Natural gas engines with fuel quality determination

A system for determining properties of fuel supplied to an internal combustion (IC) engine and for adjusting operations of the IC engine based on the determined properties to maximize performance, comprising:

• an air-flow throttle operatively coupled with an air-intake system of the IC engine and configured to control the amount of air supplied to the air-intake system;
• a fuel-flow throttle operatively coupled with the IC engine and configured to control the amount of fuel supplied to the IC engine;
• an engine control module (ECM) operatively coupled with the air-flow throttle and the fuel-flow throttle to receive readings from and control operation of the throttles and configured to:
• perform a fuel-air determination loop in which the ECM is configured to:
• determine an air-flowrate of air passing through the air-flow throttle,
• determine a fuel-flowrate of fuel passing through the fuel-flow throttle,
• determine a true air-to-fuel (AF) ratio using the determined air-flowrate and the determined fuel-flowrate,
• compare the true AF ratio to an ideal AF ratio programmed to the ECM and determine a percent-error AF ratio based on the comparison,
• determine correction values for the air-flow throttle and the fuel-flow throttle using the percent-error AF ratio and readings from an oxygen sensor of the IC engine,
• in response to the correction values being different than zero, adjust the air-flow throttle and the fuel-flow throttle based on determined correction values and restart the fuel-air determination loop, and
• in response to the correction values being zero, stop the fuel-air determination loop and perform a fuel property determination and adjustment program in which the ECM is configured to adjust operations of the IC engine based on a fuel property value of the fuel supplied to the IC engine.

A system for determining properties of fuel supplied to an internal combustion (IC) engine and for adjusting operations of the IC engine based on the determined properties to maximize performance, comprising:

• an air-flow throttle operatively coupled with an air-intake system of the IC engine and configured to control the amount of air supplied to the air-intake system;
• a fuel-flow throttle operatively coupled with IC engine and configured to control the amount of fuel supplied to the IC engine;
• an engine control module (ECM) operatively coupled with the air-flow throttle and the fuel-flow throttle to receive readings from and control operation of the throttles and configured to:
• perform a fuel-air determination loop in which the ECM is configured to:
• determine an air-flowrate of air passing through the air-flow,
• determine a fuel-flowrate of fuel passing through the fuel-flow throttle,
• determine a true air-to-fuel (AF) ratio using the determined air-flowrate and the determined fuel-flowrate,
• compare the true AF ratio to an ideal AF ratio programmed to the ECM and determine a percent-error AF ratio based on the comparison,
• determine correction values for the air-flow throttle and the fuel-flow throttle using the percent-error AF ratio and readings from an oxygen sensor of the IC engine,
• in response to the correction values being different than zero, adjust the air-flow throttle and the fuel-flow throttle based on determined correction values and restart the fuel-air determination loop, and
• in response to the correction values being zero, stop the fuel-air determination loop and perform a fuel property determination and adjustment program,
• wherein, in performing the fuel property determination and adjustment program, the ECM is configured to:
• determine a fuel property value of fuel supplied to the IC engine based on the percent-error AF ratio,
• adjust a load limit of the IC engine based on the determined fuel property;
• and
• adjust a spark plug timing sequence of the IC engine based on the determined fuel property.