Abstract: An apparatus for an exhaust gas system includes a main exhaust passage, a main catalytic converter disposed in the main exhaust passage, a bypass exhaust passage, a bypass catalytic converter disposed in the bypass exhaust passage, and a valve configured to open or close a section of the main exhaust passage. The bypass exhaust passage bypasses the main exhaust passage between a branch point of the bypass exhaust passage out of the main exhaust passage and a junction with the main exhaust passage at a upstream side of the main catalytic converter. A first sensor indicates a first air-fuel ratio of exhaust gas in the bypass exhaust passage. A second sensor indicates a second air-fuel ratio of exhaust gas flowing into the main catalytic converter. A controller determines whether the valve in the closed configuration leaks exhaust gas based on the first and second air-fuel ratios of exhaust gas.

Abstract: An internal combustion engine includes a main catalyst disposed in a main passage and a bypass catalyst disposed in a bypass passage bypassing the main passage on an upstream side of the main catalyst. The bypass passage has a smaller transverse cross-sectional area than the main passage. The internal combustion engine further includes a passage open/close unit, a residual gas amount changing unit, and a controller. The passage open/close unit is disposed in a portion of the main passage bypassed by the bypass passage to switch between an open state and a closed state. The residual gas amount changing unit is configured to change an amount of residual gas inside a combustion chamber. The controller is configured to control the residual gas amount changing unit when a passage opening condition for switching the passage open/close unit from the closed state to the open state is satisfied.

Abstract: An exhaust system for an internal combustion engine includes a catalytic device within an exhaust path of the engine, wherein the catalytic device includes a housing with a catalyst carrier. A length of the catalyst carrier along a longitudinal axis, measured along a downstream flow direction of exhaust gas within the exhaust path, is substantially the same or a shorter than the upstream distance traveled by a reverse flow of exhaust gas during an exhaust gas pulsation within the housing. With this type of configuration, due to reciprocating movements of the exhaust gas caused by the pulsations, the same exhaust gas passes through the catalyst carrier multiple times. Thus, an increased number of heat exchanges take place within the catalyst carrier, which rapidly increases the catalyst temperature after a cold engine start.

Abstract: An exhaust system for an internal-combustion engine comprises an exhaust bypass in parallel with an upstream portion of a main exhaust path having a main catalytic converter in a downstream portion thereof; an exhaust bypass catalytic converter provided in the exhaust bypass; and a flow path switching valve for blocking the main exhaust path at the upstream portion thereof. The exhaust system includes an ignition timing adjustment mechanism for adjusting ignition timing to delay sparking when the flow path switching valve is switched from the closed condition to the open condition thereof. A control method for the exhaust system is also disclosed.

Abstract: An exhaust system of the internal combustion engine comprises upstream main paths for cylinders that are attached to a side of a cylinder head and extend towards a side of the engine, and are connected to the respective cylinders; a downstream main path in which the upstream main paths join so as to become one flow path; a main catalytic converter provided on the downstream main path; bypasses that are split from the upstream main paths or the downstream main path; a bypass catalytic converter that is provided on the bypass; and flow path switching valves that open and close the upstream main paths so that exhaust discharged from the cylinders flows into the bypass. The bypass catalytic converter is provided below the upstream main paths.

Abstract: An exhaust system for an internal combustion engine is disclosed. The exhaust system includes at least one main exhaust path connected to at least one cylinder, an exhaust recirculation path that is branched out from the main exhaust path so that part of exhaust gas is recirculated to an inlet system, a bypass that is branched out from the exhaust recirculation path in which the bypass has a higher path resistance than that of the exhaust recirculation path and a bypass catalytic converter that is provided in the bypass.

Abstract: An engine start control apparatus includes an intake air amount control device for controlling an amount of air supplied to a combustion chamber, a fuel supply device for injecting fuel to be fed into the combustion chamber, and an igniting device for igniting the fuel.

Abstract: A method for controlling an exhaust system for an internal combustion engine of a vehicle includes flowing exhaust gas to a main catalyst converter provided in a main passage, flowing exhaust gas to a bypass catalyst converter provided in a bypass passage, detecting a predetermined condition related to a poisoning amount of the bypass catalyst converter, and blocking the main passage at least partially in response to the satisfaction of the predetermined condition, thereby causing more of the exhaust gas to flow to the bypass passage.

Abstract: An engine start control apparatus includes an intake air amount control device for controlling an amount of air supplied to a combustion chamber, a fuel supply device for injecting fuel to be fed into the combustion chamber, and an igniting device for igniting the fuel.

Abstract: An internal combustion engine includes a main catalyst disposed in a main passage and a bypass catalyst disposed in a bypass passage bypassing the main passage on an upstream side of the main catalyst. The bypass passage has a smaller transverse cross-sectional area than the main passage. The internal combustion engine further includes a passage open/close unit, a residual gas amount changing unit, and a controller. The passage open/close unit is disposed in a portion of the main passage bypassed by the bypass passage to switch between an open state and a closed state. The residual gas amount changing unit is configured to change an amount of residual gas inside a combustion chamber. The controller is configured to control the residual gas amount changing unit when a passage opening condition for switching the passage open/close unit from the closed state to the open state is satisfied.

Abstract: An apparatus for an exhaust gas system includes a main exhaust passage, a main catalytic converter disposed in the main exhaust passage, a bypass exhaust passage, a bypass catalytic converter disposed in the bypass exhaust passage, and a valve configured to open or close a section of the main exhaust passage. The bypass exhaust passage bypasses the main exhaust passage between a branch point of the bypass exhaust passage out of the main exhaust passage and a junction with the main exhaust passage at a upstream side of the main catalytic converter. A first sensor indicates a first air-fuel ratio of exhaust gas in the bypass exhaust passage. A second sensor indicates a second air-fuel ratio of exhaust gas flowing into the main catalytic converter. A controller determines whether the valve in the closed configuration leaks exhaust gas based on the first and second air-fuel ratios of exhaust gas.

Abstract: An exhaust system of the internal combustion engine comprises upstream main paths for cylinders that are attached to a side of a cylinder head and extend towards a side of the engine, and are connected to the respective cylinders; a downstream main path in which the upstream main paths join so as to become one flow path; a main catalytic converter provided on the downstream main path; bypasses that are split from the upstream main paths or the downstream main path; a bypass catalytic converter that is provided on the bypass; and flow path switching valves that open and close the upstream main paths so that exhaust discharged from the cylinders flows into the bypass. The bypass catalytic converter is provided below the upstream main paths.

Abstract: An exhaust system for an internal-combustion engine comprises an exhaust bypass in parallel with an upstream portion of a main exhaust path having a main catalytic converter in a downstream portion thereof, an exhaust bypass catalytic converter provided in the exhaust bypass; and a flow path switching valve for blocking the main exhaust path at the upstream portion thereof. The exhaust system includes an ignition timing adjustment mechanism for adjusting ignition timing to delay sparking when the flow path switching valve is switched from the closed condition to the open condition thereof. A control method for the exhaust system is also disclosed.

Abstract: An exhaust system for an internal combustion engine is disclosed. The exhaust system includes at least one main exhaust path connected to at least one cylinder, an exhaust recirculation path that is branched out from the main exhaust path so that part of exhaust gas is recirculated to an inlet system, a bypass that is branched out from the exhaust recirculation path in which the bypass has a higher path resistance than that of the exhaust recirculation path and a bypass catalytic converter that is provided in the bypass.

Abstract: An exhaust system for an internal combustion engine includes a catalytic device within an exhaust path of the engine, wherein the catalytic device includes a housing with a catalyst carrier. A length of the catalyst carrier along a longitudinal axis, measured along a downstream flow direction of exhaust gas within the exhaust path, is substantially the same or a shorter than the upstream distance traveled by a reverse flow of exhaust gas during an exhaust gas pulsation within the housing. With this type of configuration, due to reciprocating movements of the exhaust gas caused by the pulsations, the same exhaust gas passes through the catalyst carrier multiple times. Thus, an increased number of heat exchanges take place within the catalyst carrier, which rapidly increases the catalyst temperature after a cold engine start.