Apparatus, system, and method for catalyst presence detection
A system to detect the presence of a catalyst includes an exhaust gas tube, a first temperature sensing device, a second temperature sensing device, a flow rate measurement device, and a processing device. The first temperature sensing device measures a first temperature of exhaust gas upstream of the exhaust gas tube. The second temperature sensing device measures a second temperature of the exhaust gas downstream of the exhaust gas tube. The processing device estimates an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding to a system with a catalyst present. The processing device may also determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.
1. An apparatus to detect the presence of a catalyst in a catalyst housing, the apparatus comprising:
a temperature module configured to detect a temperature of exhaust gas at an inlet of the catalyst housing and a temperature of exhaust gas at an outlet of the catalyst housing;
an expected time delay module configured to determine an expected time delay between the detected temperature of exhaust gas at the inlet of the catalyst housing and the detected temperature of exhaust gas at the outlet of the catalyst housing corresponding with the presence of a catalyst; and
a similarity module configured to determine a temperature similarity value based on separate and discrete input values for the detected temperature of exhaust gas at the inlet of the catalyst housing, the detected temperature of exhaust gas at the outlet of the catalyst housing, and an estimated temperature of exhaust gas at the outlet of the catalyst housing equal to an estimated temperature of exhaust gas at the inlet of the catalyst housing delayed by the estimated expected time delay;
wherein a catalyst is present if the determined temperature similarity value is above a first threshold and a catalyst is not present if the determined temperature similarity value is below a second threshold;
wherein the similarity module determines the temperature similarity value by comparing the detected temperature of exhaust gas at the outlet of the catalyst housing to: (1) the detected temperature of exhaust gas at the inlet of the catalyst housing; and (2) the estimated temperature of exhaust gas at the outlet of the catalyst housing.
2. An apparatus to detect the presence of a catalyst in a catalyst housing, the apparatus comprising
a temperature module configured to detect a temperature of exhaust gas at an inlet of the catalyst housing and a temperature of exhaust gas at an outlet of the catalyst housing;
an expected time delay module configured to determine an expected time delay between the detected temperature of exhaust gas at the inlet of the catalyst housing and the detected temperature of exhaust gas at the outlet of the catalyst housing corresponding with the presence of a catalyst; and
a similarity module configured to determine a temperature similarity value based on separate and discrete input values for the detected temperature of exhaust gas at the inlet of the catalyst housing, the detected temperature of exhaust gas at the outlet of the catalyst housing, and an estimated temperature of exhaust gas at the outlet of the catalyst housing equal to an estimated temperature of exhaust gas at the inlet of the catalyst housing delayed by the estimated expected time delay;
wherein a catalyst is present if the determined temperature similarity value is above a first threshold and a catalyst is not present if the determined temperature similarity value is below a second threshold; wherein the temperature similarity value is defined as the parameter a that solves the optimization problem
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and wherein â is the estimated similarity value, T o is the outlet temperature, T i is the inlet temperature, D is the expected delay, k is a discrete sample time, and the summation is over a predefined number of samples preceding the current time.
3. An apparatus to detect the presence of a catalyst in a catalyst housing, the apparatus comprising:
a temperature module configured to detect a temperature of exhaust as at an inlet of the catalyst housing and a temperature of exhaust gas at an outlet of the catalyst housing;
an expected time delay module configured to determine an expected time delay between the detected temperature of exhaust gas at the inlet of the catalyst housing and the detected temperature of exhaust gas at the outlet of the catalyst housing corresponding with the presence of a catalyst; and
a similarity module configured to determine a temperature similarity value based on separate and discrete input values for the detected temperature of exhaust gas at the inlet of the catalyst housing, the detected temperature of exhaust as at the outlet of the catalyst housing, and an estimated temperature of exhaust gas at the outlet of the catalyst housing equal to an estimated temperature of exhaust gas at the inlet of the catalyst housing delayed by the estimated expected time delay;
wherein a catalyst is present if the determined temperature similarity value is above a first threshold and a catalyst is not present if the determined temperature similarity value is below a second threshold;
wherein the temperature similarity value is defined as the parameter a that solves the optimization problem
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and wherein â is an optimal or estimated similarity value, g is a inlet temperature sensor gain error correction, h is an inlet temperature sensor offset error correction, T o is the outlet temperature, T i is the inlet temperature, D is the expected delay, k is a discrete sample time, and the summation is over a predefined number of samples preceding the current time.
4. A system to detect the presence of a catalyst, the system comprising:
an exhaust gas tube coupled with a diesel engine through which exhaust gas from the diesel engine is flowable;
a first temperature sensing device coupled to an upstream portion of the exhaust gas tube, wherein the first temperature sensing device measures a first temperature of exhaust gas;
a second temperature sensing device coupled with a downstream portion of the exhaust gas tube, wherein the second temperature sensing device measures a second temperature of the exhaust gas; and
a processing device configured to estimate an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding with the presence of a catalyst, the processing device further configured to determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.
5. The system of claim 4 , further comprising a flow rate measurement device measuring a flow rate of the exhaust gas, wherein the expected time delay is estimated based on the measured flow rate of the exhaust gas.
6. The system of claim 4 , wherein the processing device determines a catalyst is present if the measured second temperature and the estimated delayed first temperature are similar, and the processing device determines a catalyst is missing if the measured second temperature and the measured first temperature are similar.
7. The system of claim 4 , wherein the expected time delay between the measured inlet and outlet exhaust gas temperatures is defined as the expected time for a fluctuation in the inlet exhaust gas temperature to be observed by the second temperature sensing device.
8. An apparatus to detect the presence of a catalyst in a catalyst housing, comprising:
a temperature module configured to detect a temperature of exhaust gas at an inlet of the catalyst housing and a temperature of exhaust gas at an outlet of the catalyst housing;
an expected time delay module configured to determine an expected time delay between the detected temperature of exhaust gas at the inlet of the catalyst housing and the detected temperature of exhaust gas at the outlet of the catalyst housing corresponding with the presence of a catalyst; and
a similarity module configured to determine a delayed temperature of exhaust gas at the inlet of the catalyst housing based on the expected time delay and the detected temperature of exhaust gas at the inlet of the catalyst housing, the similarity module being further configured to calculate a first difference between the detected temperature of exhaust gas at the outlet of the catalyst housing and the detected temperature of exhaust gas at the inlet of the catalyst housing, and calculate a second difference between the temperature of exhaust gas at the outlet of the catalyst housing and the delayed temperature of exhaust gas at the inlet of the catalyst housing;
wherein a catalyst is not present if the first difference is smaller than the second difference, and a catalyst is present if the second difference is smaller than the first difference.