Throttle valve control device for an internal combustion engine

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake air passage;
• and
• a throttle valve rotatably mounted in a bore of said throttle body,
• said throttle body having a bore inner wall surface having curved-surface profiles each spherical or closely analogous to a spherical form in an idle control region located in the vicinity of a fully-closed angle of said throttle valve,
• said curved-surface profiles having central positions respectively placed in positions deviated toward the upstream and downstream sides along a central line of said bore by predetermined amounts from the center of rotation of said throttle valve,
• said bore of said throttle body including, as regions following the curved-surface shapes spherical or closely analogous to the spherical form, regions each consisting of a curved-surface profile spherical or closely analogous to a spherical form and a composite surface profile of a surface substantially parallel to the flow of intake air, or regions each made up of a conical surface profile.

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake passage;
• and
• a throttle valve rotatably mounted in a bore of said throttle body;
• said throttle body having a bore inner wall surface including curved-surface profiles each spherical or closely analogous to a spherical form in an idle control region lying in the vicinity of a fully-closed angle of said throttle valve and one of regions on the upstream and downstream sides of said throttle valve, and conical surface profiles in the idle control region lying in the vicinity of the fully-closed angle of said throttle valve and the other of said regions on the upstream and downstream sides thereof,
• said curved-surface profiles each having a central position coincident with a point of intersection of the center of rotation of said throttle valve and the central line of said bore,
• said bore of said throttle body having, as regions following the curved-surface profiles spherical or closely analogous to the spherical form, regions each comprised of a curved-surface profile spherical or closely analogous to a spherical form and a composite surface profile of a surface substantially parallel to the flow of intake air or regions each consisting of a conical surface profile.

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake air passage;
• and
• a throttle valve rotatably mounted in a bore of said throttle body;
• said throttle body having a bore inner wall surface including,
• conical surface profiles in an idle control region lying in the vicinity of a fully-closed angle of said throttle valve and one of regions on the upstream and downstream sides of said throttle valve;
• curved-surface shapes each spherical or closely analogous to a spherical form in the idle control region lying in the vicinity of the fully-closed angle of said throttle valve and the other of the regions on the upstream and downstream sides thereof, said curved-surface shapes having central positions respectively placed in positions deviated toward the curved-surface profile sides along a central line of said bore by predetermined amounts from the center of rotation of said throttle valve, and
• regions each comprising a curved-surface shape spherical or closely analogous to a spherical form and a composite surface profile of a surfaces substantially parallel to the flow of intake air or regions each formed of a conical surface profile, as regions following the curved-surface profiles each spherical or closely analogous to the spherical form.

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake air passage;
• and
• a throttle valve rotatably mounted to said throttle body;
• said throttle body having a bore defined therein so that the center of rotation of said throttle valve is placed on a central line of said bore,
• said bore of said throttle body having curved-surface profiles each spherical or closely analogous to a spherical form in an idle control region lying in the vicinity of a fully-closed angle of said throttle valve, said bore having partial shapes following the curved-surface profiles, which are formed by elliptic profiles surrounded by two circular arcs.

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake air passage;
• a throttle valve rotatably mounted to said throttle body;
• an actuator for rotating said throttle valve;
• throttle degree-of-opening detecting means for detecting a degree of opening of said throttle valve turned by said actuator;
• accelerator degree-of-opening detecting means for detecting the amount of depression of an accelerator pedal;
• and
• control means for controlling said actuator based on said detected amount of depression in such a manner that the degree of opening of said throttle valve detected by said throttle degree-of-opening detecting means reaches a predetermined value,
• said throttle body including a bore defined therein having curved-surface profiles each spherical or closely analogous to a spherical form in an idle control region lying in the vicinity of a fully-closed angle of said throttle valve,
• said bore having regions each comprising a curved-surface profile spherical or closely analogous to a spherical form and a composite surface profile of a surface substantially parallel to the flow of intake air, as regions following the curved-surface profiles each spherical or closely analogous to the spherical form.

A throttle valve control device for an internal combustion engine, comprising:

• a throttle body forming a part of an intake air passage;
• and
• a throttle valve rotatably mounted to said throttle body;
• said throttle body having a bore defined therein so that the center of rotation of said throttle valve is placed on a central line of said bore,
• said bore having curved-surface profiles each spherical or closely analogous to a spherical form in an idle control region lying in the vicinity of a fully-closed angle of said throttle valve, said bore having bore wall surfaces following the curved-surface profiles, which include wall surface profiles each exhibiting the rate of change in passage sectional area, which is larger than the rate of change in passage sectional area in each of regions for said curved-surface profiles, said each wall surface profile being constructed so that the rate of change in passage sectional area thereof gradually increases.