Benzininis variklis
Benzininis variklis (benzininis variklis) yra variklis, kuris kaip kurą naudoja benziną. Kadangi benzinas yra mažo klampumo ir greitai išgaruoja, benzino įpurškimui į cilindrą galima naudoti benzino įpurškimo sistemą. Kai suspaudimas pasiekia tam tikrą temperatūrą ir slėgį, jis uždegamas uždegimo žvake, kad dujos išsiplėstų ir veiktų. Benzininiams varikliams būdingas didelis greitis, paprasta konstrukcija, lengvas svoris, maža kaina, stabilus veikimas, patogus naudojimas ir priežiūra. Benzininiai varikliai buvo plačiai naudojami automobiliuose, ypač mažuose automobiliuose, ir jų nemažėjo.
Pagal skirtingus degalų tiekimo būdus benzininius variklius galima suskirstyti į dvi kategorijas: karbiuratoriaus tipą ir įpurškimo tipą (arba elektroninio įpurškimo tipą). Karbiuratoriai dažniausiai naudojami senesnių modelių varikliuose, o dauguma variklių dabar naudoja reaktyvinio kuro tiekimą. Įpurškimo benzininiame variklyje benzinas gali būti įpurškiamas per įsiurbimo angą arba tiesiai į cilindrą įsiurbimo takto metu; kuro įpurškimo procesas gali būti valdomas kompiuterine programa, o kuras tolygiau paskirstomas kiekvienam cilindrui; tuo pačiu, nes nėra poreikio Gerklės vamzdis sumažina gamyklinio oro įsiurbimo angos pasipriešinimą ir pan., o tai gali padidinti vidutinį efektyvų slėgį ir šiluminį efektyvumą cilindre; be to, jis taip pat gali susilpninti degimą arba jo išvengti.
Palyginti su dyzeliniais varikliais, benzininių variklių šiluminis efektyvumas yra mažesnis nei dyzelinių, o degalų sąnaudos yra didesnės. Uždegimo sistema yra sudėtingesnė nei dyzelinių variklių, o patikimumas ir priežiūros patogumas nėra toks geras kaip dyzelinių variklių.
Automobilių varikliai (su stūmokliniais vidaus degimo varikliais) skirstomi į šias kategorijas pagal skirtingas charakteristikas:
● Classified by piston movement mode: Piston type internal combustion engines can be divided into reciprocating piston type and rotary piston type. The former piston makes a reciprocating linear movement in the cylinder, and the latter piston makes a rotary movement in the cylinder. (The latter applies to rotary engines)
● According to the classification of the intake system: internal combustion engines can be divided into naturally aspirated (non-supercharged) engines and forced intake (supercharged) engines according to whether the intake system adopts supercharging. If the intake is close to the atmosphere, it is a non-supercharged internal combustion engine or a naturally aspirated internal combustion engine; if the intake pressure is increased by a supercharger, and the intake density increases, it is a supercharged internal combustion engine. Supercharging can increase the power of the internal combustion engine.
● Classification according to cylinder arrangement: internal combustion engines can be divided into single row, double row and three row according to different cylinder arrangements. Each cylinder of a single-row engine is arranged in a row, which is generally arranged vertically. However, in order to reduce the height, the cylinders are sometimes arranged to be inclined or even horizontal. A dual-row engine arranges cylinders into two rows. The angle between the two rows is less than 180 degree (generally 90 degree ), which is called a V-type engine. If the angle between the two rows is 180 degree , it is called an opposed engine. The three-row type arranges the cylinders into three rows to become a W-type engine.
● Classification according to the number of cylinders: Internal combustion engines can be divided into single-cylinder engines and multi-cylinder engines according to the number of cylinders. An engine with only one cylinder is called a single-cylinder engine; an engine with more than two cylinders is called a multi-cylinder engine. For example, two-cylinder, three-cylinder, four-cylinder, five-cylinder, six-cylinder, eight-cylinder, twelve-cylinder, sixteen-cylinder, etc. are all multi-cylinder engines. Modern vehicle engines mostly use three-cylinder, four-cylinder, six-cylinder, and eight-cylinder engines.
● Classification by cooling method: Internal combustion engines can be divided into water-cooled engines and air-cooled engines according to different cooling methods. The water-cooled engine uses the coolant circulating in the cylinder block and cylinder head cooling water jacket as the cooling medium for cooling; while the air-cooled engine uses the air flowing between the cylinder block and the fins on the outer surface of the cylinder head as the cooling medium Cooled. The water-cooled engine has uniform cooling, reliable operation and good cooling effect, and is widely used in modern vehicle engines.
● Classification according to stroke: Internal combustion engines can be divided into four-stroke internal combustion engines and two-stroke internal combustion engines according to the number of strokes required to complete a working cycle. Turn the crankshaft two revolutions (720 degree ) and the piston reciprocates up and down in the cylinder for four strokes. The internal combustion engine that completes a working cycle is called a four-stroke internal combustion engine; while the crankshaft rotates one revolution (360 degree ), the piston reciprocates up and down in the cylinder An internal combustion engine that moves two strokes and completes a working cycle is called a two-stroke internal combustion engine. Four-stroke internal combustion engines are widely used in automobile engines.
● Classified by valve mechanism: side valve (SV) engine, side camshaft (OHV) engine, overhead camshaft (OHC) engine, variable gas (VTEC) engine and Desmo valve mechanism engine.
● Classified by fuel supply mode: carburetor engine, electronic injection engine, direct injection engine.
● Classification according to the fuel used: Internal combustion engines can be divided into gasoline engines and diesel engines according to the different fuels used. An internal combustion engine that uses gasoline as fuel is called a gasoline engine; an internal combustion engine that uses diesel as a fuel is called a diesel engine. Compared with diesel engines, gasoline engines have their own characteristics; gasoline engines have high speed, low quality, low noise, easy starting, and low manufacturing costs; diesel engines have large compression ratios, high thermal efficiency, economic performance and emission performance than gasoline engines. At present, it is the most widely used and the most numerous The engine is a water-cooled, four-stroke reciprocating piston internal combustion engine. Gasoline engines are used in cars, light buses and trucks, while the engines of buses, medium and heavy trucks are mostly diesel engines. A few cars and light passenger and truck engines also use diesel engines.
Dyzeliniai varikliai
Dyzelinis variklis yra variklis, kuris degina dyzeliną, kad gautų energiją ir ją išleistų. Jį 1892 m. išrado vokiečių išradėjas Rudolfas Dieselis. Šio išradėjo atminimui dyzelinas vaizduojamas jo pavarde Dyzelis, o dyzeliniai varikliai dar vadinami Dyzeliniais varikliais.
Dyzelinių variklių privalumai – didelė galia ir geri ekonominiai rodikliai. Dyzelinio variklio darbo procesas yra beveik toks pat kaip ir benzininio. Kiekvienas darbo ciklas taip pat patiria keturis taktus: įsiurbimo, suspaudimo, darbo ir išmetimo. Tačiau kadangi dyzeliniuose varikliuose naudojami dyzeliniai degalai, jų klampumas didesnis nei benzino, be to, nėra lengva išgaruoti, o savaiminio užsidegimo temperatūra žemesnė nei benzino. Todėl degiojo mišinio susidarymas ir užsidegimas skiriasi nuo benzininių variklių. Pagrindinis skirtumas yra tas, kad dyzelinio variklio cilindre esantis mišinys yra uždegamas suspaudimu-, o ne uždegamas. Kai dirba dyzelinis variklis, oras patenka į cilindrą. Kai oras cilindre suspaustas iki galo, temperatūra gali siekti 500-700 laipsnių, o slėgis – 40-50 atmosferų. Kai stūmoklis yra arti viršutinio negyvojo taško, variklio aukšto -slėgio siurblys aukštu slėgiu įpurškia dyzeliną į cilindrą. Dyzelinas sudaro smulkias alyvos daleles, kurios susimaišo su aukšto slėgio ir aukštos temperatūros oru. Šiuo metu temperatūra gali siekti 1900-2000 laipsnių, slėgis gali siekti 60-100 atmosferų, o generuojama galia yra labai didelė, todėl dyzeliniai varikliai plačiai naudojami didelėse dyzelinėse transporto priemonėse.
The advantages of diesel engines in terms of energy saving and carbon dioxide emissions cannot be replaced by all heat engines, including gasoline engines. Therefore, advanced small high-speed diesel engines, whose emissions have reached the European III standard, have become "green engines." , Has now become the power plant of many new cars in Europe and America.