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• Stratified_charge_engine abstract "In a stratified charge engine, the fuel is injected into the cylinder just before ignition. This allows for higher compression ratios without "knock," and leaner air/fuel mixtures than in conventional internal combustion engines.Conventionally, a four-stroke (petrol or gasoline) Otto cycle engine is fuelled by drawing a mixture of air and fuel into the combustion chamber during the intake stroke. This produces a homogeneous charge: a homogeneous mixture of air and fuel, which is ignited by a spark plug at a predetermined moment near the top of the compression stroke.In a homogeneous charge system, the air/fuel ratio is kept very close to stoichiometric. A stoichiometric mixture contains the exact amount of air necessary for a complete combustion of the fuel. This gives stable combustion, but places an upper limit on the engine's efficiency: any attempt to improve fuel economy by running a lean mixture with a homogeneous charge results in unstable combustion; this impacts on power and emissions, notably of nitrogen oxides or NOx.If the Otto cycle is abandoned, however, and fuel is injected directly into the combustion-chamber during the compression stroke, the petrol engine is liberated from a number of its limitations.First, a higher mechanical compression ratio (or, with supercharged engines, maximum combustion pressure) may be used for better thermodynamic efficiency. Since fuel is not present in the combustion chamber until virtually the point at which combustion is required to begin, there is no risk of pre-ignition or engine knock.The engine may also run on a much leaner overall air/fuel ratio, using stratified charge.Combustion can be problematic if a lean mixture is present at the spark-plug. However, fueling a petrol engine directly allows more fuel to be directed towards the spark-plug than elsewhere in the combustion-chamber. This results in a stratified charge: one in which the air/fuel ratio is not homogeneous throughout the combustion-chamber, but varies in a controlled (and potentially quite complex) way across the volume of the cylinder.A relatively rich air/fuel mixture is directed to the spark-plug using multi-hole injectors. This mixture is sparked, giving a strong, even and predictable flame-front. This in turn results in a high-quality combustion of the much weaker mixture elsewhere in the cylinder.Direct fuelling of petrol engines is rapidly becoming the norm, as it offers considerable advantages over port-fuelling (in which the fuel injectors are placed in the intake ports, giving homogeneous charge), with the only drawbacks being increase injector cost and complexity, higher fuel pressure requirements, carbon build up on the back of the intake valve[citation needed] due to the lack of gasoline passing by the intake valve to act as a cleaning agent for the valve on traditional multiport injection designs. Powerful electronic management systems mean that there is no significant cost penalty.With the further impetus of tightening emissions legislation, the motor industry in Europe and North America has now switched completely to direct fuelling for the new petrol engines it is introducing.It is worth comparing contemporary directly-fuelled petrol engines with direct-injection diesels. Petrol can burn faster than diesel fuel, allowing higher maximum engine speeds and thus greater maximum power for sporting engines. Diesel fuel, on the other hand, has a higher energy density, and in combination with higher combustion pressures can deliver very strong torque and high thermodynamic efficiency for more 'normal' road vehicles.".
• Stratified_charge_engine wikiPageID "158755".
• Stratified_charge_engine wikiPageRevisionID "606064244".
• Stratified_charge_engine hasPhotoCollection Stratified_charge_engine.
• Stratified_charge_engine subject Category:Internal_combustion_piston_engines.
• Stratified_charge_engine type Artifact100021939.
• Stratified_charge_engine type Device103183080.
• Stratified_charge_engine type Engine103287733.
• Stratified_charge_engine type Instrumentality103575240.
• Stratified_charge_engine type InternalCombustionPistonEngines.
• Stratified_charge_engine type Machine103699975.
• Stratified_charge_engine type Motor103789946.
• Stratified_charge_engine type Object100002684.
• Stratified_charge_engine type PhysicalEntity100001930.
• Stratified_charge_engine type Whole100003553.
• Stratified_charge_engine comment "In a stratified charge engine, the fuel is injected into the cylinder just before ignition. This allows for higher compression ratios without "knock," and leaner air/fuel mixtures than in conventional internal combustion engines.Conventionally, a four-stroke (petrol or gasoline) Otto cycle engine is fuelled by drawing a mixture of air and fuel into the combustion chamber during the intake stroke.".
• Stratified_charge_engine label "Charge stratifiée".
• Stratified_charge_engine label "Fuel Stratified Injection".
• Stratified_charge_engine label "Fuel Stratified Injection".
• Stratified_charge_engine label "Stratified charge engine".
• Stratified_charge_engine sameAs Charge_stratifiée.
• Stratified_charge_engine sameAs Fuel_Stratified_Injection.
• Stratified_charge_engine sameAs Fuel_Stratified_Injection.
• Stratified_charge_engine sameAs m.014yp_.
• Stratified_charge_engine sameAs Q2325048.
• Stratified_charge_engine sameAs Q2325048.
• Stratified_charge_engine sameAs Stratified_charge_engine.
• Stratified_charge_engine wasDerivedFrom Stratified_charge_engine?oldid=606064244.
• Stratified_charge_engine isPrimaryTopicOf Stratified_charge_engine.