Fuel injection control method of fuel reformer and fuel reforming system

Patent metadata

Field	Value
Publication number	US-10619602-B2
Application number	US-201816213688-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	May 10, 2018
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A fuel injection control method includes measuring EGR (exhaust gas recirculation) rate through a CO2 sensor measuring the amount of CO2 entering the intake side of the engine, setting an optimum SCR (Steam to Carbon Ratio) value based on the measured EGR rate, calculating the amount of steam supplied to the engine based on the measured EGR rate, calculating an actual SCR value by the ratio of the steam amount and the carbon component of the fuel supplied to the engine, comparing the actual SCR value with the optimum SCR value, calculating the SCR difference value by subtracting the optimum SCR value from the actual SCR value if the actual SCR value is greater than the optimum SCR value, calculating an additional fuel amount to be added based on the SCR difference value, and injecting fuel to the fuel reformer based on the calculated additional fuel amount.

First claim

What is claimed is:

1. A fuel injection control method, comprising:
calculating EGR (exhaust gas recirculation) rate using information from a CO2 sensor that measures an amount of CO2 entering an intake side of an engine;
setting an optimum SCR (Steam to Carbon Ratio) value based on the measured EGR rate;
calculating an amount of steam supplied to the engine based on the measured EGR rate;
calculating an actual SCR value using the ratio of the steam amount and a carbon component of fuel supplied to the engine;
comparing the actual SCR value with the optimum SCR value;
calculating an SCR difference value by subtracting the optimum SCR value from the actual SCR value if the actual SCR value is greater than the optimum SCR value;
calculating an additional fuel amount to be added based on the SCR difference value; and
injecting fuel to the fuel reformer based on the calculated additional fuel amount.

2. The fuel injection control method of claim 1 , wherein the EGR rate is calculated based on a ratio of an EGR gas flow rate with respect to the sum of the EGR gas flow rate and an intake air flow rate introduced into the intake side of the engine, and the EGR gas flow rate is calculated using the concentration of CO2 measured through the CO2 sensor.

3. The fuel injection control method of claim 1 , wherein the optimum SCR value is a certain SCR value that is determined by experiments and has a maximum hydrogen conversion efficiency at the calculated EGR rate.

4. The fuel injection control method of claim 1 , wherein the amount of steam flowing into the engine is calculated by multiplying the engine fuel consumption by the calculated EGR rate.

5. The fuel injection control method of claim 1 , wherein the additional fuel amount is calculated by the following equation (1).
F ad ( t )= K p SCR d ( t )+ K i ∫ 0 t SCR d ( t ) dt   equation (1)

(Here, F ad (t) is the additional fuel amount, SCR d (t) is an SCR difference value, K p , and K i are gain values, and t is a time.)

6. The fuel injection control method of claim 1 , further comprising:
after the comparing the actual SCR value with the optimum SCR value,
terminating without calculating an SCR difference value if the actual SCR value is not greater than the optimum SCR value.

7. A fuel reforming system, comprising:
an engine configured to combust reformed gas to generate mechanical power;
an intake line connected with the engine to supply reformed gas and air to the engine;
an exhaust line connected with the engine to circulate exhaust gas exhausted from the engine;
a CO2 sensor disposed upstream of the intake line and configured to measure the amount of CO2 contained in the reformed gas;
a fuel reformer configured to convert the fuel mixed in exhaust gas recirculation (EGR) gas into a reformed gas which is provided in an EGR line branching from the exhaust line, wherein an additional fuel injector configured to inject additional fuel into the internal combustion engine is installed in, and is configured to mix the EGR gas which is branched into the EGR line with the fuel; and
a controller configured to calculate an amount of steam supplied to the engine based on the EGR rate calculated based on information from the CO2 sensor, calculate an actual SCR value by the ratio of the steam amount and the carbon component of the fuel supplied to the engine, and calculate an additional fuel amount injected into the fuel reformer based on the difference between the actual SCR value and an optimum SCR value based on the measured EGR rate.

8. The fuel reforming system of claim 7 , further comprising:
a compressor connected with the intake line and compresses and supply the reformed gas and air to the engine; and
a turbine connected to the exhaust line and rotated by the exhaust gas to generate power.

9. The fuel reforming system of claim 7 , further comprising:
a catalyst disposed in an exhaust line upstream of the fuel reformer and configured to purify nitrogen oxides contained in the exhaust gas.

10. The fuel reforming system of claim 9 , wherein the catalyst includes a lean NOx trap (LNT) which traps the nitrogen oxide included in the exhaust gas in a lean condition and desorbs the trapped nitrogen in a rich condition, and restores the nitrogen oxide included in the exhaust gas or the desorbed nitrogen oxide.

11. The fuel reforming system of claim 9 , wherein the catalyst includes a selective catalytic reducer (SCR) restoring the nitrogen oxide included in the exhaust gas by using reducing agent.

12. The fuel reforming system of claim 7 , wherein the EGR line comprises:
an EGR valve configured to adjust flow rate of the reformed gas, and
an EGR cooler provided at a rear end of the EGR valve and configured to cool the reformed gas.

13. The fuel reforming system of claim 12 , wherein the fuel reformer is installed in front of the EGR cooler of the EGR line.

14. The fuel reforming system of claim 7 , further comprising:
a hydrogen sensor provided on the EGR line at a rear end of the fuel reformer and configured to measure a hydrogen production amount of the fuel reformer.

15. The fuel reforming system of claim 7 , further comprising:
a bypass EGR line branched from the exhaust line at the rear end of the catalyst and connected to the fuel reformer and bypassing exhaust gas and the EGR gas.

16. The fuel reforming system of claim 15 , further comprising:
a residual heat control valve being opened and closed such that the exhaust gas and the EGR gas passing through the catalyst bypasses the bypass EGR line or is directly introduced into the fuel reformer based on temperature thereof at the bypass EGR line.

17. The fuel reforming system of claim 7 , wherein the engine further includes a fuel amount sensor configured to measure an engine fuel amount, and the fuel reformer further includes an EGR amount sensor configured to measure an EGR gas amount.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Lee Seung Woo
• Lee Tae Won
• Baek Hong Kil
• Hollowell Thomas

Classifications

• F02M26/35

  with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters · CPC title

• F02M26/29

  Constructional details of the coolers, e.g. pipes, plates, ribs, insulation or materials · CPC title

• F02M26/36 Primary

  with means for adding fluids other than exhaust gas to the recirculation passage; with reformers · CPC title

• F02D41/144

  Sensor in intake manifold · CPC title

• F02D19/0671

  Means to generate or modify a fuel, e.g. reformers, electrolytic cells or membranes · CPC title