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 method and a system for controlling combustion of a natural gas engine. The method includes: determining, based on a current operation parameter of a natural gas engine, an operation state of the natural gas engine, and calculating a total injection quantity of natural gas and pilot diesel required by the natural gas engine in the operation state; adopting a direct injection diffusion-combustion mode in a case that the operation state is an idle state or a low load state; adopting a natural gas homogeneous hybrid active control compression-ignition mode in a case that the operation state is a medium load state; configuring the total injection quantity into three parts including a compression-ignition natural gas injection quantity, a pilot diesel injection quantity, and a diffusion-combustion natural gas injection quantity in a case that the operation state is a high load state, and sequentially injecting them into a combustion chamber.

A method and a system for controlling combustion of a natural gas engine. The method includes: determining, based on a current operation parameter of a natural gas engine, an operation state of the natural gas engine, and calculating a total injection quantity of natural gas and pilot diesel required by the natural gas engine in the operation state; adopting a direct injection diffusion-combustion mode in a case that the operation state is an idle state or a low load state; adopting a natural gas homogeneous hybrid active control compression-ignition mode in a case that the operation state is a medium load state; configuring the total injection quantity into three parts including a compression-ignition natural gas injection quantity, a pilot diesel injection quantity, and a diffusion-combustion natural gas injection quantity in a case that the operation state is a high load state, and sequentially injecting them into a combustion chamber.

A method of controlling a high pressure gas injection internal combustion engine includes injecting, in a first combustion mode, by a first as injection system, a first gaseous fuel into a cylinder of the engine, and accumulating in a container of a second gas injection system excess gaseous fuel from the first fuel system, shifting, in the cylinder, from the first combustion mode to a second combustion mode including determining a value of an air flow related parameter indicative of an air mass flow into the cylinder, determining, based on the determined air flow related parameter value, a value of a fuel flow related parameter indicative of a mass flow of the excess gaseous fuel, and supplying from the container, in accordance with the determined fuel flow related parameter value, the excess gaseous fuel to provide a premix of air and the excess gaseous fuel to the cylinder.

A method of controlling a high pressure gas injection internal combustion engine includes injecting, in a first combustion mode, by a first as injection system, a first gaseous fuel into a cylinder of the engine, and accumulating in a container of a second gas injection system excess gaseous fuel from the first fuel system, shifting, in the cylinder, from the first combustion mode to a second combustion mode including determining a value of an air flow related parameter indicative of an air mass flow into the cylinder, determining, based on the determined air flow related parameter value, a value of a fuel flow related parameter indicative of a mass flow of the excess gaseous fuel, and supplying from the container, in accordance with the determined fuel flow related parameter value, the excess gaseous fuel to provide a premix of air and the excess gaseous fuel to the cylinder.

A method for operating an internal combustion engine including a step of concurrently introducing at least two combustible fuel jets into a combustion chamber of an internal combustion engine. A first combustible fuel jet of the at least two combustible fuel jets is ignited at an ignition time point. In a first operating mode of the internal combustion engine a second combustible fuel jet which is different from the first combustible fuel jet of the at least two combustible fuel jets is ignited after the ignition time point.

A method of operating a dual-fuel combustion system includes reciprocating a piston between a bottom dead center and a top dead center of a cylinder, the piston including a piston bowl, a circumferentially extending recess located radially outside of the piston bowl, and a plurality of diverters in the recess. The method includes opening an intake valve to introduce a first fuel, and injecting, by a set of fuel injector orifices substantially aligned with the diverters, a second fuel toward the diverters. The method also includes autoigniting the second fuel to ignite the first fuel.

A method of operating a dual-fuel combustion system includes reciprocating a piston between a bottom dead center and a top dead center of a cylinder, the piston including a piston bowl, a circumferentially extending recess located radially outside of the piston bowl, and a plurality of diverters in the recess. The method includes opening an intake valve to introduce a first fuel, and injecting, by a set of fuel injector orifices substantially aligned with the diverters, a second fuel toward the diverters. The method also includes autoigniting the second fuel to ignite the first fuel.

A method of operating a dual-fuel combustion system includes reciprocating a piston between a bottom dead center and a top dead center of a cylinder, the piston including a piston bowl, a circumferentially extending recess located radially outside of the piston bowl, and a plurality of diverters in the recess. The method includes opening an intake valve to introduce a first fuel, and injecting, by a set of fuel injector orifices substantially aligned with the diverters, a second fuel toward the diverters. The method also includes autoigniting the second fuel to ignite the first fuel.

A method of operating a dual-fuel combustion system includes reciprocating a piston between a bottom dead center and a top dead center of a cylinder, the piston including a piston bowl, a circumferentially extending recess located radially outside of the piston bowl, and a plurality of diverters in the recess. The method includes opening an intake valve to introduce a first fuel, and injecting, by a set of fuel injector orifices substantially aligned with the diverters, a second fuel toward the diverters. The method also includes autoigniting the second fuel to ignite the first fuel.