The purpose of the present invention is to provide an engine with reforming cylinders which are fuel reforming devices capable of supplying a reformed fuel according to the outputs of outputting cylinders. The engine is provided with the outputting cylinders for burning the fuel and the reforming cylinders which are the fuel reforming devices for reforming the fuel through the reciprocating motions of pistons. The amount of reformed fuel supplied to all the outputting cylinders is changed according to the outputs of the outputting cylinders while maintaining the amount of supplied fuel and the amount of suctioned gas, which are supplied into one reforming cylinder.

The purpose of the present invention is to provide an engine with reforming cylinders which are fuel reforming devices capable of supplying a reformed fuel according to the outputs of outputting cylinders. The engine is provided with the outputting cylinders for burning the fuel and the reforming cylinders which are the fuel reforming devices for reforming the fuel through the reciprocating motions of pistons. The amount of reformed fuel supplied to all the outputting cylinders is changed according to the outputs of the outputting cylinders while maintaining the amount of supplied fuel and the amount of suctioned gas, which are supplied into one reforming cylinder.

In an alcohol concentration estimation apparatus for an engine, a first crank angular speed (ω1) within a first predetermined interval overlapping with the compression top dead center is calculated, and a first variation amount (Δω1) is calculated by subtracting ω1 from an average engine speed. A second crank angular speed (ω2) within a second predetermined interval overlapping with the combustion bottom dead center is calculated, and a second variation amount (Δω2) is calculated by subtracting ω1 from ω2. In a relationship between air fuel ratio A/F and an indicated mean effective pressure (IMEP)/charging efficiency (ηc) of the engine when the engine is operated with a predetermined fuel injection map indicating a relationship between A/F and IMEP/ηc for each desired alcohol concentration, IMEP/ηc is substituted by Δω2/Δω1 ratio to estimate an alcohol concentration in fuel. The alcohol concentration estimation apparatus eliminates requirement of sensors for detecting an intake air mass.

A method for operating an engine, comprising port injecting a first quantity of a first gaseous fuel in a cylinder cycle and direct injecting a second quantity of a secondary injectant in the cylinder cycle as a function of a desired air-to-fuel ratio (AFR), the desired AFR based on a temperature of an engine cylinder valve. The desired AFR may be outside the AFR range available during natural gas combustion alone and thus allows for cooler engine operation.

Methods and systems are provided for synergizing the benefits of an electric fuel separator in a hybrid vehicle system. A vehicle controller may hold the engine in a narrow operating range where usage of a selected higher octane or lower octane fuel fraction is optimal while using motor and/or CVT adjustments to address transients generated as driver demand varies. The controller may also adjust a fuel separator speed/pressure opportunistically during regenerative braking to maximize electrical usage as well as at low load conditions to enable extended engine operation in a more fuel efficient load region.

A secondary fuel injection system determines (precisely) a maximum amount of secondary fuel that can be injected into a cylinder during a cycle based upon the rotational speed (RPM) of the engine. A primary fuel injection pulse width of the prior cycle and is used to determine how much heat energy was requested by an engine control module based upon the duration of the injection pulse. Secondary fuel is injected into the intake port of the cylinder after the exhaust valve closes in an amount that is calculated based upon the maximum that can be injected during the allowed calculated time of crankshaft rotation and the amount of heat energy requested in the prior cycle and to include the amount of primary fuel that is then injected into the cylinder is being reduced based upon the amount of heat energy provided by the secondary fuel that was previously injected.

A secondary fuel injection system determines (precisely) a maximum amount of secondary fuel that can be injected into a cylinder during a cycle based upon the rotational speed (RPM) of the engine. A primary fuel injection pulse width of the prior cycle and is used to determine how much heat energy was requested by an engine control module based upon the duration of the injection pulse. Secondary fuel is injected into the intake port of the cylinder after the exhaust valve closes in an amount that is calculated based upon the maximum that can be injected during the allowed calculated time of crankshaft rotation and the amount of heat energy requested in the prior cycle and to include the amount of primary fuel that is then injected into the cylinder is being reduced based upon the amount of heat energy provided by the secondary fuel that was previously injected.

If the pressure in a supply passage drops at a speed greater than a first determination speed in a state in which a first mode for supplying gas fuel to an internal combustion engine is selected, a control apparatus inhibits selection of the first mode. Then, the control apparatus switches from the first mode to a second mode, in energy other than gas fuel is used. In this state, if the pressure in the supply passage drops at a speed greater than a second determination speed, the control apparatus maintains the state in which the second mode is selected. If the pressure in the supply passage drops at a speed lower than the second determination speed, the control apparatus cancels the inhibition of selection of the first mode when it is detected that a manual on-off valve is opened.

A dual fuel engine is provided. The dual fuel engine includes an engine cylinder and a piston disposed within the engine cylinder. The dual fuel engine includes a cylinder head coupled to the engine cylinder and a fuel injector coupled to the cylinder head. The fuel injector is adapted to supply a first fuel to the engine cylinder. The dual fuel engine further includes a pre-combustion chamber coupled to the cylinder head at a predetermined distance from the fuel injector. The pre-combustion chamber is in fluid communication with the engine cylinder via at least one conduit and the pre-combustion chamber is adapted to receive a second fuel and an air mixture. The second fuel is different from the first fuel. The dual fuel engine further includes a spark plug structured and arranged within the pre-combustion chamber and the spark plug is adapted to ignite the second fuel within the pre-combustion chamber.

A control apparatus for an internal combustion engine, includes circuitry. The circuitry is configured to control a ratio of an amount of low octane number fuel to be supplied to a cylinder to a total amount of the low octane number fuel and a high octane number fuel to be supplied to the cylinder in order to control an overall octane number of fuel to be supplied to the cylinder. The high octane number fuel has a second octane number higher than a first octane number of the low octane number fuel. The circuitry is configured to calculate a maximum octane number of the fuel to be supplied into the cylinder. The circuitry is configured to restrict a power generated by the internal combustion engine based on the maximum octane number.