Abstract: Methods and systems are provided for reducing turbo lag in a boosted engine. A boost reservoir coupled to the engine may be charged with compressed intake air and/or combusted exhaust gas. The pressurized charge may then be discharged during a tip-in to either the intake or the exhaust manifold.

Abstract: Embodiments for estimating intake air humidity in an engine are provided. In one example, an engine method comprises adjusting an engine parameter in response to intake air humidity estimated based on a concentration of one or more engine-out emissions. In this way, one or more exhaust emission sensors may be used to estimate intake air humidity.

Abstract: Methods and systems for monitoring an internal combustion engine are disclosed. In one example, output of a temperature sensor is converted into a fuel pressure variable to determine if fuel system components are operating as desired and cylinder air charge may be limited if degradation is determined. The methods and systems may reduce fuel system cost while also providing redundant system data.

Abstract: A method for operating a turbocharged engine is disclosed. In one example, during a first condition an engine operation is adjusted in response to a turbocharger expansion ratio exceeding a first limit and during a second condition an engine operation is adjusted in response to the turbocharger expansion ratio exceeding a second limit that differs from the first limit. Degradation of the engine may be reduced under some engine operating conditions by adjusting engine operation in response to the turbocharger expansion ratio.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: Methods and systems are provided for controlling an engine in a vehicle, the engine having a turbocharger, and a particulate filter upstream of a turbocharger turbine. In one example, the method comprises, under selected boosted operating conditions, injecting a reductant upstream of the filter during an exhaust stroke to generate an exothermic reaction at the filter.

Abstract: Embodiments for controlling cylinder air flow are provided. In one example, a method for controlling airflow into a cylinder of an engine comprises, if a previous cylinder airflow is different than a desired cylinder airflow, allocating flow into an intake manifold between a throttle and an EGR valve to provide the desired cylinder airflow while maintaining a desired EGR amount in the cylinder. In this way, transient air flow requests may be met without delay while maintaining desired cylinder EGR amounts.

Abstract: Methods and systems for operating a glow plug are disclosed. In one example, glow plugs of a compression ignition engine are selectively operated during automatic engine starting. The methods and systems may be useful to reduced glow plug degradation and improve emissions of an automatically started engine.

Abstract: Methods and systems are provided for operating an engine including an emission control system, the emission control system comprising a catalyst downstream of a turbine of a boosting device and a reductant injector upstream of the turbine. In one example, the method comprises injecting reductant into exhaust upstream of the turbine, mixing the injected reductant with exhaust gas via the turbine, and delivering the mixed reductant to the catalyst.

Abstract: An engine system for a vehicle and its method of operation are provided. In one embodiment, a control system is configured to indicate a clogging of a fuel filter based on a period of time that a fuel pressure switch remains in a low pressure state. In some embodiments, the control system may respond to an indicated clogging of the fuel system by limiting one or more of fuel pressure, fuel flow rate, and vehicle speed. By limiting the flow rate and/or the pressure at which fuel is delivered to the engine during conditions when the low pressure fuel sub-system is unable to provide sufficient fuel pressure and/or flow, degradation and/or damage to the fuel system, including the high pressure pump, may be reduced or eliminated.

Abstract: An engine system for a vehicle and its method of operation are provided. In one embodiment, a control system is configured to indicate a clogging of a fuel filter based on a period of time that a fuel pressure switch remains in a low pressure state. In some embodiments, the control system may respond to an indicated clogging of the fuel system by limiting one or more of fuel pressure, fuel flow rate, and vehicle speed. By limiting the flow rate and/or the pressure at which fuel is delivered to the engine during conditions when the low pressure fuel sub-system is unable to provide sufficient fuel pressure and/or flow, degradation and/or damage to the fuel system, including the high pressure pump, may be reduced or eliminated.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: Methods and systems are provided for operating an engine including an SCR catalyst downstream of an exhaust turbine and a particulate filter upstream of the turbine. In one example, the method comprises, adjusting a turbine wastegate to adjust a catalyst temperature to a desired catalyst temperature.

Abstract: Methods and systems are provided for operating an engine including an emission control system, the emission control system comprising a catalyst downstream of a turbine of a boosting device and a reductant injector upstream of the turbine. In one example, the method comprises injecting reductant into exhaust upstream of the turbine, mixing the injected reductant with exhaust gas via the turbine, and delivering the mixed reductant to the catalyst.

Abstract: An engine system for a vehicle and its method of operation are provided. In one embodiment, a control system is configured to indicate a clogging of a fuel filter based on a period of time that a fuel pressure switch remains in a low pressure state. In some embodiments, the control system may respond to an indicated clogging of the fuel system by limiting one or more of fuel pressure, fuel flow rate, and vehicle speed. By limiting the flow rate and/or the pressure at which fuel is delivered to the engine during conditions when the low pressure fuel sub-system is unable to provide sufficient fuel pressure and/or flow, degradation and/or damage to the fuel system, including the high pressure pump, may be reduced or eliminated.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: A fuel system for an engine is provided herein. According to one embodiment, the fuel system includes a fuel supply coupled to a low pressure fuel pump, the low pressure fuel pump coupled to a high pressure fuel pump to provide fuel to a fuel rail. Further, the fuel system includes a plurality of injectors coupled to the fuel rail to provide fuel to a plurality of engine cylinders. Further still, the fuel system includes a first fuel return line coupling the fuel rail to the fuel supply and a thermal recirculation valve, the thermal recirculation valve further coupled to a low pressure pump intake line; a second fuel return line coupling the high pressure fuel pump to the first fuel return line; and a third fuel return line coupling the plurality of injectors to a high pressure pump intake line.

Abstract: A fuel system for a diesel engine has both a low pressure pump, which extracts fuel from the fuel tank, and a high pressure pump, which is fed by the low pressure pump and supplies fuel to fuel injectors. The fuel injectors supply fuel to the engine cylinders, with a small portion of fuel routed back into the fuel system. According to an embodiment of the present disclosure, the injector return fuel is routed into a low pressure fuel line between the low and high pressure fuel pumps, with return fuel from the fuel rails returned through a fuel cooler to the fuel tank. The low pressure fuel line has a filter disposed therein and the injector return fuel is returned to the low pressure fuel line upstream of the filter.

Abstract: Methods and systems are provided for operating a turbocharged engine including a particulate filter positioned upstream of a turbocharger turbine, a catalyst positioned downstream of the turbine, and an EGR passage coupled between an engine exhaust and engine intake. In one example, the method comprises, diverting exhaust gas from downstream of the filter to the engine intake via the EGR passage, and adjusting an amount of diverted exhaust gas based on filter operating conditions.

Abstract: A method for operating a turbocharged engine is disclosed. In one example, an engine operation is adjusted in response to a turbocharger expansion ratio. Degradation of the engine may be reduced under some engine operating conditions by adjusting engine operation in response to the turbocharger expansion ratio.