Methods and systems are provided for an engine for adjusting cylinder parameter settings to optimize engine output during a transient mode. In one example, a method may include adjusting cylinder parameter settings, including a cam timing setting, a spark timing setting, and a fuel injection timing setting based on a chamber temperature in response to a rate of fuel injection acceleration being greater than a positive threshold, thus indicating the engine is in the transient mode.

An engine system is provided, including a controller which estimates an intake-valve-closing temperature inside a cylinder. When an engine operates at a given speed and a demanded engine load is a first load or a second load (>the first load), the controller controls so that a mixture gas inside the cylinder combusts by compression ignition, and controls so that, at the first load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a first temperature, and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the first temperature, whereas at the second load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a second temperature (<the first temperature), and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the second temperature.

An engine system is provided, including a controller which estimates a mass ratio (G/F) of intake air inside a cylinder (containing fresh air and burnt gas) to fuel, and controls devices of an engine at a given engine speed so that, while a demanded engine load is a first load, at least part of a mixture gas inside the cylinder combusts by flame-propagation when the estimated G/F is below a first G/F, and the entire mixture gas combusts by compression ignition when the estimated G/F is above the first G/F, whereas while the demanded load is a second load (>the first load), at least part of the mixture gas combusts by flame-propagation when the estimated G/F is below a second G/F (<the first G/F), and the entire mixture gas combusts by compression ignition when the estimated G/F is above the second G/F.

An engine system is provided, including a controller which controls devices of an engine at a given engine speed so that, when a demanded engine load is a first load, a mass ratio (G/F) of intake air inside a cylinder (containing fresh air and burnt gas) to fuel is a first G/F and mixture gas inside the cylinder combusts by flame-propagation, when the demanded load is a second load (<the first load), the G/F is a second G/F (>the first G/F) and an injection center-of-gravity is at a timing such that the entire mixture gas combusts by CI combustion, and when the demanded load is between the first and second loads, the G/F is at a third G/F (between the first and second G/Fs) and the injection center-of-gravity is at a later timing such that at least part of the mixture gas combusts by the CI combustion.

A temperature acquisition apparatus for an internal combustion engine is configured to acquire a temperature of a combustion chamber of the internal combustion engine. The apparatus includes: an electronic control unit having a processor and a memory coupled to the processor. The processor is configured to perform: acquiring an intake air amount of the internal combustion engine; calculating a cumulative intake air amount based on the intake air amount; and acquiring a temperature of the internal combustion engine based on the cumulative intake air amount.

An internal combustion engine control apparatus including a microprocessor. The microprocessor is configured to perform controlling a fuel injector so as to inject a fuel of a target injection amount by dividing into a plurality of times at a predetermined time interval in an area from a first crank angle at which an intake stroke is started to a second crank angle at which a compression stroke is ended, and setting the predetermined time interval. The microprocessor is configured to perform the setting including setting the predetermined time interval so that a spray length from a tip of the fuel injector to a tip of a spray of the fuel injected from the fuel injector becomes shorter than the spray length when the fuel of the target injection amount is injected at once in the area by a predetermined rate.

A method for predicting the combustion state of an engine sets the operating condition of the engine, calculates the temperature of a highest temperature portion of the cylinder before combustion based on the operating condition, calculates the combustion start timing based on the temperature of the highest temperature portion, calculates the temperature of a lowest temperature portion of the cylinder based on the operating condition and the combustion start timing, and calculates the combustion end timing based on the temperature of the lowest temperature portion. The method calculates the temperature of a wall surface layer portion located adjacent the wall surface in the cylinder based on state changes in a burned portion, an unburned portion, and the wall surface layer portion that constitute a combustion chamber inside of the cylinder, and applies the temperature of the wall surface layer portion as the temperature of the lowest temperature portion.

A method of controlling an engine is provided, which includes setting, by a controller, a target torque of the engine in a specific cycle in the future by a given delay time from the present time based on a present accelerator opening. The method includes selecting beforehand, by the controller, combustion in the specific cycle according to the target torque, from flame propagation combustion and compressed self-ignition combustion. The method includes outputting, by the controller, a control signal to a property adjusting device before the specific cycle so that a property inside the cylinder in the specific cycle becomes a property corresponding to the selected combustion. The method includes estimating, by the controller, the property at a timing when an intake valve is closed in the specific cycle. The method includes outputting, by the controller, a control signal corresponding to the estimated property to a spark plug or an injector.

A vehicle including an engine; a turbocharger, an intake air flow path of the vehicle defined from air entering the vehicle, passing through the compressor, and flowing into the engine air inlet; a coolant container assembly; a temperature sensor configured for determining a temperature in the intake air flow path; and a controller configured to selectively cause cooling liquid to flow from the coolant container into the intake air flow path. A method for managing engine air intake temperature or piston temperature of a turbocharged vehicle including: sensing a temperature of fluid within the air intake flow path, determining an estimated piston temperature; and in response to the estimated piston temperature and/or the temperature of the fluid being above threshold temperatures, causing an amount of cooling liquid to flow from a coolant container to the air intake flow path.

A variety of methods and arrangements are described for determining a pilot injection mass during skip fire operation of an internal combustion engine.