Patent ID: 9689292
Date: 2017-06-27
CPC Classifications: F01N,Y02T

Claim:
1. An apparatus for controlling a urea injection system of a diesel engine, comprising: an operation condition parameter acquiring module configured to acquire operation condition parameters related to a mechanical, hydraulic component of the urea injection system; an observation value determining module coupled to the operation condition parameter acquiring module and configured to determine an observation value of a urea pressure in a urea pump chamber based on the operation condition parameters and also based on an observer model which comprises a physical expression for the urea pressure in the urea pump chamber with a first adjustment item and a physical expression for the urea pressure in a urea buffer chamber with a second adjustment item, wherein the first adjustment item is formed by a first adjusting factor and by a difference between an observation value and a measured value of the urea pressure in the urea buffer chamber and wherein the second adjustment item is formed by a second adjusting factor and by the difference and wherein the first and second adjusting factors are two values selected so that both of the two adjusted expressions are stable and converged; a control quantity determining module coupled to the operation condition parameter acquiring module and configured to determine a rotation speed of a urea pump drive motor based on the operation condition parameters, the observation value of the urea pressure in the urea pump chamber, a target value of the urea pressure in the urea buffer chamber and a closed loop control model designed based on a physical model characterizing physical relationships among main mechanical, hydraulic components of the urea injection system; a drive signal determining module coupled to the control quantity determining module and configured to determine a drive signal for driving the urea pump drive motor based on the determined rotation speed of the urea pump drive motor; and wherein the urea pump drive motor is driven based on the determined drive signal.