Mounting structure for NOx reduction device for construction machine

Abstract

A mounting structure for a NOx reduction device for a construction machine has less restriction on the layout space for the NOx reduction device. The mounting structure has a urea based selective catalytic reduction catalyst (19) for reducing and purifying nitrogen oxide discharged from an engine (14), an aqueous urea solution spray device (20) for spraying an aqueous urea solution into an exhaust path of the engine (14), an aqueous urea solution supply device (23) for supplying the aqueous urea solution to the aqueous urea solution spray device (20), a first aqueous urea solution tank (24) and a second aqueous urea solution tank (27) for containing the aqueous urea solution led to the aqueous urea solution supply device (23), and a control device (30) for controlling drive of the aqueousurea solution spray device (20) and the aqueous urea solution supply device (23). A cavity (13) is formed in a counterweight (12). The aqueous urea solution supply device (23), the first aqueous ureasolution tank (24), the second aqueous urea solution tank (27), and the control device (30) are integrated together to form an assembly (21), and the assembly (21) is placed in the cavity (13) in thecounterweight (12).

Description

technical field [0001] The present invention relates to an arrangement structure of a NOx reduction device installed in a construction machine such as a hydraulic excavator and including a reducing agent spraying device, a reducing agent supply device, and a reducing agent storage tank as structural elements. Background technique [0002] As such prior art, there is a structure shown in Patent Document 1. Patent Document 1 discloses a structure in which a liquid reducing agent tank is arranged in a vehicle or a machine, such as a hydraulic excavator, in order to prevent freezing of a liquid reducing agent for reducing nitrogen oxides discharged from an engine. Insulated parts. In other words, the liquid reductant tank, i.e., the reductant storage tank, is placed near the hydraulic pump in the engine room, or near the valve, i.e., the hydraulic control valve device, or in the cab, or near the operating oil tank, etc., where heat can be maintained. [0003] Patent Document 1...

AI Technical Summary

Problems solved by technology

[0004] In the prior art mentioned above, for example, when the reducing agent storage tank is to be arranged near the hydraulic pump in the engine room, it is necessary to install equipment such as fuel filters and oil filters around the hydraulic pump at the same time. The configuration space is relatively small, and it is difficult to secure space for the configuration of the reducing agent storage box

In general, the NOx reducing device includes, as constituent elements, a reducing agent spraying device, a reducing agent supply device, a control device for controlling the driving of the reducing agent spraying device and the reducing agent supply device, etc., in addition to the reducing agent storage tank described above. , In the case of the prior art described above, there is a problem that, including the arrangement of these reducing agent spraying devices, reducing agent supplying devices, control devices, etc., the arrangement space of the NOx reducing device is easily limited.

Images