When it is determined that there is a likelihood of occurrence of an abnormality in a supercharger, a maximum engine rotation speed and a maximum MG2 rotation speed are changed to a low rotation speed side and operating points of an engine and a rotary machine are controlled such that an engine rotation speed and an MG2 rotation speed are respectively within ranges which do not exceed the changed maximum rotation speeds. Accordingly, even when the supercharger does not operate normally and an abnormal increase in a supercharging pressure occurs, it is possible to curb a high-rotation state of the engine rotation speed and the MG2 rotation speed. As a result, even when an abnormal increase in the supercharging pressure occurs, it is possible to curb a decrease in durability of components.

A fuel injection valve is for injecting fuel to cause combustion in an internal combustion engine. An injection rate adjuster is for adjusting an injection rate of the fuel injected by the fuel injection valve. A control device for the internal combustion engine includes a signal generator, and an outputter. The signal generator generates a command signal to cause the injection rate adjuster to adjust the injection rate based on a parameter, which is to estimate an internal EGR amount in which a part of exhaust gas remains in a cylinder. The outputter outputs the command signal to the injection rate adjuster.

A method of operating an engine assembly is provided. The engine assembly comprises an engine and a turbocharger assembly, wherein a control parameter of the turbocharger assembly is controllable in order to control a level of boost provided by the turbocharger assembly. The method comprises determining a desirable pressure limit of exhaust gases upstream of a turbine of the turbocharger assembly, predicting a desirable limit value of the control parameter to be applied to the turbocharger assembly in order to achieve the desirable pressure limit, determining an error in the desirable limit value of the control parameter, adjusting the desirable limit value of the control parameter based on the error, and controlling the operation of the turbocharger assembly such that the adjusted limit value is not exceeded.

A rotation adjusting device is controlled such that an engine speed rising rate at the time of acceleration request is made smaller when a turbocharging pressure is lower than the turbocharging pressure is higher. Therefore, an engine speed can be increased at such a low speed that a rising delay in the turbocharging pressure hardly occurs, in a low turbocharging pressure region. Further, when the rotation adjusting device is controlled such that the engine speed rising rate at the time of the acceleration request is set to a value corresponding to the turbocharging pressure, an MG2 torque is controlled to compensate for an insufficient drive torque of an actual engine torque for a request engine torque. Therefore, even when the engine torque is increased slowly by increasing the engine speed at a slow speed, the insufficient drive torque is compensated for by the MG2 torque.

Methods and systems are provided for detection of cylinder-to-cylinder air fuel ratio imbalance in engine cylinders. In one example, a method may include indicating air fuel ratio imbalance in an engine cylinder based on a comparison of an estimated cylinder acceleration for the cylinder and a calibrated cylinder acceleration for each of the engine cylinders. The indication of imbalance may be further confirmed based on one or more of an exhaust air-fuel ratio, an exhaust manifold pressure, and an individual cylinder torque weighted by respective confidence factors.

A system for estimating engine performance is configured to receive, via a cylinder combustion model, a cylinder pressure of a cylinder associated with operation of an internal combustion engine. The system estimates a liner bending moment based at least in part on the cylinder pressure, generates a piston side load associated with the cylinder based at least in part on the liner bending moment, and estimates a piston friction value for a piston associated with the cylinder. The piston friction value may be based at least in part on the cylinder pressure and an engine speed of the internal combustion engine. The system receives, via a convective heat transfer model, an exhaust heat transfer value indicative of a cumulative heat transfer from an exhaust manifold, and estimates an engine torque value based at least in part on the exhaust heat transfer value.

A controller is configured to perform a process of obtaining an exhaust pressure upstream of a filter inside an exhaust passage and an intake air amount detected by an air flowmeter, when the filter in which a deposition amount of particulate matter is a specified amount is referred to as a reference filter, a calculation process of calculating an exhaust pressure rate that indicates a ratio of the obtained exhaust pressure to an exhaust pressure at the reference filter for the obtained intake air amount, and a setting process of setting the exhaust pressure rate that is maintained at a specific value during engine operation.

A method for controlling an internal combustion engine system, the engine system including a combustor arranged to receive air and fuel, and combust the received air and fuel, an expander arranged to expand exhaust gases from the combustion in the combustor and to extract energy from the expanded exhaust gases, and a communication valve arranged to control a communication between the combustor and the expander, including determining during operation of the engine system whether there is a pressure difference across said communication valve.

A lean operation fault detection and isolation (FDI) technique involves receiving, from a manifold absolute pressure (MAP) sensor, a measured MAP, detecting a lean operation fault where an engine is operating with a lean air/fuel ratio, estimating, using an observer, (i) an air/fuel ratio of an exhaust gas produced by the engine and (ii) the MAP, monitoring first and second residual values indicative of differences between (i) the estimated air/fuel ratio of the exhaust gas and a measured air/fuel ratio of the exhaust gas from an exhaust O2 sensor and (ii) the estimated MAP and the measured MAP from the MAP sensor, respectively, and, based on the monitoring of the first and second residual values, determining which of (i) an air intake of the engine, (ii) the exhaust O2 sensor, and (iii) a fuel injector of the engine is malfunctioning and causing the lean operation fault.

A method for controlling a supercharging system for an internal combustion engine, the supercharging stage including a compressor and a turbine, and the turbine being settable with the aid of a VTG driving circuit. The method including: detecting an operating state setpoint variable, setting a maximum VTG control criterion for implementing the torque increase by an increase in a boost pressure. The setting of the maximum VTG control criterion comprising: ascertaining a setpoint boost pressure; ascertaining a VTG setpoint position as a function of the setpoint boost pressure; ascertaining an actual exhaust gas back pressure; ascertaining an actual exhaust gas pressure downstream from the turbine; ascertaining a maximum exhaust gas back pressure, taking into account the actual exhaust gas pressure downstream from the turbine; determining the VTG control criterion, based on the difference between the actual exhaust gas back pressure and the maximum exhaust gas back pressure.