Howden Turbo GmbH is a German engineering company, based in Frankenthal in the state of Rhineland-Palatinate. The company was formed after Colfax Corporation acquired Siemens Turbomachinery Equipment GmbH (STE) from Siemens in October 2017 for €195 million. The old brand name Kühnle, Kopp & Kausch has been returned to use. The Kühnle, Kopp & Kausch AG (AG KK&K) was a German mechanical engineering company based in Frankenthal. The company was acquired by Siemens and bore the name Siemens Turbomachinery Equipment GmbH (STE) until 2017. The company was renamed Howden Turbo GmbH through the sale to Colfax Corporation and Howden.

It was founded in 1899 by the merger of three family businesses by Georg Adam Kühnle, Hans Kopp and Rudolf Kausch.

In 1983, the Motoren- und Turbinen-Union (MTU), Munich, acquired the majority of shares. After MTU was acquired by Daimler-Benz two years later, Kühnle, Kopp & Kausch became (indirectly) a subsidiary of Daimler-Benz.

The Penske Corporation acquired in 1994 the majority of Kuhnle, Kopp & Kausch from the Daimler-Benz group MTU.

In 1997, BorgWarner Automotive, a leading global automotive supplier, acquired the majority of the shares in Kühnle, Kopp & Kausch.

In 1998 the turbocharging systems division was spun off to become 3K-Warner Turbosystems as a subsidiary of BorgWarner.

The company "Turbo Group" and the Frankfurt private equity firm ECM acquired Kühnle, Kopp & Kausch in March 2005.

In July 2006 Kühnle, Kopp & Kausch was taken over by Siemens Power Generation Group. On November 22, 2006, this acquisition was completed by Siemens.