Head engineering with brains

Valve control makes strides in the international marketplace

Maintaining its position at the cutting edge of automotive technology, Cosworth is now turning its attention to making engines as efficient as possible. In their quest, the British R&D specialists are employing Pierburg technology.

Commemorating its 60th anniversary in 2018, Cosworth has continued to evolve, building on its decades of success in Formula 1 to become, today, a ‘go-to’ Tier One technical partner for global OEMs. Cosworth engineers are constantly coming up with new solutions for the rapidly changing world of mobility. To cite just one example, Cosworth is currently working with HAITEC (Hua-chuang Automobile Information Technical Center Co., Ltd.) and CEC (China Engine Corporation), both headquartered in Taiwan, to develop a highly efficient gasoline-powered engine. The ambitious goal of this project is to combine the favorable power and toxic emissions characteristics of gasoline engines with the consumption and CO2 emissions of diesel engines. Particularly in China, there’s obviously huge market potential for an environmentally friendly engine of this kind. In a comprehensive preliminary study, along with the greatest possible reduction of all parasitic losses and optimization of oil and coolant water flow, Cosworth identified the reduction of the gas exchange work as prime focal points.

It depends on the head

This explains the focus on the cylinder head and its valve train. On the one hand, thanks to the effective gas exchange achieved here, it is possible to attain a high specific output, enabling a downsizing of the engine. On the other hand, the aim is to control the volumetric efficiency through variable valve opening duration with substantially reduced flow losses, rather than via a throttle body, as was previously the case. In subsequently selecting a system, apart from primary variability, a number of other factors were taken into account, including friction losses, complexity, as well as the degree of technical maturity, package, and weight. In the end, the specialists decided on UpValve, a purely mechanically operated, infinite variable valve-train system made by Pierburg.

At a glance

The rotating camshaft causes the UpValve rocker to oscillate. At the same time it’s possible to shift the pivot point of this rocker along the circular guide by twisting the control shaft. Thus, the lobe of the rocker engages the roller finger follower in a variable manner, changing valve lift and opening duration.

“We undertook an extensive concept study to understand what technologies were on the market and whom we could collaborate with to create a highly efficient engine that offers excellent fuel consumption over a broad operating area,” explains Bruce Wood, Managing Director of Powertrain at Cosworth. “We’re pleased with how our collaboration with Rheinmetall Automotive has enabled us to make gains in improving the efficiency of the internal combustion engine.”

Cylinder shutdown possible

In the UpValve system, an additional component is installed between the camshaft and the finger follower, which constitutes an oscillating cam in the form of a toggle rocker with a changeable pivot point. By shifting the rotational axis, the valve opening duration can be infinitely varied, up to and including complete shutdown of the valve. “Essentially, UpValve is based on tried-and-tested valve-train technology. This makes the product efficient and robust,” declares Dr. Michael Breuer, Technical Director Valve Trains at Pierburg. “The components can even be individually designed for each valve. This means that it is possible to implement two different ways of dethrottling at the same time: an infinitely variable opening duration and cylinder deactivation.”

Impressive fuel consumption figures

The reduction in throttle losses attainable in this way proved to be decisive in helping the British R&D experts to achieve their goal of greater engine efficiency. The results speak for themselves. In the case of high specific power output , fuel consumption levels were obtained that were a match for diesel engines – but without the need for complex downstream exhaust-gas aftertreatment. “At a time when future mobility is a key topic, the results of this project are very exciting,” concludes Wood. The system’s supplier is equally buoyant: “We were pretty tense when we watched our UpValve system operating at the engine dyno at rated speed right next to the turbocharger, which turned red hot. In the end, though, everything worked out fine,” recounts Breuer, not without a note of relief, “our Upvalve system proved highly resilient during all dyno and endurance tests.”

A Formula 1 legend

When people think of Cosworth, they will most likely consider its prestigious motorsport heritage, and reminisce of the engines that powered teams to multiple race wins and championships. Or perhaps they will speak of its highly successful electronics solutions and its provider-of-choice reputation it continues to have today. However, Cosworth has continued to evolve beyond this, utilizing its decades-honed motorsport knowledge in automotive and aftermarket applications. Today, Cosworth is a developer of innovative engine concepts, but also produces prototypes and small series, which continue to stand out owing to their high specific power.

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