7 August 2018
Cohort 4 researcher,Temi Jegede, attended the 'High Performance Powertrains' Seminar hosted by the Institute of Mechanical Engineers which took place on the 22nd of May in Birmingham.
We asked Temi to give a summary of the proceedings.
The chairperson, Professor Jamie Turner from the University of Bath began setting the scene by summarizing the aim of the seminar which was to highlight promising technologies that better optimize the performance of automotive powertrains. This was followed by the introduction of speakers from companies such as Ford, Mahle, Cosworth, AVL amongst many others.
Paul Freeland, a principal engineer at Cosworth spoke on the techniques employed by Cosworth to maintain the highest possible specific power output while minimising fuel consumption. Higher specific output in this case relates to increased engine speed and increased cylinder air charge which directly proportional to the amount of torque the engine can produce. With regards to fuel efficiency improvements, Cosworth have implemented techniques to maximise compression ratio while minimising frictional, pumping and heat losses. Some of these include dual cam phasing, upvalve systems, which help to reduce pumping losses, Variable displacement oil pump, roller-element valve actuation, Plasma-Sprayed Cylinder Bores which help to reduce frictional losses. Most of the benefit was made due to cylinder deactivation. This involves the temporary deactivation of one or more engine cylinders in light load operational regions. All of this together leads thermal efficiencies greater than 30% in more than 80% of the operating space of the engine.
Speakers from both Ford and JLR described approaches that were similar to those taken by Cosworth with minor differences.
It was also interesting to see the use of software simulation to reduce engine development time, Massimo Gallbati, a project manager at Enginsoft was called up to discuss the use of virtual prototyping in engine development. He discussed the use of Enginsoft’s computational fluid dynamic software which is useful for building a virtual prototype of the combustion process which can in turn provide detailed predictions of emissions, cooling system amongst many other engine subsystems. This is possible because the software allows for very detailed modelling of liquid behaviour. Gaseous fluids are not supported as there is difficulty in modelling the behaviour of an unknown mixture of gases. Research will have to be done in this area to advance this concept.
Several talks were also given on emissions and how tightening regulations are currently affecting trends in powertrain development. Hartwig Busch from the Coventry University Centre for Advanced Low-Carbon Propulsion Systems (FEV) was introduced to discuss some of the challenges emissions regulations pose. More focus is being given to CO emissions as it is being monitored under the EU6d regulations. The trend suggests that CO limits will become more stringent and replace PN emissions as the major emission challenge. The aftertreatment available on production vehicles can curtail the emissions to desired levels but this method is only effective with full combustion cycles at stoichiometry and significant degradation in performance has been observed when the AFR (lambda) is outside stoichiometry. A major factor in this problem is driver behaviour, as more aggressive drivers tend to make quick changes to engine speed and torque which increases the emissions. FEV is using virtualization of calibration to tackle emissions regulations. This involves the use of concepts like Hardware in Loop simulations, road virtualization and driver behaviour modelling. Other strategies are also employed with the goal of keeping lambda at 1 such as water injection and variable compression ratio.
Overall, this seminar offered informative insight into trends in powertrain development and highlighted the commitment of many auto manufacturers to the improvement of the internal combustion engine and powertrain as we are still decades away from full electrification.
Finally the chair and speakers held a Q/A session before giving their closing remarks.