Turbo Tech ( Basic ) - 수정중

[곰돌이]

터보 시스템은 어떤 일을 하는가?

엔진의 힘은 실린더 안으로 들어오는 연료와 공기의 양에 비례해 발생한다.

같은 이유로 큰 배기량의 엔진은 더 많은 공기를 요구하며, 그것은 큰 힘을 만들어낼 것이다.

만약 우리가 작은 배기량의 엔진에서 큰 엔진과 같은 힘을 내거나 혹은 큰 엔진보다 더 많은

힘을 내려면 결국 실린더 안으로 더 많은 공기를 집어넣으면 되는 것이다.

터보차져를 설치하는 것으로 엔진의 힘과 성능은 거짓말처럼 향상될 것이다.

터보차져가 어떡게 공기를 엔진으로 밀어넣는지 아래의 간단한 그림을 통해 알아보자.

1 컴프레서 입구 (흡기터빈을 컴프레서라 부름) 2 컴프레서 출구 3 인터쿨러 (압축된 공기를 냉각) 4 흡기밸브 5 배기밸브 6 터빈 입구 ( 배기터빈을 터빈이라 부름)  7 터빈 출구

터보차져를 구성하는 기본적인 작동원리와 순서:

• 공기 필터와 흡기 파이핑을 통해 (그림엔 안나옴) 컴프레서로 공기가 들어온다. (1)
• 공기는 압축되어 밀도가 상승하고 온도또한 상승한다. (2)
• 대다수의 터보엔진들은 인터쿨러를 가지고 있다. (3), 인터쿨러에서 차가워진 공기는 공기의 밀도를 증가시켜주고 노킹에 대한 저항성을 증가시켜준다 
• 흡기 매니폴드를 지나 실린더로 들어간다. (4), 공기의 밀도가 올라간 이후에 각각의 실린더는  많은 양의 공기를 빨아들인다. 많은 양의 공기 흡입은 더 많은 연료량을 요구한다. (물론 일정한 공연비는 유지하여야 한다.)  더 많은 양의 연료를 폭발시킨 결과로 엔진의 크기를 키운것과(=배기량이 늘어남) 같은 효과를 얻는다.
• 연료가 다 타버린 후의 실린더 내부는 배기 매니폴더로 배기가스를 배출시키는 배기 행정중일 것이다. (5)
• 고온의 배기가스는 터빈쪽으로 흐를 것이다. (6). 터빈은 엔진쪽으로 배기가스의 역압을 발생시켜 대기압보다 높은 배기가스의 압력을 만들어낸다.
• 터빈을 지나면서 배기가스의 압력과 온도가 떨어지는 상황이 발생한다. (7), 이 일련의 과정을 통해 배기가스는 컴프레서 휠을 구동시키는데에 필요한 에너지를 얻게된다.

터보차져의 구성물들은 무엇무엇이 있나?

터보차져 내부 생김새과 핵심 기능들을 간단히 요약해 논 그림이다.

 

우측 상단부터 간단히 설명해 보겠습니다.

 

 

터빈 하우징 - 엔진으로부터의 배기가스를 모아서 터빈 휠로 보내주는 역할.

 

터빈 휠 - 배기가스를 에너지로 변환하여 샤프트를 통해 컴프레서를 구동하는 역할.

 

센터 하우징 - 회전하는 것들을 지탱하는 역할.

 

오일 아웃렛 - 터보차져 베어링을 지나서 터보 밖으로 나오는 오일 출구.

 

컴프레서 하우징 - 압축된 공기를 모아 엔진으로 보내주는 역할.

 

컴프레서 휠 - 엔진으로 공기를 펌핑해 주는것.

 

백플레이트 - 컴프레서 하우징을 지탱하고 압축되지 않은 공기와 압축된 공기가 분리되는 표면

다른 장치들

블로우-오프 (바이패스) 밸브

블로우-오프 밸브는 터보 컴프레서가 서징하는 것을 막기 위해서 인테이크 라인 내부의 압력을

방출시켜 주는 장치입니다.

보통 BOV는 컴프레서 방출구와 스로틀 바디 사이에 장착하며 되도록이면 인터쿨러 출구 이후에

설치하는 것이 좋습니다. 왜냐면 액셀 페달에서 발을 떼었을때 빠르게 반응할수 있으며 공기흐름이

빨리 사라지고, 발생할수 있는 공기 유동의 불안정 상태 또는 압력 변화를 줄일수 있기 때문입니다.

BOV는 흡기 매니폴드의 압력과 스프링의 힘으로 스로틀 밸브가 닫히는걸 감지해 냅니다.

스로틀이 빠르게 닫히면 BOV는 개방되어 인테이크 파이핑 내부의 부스트를 방출하여 압력을 감소

시키며, 서징 현상을 없애는데 도움을 주게 됩니다.

Wastegates
On the exhaust side, a Wastegates provides us a means to control the boost pressure of the engine. Some commercial diesel applications do not use a Wastegates at all. This type of system is called a free-floating turbocharger.

However, the vast majority of gasoline performance applications require a Wastegates. There are two (2) configurations of Wastegates, internal or external. Both internal and external Wastegates provide a means to bypass exhaust flow from the turbine wheel. Bypassing this energy (e.g. exhaust flow) reduces the power driving the turbine wheel to match the power required for a given boost level. Similar to the BOV, the Wastegates uses boost pressure and spring force to regulate the flow bypassing the turbine.

Internal Wastegates are built into the turbine housing and consist of a “flapper” valve, crank arm, rod end, and pneumatic actuator. It is important to connect this actuator only to boost pressure; i.e. it is not designed to handle vacuum and as such should not be referenced to an intake manifold.

External Wastegates are added to the exhaust plumbing on the exhaust manifold or header. The advantage of external Wastegates is that the bypassed flow can be reintroduced into the exhaust stream further downstream of the turbine. This tends to
improve the turbine’s performance. On racing applications, this Wastegated exhaust flow can be vented directly to atmosphere.

Oil & Water Plumbing

The intake and exhaust plumbing often receives the focus leaving the oil and water plumbing neglected.

Garrett ball bearing turbochargers require less oil than journal bearing turbos. Therefore an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go “uphill” at any point.

Following a hot shutdown of a turbocharger, heat soak begins. This means that the heat in the head, exhaust manifold, and turbine housing finds it way to the turbo’s center housing, raising its temperature. These extreme temperatures in the center housing can result in oil coking.

To minimize the effects of heat soak-back, water-cooled center housings were introduced. These use coolant from the engine to act as a heat sink after engine shutdown, preventing the oil from coking. The water lines utilize a thermal siphon effect to reduce the peak heat soak-back temperature after key-off. The layout of the pipes should minimize peaks and troughs with the (cool) water inlet on the low side. To help this along, it is advantageous to tilt the turbocharger about 25° about the axis of shaft rotation.

Many Garrett turbos are water-cooled for enhanced durability.

Which Turbocharger is Right for Me or more affectionately known as My Turbo & Me
Selecting the proper turbocharger for your specific application requires many inputs. With decades of collective turbocharging experience, the Garrett Performance Distributors can assist in selecting the right turbocharger for your application.

The primary input in determining which turbocharger is appropriate is to have a target horsepower in mind. This should be as realistic as possible for the application. Remember that engine power is generally proportional to air and fuel flow. Thus, once you have a target power level identified, you begin to hone in on the turbocharger size, which is highly dependent on airflow requirements.

Other important factors include the type of application. An autocross car, for example, requires rapid boost response. A smaller turbocharger or smaller turbine housing would be most suitable for this application. While this will trade off ultimate power due to increased exhaust backpressure at higher engine speeds, boost response of the small turbo will be excellent.

Alternatively, on a car dedicated to track days, peak horsepower is a higher priority than low-end torque. Plus, engine speeds tend to be consistently higher. Here, a larger turbocharger or turbine housing will provide reduced backpressure but less-immediate low-end response. This is a welcome tradeoff given the intended operating conditions.

Selecting the turbocharger for your application goes beyond “how much boost” you want to run. Defining your target power level and the primary use for the application are the first steps in enabling your Garrett Performance Distributor to select the right turbocharger for you.

Journal Bearings vs. Ball Bearings
The journal bearing has long been the brawn of the turbocharger, however a ball-bearing cartridge is now an affordable technology advancement that provides significant performance improvements to the turbocharger.

Ball bearing innovation began as a result of work with the Garrett Motorsports group for several racing series where it received the term the ‘cartridge ball bearing’. The cartridge is a single sleeve system that contains a set of angular contact ball bearings on either end, whereas the traditional bearing system contains a set of journal bearings and a thrust bearing

Journal Bearings

Ball Bearings

Turbo Response ? When driving a vehicle with the cartridge ball bearing turbocharger, you will find exceptionally crisp and strong throttle response. Garrett Ball Bearing turbochargers spool up 15% faster than traditional journal bearings. This produces an improved response that can be converted to quicker 0-60 mph speed. In fact, some professional drivers of Garrett ball-bearing turbocharged engines report that they feel like they are driving a big, normally aspirated engine.

Tests run on CART turbos have shown that ball-bearings have up to half of the power consumption of traditional bearings. The result is faster time to boost which translates into better drivability and acceleration.

On-engine performance is also better in the steady-state for the Garrett Cartridge Ball Bearing

Reduced Oil Flow ? The ball bearing design reduces the required amount of oil required to provide adequate lubrication. This lower oil volume reduces the chance for seal leakage. Also, the ball bearing is more tolerant of marginal lube conditions, and diminishes the possibility of turbocharger failure on engine shut down.

Improved Rotordynamics and Durability ? The ball bearing cartridge gives better damping and control over shaft motion, allowing enhanced reliability for both everyday and extreme driving conditions. In addition, the opposed angular contact bearing cartridge eliminates the need for the thrust bearing commonly a weak link in the turbo bearing system.

Competitor Ball Bearing Options ? Another option one will find is a hybrid ball bearing. This consists of replacing only the compressor side journal bearing with a single angular contact ball bearing. Since the single bearing can only take thrust in one direction, a thrust bearing is still necessary and drag in the turbine side journal bearing is unchanged. With the Garrett ball bearing cartridge the rotor-group is entirely supported by the ball bearings, maximizing efficiency, performance, and durability.

Ball Bearings in Original Equipment ? Pumping up the MAZDASPEED Protege’s heart rate is a Garrett T25 turbocharger system. With Garrett technology on board, the vehicle gains increased acceleration without sacrificing overall efficiency and it has received many rave reviews from the world’s top automotive press for it’s unprecedented performance.

[도라이바]

자동차 정보 또는 GTO 정보내의 모든 자료는 불펌금지 ..

[강쥐사랑]

좋은정보 감솨~