Exhaust gas purification system in plateau

Abstract

Provided is an exhaust gas purification system in an upland area capable of maintaining engine performance when a vehicle travels in a normal drive mode in an upland area, securing the amount of oxygen required for post-injection when the vehicle is in a regeneration mode, and switching between the normal mode and the regeneration mode without causing incongruity. When a DPD 25 of the vehicle traveling in the normal drive mode in the upland area is to be automatically regenerated by raising the temperature of exhaust gas from a diesel engine 10, the exhaust gas purification system determines an upland full-load injection quantity from the atmospheric pressure in the upland area and an engine speed while the vehicle is in motion and drives the vehicle with the injection quantity determined. The exhaust gas purification system determines, during the regeneration mode, an upland drive regeneration injection quantity obtained by decreasing the upland full-load injection quantity on the basis of the quantity required for the post-injection. The injection quantity is gradually decreased from the upland full-load injection quantity to the upland regeneration drive injection quantity when the vehicle shifts from the normal drive mode in the upland area to the upland regeneration mode, so that the decreased quantity is used for the post-injection. After the regeneration is completed, the injection quantity is increased from the upland regeneration drive injection quantity to the upland full-load injection quantity.

Description

technical field [0001] The present invention relates to an exhaust gas purification system that captures PM (Particulate Matter: Particulate Matter) in exhaust gas of a diesel engine and purifies NOx to exhaust the exhaust gas. In particular, it relates to a system capable of regenerating DPD at high altitudes without degrading normal driving performance. Exhaust gas purification system in the plateau. Background technique [0002] As an exhaust gas purification system that purifies and exhausts the exhaust gas of a diesel engine, an exhaust gas purification system that connects a DPD (Diesel Particulate Defuser; Diesel Particulate Eliminator) and an SCR (Selective Catalytic Reduction) device to the exhaust pipe has been developed. system. [0003] In this exhaust gas purification system, PM in the exhaust gas is captured by the DPD. In addition, in the exhaust gas purification system, through the SCR system equipped with the SCR device, the ammonia water stored in the ure...

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Problems solved by technology

[0017] Here, it is conceivable that in the normal driving mode, the full load injection amount of fuel is set in a state close to the theoretical air-fuel ratio, and in the regeneration mode, the full load injection amount is divided into the driving amount and the post injection amount, but when the regeneration mode is switched to When the regeneration is completed, the torque drops sharply, and when the regeneration ends, the torque rises sharply, seriously impairing the drivability

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