37results about How to "Effective compression ratio" patented technology

A supercharged engine has a geometric compression ratio ser to 16 or more and is designed to perform a compression self-ignition combustion under an air-fuel ratio leaner than a stoichiometric air-fuel ratio at least in a low engine speed range. On a lower engine load side than a given engine load within an engine operating region at which the compression self-ignition combustion is performed, a fresh air amount is reduced and an effective compression ratio (ε′) is increased, as compared with a higher engine load side than the given engine load within the engine operating region, and, on the higher engine load side than the given engine load, a supercharging pressure based on a supercharger (25) is increased to increase the fresh air amount, and the effective compression ratio (ε′) is reduced, as compared with the lower engine load side than the given engine load. This makes it possible to perform the compression self-ignition combustion under a lean air-fuel ratio in a wider engine load range to effectively enhance engine thermal efficiency, while eliminating a need for an operation of forcedly raising/lowering a temperature of fresh air.

A pre-ignition estimation/control device includes: an octane number estimation module for estimating an octane number of a fuel based on detection signals received from an intake air temperature sensor, a water temperature sensor, etc; a pre-ignition-occurrence-index calculation module for calculating a pre-ignition occurrence index based on the estimated octane number and the like; a pre-ignition-occurrence-index correction module for correcting the pre-ignition occurrence index so as to cause the pre-ignition more likely to occur; an effective-compression-ratio-boundary calculation module for calculating a boundary of an effective compression ratio based on the pre-ignition occurrence index; an intake-cam-phase-advance calculation module for calculating a phase advance of an intake cam based on the boundary of the effective compression ratio and the like; and an intake-cam-phase control module for controlling an intake-cam variable phasing system based on the phase advance of the intake cam, to thereby restrict a change in phase advance.

Methods and systems are provided for optimizing the operation of a multi-cylinder auto-ignition internal combustion engine. By configuring the cylinders in multiple groups based on compression ratios, and operating the cylinders in a load-dependent manner, fuel consumption may be optimized.

An engine control apparatus is provided with an engine, an ignition device, a valve timing changing mechanism, an intake valve close timing detecting device, a supercharger and a controller. The engine achieves a Miller cycle by the valve timing changing mechanism setting an intake valve close timing to occur after a bottom dead center timing. The controller controls an ignition timing of the ignition device, the open timing of the intake valve and the close timing of the intake valve. The controller retards the ignition timing during supercharging and when a detected value of the intake valve close timing is earlier than a target value of the intake valve close timing by at least a prescribed value in comparison with a situation in which the detected value matches the target value of the intake valve close timing.

A variable compression ratio piston (26) and connecting rod (18) assembly for an internal combustion engine (14) includes an eccentric bushing (28) that carries a piston pin bushing (42) and contains a journaled portion (48) held in the rod bore (24) of the connecting rod (18). The eccentric bushing (28) can be selectively rotated between either of two angle adjusted positions to effect a change in the height of the piston (26) relative to the connecting rod (18), and thus change the compression ratio of the assembly. A latch (50) mechanism is actuated by oil jets (90, 91) external to the connecting rod (18). The latch (50) includes bolts (54, 56) with tapered tips that seat in oblong holes (60, 62) in a flange plate (58) to reduce destructive lash. A resilient stop post (80) bears the brunt of stresses associated with stopping the flange plate (58) during switching events to protect the latching bolts (54, 56).

An internal combustion engine variable compression ratio system is provided that includes a piston inner (5a), a piston outer (5b) that is fitted around the outer periphery of the piston inner (5a) so that it can slide only in the axial direction and is capable of moving between a low compression ratio position (L) and a high compression ratio position (H), a raising member (14) that can pivot around axes of the piston inner and outer (5a, 5b) between a non-raised position (A) and a raised position (B), and an actuator (20) connected to the member (14) and pivoting it to the non-raised position (A) or the raised position (B), in which piston outer high compression ratio position latching means (30b) is disposed between the piston inner (5a) and the piston outer (5b) and operates, when the piston outer (5b) has reached the high compression ratio position (H), so as to prevent relative axial movement of the piston inner (5a) and the piston outer (5b). It is thereby possible to provide a variable compression ratio system that enables the piston outer to be moved to the low compression ratio position and the high compression ratio position simply and reliably without rotating the piston outer.

An arrangement and a method for controlling a combustion engine, e.g. of the type called HCCI engine. A control unit is operable for controlling the self-ignition of the fuel mixture towards an optimum crankshaft angle (cad_iopt) within a load range (L_tot). The load range (L_tot) can be divided into at least two subranges (L_II, L_III). The control unit is operable to controlling the self-ignition of the fuel mixture towards an optimum crankshaft angle (cad_iopt) within one of the subranges (L_II) by a strategy (II) which entails the effective compression ratio (c) in the cylinder being varied, and within the second subrange (L_III) by another strategy (III) which entails a variable amount of cooled exhaust gases (ceg) being led to the combustion chamber also enabling in the second subrange (L_III) to control the self-ignition of the fuel mixture towards an optimum crankshaft angle (cad_iopt) by variation of the effective compression ratio (c) in the cylinder without it falling below a lowest acceptable value {circle around (c)}_min).

A method for operating an internal combustion engine includes a fuel supply device for at least one first and one second fuel, wherein the internal combustion engine has at least one cylinder which includes at least one intake valve and into which air, in particular fresh air, can be supplied via an intake pipe. In a first operating mode of the internal combustion engine, the first fuel is introduced only into the intake pipe, and in a second operating mode, the second fuel is exclusively introduced directly into the cylinder, and in the second operating mode an intake valve opening time period is adjusted to be shorter than in the first operating mode.

A method for differential compression of a sequence of digital values adapted to avoid error propagation during restoration of the values.