Constraints are often seen as the enemy of designers, architects and engineers. It’s clearly the case that the number of potential solutions to a problem has to decrease with each additional design constraint. However, just because the number of potential solutions goes down, it does not mean than the actual solution the designer comes up with is less effective that they would have created without the constraints. Constraints can often lead to better solutions by forcing designers to think outside of a design pathway heavily influenced by previous revisions, a pathway potentially incrementally approaching a local optimal solution.
For example, consider the internal combustion engine. It has made steady efficiency and performance gains since it was first invented in 1798 by John Stevens. However the maximum efficiency of a heat engine is bounded, as illustrated by Carnot in his 1824 publication Reflections on the Motive Power of Fire. Another limitation of the combustion engine, and one that has resulted in several significant revisions to the design, is the low output torque at low RPM due to the low combustion compression. As the RPM of the engine increases, so does the torque until a maximum is reached, after which, the torque decreases as illustrated by the engine’s power band.
Fast forward two hundred years since the first combustion engine, we are now faced with additional constraints to continue using them in cars. Firstly, there’s the constraint of needing to design increasingly efficient engines due to the cost of fossil fuels as a result of them being a finite and rapidly depleting resource; the second is the need to reduce omissions to reduce greenhouse gasses. In recent years, these two constraints, have pushed designers, architects and engineers to explore hybrid and fully electric motors. Early automotive electric motors and batteries were considered a significant compromise compared to the internal combustion engine, with performance, range and cost being inferior. However the continued and increasingly important constraints placed upon automotive motors has resulted in the electric motor surpassing the performance of the internal combustion engine. Furthermore, recent improvements in both engine design and battery technology is rapidly making range and cost not a consideration for the average motorist. An electric motor also has 3~4 times the efficiency of an internal combustion engine; anything but an incremental improvement.
The point here is, incremental gains are typically a result of basing the next iteration of a design on the previous version and looking for small improvements. Significant improvements come about from radically new approaches, sometimes as a result of additional design constraints. The next time you think about a problem, consider introducing a few artificial constraints to see if that radically changes your perspective or approach to solving a problem. The results might surprise you.