A signal conditioning module for a wide-band oxygen sensor and methods of installing the same. One signal conditioning module includes an electronic processor, a first electrical coupling, and a second electrical coupling. The first coupling is configured to be coupled to a port of an electrical harness. The power is configured to receive an electrical coupling of a narrow-band oxygen sensor signal for providing power to the narrow-band oxygen sensor. The second coupling is configured to be coupled to the wide-band oxygen sensor. The electronic processor receives power over the first coupling, powers the wide-band oxygen sensor over the second coupling using the received power, receives first data over the second coupling from the wide-band oxygen sensor, converts the first data to second data, and outputs the second data over the first coupling to the electrical harness for transmission to an electronic control unit coupled to the electrical harness.

Methods and systems are provided for indicating a presence or absence of a source of degradation stemming from one of an intake manifold, exhaust system, or engine of an engine system. In one example, a method comprises rotating the engine unfueled and indicating the source of degradation based on both an intake air flow and an exhaust flow, as compared to baseline intake air flow and baseline exhaust flow. In this way, a source of degradation may be pinpointed, which may increase a lifetime of a vehicle engine system, reduce undesired emissions, and which may increase customer satisfaction resulting from shorter time spent on diagnosing such a source of degradation.

Method for the operation of an internal combustion engine having a plurality of cylinders (11 to detect misfires. An exhaust gas sensor at the exhaust gas of every cylinder of the internal combustion engine measures at least one actual exhaust gas value individually for the respective cylinder, and the respective measured actual exhaust gas value is compared with a reference exhaust gas value to determine at least one cylinder-specific deviation between the reference exhaust gas value and the actual exhaust gas value for each of the cylinders. It is determined for every cylinder based on the cylinder-specific deviation or based on every cylinder-specific deviation whether or not misfires are occurring at the respective cylinder.

A method of controlling a fuel injection of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, is provided, which includes acquiring an oxygen concentration inside the cylinder, performing, on compression stroke, the plurality of fuel injections at substantially even injection intervals while increasing the injection intervals as the oxygen concentration decreases, and performing, after the plurality of fuel injections, another fuel injection including a larger injection amount than in the plurality of fuel injections, near a top dead center of the compression stroke.

A method to adjust an oil control valve actuation response time using cylinder valve diagnostic results includes commanding an engine cylinder to deactivate/reactive when conditions are met and then detecting if a deactivation/reactivation response time failure has occurred by analyzing the cylinder diagnostics results. If a predetermined number of failures are detected at the cylinder within a predetermined number of engine cycles then the engine controller operates to adjust the oil control valve response time to improve the response time accuracy.

The exhaust purification system of an internal combustion engine 100, 100, 100 comprises: a catalyst 20 arranged in an exhaust passage 22 and able to store oxygen; an ammonia detection device 46, 71 and an air-fuel ratio detection device 41, 72 arranged in the exhaust passage at a downstream side of the catalyst; and an air-fuel ratio control part configured to control an air-fuel ratio of exhaust gas flowing into the catalyst to a target air-fuel ratio. The air-fuel ratio control part performs rich control making the target air-fuel ratio richer than a stoichiometric air-fuel ratio, in the rich control, reduces a rich degree of the target air-fuel ratio when an output value of the ammonia detection device rises to a reference value, and ends the rich control when an air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio.

A method for determining an air volume in a combustion chamber of a fuel-injection internal combustion engine, especially during a load change condition, including synchronizing a throttle valve setpoint signal to an operating state criterion (t.sub.n); determining a curve dynamics of the throttle valve position taking into account the synchronized throttle valve setpoint signal; determining an actual air volume quantity at an ACTUAL time point (t.sub.0); determining a desired time point (t.sub.0+t); predicting a further air volume quantity for the desired time point (t.sub.0+t) and determining a total air volume quantity from the ACTUAL air volume quantity and the further air volume quantity for the desired time point (t.sub.0+t).

A diesel engine is provided with a fuel injector which injects fuel into a combustion chamber. An ECU includes a parameter obtaining portion which obtains multiple property parameters indicative of a property of the fuel, and a molecular-weight computing portion which computes multiple molecular-weights based on the multiple property parameters in view of a correlation data which defines a correlation between the multiple property parameters and the multiple molecular-weights of the fuel. Further, the ECU includes a combustion-condition computing portion which computes a combustion parameter indicative of a combustion condition of the diesel engine based on the multiple molecular-weights, and a control portion which performs a combustion control based on the combustion parameter.

A method to adjust an oil control valve actuation response time using cylinder valve diagnostic results includes commanding an engine cylinder to deactivate/reactive when conditions are met and then detecting if a deactivation/reactivation response time failure has occurred by analyzing the cylinder diagnostics results. If a predetermined number of failures are detected at the cylinder within a predetermined number of engine cycles then the engine controller operates to adjust the oil control valve response time to improve the response time accuracy.

Methods and systems are provided for catalyst control. In one example, a method may include controlling an air-fuel ratio downstream of a catalyst by adjusting fuel injection. The fuel injection is adjusted based on control parameters updated online through system identification at a point of feedback control instability.