Engine fuel reformer monitoring
Systems and methods for monitoring a fuel reformer which reforms ethanol into a reformate gas comprising H 2 , CO, and CH 4 for fueling an engine are provided. Degradation of the fuel reformer may be indicated based on an amount of ethanol injected into the fuel reformer and an amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer.
1. A method for monitoring a fuel reformer which reforms ethanol into a reformate gas comprising H 2 , CO, and CH 4 for fueling an engine, comprising:
measuring a flow rate of the reformate gas; and
indicating degradation of the fuel reformer based on a ratio of an amount of the flow rate of the reformate gas to an amount of alcohol injected into the fuel reformer being less than a threshold.
2. The method of claim 1 wherein the flow rate of the reformate gas is determined in response to temporarily stopping reformate gas flow into the engine.
3. The method of claim 1 wherein the flow rate of the reformate gas is measured based on a flow rate sensor in a fuel line between the fuel reformer and the engine.
4. The method of claim 1 wherein the flow rate of the reformate gas is measured based on an amount of stored reformate gas and a sonic metering valve in a fuel line between the fuel reformer and the engine.
5. The method of claim 1 further comprising performing mitigation actions if degradation of the fuel reformer is indicated.
6. The method of claim 5 wherein the mitigation actions include adjusting a temperature of the fuel reformer.
7. The method of claim 5 wherein the mitigation actions include stopping ethanol injection into the fuel reformer.
8. The method of claim 5 wherein the mitigation actions include injecting ethanol into the fuel reformer only when a temperature of the fuel reformer is such that injected ethanol would remain in vapor form.
9. The method of claim 5 wherein the mitigation actions include reducing an ethanol injection rate into the fuel reformer until the ratio returns to a target level.
10. A method for monitoring a fuel reformer which reforms ethanol into a reformate gas comprising H 2 , CO, and CH 4 , comprising:
injecting an amount of fuel including an amount of alcohol to be reformed into the fuel reformer; and
indicating degradation of the fuel reformer based on the amount of alcohol injected into the fuel reformer and an amount of H 2 , CO, and CH 4 produced by the fuel reformer.
11. The method of claim 10 wherein indicating degradation of the fuel reformer is further based on a ratio of the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer to the amount of alcohol injected into the fuel reformer being less than a threshold value.
12. The method of claim 11 wherein the amount of alcohol injected into the fuel reformer is a molar flow rate of alcohol injected into the fuel reformer and the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer is a molar flow rate of at least one of H 2 , CO, and CH 4 produced by the fuel reformer.
13. The method of claim 11 wherein the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer is determined by temporarily stopping reformate gas flow into the engine and determining the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer via a pressure rise.
14. The method of claim 11 wherein the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer is based on a flow rate sensor in a fuel line between the fuel reformer and the engine.
15. The method of claim 11 wherein the amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer is based on an amount of stored reformate gas and a sonic metering valve in a fuel line between the fuel reformer and the engine.
16. The method of claim 10 wherein the amount of alcohol injected into the fuel reformer is determined when the alcohol is in a liquid state.
17. The method of claim 10 further comprising performing mitigation actions if degradation of the fuel reformer is indicated, the method further comprising delivering alcohol and the reformate gas to an internal combustion engine.
18. A system comprising:
a fuel reformer which reforms alcohol into H 2 , CO, and CH 4 ;
an engine receiving the reformed alcohol;
a computer readable storage medium having instructions encoded thereon, including:
instructions to indicate degradation of the fuel reformer based on an amount of alcohol injected into the fuel reformer and an amount of at least one of H 2 , CO, and CH 4 produced by the fuel reformer.
19. The system of claim 18 , wherein the computer readable storage medium having instructions encoded thereon further includes instructions to perform mitigation actions if degradation of the fuel reformer is indicated.
20. A method for monitoring a fuel reformer which reforms ethanol into a reformate gas comprising H 2 , CO, and CH 4 for fueling an engine, comprising:
indicating degradation of the fuel reformer via a controller based on an amount of engine knock which occurs while reformate gas is delivered to the engine.
21. The method of claim 20 , wherein the reformate gas is cooled before being delivered to the engine.