The invention relates to a system for providing a fluid, comprising at least a first and a second cryogenic container for storing the fluid, wherein the system comprises a first retrieval line connecting to the first cryogenic container for retrieving a first mass flow (M1) of fluid and a second retrieval line connecting to the second cryogenic container for retrieving a second mass flow (M2) of fluid, wherein the system comprises means, which are configured to establish two mass flows (M1, M2) of different dimensions such that in a first operational mode a hold time of the two cryogenic containers converges upon retrieval and/or in a second operational mode the hold time of the two cryogenic containers essentially decreases at the same rate if the hold times of the two cryogenic containers are essentially equal.

Methods and systems are provided for injecting gaseous fuel during an engine start. In one example, a method comprises generating gaseous fuel via a fuel gasification device and injecting the gaseous fuel via a fuel injector. The fuel injector is configured to inject adjacent to an ignition device.

A method of operating a dual fuel engine includes conveying intake air, and a first fuel as a vapor and as a liquid, into a combustion cylinder in an engine, and directly injecting a second fuel into the combustion cylinder to form a first combustion charge of the first fuel as a vapor and as a liquid, the second fuel, and intake air. The second fuel is ignited to initiate combustion of the first combustion charge. Operating the dual fuel engine further includes varying at least one of, a vapor proportion of the first fuel or a total proportion of the first fuel, in a subsequent combustion charge to mitigate undesired combustion. The first fuel can include a liquid alcohol fuel. The second fuel can include a liquid compression-ignition fuel. Related apparatus and control logic is also disclosed.

Methods and systems are provided for injecting gaseous fuel during an engine start. In one example, a method comprises generating gaseous fuel via a fuel gasification device and injecting the gaseous fuel via a fuel injector. The fuel injector is configured to inject adjacent to an ignition device.

Various methods and systems are provided for skipping fire in one or more cylinders in a dual fuel engine. In one example, a method may include injecting a combination of two fuels to a first set of cylinders of the engine while disabling fuel injection to all remaining cylinders of the engine.

A system for supplementing a fixed fuel source for an engine includes a motor-generator set connected to a mechanical load device and a controller. The motor-generator set includes a motor and a generator. The engine is configured to provide a first torque from a fixed fuel source from an independent variable flow input. The fixed fuel source is independent of the engine and set external to the engine. The mechanical load device is driven by the engine and configured to require a second torque defined by an independent flow device. The controller is configured to compare the first torque and the second torque, provide a first control signal to the motor to provide power to the engine when the second torque exceeds the first torque and provide a second control signal to the generator to draw power from the engine when the first torque exceeds the second torque.

A system for supplementing a fixed fuel source for an engine includes a motor-generator set connected to a mechanical load device and a controller. The motor-generator set includes a motor and a generator. The engine is configured to provide a first torque from a fixed fuel source from an independent variable flow input. The fixed fuel source is independent of the engine and set external to the engine. The mechanical load device is driven by the engine and configured to require a second torque defined by an independent flow device. The controller is configured to compare the first torque and the second torque, provide a first control signal to the motor to provide power to the engine when the second torque exceeds the first torque and provide a second control signal to the generator to draw power from the engine when the first torque exceeds the second torque.

Provided is a fuel-reforming device comprising: an ammonia tank (4); a reformer (5) for reforming ammonia and generating high-concentration hydrogen gas having a hydrogen content of at least 99%; a mixing tank (7) for mixing ammonia and hydrogen for temporary storage; and a control means (10) for controlling the respective supply amounts of ammonia and high-concentration hydrogen gas that are supplied to the mixing tank (7). The control means (10) calculates the combustion rate coefficient C of mixed gas with respect to a reference fuel on the basis of equation (1). Equation (1): S.sub.0=S.sub.H×C+S.sub.A×(1−C). In equation (1), S.sub.0 is the combustion rate of the reference fuel, S.sub.H is the combustion rate of hydrogen, S.sub.A is the combustion rate of ammonia, and C is the combustion rate coefficient of mixed gas. In addition, on the basis of equation (2), the control means (10) determines the volume fractions of ammonia and hydrogen that are supplied to the mixing tank. Equation (2): C=1−exp(−A×M.sub.B). In equation (2), M is the volume fraction of hydrogen in mixed gas, and A and B are constants.

An engine system includes an engine having a combustion chamber, an intake gas passage through which air to be supplied to the combustion chamber flows, an exhaust gas passage through which exhaust gas generated from the combustion chamber flows, a reformer configured to reform the fuel to generate a reformed gas containing hydrogen, a gas supply passage through which air to be supplied to the reformer flows, a bypass passage connected to the gas supply passage and the exhaust gas passage so as to bypass the reformer and through which the fuel having passed through the reformer is circulated to an upstream of the reformer, and a switching valve switched between a normal position that does not allow the fuel having passed through the reformer to flow to the bypass passage and a circulating position that allows the fuel having passed through the reformer to flow to the bypass passage.

An opposed-piston engine is configured to use hydrogen fuel. The opposed-piston engine has at least one cylinder and a pair of pistons disposed for opposed motion in a bore of the cylinder. Hydrogen fuel is directly side-injected into the cylinder in a compression stroke of the opposed-piston engine, mixed with charge air in the cylinder, and auto-ignited in a combustion chamber formed in the cylinder between the pistons during the compression stroke. A method of operating the hydrogen opposed-piston engine includes switching between a first ignition mode using an externally-generated ignition impulse to ignite the mixture of hydrogen fuel and charge air, and a second ignition mode using compression to ignite the mixture.