A direct-injected compression ignition internal combustion engine includes an engine housing having a cylinder and a piston movable within the cylinder and including a piston end face forming a combustion bowl. The piston end face has an annular piston rim with a rounded inner rim surface that extends radially inward and axially downward from a planar outer rim surface to a combustion bowl edge. An antebowl is defined by the rounded inner rim surface and has an antebowl volume that is about 0.8% or greater of a total volume of the combustion bowl and the antebowl together. A configuration and dimensional attributes of the antebowl is associated with reduced smoke production during operation, particularly for low to mid-load transients.

In internal combustion engine, a fuel injector has a nozzle tip forming first and second pluralities of nozzle openings configured to inject respective pluralities of first and second fuel jets into a combustion chamber. The first fuel jets are directed between projections formed in a piston during a main injection, and the second fuel jets are directed towards the protrusions during a post injection. The protrusions are asymmetrical to redirect the first fuel jets.

In a supercharged, two-stroke cycle, opposed-piston engine with an EGR loop, exhaust gas recirculated to a charge air channel through which charge air is provided to a supercharger inlet is cleansed of particulate materials by a particulate filter located in the EGR channel to capture and oxidize particulate matter before EGR is allowed to flow through the supercharger and any cooler in the EGR flow path. A diesel oxidation catalyst device may be provided in the EGR channel, in series with the particulate filter.

Methods and systems are provided for a multi-hole nozzle of a fuel injector. In one example, a nozzle for a fuel injector may include multiple nozzle holes arranged at a nozzle tip, where each nozzle hole has a straight flow axis and a cross-section that twists around the straight flow axis, from an inlet to an outlet of the nozzle hole. Additionally, a long side of the cross-section may increase in length, along the nozzle hole, from the inlet to the outlet.

Disclosed is a fuel level estimation device including: an information acquiring unit acquiring information about a closed system internal pressure of a closed fuel vapor system including the fuel tank, a vent passage, and a canister; a flow rate controlling unit controlling, by actuating a negative pressure pump, a flow rate of fuel vapor-containing gas in the closed fuel vapor system; a fuel level estimating unit estimating a fuel level based on a total volume of the closed fuel vapor system and an occupied volume of the gas. The fuel level estimating unit estimates the occupied volume of the gas by using a change in a closed system internal pressure before and after the closed fuel vapor system is subjected to pressure-reducing treatment for a predetermined interval and a reference discharging rate when the gas is subject to the pressure-reducing treatment. An abnormality diagnostic apparatus is also disclosed.

A diesel engine comprises: a cylinder head covering one end of a cylinder; a piston having a crown surface opposed to the cylinder head and reciprocatingly movable in the cylinder; and a fuel injection valve attached to the cylinder head, wherein the crown surface of the piston is formed with a cavity which is concaved toward a side opposite to the cylinder head, and has a round shape in top plan view, and the fuel injection valve is formed with a nozzle hole directed toward the inside of the cavity, and wherein a wall surface defining the cavity has a wall segment formed in a periphery of the cavity at a position deviated from a directional direction of the nozzle hole and protruding toward a radially inward side of the piston in approximately parallel to a plane including a central axis of the piston.

A method to control an internal combustion engine including exhaust gas recirculation (EGR) system and an air charging system includes the following steps: (a) determining, via an engine controller, a first EGR mass flow rate using an orifice model; (b) determining, via the engine controller, a second EGR mass flow rate using a cylinder volumetric efficiency model; (c) determining, via the engine controller, a hybrid EGR mass flow rate based on the first EGR flow rate and the second EGR flow rate; and (d) controlling the air charging system based on the hybrid EGR flow rate.

Embodiments disclosed herein relate to internal combustion engines, combustion systems that include such internal combustion engines, and controls for controlling operation of the combustion engine. The internal combustion engine may include one or more mechanisms for injecting fuel, air, fuel-air mixture, or combinations thereof directly into one or more cylinders, and controls may operate or direct operation of such mechanisms.

A first engine fuel, for example diesel fuel, is reformed (preferably via steam reforming) to produce syngas for use as a second engine fuel, with the fuels then both being used in an internal combustion engine to perform Reactivity Controlled Compression Ignition (RCCI). The syngas is produced and supplied to the engine as a supercritical fluid, thereby avoiding the pumping losses that would occur if syngas was pressurized for supply/injection. The reforming is done by a reformer which is provided as a unit with the engine (e.g., both the engine and reformer are onboard a vehicle), thereby effectively allowing use of a single fuel for RCCI engine operation.

A fuel injector, comprising a nozzle body having a proximal end and a distal end, an upper row of nozzle holes being equally spaced about a first circumference of the nozzle body, and a lower row of nozzle holes located between the distal end and the upper row of nozzle holes, wherein the upper row has a first number of holes that is greater than a second number of holes in the lower row and wherein one of the first number of holes and the second number of holes is odd.