摘要:
A methodology of computing a combustion stability value and using the combustion stability value to control engine operation is provided. The combustion stability value is determined by monitoring engine operation. The combustion stability value is compared to an expected combustion stability value. Where the combustion stability value is greater than the expected combustion stability value, combustion of the internal combustion engine is controlled as a function of the combustion stability value. Where the combustion stability value is not greater than the expected combustion stability value, combustion of the internal combustion engine is controlled as a function of an O2 sensor value. In either case, engine control is accomplished by modifying a target fuel injection value.
摘要:
A method is provided for controlling spark advance based on a fuel modifier. Initially, engine fueling is reduced according to a known dynamic crankshaft fuel control (DCFC) methodology. As a result, the engine tends to run rougher. In response, spark advance is varied based on the overall fuel multiplier reduction from the DCFC methodology. For instance, a look-up table, or mathematical function based on the DCFC multiplier can be utilized as the basis for the spark advance.
摘要:
An exhaust system is provided including two catalysts and three oxygen sensors. The second catalyst is disposed downstream of the first catalyst. The first oxygen sensor is disposed upstream of the first catalyst, the second oxygen sensor is disposed downstream of the first catalyst and upstream of the second catalyst, and the third oxygen sensor is disposed downstream of the second catalyst. A goal voltage corresponding to a desired level of oxygen within the exhaust is provided for the third oxygen sensor based on engine RPM and MAP. The engine controller compares the goal voltage to an actual voltage generated by the third oxygen sensor and an error value is obtained and converted into a goal voltage for the second oxygen sensor. The engine controller compares the goal voltage to an actual voltage generated by the second oxygen sensor and an error value is obtained and converted into a goal voltage for the first oxygen sensor. The engine controller compares the goal voltage to an actual voltage generated by the first oxygen sensor and an error value is obtained and converted into a percent-fuel correction by the engine controller.
摘要:
An exhaust system is provided including two catalysts and three oxygen sensors. The second catalyst is disposed downstream of the first catalyst. The first oxygen sensor is disposed upstream of the first catalyst, the second oxygen sensor is disposed downstream of the first catalyst and upstream of the second catalyst, and the third oxygen sensor is disposed downstream of the second catalyst. A goal voltage corresponding to a desired level of nitrous oxide and hydrocarbon within the exhaust is provided for the third oxygen sensor. This goal voltage is based on engine RPM and MAP. The engine controller compares the goal voltage to an actual voltage generated by sensing the level of oxygen downstream of the second catalyst. Based on this comparison, an error value between the goal voltage and the actual voltage is obtained. This error value is converted into a goal voltage for the first oxygen sensor. An actual voltage generated by the first oxygen sensor sensing the amount of oxygen upstream of the first catalyst is compared to the goal voltage derived from the third oxygen sensor. The difference between the goal voltage and actual voltage is used to modulate the pulse width of a signal sent to the fuel injectors of an engine such that the amount of fuel delivered by the fuel injectors is modified. The second oxygen sensor generates an actual voltage corresponding to the amount of oxygen the second oxygen sensor senses downstream of the first catalyst and upstream of the second catalyst. Changes in the actual voltage generated by the second oxygen sensor are compared to changes in the actual voltage generated by the first oxygen sensor. By monitoring the nature of theses changes as they relate to one another, the performance of the first catalyst can be determined.
摘要:
The analog input of a sensor is connected to a 10-bit analog-to-digital converter. The converted is powered using a 5V supply. The A/D is interfaced with a microprocessor; however, only the least significant eight bits of the A/D output are connected to the microprocessor input. The microprocessor is used to adjust the fuel-air mixture used in engine combustion based on the output of the sensor. The use of the 10-bit A/D interfaced with only eight bits allows increased precision and increased computational speed. The increased precision allows more accurate adjustment of the fuel-air mixture to enable the engine to run closer to its stoichiometric point.
摘要:
A method is provided for controlling the delivery of fuel to an engine of an automotive vehicle equipped with a dynamic crankshaft fuel control system and an oxygen sensor feedback based fuel control system. The method includes determining an averaged combustion metric from the dynamic crankshaft fuel control system. The combustion metric is compared to an allowable engine roughness value and a dynamic crankshaft fuel control fuel multiplier is adjusted based on the comparison via a proportional-integral-derivative control calculation. Thereafter, the integral term of the dynamic crankshaft fuel control system's proportional-integral-derivative control calculation is stored. If it is time to switch fuel control from the dynamic crankshaft fuel control system to the oxygen sensor feedback fuel control system, the stored integral term of the dynamic crankshaft fuel control system's fueling multiplier is transferred to the proportional-integral-derivative calculation of the oxygen sensor feedback fuel control system. As such, the last integral term used in determining the fuel multiplier of the dynamic crankshaft fuel control system is used as the first integral term determining the fuel multiplier of in the oxygen sensor feedback fuel control system. As such, the transition from one fuel control system to the other is smoothed.
摘要:
A fuel control system is provided including a fuel tank, a purge vapor canister, a vapor line, and a fuel injector connected to an internal combustion engine. A purge vapor canister vent valve seals the purge vapor canister from the atmosphere such that the fuel tank, purge vapor canister, and fuel injector form a closed system. Upon initial starting of the engine, the purge vapor pressure is such that the purge vapor is drawn to the fuel injector from the dome portion of the fuel tank after passing through the purge vapor canister. Simultaneously therewith, the amount of liquid fuel is reducing or increasing by an amount of equally increasing or decreasing, respectively, vapor fuel so that a necessary mass flow rate is achieved to support combustion. As the amount of fuel vapors decreases to a negligible amount, combustion is supported by the atomization of liquid fuel. The delivery of the liquid fuel and vapor fuel is completed through the use of a fuel injector to accommodate both liquid and vapor form of fuel.
摘要:
A method is provided for enriching a fuel to air ratio in an engine during acceleration based on a known fuel multiplier. Initially, the method retrieves the fuel multiplier from a dynamic crankshaft fuel control (DCFC) system. This system uses the fuel multiplier to reduce the amount of fuel delivered to the engine. When acceleration is desired, the method increases the overall acceleration enrichment values as a function of the DCFC fuel multiplier. Thus, when the vehicle is launched via a throttle tip-in while the DCFC system is active, the acceleration enrichment values are increased thereby improving drivability by having combustion taking place in a richer environment.
摘要:
A circuit and method are provided for heating a dual heater oxygen sensor. One resistance element is of relatively low resistance such that the oxygen sensor is heated quickly and the other element is of relatively high resistance such that the oxygen sensor is heated and maintained at an optimal operating temperature. The circuit and associated method turn on a low resistance start heater that is in communication with the oxygen sensor given start-up conditions. Once the oxygen sensor has reached an operating temperature range a high resistance operating temperature heater is turned on and the start heater is turned off.
摘要:
Ignition timing for a combustion engine may be controlled by determining the roughness of current engine operation, comparing the determined roughness with a control roughness to determine if the determined roughness is within a threshold limit of the control roughness, and changing the ignition timing in a subsequent fuel delivery event as a function of the difference between the determined roughness and the control roughness. Preferably, the ignition timing is changed at least when the determined roughness is not within the threshold limit, although other factors may be taken into account when changing the ignition timing.