System and method for controlling the fuel injection event in an internal combustion engine

A fuel injection system for controlling fuel injection in an internal combustion engine having an engine block with one or more cylinders within which fuel is injected, the fuel injection system comprising:

• a fuel pump in fluid communication with a fuel reservoir;
• a fuel accumulator, in fluid communication with the fuel pump;
• one or more injectors that are in fluid communication with the fuel accumulator and each of the fuel injectors are in fluid communication with a corresponding cylinder in which a piston is supported;
• the one or more injectors each having a valve that opens or closes responsive to electrical pulses;
• one or more air manifolds in fluid communication with the cylinders for delivery of air to the cylinders;
• a controller, in electrical communication with the one or more of the injectors and the fuel pump that, during operation of the engine, generates one or more first signals responsive to which the valve in the injector opens or closes and one or more second signals responsive to which the fuel pump increases or decreases a pressure level in the fuel accumulator;
• one or more sensors for detecting operating parameters including an air pressure within the air manifold and a pressure within the fuel accumulator, wherein the one or more sensors send data, indicative of the air pressure within the air manifold and pressure within the fuel accumulator, to the controller;
• wherein the controller calculates an in-cylinder pressure based on the detected pressure within the air manifold and the detected pressure within the fuel accumulator;
• a database that includes data relative to a predetermined maximum in-cylinder gas pressure, wherein the database further includes data relative to a fuel injection strategy, the data relative to the fuel injection strategy including data indicative of a plurality of different timings of a fuel injection relative to a top-dead center position of a piston and/or data relative to a plurality of different pressures in the fuel accumulator;
• and,
• the controller is programmed to select a fuel injection strategy from the database responsive to a calculated in-cylinder pressure that reaches or exceeds the predetermined maximum in-cylinder gas pressure, wherein according to the selected fuel injection strategy a selected timing of a fuel injection is adjusted relative to a previously selected fuel injection timing and/or a selected pressure in the fuel accumulator is adjusted relative to a previously selected pressure, whereby NOx emissions of the engine and/or fuel consumption are maintained within designated limits.

A method for controlling fuel injection in an internal combustion engine mounted in a vehicle and having an engine block with one or more cylinders within which fuel is injected and provided from a fuel accumulator under pressure, wherein the engine further includes an air manifold for providing air to cylinders associated with the injectors, the method comprising the steps of:

• monitoring, from one or more sensors, an air pressure in the air manifold and a pressure within the fuel accumulator;
• transmitting, from the one or more sensors, one or more signals indicative of the air pressure in the air manifold and the pressure within the fuel accumulator to a fuel injection controller;
• calculating, at the fuel injection controller, an in-cylinder gas pressure using the data relative to the pressure within the air manifold and the pressure within the fuel accumulator;
• and,
• transmitting, in response to the calculated in-cylinder gas pressure, from the controller, one or more commands relative to a fuel injection strategy for each cylinder including commands associated with a timing of a fuel injection during a piston cycle, the number of injections, and the duration of each injection made during a piston cycle;
• and,
• wherein in response to the one or more commands from the controller, adjusting the timing of a fuel injection relative to a top-dead center position of the piston and relative to a previously selected fuel injection timing and/or adjusting the pressure in the fuel accumulator relative to a previously selected pressure, when the calculated in-cylinder gas pressure exceeds a predetermined maximum pressure limit, whereby NOx emissions of the engine and/or fuel consumption are maintained within designated limits.