摘要:
A method and apparatus for controlling the operation of a "lean-burn" internal combustion engine in co-operation with an exhaust gas purification system having an emissions control device capable of alternatively storing and releasing NO x when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, determines a performance impact, such as a fuel-economy benefit, of operating the engine at a selected lean operating condition, with due consideration of the periodic rich operating condition necessary to release stored NO x from the device. The method and apparatus further determine a measure representative of the instantaneous NO x -storing efficiency of the device. The method and apparatus enable the selected lean operating condition as long as the determined performance impact and the determined device efficiency are each above respective predetermined minimum levels.
摘要:
A method and apparatus for controlling the operation of a "lean-burn" internal combustion engine in co-operation with an emissions control device capable of alternatively storing and releasing an exhaust gas constituent, such as oxygen, when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, determines an ability of the device only when the engine is operating at a relatively-low mass air flow rate.
摘要:
An engine control system of an internal combustion engine coupled to a NOx trap (72) uses a integrated difference between NOx exiting the trap (72) and NOx entering the trap (72) to determine NOx storage capacity. NOx exiting the trap is measured by a NOx sensor downstream of the trap. NOx entering the trap (72) is determined based on engine operating conditions. The values are integrated until the ratio of NOx exiting to NOx entering reaches a predetermined threshold.
摘要:
An engine control system for managing lean NOx trap decontamination uses associated fuel economy impacts to determine when decontamination is enabled. In particular, a maximum achievable benefit provided by lean operation with a decontaminated NOx trap (72), a present fuel economy benefit being provided by lean operation, and a fuel economy penalty for performing decontamination are used. When a resulting benefit is greater than a penalty, decontamination is enabled.
摘要:
An engine control system for managing lean operation of an internal combustion engine coupled to a lean NOx trap (72) uses an indication of vehicle activity. A target amount of tailpipe emission per distance is adjusted based on the vehicle activity indication. Then, engine air-fuel ratio is controlled based on the adjusted target amount of tailpipe emission per distance. Also, the indication of vehicle activity is used to enable decontamination cycles of the lean NOx trap (72).
摘要:
An engine control system of an internal combustion engine coupled to a NOx trap (72) uses a integrated difference between NOx exiting the trap (72) and NOx entering the trap (72) to determine NOx storage capacity. NOx exiting the trap is measured by a NOx sensor downstream of the trap. NOx entering the trap (72) is determined based on engine operating conditions. The values are integrated until the ratio of NOx exiting to NOx entering reaches a predetermined threshold.
摘要:
A method and apparatus for controlling the operation of a "lean-burn" internal combustion engine (12) in co-operation with an exhaust gas purification system having an emissions control device (34,36) capable of alternatively storing and releasing an exhaust gas constituent, such as NO x , when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, wherein a measure of the efficiency of the device (34,36) to remove the exhaust gas constituent from engine exhaust gas is determined, and a purge event for releasing previously-stored NO x is initiated when the efficiency measure falls below a threshold value.
摘要:
An engine diagnostic system for use with an internal combustion engine (11) coupled to a lean NOx trap (72) with a sensor coupled downstream of the trap (72). The sensor provides two output signals, one indicative of an air-fuel ratio and the second indicative of a NOx concentration. Construction of the sensor (140) insists that proper indication of NOx concentration is dependent upon proper operation of the first output signal. Degradation of the NOx concentration signal is determined when the first output signal has degraded.