Description:Complete Specification

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a method to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine, and more specifically to monitor the presence of the oxidation catalyst in the exhaust gas flow path by determining a difference in the NOX concentrations between the downstream and the upstream ends of the oxidation catalyst.

Background of the invention
[0002] WO 23222715 A1 describes a hydrogen oxidation catalyst for hydrogen-internal combustion engine systems. The emission treatment system comprises a hydrogen oxidation catalyst, the use of the catalyst for oxidizing hydrogen gas in an emission treatment system, and a method for heat generation in an engine exhaust system. The hydrogen oxidation catalyst is capable of increasing the downstream temperature to allow for a system providing enhanced NOx removal and decreased N2O emissions relative to comparable exhaust gas treatment systems.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a method to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a method 100 to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine. The method 100 comprises positioning 110 a urea injector upstream of the oxidation catalyst, injecting 120 urea into the exhaust gas flow path of the hydrogen engine, and measuring 130 a concentration of NOX downstream of the oxidation catalyst by means of a first NOX sensor, and measuring 140 a concentration of NOX upstream of the oxidation catalyst by means of a second NOX sensor. The method 100 further comprises determining 150 a difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst, estimating 160 an effectiveness of the oxidation catalyst based on the difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst, and determining 170 an absence of the oxidation catalyst if a spike in the NOX sensor downstream of the oxidation catalyst is observed.

[0005] Figure 1 illustrates a method 100 to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine. The method 100 comprises positioning 110 a urea injector upstream of the oxidation catalyst. The urea injector is adapted to inject 120 urea into the exhaust gas flow stream for oxidizing the exhaust gas flow stream in the oxidation catalyst. The method 100 to monitor the presence of the oxidation catalyst in the exhaust gas flow path of the hydrogen engine further comprises measuring 130 a concentration of NOX downstream of the oxidation catalyst by means of a first NOX sensor. More specifically, the first NOX sensor measures a concentration of the NOX in the exhaust gas flow path of the hydrogen engine in order to determine a presence of the oxidation catalyst.

[0006] The method 100 to monitor the presence of the oxidation catalyst in the exhaust gas flow path of the hydrogen engine further comprises measuring 140 a concentration of NOX upstream of the oxidation catalyst by means of a second NOX sensor. More specifically, the second NOX sensor measures a concentration of the NOX in the exhaust gas flow path of the hydrogen engine in order to determine a presence of the oxidation catalyst. The method 100 further comprises determining 150 a difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst. Based on the difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst, an effectiveness of the oxidation catalyst is estimated 160. In addition, if a spike in the NOX sensor downstream of the oxidation catalyst is observed, it is determined 170 that the oxidation catalyst is absent.

[0007] The method 100 to monitor the presence of the oxidation catalyst in the exhaust gas flow path of the hydrogen engine further comprises measuring 180 a temperature of NOX downstream of the oxidation catalyst by means of a first temperature sensor. More specifically, the first temperature sensor measures a temperature of the NOX in the exhaust gas flow path of the hydrogen engine in order to determine a presence of the oxidation catalyst.

[0008] The method 100 to monitor the presence of the oxidation catalyst in the exhaust gas flow path of the hydrogen engine further comprises measuring 190 a temperature of NOX upstream of the oxidation catalyst by means of a second temperature sensor. More specifically, the second temperature sensor measures a temperature of the NOX in the exhaust gas flow path of the hydrogen engine in order to determine a presence of the oxidation catalyst. The method 100 further comprises determining 200 a difference between the temperature of NOX downstream of the oxidation catalyst and the temperature of NOX upstream of the oxidation catalyst. Based on the difference between the temperature of NOX downstream of the oxidation catalyst and the temperature of NOX upstream of the oxidation catalyst, an effectiveness of the oxidation catalyst is estimated 210. In addition, if a temperature of NOX downstream of the oxidation catalyst is substantially equal to the temperature of NOX upstream of the oxidation catalyst, an absence of the oxidation catalyst is determined 220.

[0009] In an exemplary embodiment, a method 100 to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine is described. The method 100 comprises positioning 230 a urea injector upstream of the oxidation catalyst, and injecting 240 urea into the exhaust gas flow path of the hydrogen engine. The method 100 further comprises measuring 250 a concentration of NOX downstream of the oxidation catalyst by means of a first NOX sensor, and measuring 260 a concentration of NOX upstream of the oxidation catalyst by means of a second NOX sensor.

[0010] The method further comprises determining 270 a difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst. Based on the difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst, an effectiveness of the oxidation catalyst is estimated 280. In addition, if a spike in the NOX sensor downstream of the oxidation catalyst is observed, it is determined 290 that the oxidation catalyst is absent.

[0011] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.
, Claims:We Claim

1. A method (100) to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine, the method (100) comprising:
positioning (110) a urea injector upstream of the oxidation catalyst;
injecting (120) urea into the exhaust gas flow path of the hydrogen engine;
measuring (130) a concentration of NOX downstream of the oxidation catalyst by means of a first NOX sensor;
measuring (140) a concentration of NOX upstream of the oxidation catalyst by means of a second NOX sensor;
determining (150) a difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst;
estimating (160) an effectiveness of the oxidation catalyst based on the difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst; and
determining (170) an absence of the oxidation catalyst if a spike in the NOX sensor downstream of the oxidation catalyst is observed.

2. The method (100) to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine further comprising:
measuring (180) a temperature of NOX downstream of the oxidation catalyst by means of a first temperature sensor;
measuring (190) a temperature of NOX upstream of the oxidation catalyst by means of a second temperature sensor;
determining (200) a difference between the temperature of NOX downstream of the oxidation catalyst and the temperature of NOX upstream of the oxidation catalyst;
estimating (210) an effectiveness of the oxidation catalyst based on the difference between the temperature of NOX downstream of the oxidation catalyst and the temperature of NOX upstream of the oxidation catalyst; and
determining (220) an absence of the oxidation catalyst if a temperature of NOX downstream of the oxidation catalyst is substantially equal to the temperature of NOX upstream of the oxidation catalyst.

3. A method (100) to monitor a presence of an oxidation catalyst in an exhaust gas flow path of a hydrogen engine, the method comprising:
positioning (230) a urea injector upstream of the oxidation catalyst;
injecting (240) urea into the exhaust gas flow path of the hydrogen engine;
measuring (250) a concentration of NOX downstream of the oxidation catalyst by means of a first NOX sensor;
measuring (260) a concentration of NOX upstream of the oxidation catalyst by means of a second NOX sensor;
determining (270) a difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst;
estimating (280) an effectiveness of the oxidation catalyst based on the difference between the concentration of NOX downstream of the oxidation catalyst and the concentration of NOX upstream of the oxidation catalyst; and
determining (290) an absence of the oxidation catalyst if a spike in the NOX sensor downstream of the oxidation catalyst is observed.