Electronic Controls - Breeding New Engines 2001-01-0255
Internal combustion engines evolve based on the technical and economic pressures that surround their design and manufacture. Today, the perspective is one of overall effectiveness and not just specific technical performance.
From the earliest internally fuel-burning engines, the process has been continually refined. Modern demands on both efficiency and emissions have raised the requirements significantly. Stricter performance limits, involving very accurate systems control, have hastened the evolution of new forms of design. Electronic systems have become the heart of the unit, coordinating overall operation. We look forward here towards the next stages of evolution, where the powerplant is enabled almost entirely by software, making a new balance between the engine mechanical design and the control strategy. The level of engineering effort and time allocated to accomplish the higher performance levels is reducing. The engineering process must therefore become more effective and more efficient - another challenge.
We look at the future as involving a range of non-traditional operational schemes. Some are re-inventions, appearing since they are now achievable using electronic systems, others may be entirely new concepts that again are enabled through the greater reach that we have as a result of mechatronic systems (ones where there is an inseparable collaboration between the mechanical and the electronics.)
One such example is HCCI (homogeneous charge compression ignition), which as an emerging engine technology offers the possibility of such a co-design approach. The control needs are accentuated by the absence of any “ignition” actuation. The engine requires precise control of temperature, pressure and equivalence ratio such that during the compression stroke, the burn occurs at the required point. Predictive approaches to control are thus essential, but the control system and the design of mechanical parts must be developed synchronously. There is a further step forward, where the calibration process is developed and optimized alongside the design.