An efficient engine combustion system with multiple combustion modes, includes a valve actuating mechanism, a pre-combustion chamber, and a main combustion chamber. The valve actuating mechanism is a fully variable valve mechanism; an intake valve and an exhaust valve are driven by high-pressure oil; ignition is implemented by means of an ignition apparatus of the pre-combustion chamber; and a spark plug and a single-hole fuel injector are mounted in the pre-combustion chamber, a bottom end of which is provided with a flame jet hole. The continuous variable of valve timing and real-time adjustment of valve lift are realized by the control of a three-position four-way servo valve, driven by the high-pressure oil and monitored by a displacement sensor. The efficient engine combustion system with multiple combustion modes employs different combustion modes under different engine conditions, so as to ensure optimal thermal efficiency under different operating condition regions.

The present invention provides a method for avoiding knocking in an internal combustions engine, preferably in a gasoline engine with a high compression ratio and a variable valve train which is able to perform EIVC, by injecting a non-combustible fluid into the intake port and/or in the cylinder during a transient operating mode.

When an operation state switches from a first operation region A to a second operation region B, the valve timing of an intake valve and an exhaust valve is switched upon switching of the operation state from the first operation region A to the second operation region B. When the operation state switches from the first operation region A to the second operation region B, the air-fuel ratio is switched after a first predetermined time T1 has elapsed since when the actual valve timing of the intake valve became a second intake valve timing and the actual valve timing of the exhaust valve became a second exhaust valve timing. In this way, it becomes possible to ensure ignition when the operation state switches.

The present invention provides a method for avoiding knocking in an internal combustions engine, preferably in a gasoline engine with a high compression ratio and a variable valve train which is able to perform EIVC, by injecting a non-combustible fluid into the intake port and/or in the cylinder during a transient operating mode.

When an operation state switches from a first operation region A to a second operation region B, the valve timing of an intake valve and an exhaust valve is switched upon switching of the operation state from the first operation region A to the second operation region B. When the operation state switches from the first operation region A to the second operation region B, the air-fuel ratio is switched after a first predetermined time T1 has elapsed since when the actual valve timing of the intake valve became a second intake valve timing and the actual valve timing of the exhaust valve became a second exhaust valve timing. In this way, it becomes possible to ensure ignition when the operation state switches.

Various embodiments may include a method for controlling the residual gas mass remaining in a cylinder of an internal combustion engine after a gas exchange process and/or the purge air mass introduced into an exhaust manifold during a gas exchange process, the method comprising: specifying at least one of a desired residual gas mass or a purge air mass of the cylinder of the internal combustion engine; determining a setpoint position of an actuator which influences the specified mass, based on an inverse residual gas model; and setting the determined setpoint position of the actuator.

Methods, devices, controllers, and algorithms are described for operating an internal combustion engine wherein at least some firing opportunities utilize low temperature gasoline combustion (LTGC). Other firing opportunities may be skipped or utilize some other type of combustion, such as spark ignition. The nature of any particular firing opportunity is dynamically determined during engine operation, often on a firing opportunity by firing opportunity basis. Firings that utilize LTGC produce little, if any, nitrous oxides in the exhaust stream and thus, in some implementations, may require no aftertreatment system to remove them from the exhaust stream.

When the geometric compression ratio of an engine body is set to 13:1 or more and the engine body operates in a preset high load region, the effective compression ratio of the engine body is set to 12:1 or more with a difference from the geometric compression ratio being within 2, a gas to be introduced into a combustion chamber is supercharged by a supercharging system, fuel is injected at least in a compression stroke by an injector, and after the fuel injection is finished, an air-fuel mixture in the combustion chamber is ignited by an ignition device before the compression top dead center and is thus burned by flame propagation in the engine body, and then the unburned air-fuel mixture is burned by compression ignition.

An engine control device is provided, which includes an engine body where a cylinder is formed, an exhaust passage through which exhaust gas discharged from the engine body circulates, a NO.sub.x sensor disposed in the exhaust passage and configured to detect a concentration of NO.sub.x in the exhaust gas, an injector configured to change an air-fuel ratio inside the cylinder, an in-cylinder temperature changer configured to change a temperature inside the cylinder, and a controller configured to control the injector and the exhaust shutter valve. The controller controls the injector based on a detection value of the NO.sub.x sensor to variably set the air-fuel ratio inside the cylinder, and when a particular condition that the air-fuel ratio inside the cylinder is leaner than a preset upper limit is satisfied, and causes the in-cylinder temperature changer to raise the temperature inside the cylinder.

The present invention relates to a method for controlling lubrication of a connecting rod bearing of an internal combustion engine arrangement. The method comprises the steps of controlling an inlet valve to be maintained in the closed position during a movement of the reciprocating piston from the top dead center during an intake stroke for a predetermined number of crank angle degrees; and positioning the inlet valve in the open position when the reciprocating piston has traveled the predetermined number of crank angle degrees from the top dead center, wherein lubricating medium is provided to the connecting rod bearing within a predetermined time period before the inlet valve is arranged in the open position.