Spark-ignition engine

About: Spark-ignition engine is a research topic. Over the lifetime, 4352 publications have been published within this topic receiving 66550 citations.

Direct fuel injection and ignition system for internal combustion engines

Abstract: A direct injection fuel system for internal combustion engines is disclosed, which relies on a novel device for preparing, injecting and igniting a stratified air-fuel charge inside the cylinder of an internal combustion engine. A single, preferably electrically triggerable, injection and ignition device prepares, supplies and ignites the stratified air-fuel charge. The device of the invention favorably uses the variable pressure existing inside the cylinder, during the compression stroke, to control fuel flow and fuel jet penetration. The injection and ignition device of the invention divides the total amount of fuel injected per cycle into a main fuel dose and a pilot fuel dose. The main fuel dose is injected into the combustion chamber through a set of main injection ports, forming a lean mixture therein. The pilot fuel dose is a small fraction of the total fuel dose and it is injected, through a set of pilot injection ports, in the proximity of the ignition source of the device. One preferred embodiment of the device of the invention has a combustion shell, which physically defines a predetermined volume inside the combustion chamber. The combustion shell surrounds both the pilot ports and an ignition source. The combustion shell has a plurality of torch nozzles cut through its walls. Thus, a stratified charge is formed in the cylinder, with a rich mixture kernel being created in the vicinity of the injection and ignition device, and a lean mixture field being created in the remaining volume of the combustion chamber. When a high voltage is applied to one of the two electrodes of the injection and ignition device, at least one electric spark is created between two electrodes. In the preferred embodiment, the electrodes are designed to create a plurality of sparks, in a circular pattern surrounding the central injection valve. The spark or sparks easily ignite the rich mixture kernel. As the fuel burns inside the combustion shell, the pressure therein will rise and the combustion flames will be ejected through torch nozzles into the combustion chamber. Other embodiments do not use a combustion shell, but rely solely on the kinetic energy of the flames to initiate and propagate combustion through the lean mixture field. Thus torch ignition of the lean mixture field occurs, permitting the engine to run efficiently on an overall leaner mixture than a homogenous charge spark ignition engine.

Characterisation of Flow Structures in a Direct-Injection Spark-Ignition Engine Using PIV, LDV and CFD

Abstract: In-cylinder air flow structures are known to play a major role in mixture preparation and engine operating limits for DISI engines. In this paper PIV was undertaken on in-cylinder flow fields for three different planes of measurement in the intake and compression strokes of a DISI engine for a lowload engine operating condition at 1500 RPM, 0.5 bar inlet plenum pressure (World Wide Mapping Point). One of these planes was vertical, cutting through the centrally located spark plug (tumble plane); the other two planes were horizontal, one close to TDC (10 mm below fire face) and the other one close to mid stroke (50 mm below fire face). Statistical analysis was undertaken on the numbers of cycles needed to determine ensemble average flow-field and turbulent kinetic energy maps with up to 1200 cycles considered. The effect of engine head temperature was also examined by obtaining flow fields using PIV with the engine head coolant held at 20 °C and 80 °C. LDV measurements were also performed and compared to the data obtained by PIV. Finally comparisons were made between the experimental data and results from CFD simulations using two different turbulence models on a grid of 1 million cells.