Direct-injection type spark-ignition internal combustion engine

A direct-injection type spark-ignition internal combustion engine, comprising:

• a cylinder head having an intake-valve port and an exhaust-valve port;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber, and so that an uppermost line of fuel spray injected through said spray hole is set at a lower level than an electrode end of said spark plug and a lowermost line of said fuel spray is in spaced relationship with a cylinder inner wall close to said spray hole;
• wherein said piston crown is formed with a recessed portion and a raised flat-surface portion, said recessed portion facing said inlet-valve port essentially at a top dead center and receiving almost all of said fuel spray at a fuel-injection period near the top dead center, and said raised flat-surface portion facing said exhaust-valve port essentially at the top dead center and gradually up-sloped in a direction extending from said exhaust-valve port to said intake-valve port,
• wherein a ridge line is defined as an intersecting line between said recessed portion and said raised flat-surface portion, and said ridge line is offset from a center axis of said cylinder by a predetermined distance toward a side of said exhaust-valve port, and said ridge line is formed on said piston crown so that an outermost curved line of a collision area of the fuel spray on said piston crown intersects said ridge line during at least a fuel-injection period from initiation of fuel injection essentially to a crank angle of 120.degree. after the top dead center, and
• wherein a spray angle between said uppermost and lowermost lines is set within a predetermined angle range of 70.degree..+-.20.degree..

A direct-injection type spark-ignition internal combustion engine, comprising:

• a cylinder head having an intake-valve port and an exhaust-valve port;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber, and so that an uppermost line of fuel spray injected through said spray hole is set at a lower level than an electrode end of said spark plug and a lowermost line of said fuel spray is in spaced relationship with a cylinder inner wall close to said spray hole;
• wherein said piston crown is formed with at least a raised flat-surface portion facing said exhaust-valve port essentially at a top dead center and gradually up-sloped in a direction extending from said exhaust-valve port to said intake-valve port, for defining a ridge line by a maximum raised edge of said raised flat-surface portion,
• wherein said ridge line is offset from a center axis of said cylinder by a predetermined distance toward a side of said exhaust-valve port, and said ridge line is formed on said piston crown so that an outermost curved line of a collision area of the fuel spray on said piston crown intersects said ridge line during at least a fuel-injection period from initiation of fuel injection essentially to a crank angle of 120.degree. after the top dead center, and
• wherein a spray angle between said uppermost and lowermost lines is set within a predetermined angle range of 70.degree..+-.20.degree..

A direct-injection type spark-ignition internal combustion engine comprising:

• an intake-valve port formed in a cylinder head;
• an exhaust-valve port formed in said cylinder head;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed between said intake-valve port and said exhaust-valve port and essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber;
• wherein said intake-valve port is directed toward a cylinder inner wall closer to said exhaust-valve port for producing a vortex flow rotating from said cylinder inner wall toward said piston crown by colliding intake air coming from said intake-valve port with said cylinder inner wall,
• wherein said piston crown is formed with a recessed portion and a raised flat-surface portion, said recessed portion facing said inlet-valve port essentially at a top dead center, and said raised flat-surface portion facing said exhaust-valve port essentially at the top dead center and gradually up-sloped in a direction extending from said exhaust-valve port to said intake-valve port, and
• wherein a ridge line is defined as an intersecting line between said recessed portion and said raised flat-surface portion and said ridge line is offset from a center axis of said cylinder by a predetermined distance toward a side of said exhaust-valve port.

A direct-injection type spark-ignition internal combustion engine comprising:

• an intake-valve port formed in a cylinder head;
• an exhaust-valve port formed in said cylinder head;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed between said intake-valve port and said exhaust-valve port and essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber;
• wherein said piston crown is formed with a recessed portion and a raised flat-surface portion, said recessed portion facing said inlet-valve port essentially at a top dead center, and said raised flat-surface portion facing said exhaust-valve port essentially at the top dead center and gradually up-sloped in a direction extending from said exhaust-valve port to said intake-valve port,
• wherein a ridge line is defined as an intersecting line between said recessed portion and said raised flat-surface portion and said ridge line is offset from a center axis of said cylinder by a predetermined distance toward a side of said exhaust-valve port, and
• wherein said intake-valve port is directed toward a cylinder inner wall closer to said exhaust-valve port for producing a first vortex flow (22) rotating from said cylinder inner wall toward said piston crown by colliding intake air coming from said intake-valve port with said cylinder inner wall and a second vortex flow (23) rotating from said ridge line toward a cylinder inner wall closer to said intake-valve port, on an intake stroke.

A direct-injection type spark-ignition internal combustion engine comprising:

• a cylinder head having an intake-valve port and an exhaust-valve port;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed between said intake-valve port and said exhaust-valve port and essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber, and so that an uppermost line of fuel spray injected through said spray hole is set at a lower level than an electrode end of said spark plug and a lowermost line of said fuel spray is in spaced relationship with a cylinder inner wall close to said spray hole;
• wherein a spray angle between said uppermost and lowermost lines is set within a predetermined angle range of 70.degree..+-.20.degree., and
• wherein an angle-of-elevation, which is defined as an angle between a bottom face of said cylinder head and a center axis of said fuel-injection valve, is defined by an inequality .alpha./2.ltoreq..theta..ltoreq.90.degree.-.alpha./2, where .alpha. denotes said spray angle and .theta. denotes said angle-of-elevation.

A direct-injection type spark-ignition internal combustion engine comprising:

• a cylinder head having an intake-valve port and an exhaust-valve port;
• a cylinder block having a cylinder;
• a piston moveable up and down within said cylinder;
• a spark plug disposed between said intake-valve port and said exhaust-valve port and essentially in a center of a combustion chamber defined by a piston crown of said piston and said cylinder head;
• and
• a fuel-injection valve mounted on said cylinder head near and below said intake-valve port so that a spray hole of said injection valve opens through a combustion-chamber wall into said combustion chamber, and so that an uppermost line of fuel spray injected through said spray hole is set at a lower level than an electrode end of said spark plug and a lowermost line of said fuel spray is in spaced relationship with a cylinder inner wall close to said spray hole;
• wherein a spray angle between said uppermost and lowermost lines is set within a predetermined angle range of 65.degree..+-.5.degree., and
• wherein an angle-of-elevation, which is defined as an angle between a bottom face of said cylinder head and a center axis of said fuel-injection valve, is defined by an inequality .alpha./2.ltoreq..theta..ltoreq.90.degree.-.alpha./2, where .alpha. denotes said spray angle and .theta. denotes said angle-of-elevation.