TRADING-OFF AND OPTIMISING

Dear Readers,

With the timely implementation of marine emissions legislation now agreed and the technologies for affordable com-pliance having largely selected them-selves, the large engine industry should now be able to look forward to an extended period in which it can optimise the performance of its products in all areas – not just NOx emissions.

One major focus is sure to be the famous – or infamous – NOx-SFC trade-off. What is often called “the diesel dilemma” – but obviously also affects spark ignited engines – has now become a double dilemma. Since the first exhaust emis-sions legislation was implemented, aware-ness of the effects of greenhouse gases on the environment has grown exponentially and commitments have been made. The SFC side of the trade-off is now, equally, the CO2 side – and hence a focus not only for engine operators but, rightly, also for ecologists and legislators.

It is interesting, then, to read of methods which, even without NOx sensors, can be used to integrate NOx data into closed loop control systems. The result will be that both sides of the trade-off can be optimised. So, where a few years ago we might have praised the security that large margins of NOx compliance give in terms of environmental protection and been sceptical of efforts to narrow them, we can now unreservedly welcome them. Indeed, what used to be a compro-mise between legal obligations and oper-ating costs should now also become a very precise balancing act between two categories of emissions.

Looking at another area ripe for optimi-sation, in 2012 the subject of the CIMAC CASCADES seminar for younger engi-

neers in Zürich was “Towards the Elastic Engine”, the title referring to the poten-tials for improving tractability and load acceptance via the flexible parameter setting possible with digital electronic control. However, at the recent Torsional Vibration Symposium in Salzburg, dele-gates learnt about a very literal and undesirable form of engine elasticity.

A major theme was the effects of torsion in the crankshaft, due to alternating loads, on the accuracy of ignition timing and, by extension, fuel injection. The errors thus introduced into engine para meter settings are not trivial and highly relevant to the current interest in cylinder balancing as a means of reducing fuel consumption and engine wear and tear. Appropriately, research into this field is underway and promising approaches under investigation.

What projects like these underline, of course, is the engine industry’s commit-ment to pursue every avenue leading to improved engine performance.

JONATHAN WALKER, Chief Correspondent, MTZ industrial, Kaufbeuren, 25 August 2014

3 Special Edition MTZ I September 2014

EDITORIAL

75 YEARS AT THE CUTTING EDGE OF ENGINE TECHNOLOGY.

IT’S OUR BIRTHDAY!