A method of implementing control logic of a compression-ignition engine is provided. A control part of the engine performs a calculation according to the control logic corresponding to an engine operating state in response to a measurement of a measurement part, controls a fuel injection part, a variable valve operating mechanism, an ignition part and a supercharger so that a G/F becomes leaner than a stoichiometric air fuel ratio and a A/F becomes equal to or richer than the stoichiometric air fuel ratio, while causing the supercharger to boost, and controls the ignition part so that unburnt mixture gas combusts by self-ignition after the ignition. The method includes determining a supercharging pressure P, and determining control logic defining a close timing IVC of an intake valve. When determining the control logic, the close timing IVC (deg.aBDC) is determined so that the supercharging pressure P (kPa) satisfies the following expression: P8.010.sup.11IVC.sup.61.010.sup.8IVC.sup.5+3.010.sup.7IVC.sup.44.010.sup.6IVC.sup.3+0.0068IVC.sup.20.3209IVC+116.63.

A control system of a compression-ignition engine which performs SPCCI combustion in which mixture gas is ignited with a spark plug to be partially combusted by SI combustion and the rest of mixture gas self-ignites to be combusted by CI combustion, is provided. When the engine is operated at least in a given first operating range, a controller of the device controls a variable intake mechanism so that an A/F lean environment where an air-fuel ratio in a cylinder becomes higher than a stoichiometric air-fuel ratio is formed, while causing the spark plug to perform spark ignition at a given timing so that the mixture gas combusts by SPCCI combustion, and controls so that, under the same engine load condition, an intake valve close timing is more retarded as the engine speed decreases, within a range where an amount of air inside the cylinder decreases by retarding the close timing.

A compression-ignition engine control system is provided, which includes an intake phase-variable mechanism and a controller. Within a first operating range and a second operating range on a higher engine load side, the controller controls the variable mechanism to form a gas-fuel ratio (G/F) lean environment in which an air-fuel ratio inside a cylinder is near a stoichiometric air-fuel ratio and burnt gas remains inside the cylinder, and controls a spark plug to spark-ignite mixture gas inside the cylinder to combust in a partial compression-ignition combustion. The controller controls the variable mechanism to retard the intake valve open timing on an advancing side of TDC of an exhaust stroke, as the engine load increases within the first range, and advance the intake valve close timing on a retarding side of TDC of intake stroke, as the engine load increases within the second range.

A control system for internal combustion engines having four valves per cylinder. An inlet valve and an exhaust valve are controlled by a basic camshaft. Another inlet valve and another exhaust valve are controlled by a control camshaft. The two camshafts are connected to a crankshaft and engine torque is managed by an electronic control unit. The system comprises a motor/generator unit, connected to the control camshaft; a differential, connected to the crankshaft and to the control camshaft; a control shaft, connected to the differential; an actuator, connected to the control shaft; a one-way restrictor valve connected to a shut-off valve and to the actuator; an oil circuit, connected to the actuator by means of the shut-off valve and a control solenoid that acts on the shut-off valve.

A method for controlling a valve arrangement for an internal combustion engine, the valve arrangement including a piston arrangement comprising a piston having a piston end portion facing an inlet valve of the valve arrangement. The method includes receiving a signal indicative of a temperature level of an exhaust gas after treatment system and when the signal indicates a temperature level below a predetermined threshold level: advancing an exhaust event of the internal combustion engine; and controlling the piston arrangement for reducing the distance between the piston end portion and the inlet valve before the internal combustion engine assumes an air intake event.

Embodiments described herein relate to systems and methods of operating internal combustion (IC) engines by combusting various fuel chemistries therein. Specifically, engines described herein can operate a wide range of fuel chemistries with varying molecular formulas. The chemical compositions of the fuels described herein make them more difficult to ignite than long chain hydrocarbons (i.e., fuels that include 6 or more carbon atoms in a molecule). In some embodiments, engines described herein can combust fuels that have the chemical properties of alcohols. In some embodiments, engines described herein can combust fuels that include hydroxide groups. Examples of such fuels include methanol and/or ethanol. In some embodiments, engines described herein can combust natural gas. These fuel chemistries are difficult to ignite, particularly at low temperatures and during initial engine startup. Systems and methods described herein address these ignition difficulties, particularly in diesel engine architectures.

A spool is configured to reciprocate at an inside space of a sleeve and includes: a spool tube; a spool cover, which closes an end portion of the spool tube located on a camshaft side; a pressure accumulation space, which is formed at an inside of the spool tube; a supply passage, which is configured to connect between the pressure accumulation space and a supply port; a control passage, which is configured to connect between the pressure accumulation space and a primary control port; and a control passage, which is configured to connect between the pressure accumulation space and a secondary control port. A variable volume space is formed between the spool cover and a sleeve bottom. The sleeve includes a breathing hole at an outside of the inside space while the breathing hole is a hole that communicates between the variable volume space and the atmosphere.

A retard supply passage connects between a hydraulic oil supply source and a retard chamber through a hydraulic oil controller. An advance supply passage connects between the hydraulic oil supply source and an advance chamber through the hydraulic oil controller. A drain passage and a drain passage connect the retard chamber and the advance chamber to an oil discharge portion, respectively. A recycle passage connects the drain passage and the drain passage to the retard supply passage and the advance supply passage, respectively. A recycle check valve enables only a flow of hydraulic oil from the drain passages toward the retard supply passage and the advance supply passage in the recycle passage. The recycle passage is connected to the drain passages at an inside of the hydraulic oil controller.

The present invention relates to a method for controlling a compression-ignition internal combustion engine, having at least one combustion chamber, wherein intake of air to said combustion chamber is controlled using an intake valve, and evacuation of said combustion chamber is controlled using an exhaust valve. The method comprises: controlling opening of said intake valve and closing of said exhaust valve in dependence of the position of a reciprocating member in said combustion chamber, wherein opening of said intake valve and closing of said exhaust valve, respectively, in relation to the position of said reciprocating member is individually controllable, and controlling opening and closing in relation to the position of said reciprocating member on the basis of a first control parameter, wherein said opening and closing of said intake valve and exhaust valve, respectively, are controlled such that an actual value of said control parameter is adjusted towards a desired value.

The present invention relates to method for controlling a compression-ignition internal combustion engine, said internal combustion engine having at least one combustion chamber, wherein intake of air to said combustion chamber is controlled using an intake valve, and wherein evacuation of said combustion chamber is controlled using an exhaust valve. The method includes: controlling opening of said intake valve and closing of said exhaust valve in dependence of the position of a reciprocating member in said combustion chamber, wherein opening of said intake valve and closing of said exhaust valve, respectively, in relation to the position of said reciprocating member is individually controllable, and wherein, in one mode of operation, opening of said intake valve and closing of said exhaust valve, respectively, are controlled such that both valves are simultaneously open during a period of variable length.