System and method for controlling air-fuel ratio of cng engine
AssigneeHyundai Motor Company
InventorJin Woo CHOUNG
Life of this patent
Estimating the term…
Abstract
A system includes a compressed natural gas (CNG) engine, a three-way catalyst (TWC), a first oxygen sensor connected to the CNG engine, and a second oxygen sensor connected to the three-way catalyst. A method for controlling an air-fuel ratio of the CNG engine includes determining whether or not the CNG engine and the three-way catalyst are normal by measuring output voltages of the first and second oxygen sensors, determining whether or not the three-way catalyst is aged, and adjusting the air-fuel ratio of the CNG engine based on a result of the step of determining whether or not the three-way catalyst is aged
Claims10
A method for controlling an air-fuel ratio of a CNG engine, in which a first oxygen sensor is connected to the CNG engine and a second oxygen sensor is connected to a three-way catalyst, the method comprising:
- determining whether or not the CNG engine and the three-way catalyst are normal by measuring output voltages of the first and second oxygen sensors;
- determining whether or not the three-way catalyst is aged;
- and
- adjusting the air-fuel ratio of the CNG engine based on a result of the step of determining whether or not the three-way catalyst is aged.
A method for controlling an air-fuel ratio of a CNG engine, in which a first oxygen sensor is connected to the CNG engine and a second oxygen sensor is connected to a three-way catalyst, the method comprising:
- measuring an output voltage of the first oxygen sensor;
- determining whether or not the CNG engine is normal by comparing the output voltage of the first oxygen sensor with a first CNG reference range;
- measuring an output voltage of the second oxygen sensor;
- determining whether or not the three-way catalyst is normal by comparing the output voltage of the second oxygen sensor with a first TWC reference range;
- determining whether or not the three-way catalyst is aged by comparing the output voltage of the second oxygen sensor with a second TWC reference range;
- and
- adjusting the air-fuel ratio of the CNG engine according to a result of the step of determining whether or not the three-way catalyst is aged.
A system comprising:
- a CNG engine;
- a three-way catalyst;
- a first oxygen sensor connected to the CNG engine;
- a second oxygen sensor connected to the three-way catalyst;
- and
- a controller configured to measure an output voltage of the first oxygen sensor,
- determine whether or not the CNG engine is normal by comparing the output voltage of the first oxygen sensor with a first CNG reference range,
- measure an output voltage of the second oxygen sensor,
- determine whether or not the three-way catalyst is normal by comparing the output voltage of the second oxygen sensor with a first TWC reference range, determine whether or not the three-way catalyst is aged by comparing the output voltage of the second oxygen sensor with a second TWC reference range, and
- adjust an air-fuel ratio of the CNG engine depending on whether or not the three-way catalyst is aged.
Dependencies are inferred from the claim text.