A sound bypass device configured to transmit engine-generated sound pulses from an engine to a sound outlet whilst preventing flow of gases to the sound outlet, the sound bypass device comprising: an input tube configured to conduct the engine-generated sound pulses from the engine; and a sound transmission device connected to the input tube at a first end and to the sound outlet at a second end, the sound transmission device comprising: a first volume connected to the first end, a second volume connected to the second end, and a flexible diaphragm separating the first volume from the second volume and configured to transfer variations in pressure in the first volume to the second volume; wherein the first volume has a cross-sectional area that is greater at the diaphragm than at the first end and the second volume has a cross-sectional area that is greater at the diaphragm than at the second end.

The device includes an exhaust passage having an upstream end connected to an exhaust port of the engine and a downstream end provided with a catalytic converter, a secondary air passage having a downstream end connected to an intermediate point of the exhaust passage and an upstream end communicating with the atmosphere, and a reed valve provided in an upstream end of the secondary air passage to permit air flow from the atmosphere to the exhaust passage but not in the opposite direction. The reed valve has a resonance frequency which is z times the prescribed exhaust frequency of the engine, where z is an integer. The length of the secondary air passage is selected that the pulsation effect of air in the secondary air passage may be advantageously utilized.

Methods and systems are provided for a resonator of an exhaust system. In one example, the resonator is a quarter wave resonator with a diaphragm configured to provide pulsations during low-end engine torque conditions.

An internal combustion engine system includes a combustion engine configured to produce exhaust gases as a product of a combustion reaction. An exhaust discharge pipe coupled to the internal combustion engine, and an adaptive valve assembly. The adaptive valve assembly is coupled to the exhaust discharge pipe and configured to receive the exhaust gases prior to the exhaust gases reaching the atmosphere. The adaptive valve assembly includes a valve flapper arranged in the passageway and configured to pivot about a flapper pivot axis from a normally-closed position to an opened position.

A pulse exhaust pipe for use with diesel engines an end of the pulse exhaust pipe is in communication with eight cylinders, and another end is in communication with two turbochargers; the pulse exhaust pipe includes three exhaust pipe sections which are separated from each other, each exhaust pipe section discharging to a turbocharger independently, wherein a first exhaust pipe section is in communication with a first and second cylinder, while a second exhaust pipe section is in communication with a third to a sixth cylinder, and a third exhaust pipe section is in communication with a seventh and eighth cylinder. The pulse exhaust pipe may prevent the backward flow of exhaust gas and inlet air back flow, thus increasing inflation efficiency and improving the uniformity of each cylinder. Also provided is a diesel engine installed with said pulse exhaust pipe.

Methods and systems are provided for a resonator of an exhaust system. In one example, the resonator is a quarter wave resonator with a diaphragm configured to provide pulsations during low-end engine torque conditions.

A reductant insertion assembly comprises a reductant bladder defining a bladder internal volume for holding a reductant. The reductant bladder comprises a bladder inlet and a bladder outlet. A pressure sensor is positioned downstream of the bladder outlet. The pressure sensor is operable to sense a pressure of the reductant downstream of the reductant bladder, and generate a pressure signal indicative of the pressure. A compression mechanism is operably coupled to the reductant bladder. The compression mechanism is configured to selectively exert a compressive force on the reductant bladder so as to expel the reductant therefrom via the bladder outlet. The compression mechanism exerts the compressive force in response to the pressure signal.

An internal combustion engine system includes a combustion engine configured to produce exhaust gases as a product of a combustion reaction. An exhaust discharge pipe coupled to the internal combustion engine, and an adaptive valve assembly. The adaptive valve assembly is coupled to the exhaust discharge pipe and configured to receive the exhaust gases prior to the exhaust gases reaching the atmosphere. The adaptive valve assembly includes a valve flapper arranged in the passageway and configured to pivot about a flapper pivot axis from a normally-closed position to an opened position.

A reductant insertion assembly comprises a reductant bladder defining a bladder internal volume for holding a reductant. The reductant bladder comprises a bladder inlet and a bladder outlet. A pressure sensor is positioned downstream of the bladder outlet. The pressure sensor is operable to sense a pressure of the reductant downstream of the reductant bladder, and generate a pressure signal indicative of the pressure. A compression mechanism is operably coupled to the reductant bladder. The compression mechanism is configured to selectively exert a compressive force on the reductant bladder so as to expel the reductant therefrom via the bladder outlet. The compression mechanism exerts the compressive force in response to the pressure signal.

A self-cleaning duct assembly. The self-cleaning duct assembly includes a hollow member having an inner surface, the inner surface defining a central axis and a flow passage for directing a fluid flow along the central axis. The self-cleaning duct assembly also includes a resilient member including a plurality of arcuate segments disposed along the central axis, each of the arcuate segments spaced from the inner surface. The arcuate segments intermittently contact the inner surface as the resilient member is induced to move within the hollow member.