Datum l-automotive.com



September 15, 2015

Pierburg

Order booked for 5th-generation bypass valve

Pierburg GmbH's 5th-generation bypass valve will go into series production, an order now having been placed for ten million units of this latest version. Series start-up is scheduled for 2017 with major German and French OEMs that have been supplied by a further manufacturer with the Pierburg product already mounted to the turbocharger. To be produced in Germany, the valve will be used on 3- and 4-cylinder engines. For markets in China and the USA, future plans envisage local production at the Pierburg plants in these countries.

In contrast to the compact version of the bypass valve, the newest product generation has proven itself especially in challenging environments. In fact, it can cope with temperatures of up to 220 deg. C and very high pressures, too. Installation options include, beside the turbocharger, the charge-air duct. Its reduced size compared with the preceding generations results in package advantages and also facilitates its installation in the engine compartment.

The open/close functions are quieter by about 10 decibels, in terms of human hearing a reduction of about 50 percent. Overall valve leakage is also down—by over one half.

Market leader in bypass valves

Pierburg ranks as world-market leader in bypass valves for turbochargers. Since 2004, the valves have been manufactured on now five automatic assembly lines at the German location in Neuss. In 2014, some 7.5 million units were produced in all and the numbers are rising. So far, around 25 million have been sold—to almost all the important OEMs as well as manufacturers of turbochargers.

The bypass valve is a solenoid-type unit with built-in pressure compensation to allow the valve to largely work independently of the turbocharger pressure. This allows the magnetic force to be kept low in relation to pressure conditions which, in turn, translates into cost savings.

Turbocharger regulation

The electric bypass valve goes into operation whenever the driver takes his foot off the accelerator and the throttle flap is closed. But for this regulating function, backpressure could cause damage to the turbocharger. With the flap closed, there is a sharp rise in pressure, and if this is not diverted via a valve, the air will flow through the compressor, resulting in a “surging” action in the turbocharger. That means the air flow is released from the compressor blades and the pumping process is interrupted. The air flows backward through the compressor until the pressure stabilizes and the air flow reverts to positive. The pressure builds up again and the sequence of events is repeated in rapid succession.

It is from the noise generated in the course of this procedure that the term "surging" has been derived. To avoid pumping, the electric bypass valve opens up a bypass around the compressor wheel. This must be big enough to allow the pressure in the intake manifold to drop quickly enough so as to keep the turbocharger away from the surge line at lower RPMs. The turbocharger can then continue to rotate freely, renewed pressure buildup is shorter and the outcome is faster acceleration of the turbocharger in favor of improved response after gear change.

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KSPG AG

Unternehmenskommunikation · Karl-Schmidt-Straße · 74172 Neckarsulm

Tel. +49 7132 33-3141 · Fax +49 7132 33-3150 · · A Rheinmetall Company

press release

KSPG AG

Unternehmenskommunikation · Karl-Schmidt-Straße · 74172 Neckarsulm

Tel. +49 7132 33-3141 · Fax +49 7132 33-3150 · · A Rheinmetall Company

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