外側に膨らませて形成したことを特徴とする請求項１に記載の内燃機関の燃焼室構造。   The combustion chamber top wall formed in the cylinder head has a conical shape, and an intake side cylinder head peripheral wall facing the piston top peripheral wall is formed to bulge outward from an exhaust side cylinder block peripheral wall. 2. A combustion chamber structure of an internal combustion engine according to 1. シリンダヘッドとシリンダブロックの接合面が、排気バルブ側から吸気バルブ側に向かって、クランクシャフトに近づく方向に傾斜して形成されていることを特徴とする請求項１または請求項２に記載の内燃機関の燃焼室構造。   3. The internal combustion engine according to claim 1, wherein a joint surface between the cylinder head and the cylinder block is formed to be inclined in a direction approaching the crankshaft from the exhaust valve side toward the intake valve side. Engine combustion chamber structure. 上死点付近において、ピストンとシリンダヘッド及びシリンダブロックとで形成される燃焼室のシリンダ中心軸と直交する断面形状が卵形であることを特徴とする請求項１〜請求項３のいずれか１つに記載の内燃機関の燃焼室構造。   4. The cross section of the combustion chamber formed by the piston, the cylinder head, and the cylinder block in the vicinity of the top dead center is perpendicular to the cylinder central axis, and is in an oval shape. A combustion chamber structure of an internal combustion engine according to claim 1. シリンダヘッドがアルミ系材料、シリンダブロックがスティール系材料で形成されていることを特徴とする請求項１〜請求項４のいずれか１つに記載の内燃機関の燃焼室構造。   The combustion chamber structure for an internal combustion engine according to any one of claims 1 to 4, wherein the cylinder head is made of an aluminum material and the cylinder block is made of a steel material.
JP2006276521A 2006-10-10 2006-10-10 Structure of combustion chamber for internal combustion engine Pending JP2008095576A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015140887A (en) * 2014-01-30 2015-08-03 Nok株式会社 Sealed structure with gasket

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015140887A (en) * 2014-01-30 2015-08-03 Nok株式会社 Sealed structure with gasket

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