| rdfs:comment
| - Un siège de soupape de moteur à combustion interne est la pièce sur laquelle les soupapes d'admission ou d'échappement viennent en contact afin de fermer la chambre de combustion. Les sièges de soupapes sont des pièces critiques des moteurs thermiques. En effet, si elles sont mal positionnées, orientées ou mal usinées, des fuites au niveau des soupapes se produiront et réduiront la pression dans le cylindre, et donc son rendement, sa puissance, son niveau d'émissions polluantes ainsi que sa durée de vie. (fr)
- 내연 가솔린 또는 디젤 기관의 밸브 시트는 밸브가 폐쇄 될 때 흡입 또는 배기 밸브가 엔진 작동 주기의 부분에서 놓이는 표면이다. 저렴한 엔진은 단순히 실린더 헤드 또는 엔진 블럭 (엔진의 디자인에 따라)의 재료로 절단되어 밸브 시트를 가질 수있다. 밸브 시트의 위치가 잘못되거나 또는 가공 할 수 있는 몇 가지 방법이 있다. 삽입된 가공 밸브 시트의 자동화 된 품질 관리는 전통적으로 이러한 편차가 나열된 모든 측정되는 을 활성화 한 의 출현까지 달성하는 것은 매우 어려웠다. (ko)
- The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (engine power and ), exhaust emissions, and engine life. (en)
- De klepzetel of klepzitting vormt het oppervlak waarop de klep van een verbrandingsmotor rust als ze gesloten is. De klepzetel heeft drie taken: 1. Samen met de klep afsluiten van de in- en uitlaatkanalen. 2. Het geleiden van de in- of uitstromende gassen. 3. Het overdragen van de warmte van de klep aan de cilinderkop. Tegenwoordig zijn klepzetels gemaakt van een geharde metaallegering, zoals . Dat kan hoge temperaturen verdragen, noodzakelijk omdat sinds de jaren tachtig het koelende effect van lood in de benzine ontbreekt. (nl)
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| has abstract
| - Un siège de soupape de moteur à combustion interne est la pièce sur laquelle les soupapes d'admission ou d'échappement viennent en contact afin de fermer la chambre de combustion. Les sièges de soupapes sont des pièces critiques des moteurs thermiques. En effet, si elles sont mal positionnées, orientées ou mal usinées, des fuites au niveau des soupapes se produiront et réduiront la pression dans le cylindre, et donc son rendement, sa puissance, son niveau d'émissions polluantes ainsi que sa durée de vie. (fr)
- The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (engine power and ), exhaust emissions, and engine life. Valve seats are often formed by first press-fitting an approximately cylindrical piece of a hardened metal alloy, such as Stellite, into a cast depression in a cylinder head above each eventual valve stem position, and then machining a conical-section surface into the valve seat that will mate with a corresponding conical section of the corresponding valve. Generally two conical-section surfaces, one with a wider cone angle and one with a narrower cone-angle, are machined above and below the actual mating surface, to form the mating surface to the proper width (called "narrowing" the seat), and to enable it to be properly located with respect to the (wider) mating surface of the valve, so as to provide good sealing and heat transfer, when the valve is closed, and to provide good gas-flow characteristics through the valve, when it is opened. Inexpensive engines may have valve seats that are simply cut into the material of the cylinder head or engine block (depending on the design of the engine). Some newer engines have seats that are sprayed on rather than being pressed into the head, allowing them to be thinner, creating more efficient transfer of heat through the valve seats, and enabling the valve stems to function at a lower temperature, thus allowing the valve stems (and other parts of the valvetrain) to be thinner and lighter. There are several ways in which a valve seat may be improperly positioned or machined. These include incomplete seating during the press-fitting step, distortion of the nominally circular valve seat surfaces such that they deviate unacceptably from perfect roundness or waviness, tilt of the machined surfaces relative to the valve guide hole axis, deviation of the valve seat surfaces from concentricity with the valve guide holes, and deviation of the machined conical section of the valve seat from the cone angle that is required to match the valve surface. Automated quality control of inserted and machined valve seats was historically very difficult to achieve until the advent of digital holography, which has enabled high-definition metrology for measuring all of these listed deviations. (en)
- 내연 가솔린 또는 디젤 기관의 밸브 시트는 밸브가 폐쇄 될 때 흡입 또는 배기 밸브가 엔진 작동 주기의 부분에서 놓이는 표면이다. 저렴한 엔진은 단순히 실린더 헤드 또는 엔진 블럭 (엔진의 디자인에 따라)의 재료로 절단되어 밸브 시트를 가질 수있다. 밸브 시트의 위치가 잘못되거나 또는 가공 할 수 있는 몇 가지 방법이 있다. 삽입된 가공 밸브 시트의 자동화 된 품질 관리는 전통적으로 이러한 편차가 나열된 모든 측정되는 을 활성화 한 의 출현까지 달성하는 것은 매우 어려웠다. (ko)
- De klepzetel of klepzitting vormt het oppervlak waarop de klep van een verbrandingsmotor rust als ze gesloten is. De klepzetel heeft drie taken: 1. Samen met de klep afsluiten van de in- en uitlaatkanalen. 2. Het geleiden van de in- of uitstromende gassen. 3. Het overdragen van de warmte van de klep aan de cilinderkop. De klepzetel is cirkelvormig en in de cilinderkop geperst. Het persen wordt vereenvoudigd door de cilinderkop te verwarmen en de klepzetel te koelen. Ze moet exact geproduceerd en gevormd zijn en conisch ingeslepen op de klep om lekkage te voorkomen. Als dat gebeurt gaat er compressie- of verbrandingsdruk verloren en werkt de motor niet meer efficiënt. In het algemeen worden verschillende conische vlakken boven en onder het werkelijke raakvlak van de klep gevormd om een zekere sluiting te verkrijgen, maar ook omdat de klepzetel invloed heeft op de gasstromen, bij de inlaatklep van het binnenstromende gas(mengsel) en bij de uitlaatklep van de uitstromende uitlaatgassen. Tegenwoordig zijn klepzetels gemaakt van een geharde metaallegering, zoals . Dat kan hoge temperaturen verdragen, noodzakelijk omdat sinds de jaren tachtig het koelende effect van lood in de benzine ontbreekt. Bij goedkope motoren kunnen de klepzetels eenvoudig uit de cilinderkop zijn gefreesd, bij moderne motoren wordt soms een harde laag in de cilinderkop gespoten. Dan vormt zich een zeer dunne klepzetel die een betere warmteafdracht aan de cilinderkop (en de daarin stromende koelvloeistof) kent waardoor de klepsteel dunner en lichter geconstrueerd kan worden. (nl)
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