The present disclosure provides a rain cover assembly, a pipe assembly and a turbine fracturing unit. The rain cover assembly comprises at least two sets of cover plate assemblies, wherein each set of cover plate assembly comprises a cover plate, a transmission mechanism and a locking device. When the cover plate(s) is(are) at a closed position, the opening is covered; when the cover plate of each set of cover plate assembly is at an open position, an additional pipe structure which is open at both ends and extends along an extension direction of the pipe is formed by which. According to the present disclosure, the cover plate(s) of the rain cover assembly, when opened, will jointly form an additional pipe structure connected to the open end of the pipe to guide the exhaust gas of the pipe to a further space. Such an arrangement may reduce noise on the one hand, and prevent backflow of the exhaust gas on the other hand. The cover plate(s) of the rain cover assembly, when closed, can shield the opening of the pipe to prevent entry of rainwater.

A muffler for a vehicle includes: a muffler shell; a baffle disposed within the muffler shell, and having a first opening and a second opening which allow an exhaust gas to pass therethrough; and a variable valve mounted on the baffle. In particular, the variable valve includes: a valve plate rotatably mounted to open and close the first opening of the baffle; a valve arm connected to the valve plate; and a valve actuator to move the valve arm by variations in pressure of the exhaust gas. The valve plate is capable of rotating in a plane parallel to a plane of the baffle.

A variable valve may include a housing having hinge support portions protruding from a first side thereof, and an opening at a second side thereof, a first gate rotatably coupled to the hinge support portions so as to open and close a part of the opening, a first spring mounted on the housing to apply elastic force in a direction in which the first gate is closed, a second gate rotatably coupled to the hinge support portions so as to open and close a remaining part of the opening, and a second spring mounted on the housing to apply elastic force in a direction in which the second gate is closed, in which the first spring and the second spring may have different spring constants.

An emission module for treating exhaust gas including a housing, a first catalyst substrate positioned within the housing and having an inlet end, the first catalyst substrate defining a plurality of flow passages extending longitudinally from the inlet end, and a first restrictor plate positioned at the inlet end of the first catalyst substrate to block exhaust flow through a first portion of the plurality of flow passages while allowing exhaust flow through the remainder of the plurality of flow passages.

An emission module for treating exhaust gas including a housing, a first catalyst substrate positioned within the housing and having an inlet end, the first catalyst substrate defining a plurality of flow passages extending longitudinally from the inlet end, and a first restrictor plate positioned at the inlet end of the first catalyst substrate to block exhaust flow through a first portion of the plurality of flow passages while allowing exhaust flow through the remainder of the plurality of flow passages.

The present disclosure provides a rain shield assembly, a pipe assembly and a turbine fracturing unit. The rain shield assembly comprises at least two sets of cover plate assemblies, wherein each set of cover plate assembly comprises a cover plate, a transmission mechanism and a locking device. When the cover plate(s) is(are) at a closed position, the opening is covered; when the cover plate of each set of cover plate assembly is at an open position, an additional pipe structure which is open at both ends and extends along an extension direction of the pipe is formed by which. According to the present disclosure, the cover plate(s) of the rain shield assembly, when opened, will jointly form an additional pipe structure connected to the open end of the pipe to guide the exhaust gas of the pipe to a further space. Such an arrangement may reduce noise on the one hand, and prevent backflow of the exhaust gas on the other hand. The cover plate(s) of the rain shield assembly, when closed, can shield the opening of the pipe to prevent entry of rainwater.

A muffler for a vehicle includes: a muffler shell; a baffle disposed within the muffler shell, and having a first opening and a second opening which allow an exhaust gas to pass therethrough; and a variable valve mounted on the baffle. In particular, the variable valve includes: a valve plate rotatably mounted to open and close the first opening of the baffle; a valve arm connected to the valve plate; and a valve actuator to move the valve arm by variations in pressure of the exhaust gas. The valve plate is capable of rotating in a plane parallel to a plane of the baffle.

An engine system is provided. The engine system may include an exhaust gas heat exchanger valve including an actuatable valve plate, a valve actuation assembly adjusting the position of the valve plate through operation of mechanical linkage coupled to the valve plate, and a flow reversal valve positioned in a coolant passage, the flow reversal valve configured to reverse the coolant flow in a flapper coolant conduit to trigger actuation of the mechanical linkage.

An engine system is provided. The engine system may include an exhaust gas heat exchanger valve including an actuatable valve plate, a valve actuation assembly adjusting the position of the valve plate through operation of mechanical linkage coupled to the valve plate, and a flow reversal valve positioned in a coolant passage, the flow reversal valve configured to reverse the coolant flow in a flapper coolant conduit to trigger actuation of the mechanical linkage.

A snap-action valve assembly for an exhaust system includes a valve flap positioned within a conduit. A shaft supports the valve flap in the conduit for rotation about a pivot axis between a closed position and an open position. A roller is supported for rotation on a post. The post is fixed to the shaft by a lever arm. A torsion spring includes a first end coupled to the conduit and a second end coupled to the roller. The torsion spring is preloaded to urge the valve flap into contact with an inner surface of the conduit when the valve flap is in the closed position. A method of assembling the snap-action valve assembly with a predetermined spring preload torque is also discussed.