One exemplary embodiment is a system comprising a multi-fuel engine structured to selectably combust varying proportions of a first type of fuel and a second type of fuel, and an electronic control system structured to control the provision of at least one of the first type of fuel and the second type of fuel to the engine using a multi-factor cost optimization. The multi-factor cost optimization may account for a plurality of factors including one or more environment factors, location factors, mission factors, warranty factors, operator-specified factors and/or fleet-specified factors.

Various systems and methods are described for diagnosing injector variability in a dual fuel, multi-injector system. In one example, a single injector in one cylinder is enabled while remaining cylinders are fueled with a first fuel and subsequently, a second fuel is injected via the enabled injector into the one cylinder in a predetermined sequence and fuel rail pressure drops are measured. Further, measured pressure drop after each injection event is corrected for an increase in injector closing delay.

Engine control apparatus includes: an engine including an injector and ignition plug, and a controller configured to control the injector and ignition plug to switch combustion mode to a second homogenous charge compression ignition combustion of reformed fuel with ignition at required torque less than a first predetermined value, to a first homogenous charge compression ignition combustion of reformed fuel, obtained by reforming a portion of gasoline fuel into peroxide, without ignition at required torque more than the first predetermined value and less than a second predetermined value, to spark ignition combustion of gasoline with ignition at required torque more than the second predetermined value and less than a third predetermined value, and to diffusion combustion of reformed fuel without ignition at required torque more than the third predetermined value.

An internal combustion engine system is described herein. The system uses a mixer to mix two fuels to provide for a transition from using only one of the fuels to using only the other fuel as power demand changes. The output of the mixer is provided to the engine as a primary fuel. A controller opens and closes throttle valves to adjust the relative concentrations of a first fuel (e.g., diesel) and a second fuel (e.g., methanol) that enter the mixer. In some examples, rather than removing the desired performance and/or environmental benefits achieved by using the second fuel at power demand levels greater than the maximum achievable by only using the second fuel, the systems described herein allow the use of at least a portion of the second fuel in the primary fuel at those power demand levels.

A method for controlling an internal-combustion engine includes detecting knocking in the internal-combustion engine. An EGR gas quantity of EGR gas is increased in a case where the knocking is detected. A part of exhaust gas is circulated into an intake passage as the EGR gas. A fuel octane number of fuel supplied to a cylinder is increased in the case. The fuel octane number is decreased after the fuel octane number has been increased. The EGR gas quantity is maintained so as to prevent the knocking after the EGR gas quantity has been increased.

A two-stroke uniflow engine is provided with: a cylinder; a piston; an exhaust valve that is opened and closed in order to discharge exhaust gas that is generated inside the cylinder; a scavenging port that takes active gas into the interior of the cylinder in accordance with a sliding movement of the piston; a fuel injection port that is provided in the internal circumferential surface of the cylinder; a fuel injection valve that injects fuel gas into the fuel injection port; and a fuel injection control unit that executes control of the injection of the fuel gas in the fuel injection valve, wherein the fuel injection control unit decides at least one of an injection pressure and an injection time of the fuel injection valve based on a change in pressure inside the cylinder that is caused by a reciprocating movement of the piston.

A method for optimal fueling of an engine is disclosed. The method includes determining a quantity of exhaust residuals in each cylinder among a plurality of cylinders in the engine. Further, the method includes determining at least one of an intake and exhaust manifolds temperature, at least one of an intake and exhaust manifolds pressure, and a quantity of a first fuel being injected to each cylinder, and calculating a characteristic temperature of each cylinder based on the quantity of exhaust residuals, at least one of the intake and exhaust manifolds temperature and pressure, and the quantity of the first fuel. The method further includes determining a substitution rate of the first fuel for each cylinder based on the characteristic temperature, and controlling at least one of the quantity of the first fuel, and a quantity of a second fuel being injected to each cylinder based on the substitution rate.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

A fuel system comprises a first fuel rail. A first fuel delivery system, including a first plurality of fuel injectors, is connected to the first fuel rail. The first plurality of fuel injectors injects an amount of fuel into a first portion of an engine. A second fuel rail has a second fuel delivery system, including a second plurality of fuel injectors. The second plurality of fuel injectors inject an amount of fuel into a second portion of the engine, distinct from the first portion. A controller, operatively connected to the first fuel delivery system and the second fuel delivery system selectively enables and disables operation of the first fuel delivery system and the second fuel delivery system based on one of a detected temperature and a detected pressure of fuel passing to corresponding ones of the first plurality of fuel injectors and the second plurality of fuel injectors.

Methods and systems are provided for a multi-fuel engine. In one example, a method includes operating engines of rail vehicles at a desired substitution ratio to recharge an energy storage device of a rail vehicle operating in an all-electric mode to meet a requested total power.