Patent ID: 7647767

Claim:
An exhaust gas purifying apparatus in an engine, comprising: a reduction catalyst for accelerating the reduction of nitrogen oxide in an exhaust gas, the reduction catalyst being disposed in an exhaust passage of the engine; a storage tank for storing a reducing agent for the reduction of nitrogen oxide in the exhaust gas; a supply device configured to supply the reducing agent upstream of the reduction catalyst in the exhaust passage; a supply pipe inserted into the storage tank for leading the reducing agent in the storage tank to the supply device; a first detecting device configured to detect a concentration of the reducing agent in the storage tank, wherein the first detecting device comprises a detecting section disposed to soak in the reducing agent within the storage tank for generating an electric signal corresponding to the concentration of the reducing agent; and a heating device comprising a pipe member disposed inside the storage tank to partially form first piping for circulation of a heat carrier from the engine, wherein the heating device is configured to heat the reducing agent in the storage tank by circulating the heat carrier through the pipe member, wherein the pipe member includes a bent portion substantially formed in a U-shape, the bent portion surrounding the detecting section of the first detecting device to heat the reducing agent at least in the vicinity of the detecting section, and wherein the pipe member is connected via a heating medium to a suction portion of the supply pipe inside the storage tank.