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filter to simulate the flame front in the cylinder head. Typically, the Reaction Design team saw knock occurring on the far side of the cylinder wall, with a variation of as little as 0.3 bar pressure doubling the amount of knock. “The methodology we’re using is really
matched to the methodology that a test engineer would use on an actual engine. In other words, he’s going to put pressure transducers on the engine and listen for the knock. And we said: ‘Well, we’re modelling that engine, so we ought to be able to put down these virtual pressures transducers, look at the pressure and listen.’ “We stepped back and said, if we were
mechanical engineers working on it, how would we be doing this and how are they doing this now? And how close can we get to that, as they will understand it better. “The other piece is really making these
models have the capability to follow what is physically happening. It’s not so much a knock model, it’s more of a methodology for understanding what’s coming out of the simulation, from a combustion standpoint, and translating that into an index that a mechanical engineers could find useful,” Rosenthal added.
Strong interest He foresees engineers using the software to give them a better starting point when developing engine controllers. “The knock sensor engine controller’s software programme runs on a real-time basis and I think this understanding will help them get back some of the margin they might be putting in; and certainly avoid not having enough margin.” He reveals that a couple of German and
Japanese suppliers have shown “very strong” interest in the system and at least one of the USA’s big three.
New software speeds up driveline design One of the key advances with the new
Design processes that normally take weeks can be completed in a matter of hours, thanks to new digital tools from Nottingham-based Romax. The new suite, formed of three components, seamlessly integrates the traditional stages of driveline design and prototyping, allowing analysis and key design decisions to take place in the concept design phase when the design space is wide open. It also allows a lot of options to be investigated, reducing re-work later in the process. “Ten years ago, people were still building
prototypes and testing them to see what broke,” said Charles Watson, head of marketing for Romax. “Early CAD systems gave high incremental effectiveness, but now our newer processes don’t support legacy processes, but replace them entirely.”
suite, according to Dr Jamie Pears, head of product management, is that it is able to perform detailed analyses and simulations within the design package. Most notably, the system integrates and automates notoriously complicated multi-body dynamics (MBD) techniques, such as Adams, so they can be used in driveline design. “These MBD models usually take weeks to
build,” said Pears. “You needed different MBDs for different types and it requires high-end knowledge – that is why MBD is rarely used in driveline design. Our model takes seconds.” Romax’s CAD Fusion, Dynamic Fusion and
Concept tools will reduce design and development costs, increase innovation and improve driveline efficiency.
The new control system, steered by small
computers in each injector, as well as by the central ECU, is also helpful in reducing NVH by adjusting pilot injection through a feedback loop; additionally, the system ensures perfect balance between cylinders, helping emissions, as well as overall smoothness. Crabb is reluctant to give away too many
performance details ahead of i-ART’s official launch in September, but confirmed that the system is worth “several per cent, in terms of fuel economy”. Direct comparisons would be misleading, he said, as i-ART is part of a downsizing and down-speeding programme that also delivers its own efficiency benefits.
Irregular combustion (without i-Art) Cylinder pressure/momentum
i-Art combustion - controlled and optimised Cylinder pressure/momentum
Time/engine position
Time/engine position
May/June 2013
www.automotivedesign.eu.com
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