BACKGROUND

Many modern engines incorporate a number of environmental control mechanisms to limit emissions generation. With each added control mechanism, added complexity and potential failure modes arise. New and alternative monitoring and diagnostic analyses are desired.

OVERVIEW

The present inventors have recognized, among other things, that a problem to be solved is the need for new and/or alternative monitoring and diagnostic analyses are desired. In some examples, the system mass flow and models for such flow are used to extract and monitor aging factors such as, for example, fuel injector drift, exhaust gas recirculation valve obstruction, and/or mass air flow sensor bias.

A first illustrating and non-limiting example takes the form of a system comprising an engine comprising at least one cylinder, at least one fuel injector, an intake manifold and an exhaust manifold, wherein the at least one fuel injector is configured to inject a quantity of fuel to the cylinder, subject to fuel injector drift; an air intake comprising a mass air flow (MAF) sensor having an inlet and an outlet that generates a MAF sensor output subject to MAF sensor bias; a fuel-air mix (FAM) sensor having a FAM sensor output; a throttle positioned between the air intake and the engine intake manifold; an ambient pressure sensor and an ambient temperature sensor each having an output; a intake manifold (IM) pressure sensor and IM temperature sensor configured to sense pressure and temperature respectively at the intake manifold; and a system monitor configured to calculate each of the following using a model and the ambient pressure sensor and ambient temperature sensor outputs: a first pressure and a first temperature downstream of the MAF sensor; a second pressure and a second temperature at the exhaust manifold; a third pressure and a third temperature at the FAM sensor; a controller configured to calculate each of fuel injector drift and MAF sensor bias using the IM pressure and IM temperature, the MAF sensor output, the FAM sensor output, the fuel injector output, the first, second and third pressures, and the first, second, and third temperatures.

Additionally or alternatively, the system may further comprise a turbocharger having a turbine coupled to receive exhaust gas from the exhaust manifold and a compressor coupled to provide compressed air to the throttle; wherein the system monitor is configured to calculate the first pressure and first temperature upstream of the compressor.

Additionally or alternatively, the controller is further configured to: record a plurality of calculated fuel injector drift values, determine a rate of change of the fuel injector drift, and estimate and record a percentage of useful life remaining for the fuel injector.

Additionally or alternatively, the controller is further configured to: compare the calculated fuel injector drift to a threshold, and if the threshold is met, issue an alert for maintenance of the fuel injector.

Additionally or alternatively, the controller is further configured to: record a plurality of MAF sensor bias values, determine a rate of change of the MAF sensor bias, and estimate and record a percentage of useful life remaining for the MAF sensor.

Additionally or alternatively, the controller is further configured to: compare the calculated MAF sensor bias to a threshold, and if the threshold is met, issue an alert for maintenance of the MAF sensor.

Additionally or alternatively, the system may further comprise an exhaust gas recirculation (EGR) valve configured to recirculate air from the exhaust manifold back to the intake manifold, the EGR valve selectively operable between open and closed positions and subject to reduction of flow area (FEA), wherein the controller is further configured to estimate the FEA of the EGR valve using the IM pressure and IM temperature, the MAF sensor output, the FAM sensor output, the fuel injector output, the first, second and third pressures, and the first, second, and third temperatures.

Additionally or alternatively, the controller is further configured to: record a plurality of estimated FEA values, determine a rate of change of the FEA, and estimate and record a percentage of useful life remaining for the EGR valve.

Additionally or alternatively, the controller is further configured to: compare the estimated FEA to a threshold, and if the threshold is met, issue an alert for maintenance of the EGR valve.

Additionally or alternatively, the above described system may be incorporated into a hybrid electric vehicle which also includes and an electric motor, wherein the electric motor is controlled using a hybrid power split optimization routine, wherein the vehicle is configured to update the hybrid power split optimization routine using the estimated fuel injector drift.

A second illustrative and non-limiting example takes the form of a system comprising: an engine comprising at least one cylinder, at least one fuel injector, an intake manifold and an exhaust manifold, wherein the at least one fuel injector is configured to inject a quantity of fuel to the cylinder, subject to fuel injector drift; an air intake comprising a mass air flow (MAF) sensor having an inlet and an outlet that generates a MAF sensor output subject to MAF sensor bias; a fuel-air mix (FAM) sensor having a FAM sensor output; a high pressure exhaust gas recirculation (HPEGR) valve, having an input at the engine exhaust manifold and an output at the engine intake manifold, the HPEGR valve selectively operable between open and closed positions and subject to reduction of flow area (FEA_HPEGR); a throttle positioned between the air intake and the junction of the HPEGR and the engine intake manifold; a low pressure exhaust gas recirculation (LPEGR) valve, having an LPEGR input at the exhaust output and an LPEGR output coupled to the MAF sensor outlet, the LPEGR valve subject to reduction of flow area (FEA_LPEGR); an ambient pressure sensor and an ambient temperature sensor; a intake manifold (IM) pressure sensor and IM temperature sensor configured to sense pressure and temperature respectively at the intake manifold; a system monitor configured to calculate each of the following using a model: a first pressure and a first temperature downstream of the MAF sensor; a second pressure and a second temperature at the exhaust manifold; a third pressure and a third temperature at the FAM sensor; a controller configured to calculate each of the FEA_LPEGR, FEA_HPEGR, fuel injector drift, and MAF sensor bias using the IM pressure and IM temperature, the MAF sensor output, the FAM sensor output, the fuel injector output, the first, second and third pressures, and the first, second, and third temperatures.

Additionally or alternatively, the system may further include a turbocharger having a turbine coupled to receive exhaust gas from the exhaust manifold and a compressor coupled to provide compressed air to the throttle; wherein the system monitor is configured to calculate the first pressure and first temperature upstream of the compressor.

Additionally or alternatively, the controller is further configured to: record a plurality of calculated FEA_LPEGR values, determine a rate of change of the FEA_LPEGR, and estimate and record a percentage of useful life remaining for the LPEGR.

Additionally or alternatively, the controller is further configured to: compare the calculated FEA_LPEGR to a threshold, and if the threshold is met, issue an alert for maintenance of the LPEGR valve.

Additionally or alternatively, the controller is further configured to: record a plurality of calculated FEA_HPEGR values, determine a rate of change of the FEA_HPEGR, and estimate and record a percentage of useful life remaining for the HPEGR.

Additionally or alternatively, the controller is further configured to: compare the calculated FEA_HPEGR to a threshold, and if the threshold is met, issue an alert for maintenance of the HPEGR valve.

Further illustrative examples may include vehicles having incorporated therein the first or second illustrative, non-limiting examples (and variants thereof) and/or methods of operating systems as described in the first and second illustrative, non-limiting examples. A third illustrative, non-limiting example takes the form of a method of operating a system including an engine with an intake manifold, an exhaust manifold, and at least one fuel injector having an output subject to drift, the system also including a mas air flow (MAF) measurement device subject to drift and a fuel-air mix (FAM) measurement device; the method comprising: calculating a mass flow into the intake manifold, using an output of the MAF device; observing a ratio of fuel to air exiting the exhaust manifold using the FAM measurement device; determining an expected quantity of fuel from the fuel injector; determining a pressure in the intake manifold; using the ratio and the pressure, estimating the drift of the fuel injector; and using the ratio and the pressure, estimating the bias of the MAF device.

Additionally or alternatively, the method may be performed in a system further including an exhaust gas recirculation (EGR) valve having a factor of effective area (FEA) indicating a degree of obstruction of the EGR valve, the valve controlled by a control signal, the method further comprising: using the ratio, the pressure, and a value of the control signal of the EGR valve, estimating the FEA of the EGR valve.

Additionally or alternatively, the steps of estimating the drift of the fuel injector and estimating the bias of the MAF device further comprise using the value of the control signal of the EGR valve.

Additionally or alternatively, the method may further include determining that at least one of the estimated drift, bias, or FEA has crossed a threshold, and communicating a need for service of the system.

This overview is intended to provide an introduction to the subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation. The detailed description is included to provide further information about the present patent application.

