JP2014074411A5

JP2014074411A5 -

Info

Publication number: JP2014074411A5
Application number: JP2014007400A
Authority: JP
Filing date: 2014-01-20
Publication date: 2014-09-11
Anticipated expiration: 2029-10-22

Description

本発明は、前記研究結果に基づいてなされたものであり、シリンダと当該シリンダ内を往復移動するピストンと前記シリンダ上に設けられて前記ピストンの上面との間で燃焼室を形成するシリンダヘッドとを備えるエンジン本体と、前記シリンダヘッドに設けられて前記シリンダ内への空気の流入をそれぞれ遮断可能な２つの吸気弁と、前記シリンダヘッドに設けられて前記シリンダからの排気の流出をそれぞれ遮断可能な２つの排気弁と、前記シリンダヘッドに設けられて前記燃焼室に臨む点火プラグと、前記シリンダヘッドに設けられて前記燃焼室に臨む燃料噴射弁とを有する火花点火式内燃機関であって、少なくともエンジン本体の回転数が低く負荷が高いためにノッキングが懸念される運転領域において、前記吸気弁および排気弁の開弁期間が上死点を挟んで互いにオーバーラップするように、かつ、前記運転領域の少なくとも一部の運転条件においてこのオーバーラップ期間が３５°ＣＡ以上となるように、前記吸気弁および排気弁を開弁する動弁機構を備え、前記エンジン本体の幾何学的圧縮比は１４以上に設定されており、上死点にある前記ピストンの上面と閉弁状態にある前記吸気弁の下面との距離を前記吸気弁の下面に直交する方向に測った場合における最小値をピストンと吸気弁との離間距離、上死点にある前記ピストンの上面と閉弁状態にある前記排気弁の下面との距離を前記排気弁の下面に直交する方向に測った場合における最小値をピストンと排気弁との離間距離としたとき、前記各離間距離はそれぞれ５ｍｍ以上に設定されており、前記ピストンのストロークＳ（ｍｍ）は、前記シリンダのボア径をＢ（ｍｍ）としたときに、Ｓ≦０．９７７×Ｂ＋１８．２ｍｍとなる長さに設定されており、前記燃焼室の天井部は吸気側及び排気側の２つの傾斜面からなる三角屋根状をなしており、前記ピストンの上面に吸気側及び排気側からそれぞれ中央寄りに向かい隆起する隆起部が形成されている、ことを特徴とするものである。 The present invention has been made based on the above research results, and a cylinder head, a piston that reciprocates in the cylinder, and a cylinder head that is provided on the cylinder and forms a combustion chamber between the upper surface of the piston, An engine main body, two intake valves provided in the cylinder head and capable of blocking the inflow of air into the cylinder, and an exhaust body provided in the cylinder head and capable of blocking outflow of exhaust gas from the cylinder. A spark ignition type internal combustion engine having two exhaust valves, an ignition plug provided in the cylinder head and facing the combustion chamber, and a fuel injection valve provided in the cylinder head and facing the combustion chamber , in operation region where knocking is concerned due to the high load low rotation speed of the engine body even without low, of the intake and exhaust valves So as to overlap each other across the top dead center the valve period, and so the overlap period and 35 ° CA or more at least part of the operating condition of the operating range, the intake and exhaust valves A valve mechanism for opening the valve, wherein the geometric compression ratio of the engine body is set to 14 or more, and the distance between the upper surface of the piston at the top dead center and the lower surface of the intake valve in the closed state Is the distance between the piston and the intake valve, and the distance between the upper surface of the piston at the top dead center and the lower surface of the exhaust valve in the closed state when measured in the direction perpendicular to the lower surface of the intake valve When the minimum value when measured in the direction perpendicular to the lower surface of the exhaust valve is the separation distance between the piston and the exhaust valve , each separation distance is set to 5 mm or more. Low click S (mm) is a bore diameter of the cylinder when the B (mm), is set to a length which is a S ≦ 0.977 × B + 18.2mm, a ceiling portion of the combustion chamber intake It has a triangular roof shape composed of two inclined surfaces on the side and the exhaust side, and a raised portion is formed on the upper surface of the piston so as to protrude toward the center from the intake side and the exhaust side, respectively. Is.

Claims

An engine body including a cylinder, a piston that reciprocates in the cylinder, and a cylinder head that is provided on the cylinder and forms a combustion chamber between the upper surface of the piston; Two intake valves that can block the inflow of air to the cylinder, two exhaust valves that are provided in the cylinder head and each can block the outflow of exhaust gas from the cylinder, and the combustion that is provided in the cylinder head A spark ignition internal combustion engine having a spark plug facing a chamber and a fuel injection valve provided in the cylinder head and facing the combustion chamber;
In operation region where knocking is concerned due to the high load low rotation speed of the engine body even without low, as the opening period of the intake and exhaust valves are overlapped each other across the top dead center, and, A valve operating mechanism for opening the intake valve and the exhaust valve so that the overlap period is 35 ° CA or more in at least a part of the operation conditions of the operation region ;
The geometric compression ratio of the engine body is set to 14 or more,
The minimum distance when the distance between the upper surface of the piston at the top dead center and the lower surface of the intake valve in the closed state is measured in a direction perpendicular to the lower surface of the intake valve, the separation distance between the piston and the intake valve , When the distance between the top surface of the piston at the top dead center and the bottom surface of the exhaust valve in the closed state is measured in a direction perpendicular to the bottom surface of the exhaust valve, the minimum value is the separation distance between the piston and the exhaust valve. Each of the separation distances is set to 5 mm or more,
Stroke S (mm) of the piston, when the bore diameter of the cylinder was set to B (mm), is set to a length which is a S ≦ 0.977 × B + 18.2mm,
The ceiling portion of the combustion chamber has a triangular roof shape composed of two inclined surfaces on the intake side and the exhaust side, and a raised portion is formed on the upper surface of the piston so as to protrude from the intake side and the exhaust side toward the center. A spark ignition type internal combustion engine characterized by comprising:

The spark ignition internal combustion engine according to claim 1,
A spark ignition type internal combustion engine, wherein a concave portion is formed at the center of the raised portion of the piston.