摘要:
A method of monitoring, while on board an automotive vehicle, one or more of catalyst performance, engine misfire, and combustion quality, the vehicle having an internal combustion engine equipped with a catalyst for converting noxious emissions of the engine, comprising: (i) exposing at least one pair of EGO sensors to substantially the same emissions either exiting from the engine or from the catalyst, one of the EGO sensors having its electrode highly catalytic, and the other sensor having its electrode low-to-noncatalytic; (ii) comparing the outputs of the sensor electrodes (amplitude, frequency, or phase shift) to determine if there is a sufficient differential to indicate a misfire or poor combustion in the case of the sensors being located downstream of the engine exhaust but upstream of the catalyst, or indicating poor catalyst efficiency in the case of the sensors being placed substantially immediately downstream of the catalyst. The catalyst may be a three-way catalyst (or an oxidation catalyst). The sensors may be of the EGO, HEGO, or UEGO types. Two pairs of sensors may be used, a first pair being placed substantially immediately upstream of the catalyst and the second pair being placed substantially immediately downstream of the catalyst, the pairs of EGO sensors being incorporated into a closed-loop feedback control of the engine fuel control system.
摘要:
A method of monitoring, while on board an automotive vehicle, one or more of catalyst performance, engine misfire, and combustion quality, the vehicle having an internal combustion engine equipped with a catalyst for converting noxious emissions of the engine, comprising: (i) exposing at least one pair of EGO sensors to substantially the same emissions either exiting from the engine or from the catalyst, one of the EGO sensors having its electrode highly catalytic, and the other sensor having its electrode low-to-noncatalytic; (ii) comparing the outputs of the sensor electrodes (amplitude, frequency, or phase shift) to determine if there is a sufficient differential to indicate a misfire or poor combustion in the case of the sensors being located downstream of the engine exhaust but upstream of the catalyst, or indicating poor catalyst efficiency in the case of the sensors being placed substantially immediately downstream of the catalyst. The catalyst may be a three-way catalyst (or an oxidation catalyst). The sensors may be of the EGO, HEGO, or UEGO types. Two pairs of sensors may be used, a first pair being placed substantially immediately upstream of the catalyst and the second pair being placed substantially immediately downstream of the catalyst, the pairs of EGO sensors being incorporated into a closed-loop feedback control of the engine fuel control system.
摘要:
An engine air/fuel control system modulates the flow of fuel delivered to the engine with a modulation signal (100, 144) The feedback variable generated (210-228) from a two-state exhaust gas oxygen sensor (16) corrects the fuel flow (156). During each of a plurality of pre-determined intervals, the fuel flow is biased with a rich offset (342). Amplitude of the modulation signal is corrected by a difference between the feedback variable generated during two successive occurrences of the predetermined interval (346-378).
摘要:
An engine air/fuel control system (8) and method for controlling an engine (28) coupled to a catalytic converter (50) and for providing a measurement of engine emissions (202-296). Nitrogen oxides concentration, hydrocarbon concentration, and carbon monoxide concentration of exhaust gases downstream of the converter are measured (46, 54, and 52). Each concentration measurement is averaged for the speed load cell in which such measurement occurred (244-256). Each concentration average measurement is converted to a measurement of mass emissions emitted during a test cycle (268-284). Fuel delivered to the engine is corrected by a feedback variable (104-134, 158-178) derived from both an exhaust gas oxygen sensor (44) positioned upstream of the converter and the three sensors positioned downstream of the converter (46, 52, 54). A measurement of emissions in response to the averaged mass measurements of emission concentration downstream of the converter is also provided (278-296).
摘要:
Method, for controlling fuel supply to an internal combustion engine utilizing a modulated air-fuel signal having a modified square-wave waveform, of monitoring operation of an oxygen sensor for sensing engine exhaust gas oxygen level. The method includes generating the modulated air-fuel signal having the modified square-wave waveform designed to produce a particular engine exhaust response for interrogating the oxygen sensor, and operating the engine based on the modulated air-fuel signal. The oxygen sensor produces an associated output signal in response to sensed exhaust gas oxygen levels. The method also includes processing the output signal of the oxygen sensor associated with the particular engine response so as to determine the operating condition of the oxygen sensor and to verify acceptable test conditions.
摘要:
An exhaust gas oxygen sensor is used to control the air/fuel ratio of an internal combustion engine in combination with an electronic engine control. The exhaust gas oxygen sensor is positioned in the exhaust stream flow from the engine. The electronic engine control utilizes different air/fuel ratio feedback strategies depending upon whether the signal output from the exhaust gas oxygen sensor is saturated indicating a rich air/fuel ratio, saturated indicating a lean air/fuel ratio or operating in a linear region.
摘要:
A method of monitoring, while on board an automotive vehicle, one or more of catalyst performance, engine misfire, and combustion quality, the vehicle having an internal combustion engine equipped with a catalyst for converting noxious emissions of the engine, comprising: (i) exposing at least one pair of EGO sensors to substantially the same emissions either exiting from the engine or from the catalyst, one of the EGO sensors having its electrode highly catalytic, and the other sensor having its electrode low-to-noncatalytic; (ii) comparing the outputs of the sensor electrodes (amplitude, frequency, or phase shift) to determine if there is a sufficient differential to indicate a misfire or poor combustion in the case of the sensors being located downstream of the engine exhaust but upstream of the catalyst, or indicating poor catalyst efficiency in the case of the sensors being placed substantially immediately downstream of the catalyst. The catalyst may be a three-way catalyst (or an oxidation catalyst). The sensors may be of the EGO, HEGO, or UEGO types. Two pairs of sensors may be used, a first pair being placed substantially immediately upstream of the catalyst and the second pair being placed substantially immediately downstream of the catalyst, the pairs of EGO sensors being incorporated into a closed-loop feedback control of the engine fuel control system.
摘要:
An engine air/fuel control and catalyst monitoring means includes a first EGO sensor positioned upstream of a catalyst and a second EGO sensor positioned downstream of the catalyst. Outputs from both EGO sensors are applied to a complementary filter set. The output from the upstream EGO sensor is applied to a high pass filter section and the output from the downstream EGO sensor is applied to a low pass filter section. The summer receives inputs from each of the high pass and low pass filter sections and provides an output to a feedback controller which in turn controls a fuel metering system applying fuel to the engine. The downstream EGO sensor also provides a signal indicative of the efficiency of the catalyst.
摘要:
A system and method for controlling operation of an engine wherein a fuel vapor recovery system is coupled between an air/fuel intake and a fuel supply system. An air/fuel ratio indication is provided by a proportional plus integral feedback controller coupled to a two-state exhaust gas oxygen sensor. In response to the air/fuel ratio indication and a measurement of inducted air flow, a base fuel command is generated. To compensate for purging of fuel vapors, a reference air/fuel ratio is subtracted from the air/fuel ratio indication and the resulting error signal generated. This compensation factor represents a learned value which is directly related to fuel vapor concentration, and it is subtracted from the base fuel command to correct for induction of fuel vapors.
摘要:
Fuel vapors are purged from a vapor storage canister to the intake of an internal combustion engine by inducting air into the vapor canister, modulating the purge flow of an air and fuel vapor mixture from the canister, and establishing a predetermined magnitude of combustion exhaust emissions by gradually changing the magnitude of a transient flow between no purge flow and a full purge flow so that the amount of combustion exhaust emissions is maintained below the predetermined magnitude.