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Garrett ® VNT™ Turbos Engineered for Performance (October 25, 2005)

When Honeywell's Garrett® VNT™ (Variable Nozzle Turbine) turbocharger was first introduced into passenger cars in 1991, it heralded the arrival of a true breakthrough technology.

VNT™ satisfied the demand for rapid boost response in diesel engines – and in doing so helped to transform the driving habits of an entire continent. Over the last 14 years, more than 15 million turbochargers have been installed in passenger cars around the world, most notably in Europe where diesel engines now account for 50% of the marketplace.

At the heart of the success of VNT™ is design and engineering excellence. In VNT™ turbos, a row of moveable vanes, positioned in a ring around the inlet of the turbine wheel, allows the exhaust gas flow to be varied instantaneously.

At low engine speed and low gas flow, the vanes of the VNT™ close, reducing the inlet area to the turbine. This results in an increase in turbine inlet pressure, which enhances turbine power and drives higher engine boost pressure. At full engine speed and load and high gas flow, the vanes open, increasing the turbine inlet area, preventing over-boost and reducing engine outlet pressure for improved fuel economy.

Today, Honeywell supplies third generation Garrett® VNT™ turbos to automotive manufacturers around the world, raising the bar still further on engine boosting performance. More power, more torque, greater fuel efficiency and lower emissions – VNT™ technology continues to set new standards.

Garrett® VNT™ turbos are highly complex units, engineered and calibrated to meet the exacting performance parameters of automotive manufacturers.

The first requirement is to set the turbo's critical minimum flow vane position. This intricate process takes account of the large number of parts and extremely tight tolerances within the Garrett® VNT™ and involves using a highly accurate turbine flow bench to measure and compensate for any variation in gas flow through the vanes of the turbo.

Highly skilled technicians then set and lock the minimum flow position to suit the requirements of each individual application. It is only when the ‘minimum vane open' position is set that it is possible to calibrate the unit (to three decimal places), using four checkpoints to ensure correct operation.

Each of these steps is vital in ensuring the optimum performance of Garrett® VNT™ turbochargers. Indeed, these engineering complexities cannot be compromised – which is why Honeywell's official Aftermarket distributors are committed to supplying only new Garrett® VNT™ turbos that are quality assured and matched to the original OEM specification.

Any attempt at remanufacture, using substitute parts, is fraught with difficulty because of the turbo's technical complexities and can lead to potentially serious problems, such as:

  • Conflict with the engine management system
  • Low flow/pressure, causing poor response, poor overall performance and increased emissions
  • Over-rich diesel fuel/air mix, causing excessively high temperatures, damaging both the turbo and the engine
  • High flow/pressure, leading to the over-speeding of the turbo, wheel bursting and damage to turbo and engine
  • Excessive boost pressure, causing physical engine damage

"Garrett® VNT™ turbos are highly complex and meticulously calibrated components renowned for their performance," says Ed Goodwin, Director, Independent Aftermarket Europe. "Our distributors are committed to safeguarding the interests of their customers by protecting the integrity of the technology – and will therefore supply only new replacement Garrett® VNT™ turbochargers."

Honeywell's Garrett® turbochargers are products of Honeywell Transportation Systems. With $4.3 billion in revenues in 2004, Honeywell Transportation Systems also manufactures Bendix â brake products, Fram â filters, Prestone â antifreeze, Autolite â spark plugs and Holts â automotive products

Honeywell International is a $26 billion diversified technology and manufacturing leader, serving customers worldwide with aerospace products and services; control technologies for buildings, homes and industry; automotive products; turbochargers; and specialty materials. Based in Morris Township , N.J., Honeywell's shares are traded on the New York , London , Chicago and Pacific Stock Exchanges. It is one of the 30 stocks that make up the Dow Jones Industrial Average and is also a component of the Standard & Poor's 500 Index.

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