A concentration measuring device includes a circulation passage, an aspirator, a differential pressure sensor, and a control unit. The aspirator is disposed in a fuel tank and is connected to the circulation passage. While a gas flows from a gaseous layer within a fuel tank through the circulation passage due to a negative pressure generated in the aspirator, the differential pressure sensor measures a pressure difference of the gas within the circulation passage between an upstream side of a narrowed part, having a narrower passage area than an adjacent portion of the circulation passage, and a downstream side of the narrowed part. The control unit is configured to calculate a density of the fuel vapor from the pressure difference of the gas and to calculate a concentration of the fuel vapor from the density of the fuel vapor.

To provide a controller for internal combustion engine which suppresses that estimation of the combustion state is performed based on the angle information on which the component due to the torsional vibration is superimposed, when the torsional vibration occurs in the crankshaft. A controller for internal combustion engine determines whether a torsional vibration occurs in a crankshaft based on an angle period; calculates a gas pressure torque in burning based on a crank angle acceleration which is calculated based on the angle period; estimates a combustion state of an internal combustion engine based on the gas pressure torque in burning; and stops estimation of the combustion state, when it is determined that the torsional vibration occurred.

An arrangement and method for determining the service interval of a fluid filter includes a filter and a pump driven by an electric motor. A control module calculates pressure drop across the filter by way of voltage, current, and/or PWM provided to the electric motor. The control module monitors the rate of change of the pressure drop across the filter over the life of the filter. The volume flow rate of the fluid may or may not be held constant. If an abrupt or sudden characteristic change in the pressure drop across the filter occurs, or if the pressure drop across the filter exceeds a threshold amount, the arrangement and method provides a notification that either the filter needs to be replaced or serviced, or that it is probable that a mechanical condition has developed, depending upon the characteristics of the change in pressure drop across the filter.

Provided is an internal combustion engine control device that is capable of accurately estimating a stable combustion state at low cost. An internal combustion engine control device according to one aspect of the present invention includes: a rotational speed calculation unit 122a that calculates a time-series value of a crank rotational speed of an internal combustion engine; a rotational, speed phase calculation unit 122b that calculates a phase of the crank rotational speed from the time-series value of the crank rotational speed calculated by the rotational speed calculation unit; and a cycle variation calculation unit 122c that calculates the magnitude of variation between cycles of the phase of the crank rotational speed calculated by the rotational speed phase calculation unit.

A method of controlling a skip-fire cylinder deactivation system of an engine system is provided. The method includes a controller deactivating a cylinder of the engine system to operate the engine system in a skip-fire mode. The method further includes determining a temperature of an injector tip nozzle associated with the cylinder and comparing the temperature of the injector tip nozzle to a threshold a temperature. In response to determining that the temperature of the injector tip nozzle is greater than the threshold temperature, the cylinder is activated by the controller.

Provided is an internal combustion engine control device that is capable of accurately estimating a stable combustion state at low cost. An internal combustion engine control device according to one aspect of the present invention includes: a rotational speed calculation unit 122a that calculates a time-series value of a crank rotational speed of an internal combustion engine; a rotational, speed phase calculation unit 122b that calculates a phase of the crank rotational speed from the time-series value of the crank rotational speed calculated by the rotational speed calculation unit; and a cycle variation calculation unit 122c that calculates the magnitude of variation between cycles of the phase of the crank rotational speed calculated by the rotational speed phase calculation unit.

An EGR estimation method for estimating an EGR rate in an intake and exhaust system of an internal combustion engine, the intake and exhaust system including: an intake system including an air cleaner and an intake passage that connects the air cleaner and the engine, an exhaust system including an exhaust passage, and a supercharger that is provided in the intake passage and the exhaust passage, the intake and exhaust system including an EGR device including an EGR passage that connects the intake passage and the exhaust passage and an EGR valve, and the intake system including an intake bypass passage that connects an upstream pressure portion and a downstream pressure portion of the supercharger and a recirculation valve. The EGR estimation method includes: opening the recirculation valve during supercharging, and estimating the EGR rate after closing the EGR valve based on the EGR rate before opening the recirculation valve.

Methods and systems for heating an emission control device are provided. In one example, a method for a vehicle comprises during an engine cold start, heating an emission control device of the engine using a dual heat exchanger to heat secondary air and cool exhaust gas, and further heat secondary air with an electric heater. The method further comprises directing the heated secondary air to each exhaust runner of the engine via individual air injectors to mix with exhaust gas. In this way, an improved mixture of air and exhaust reduces catalyst light-off time and increases conversion efficiency, thereby reducing hydrocarbon emissions during engine cold start.

Methods and systems are provided for controlling a vehicle engine to reduce engine knock and increase fuel efficiency by reducing hydrocarbon breakthrough. In one example, a method may include adjusting a compression ratio of a variable compression engine in response to hydrocarbon breakthrough above a threshold from a fuel vapor canister of an evaporative emissions system.

Disclosed is a multiple combustion mode engine with ammonia fuel including an cylinder head, a cylinder sleeve, a piston, a main combustion chamber, an inlet valve and an exhaust valve, and further including a jet ignition device arranged on the cylinder head and used for providing an ignition source for the main combustion chamber, and an ammonia injector used for providing ammonia/air mixture gas for the main combustion chamber. Also disclosed is a control method of the multiple combustion mode engine with ammonia fuel. The time sequence of ammonia injection of the main combustion chamber and jet flame generation of the pre-chamber is controlled, the mixed state of the fuel/air in the main combustion chamber before ignition can be controlled, and finally different combustion modes, i.e. a premixed combustion mode and a diffusion combustion mode, are formed in the main combustion chamber.