Abstract: A reduction-causing agent supply device includes a tank to store a reduction-causing agent, a pumping unit to pump the reduction-causing agent, a reduction-causing agent supply passage to supply the reduction-causing agent, an injection nozzle to inject the reduction-causing agent into an exhaust pipe, a drawing-back unit to draw the reduction-causing agent toward the tank, and a controller. After stop of an engine, the controller performs: reduction-causing agent drawing-back process of drawing the reduction-causing agent toward the tank and introducing exhaust gas from the injection nozzle into the reduction-causing agent supply passage; and gas discharge process of supplying the reduction-causing agent to compress the exhaust gas inside the reduction-causing agent supply passage, discharging the compressed exhaust gas from the injection nozzle, and closing a valve of the injection nozzle before the reduction-causing agent reaches the injection nozzle.

Abstract: A reduction-causing agent supply device includes a tank to store a reduction-causing agent, a pumping unit to pump the reduction-causing agent, a reduction-causing agent supply passage to supply the reduction-causing agent, an injection nozzle to inject the reduction-causing agent into an exhaust pipe, a drawing-back unit to draw the reduction-causing agent toward the tank, and a controller. After stop of an engine, the controller performs: reduction-causing agent drawing-back process of drawing the reduction-causing agent toward the tank and introducing exhaust gas from the injection nozzle into the reduction-causing agent supply passage; and gas discharge process of supplying the reduction-causing agent to compress the exhaust gas inside the reduction-causing agent supply passage, discharging the compressed exhaust gas from the injection nozzle, and closing a valve of the injection nozzle before the reduction-causing agent reaches the injection nozzle.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, an inner pipe and a tubular guide member. The exhaust pipe includes an elbow part having a curved portion, and a linear part disposed downstream of the elbow part. The injector is disposed outside of the curved portion, and injects a reducing agent aqueous solution into the elbow part towards the linear part. The inner pipe is disposed downstream of the injector within the exhaust pipe. The inner pipe has an inlet portion opening facing the injector and an outer peripheral surface spaced apart from the inner wall of the linear part. The inner pipe allows the exhaust gas to flow through the inside of the inner pipe and along the outer periphery of the inner pipe. The tubular guide member directs the reducing agent aqueous solution injected from the injector to the inner pipe.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, a mixing pipe, an inner pipe and a flow section. The exhaust pipe includes an elbow part and a linear part. The injector is disposed in the elbow part and injects a reducing agent aqueous solution. The mixing pipe receives the reducing agent aqueous solution injected from the injector, and includes an outlet portion formed spaced apart from an inner wall of the exhaust pipe, and a plurality of openings formed on the outer peripheral surface thereof. The inner pipe is disposed in the linear part and allows the exhaust gas to flow through the inside and the outer periphery thereof. The flow section is formed between the outlet portion of the mixing pipe and the inner wall of the exhaust pipe to direct the exhaust gas to the inner pipe.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, a mixing pipe and an inner pipe. The exhaust pipe includes an elbow part having a curved portion, and a linear part disposed downstream of the elbow part. The injector is disposed outside the curved portion and injects the reducing agent aqueous solution towards the linear part. The mixing pipe is disposed inside the elbow part to surround the reducing agent aqueous solution injected from the injector. The mixing pipe includes a plurality of openings on its outer peripheral surface. The inner pipe is disposed downstream of the mixing pipe and spaced apart from an outlet portion of the mixing pipe and from an inner wall of the linear part to allow the exhaust gas to flow through the inside of the inner pipe and along the outer periphery of the inner pipe.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, a mixing pipe, an inner pipe and a flow section. The exhaust pipe includes an elbow part and a linear part. The injector is disposed in the elbow part and injects a reducing agent aqueous solution. The mixing pipe is disposed to enclose a surrounding of the reducing agent aqueous solution injected from the injector, and includes an outlet portion formed spaced apart from an inner wall of the exhaust pipe, and a plurality of openings formed on the outer peripheral surface thereof. The inner pipe is disposed in the linear part and allows the exhaust gas to flow through the inside and the outer periphery thereof. The flow section is formed between the outlet portion of the mixing the inner wall of the exhaust pipe and directs the exhaust gas to the inner pipe.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, a mixing pipe and an inner pipe. The exhaust pipe includes an elbow part having a curved portion, and a linear part disposed on the downstream side of the elbow part. The injector is disposed outside the curved portion and injects the reducing agent aqueous solution towards the linear part. The mixing pipe is disposed inside the elbow part to enclose a surrounding of the reducing agent aqueous solution injected from the injector, and includes a plurality of openings on an outer peripheral surface thereof. The inner pipe is disposed on the downstream side of the mixing pipe and spaced apart from an outlet portion of the mixing pipe and from an inner wall of the linear part, and allows the exhaust gas to flow through the inside thereof and the outer periphery thereof.

Abstract: A reducing agent aqueous solution mixing device includes an exhaust pipe, an injector, an inner pipe and a tubular guide member. The exhaust pipe includes an elbow part having a curved portion, and a linear part disposed on a downstream side of the elbow part. The injector is disposed outside the curved portion and injects only a reducing agent aqueous solution into the elbow part towards the linear part. The inner pipe is disposed on an exhaust stream downstream side of the injector within the exhaust pipe with an inlet portion opening thereof facing the injector and an outer peripheral surface thereof being spaced apart from the inner wail of the linear art. The inner pipe allows the exhaust as to flow through the inside thereof and the outer periphery thereof. A tubular guide member directs the reducing agent aqueous solution injected from the injector to the inner pipe.

Abstract: An exhaust gas recirculation system having an exhaust line connected to an exhaust manifold of an engine; an intake line connected to an intake manifold of the engine; and an EGR line that intercommunicates the exhaust line and the intake line, in which a part of exhaust gas exhausted from the exhaust line is delivered to the intake line via the EGR line to be recirculated in the engine, is provided with a liquid cooling heat exchanger made of a corrosion-resistant material at downstream of an intersection with the EGR line in the intake line.