The Portable Emissions Measuring...
The Portable Emissions Measuring System from Sensors Inc. is not much bigger than a case of oil. Here it is hooked up to the Project G.R.E.E.N. engine during our recent dyno test at Mast Motorsports. That long gray hose houses the wires for the a that are attached to the engine's headers which you can just see in the picture to the left.
In the early 1990s, the Superflow Corporation was attempting to commercialize a means for measuring real-time combustion pressure as a function of incremental crankshaft angles (positions).
Although the academic community and certain factions within the automotive OEMs had been previously perfecting this technology, nothing was then on the market that was practical and effective.
The engine research company I had at the time became a beta site for the development of Superflow's efforts, allowing our little "skunkworks" to become exposed to a fascinating method for combustion analysis. The technique was called Engine Cycle Analysis (ECA) and it has become an invaluable approach to combustion space evaluation in more recent times.
Prior to that experience, I'd had the benefit of designing major engine components affecting the combustion process by the use of rather crude (compared to today's methods) exhaust emissions measuring techniques.
Sensors' Dave Kalen reviews...
Sensors' Dave Kalen reviews the real time results from the PEMS unit during a dyno pull.
By evaluating the byproducts of combustion, as you might expect, some insight was possible about the efficiency of the "burn" as it related to power development. It made sense, and it worked to the extent limited by the measurement technology itself. Stated another way, the value of measured data was only as good as the equipment's accuracy, repeatability, and information collection speed. Stay with me, it gets more interesting.
Roughly two years ago, I learned about a newer technology that provided a way to measure on-board vehicle exhaust emissions in real time. Let me be more specific. The method enabled the collection of combustion byproducts under virtually any condition of vehicle operation. At this point, a light came on.
If this equipment was capable of quantifying the components in an internal combustion engine's exhaust byproducts, why wouldn't the technique be a window to optimizing crankshaft torque? So, based on this presumption, I had my initial conversation with Dave Kalen at Sensors, Inc. (a preeminent producer of portable emissions measuring systems or PEMS Account Executive and now a member of the Circle Track G.R.E.E.N. project team). That initial discussion led to meeting his company's president and CEO, Dr. Andrew Reading, and the information that follows. To the serious race teams and engine builders who may read this column, I encourage you to absorb the next few paragraphs.
Over time, engine builders and tuners have tended to focus on a number of combustion-influencing variables, particularly air/fuel charge ratios. According to Dave, "long-established ASTM fuel standards gave people known fuel concentrations for the combustion chamber. It wasn't until recent years when other factors such as real-time exhaust gas measurements allowed engine developers the opportunity to tweak and control the conversion of fuel into heat, causing some changes in conventional or old-school thinking."
What Dave is talking about includes the conditioning of air/fuel charges by various methods of mixture motion and how this can affect optimal spark timing, mechanical compression ratio and (ultimately) crankshaft torque. These factors alone provided evidence that maintaining specific mixtures of air and fuel under equally specific engine operating conditions was not sufficient to achieve maximum power.
However, given these additional techniques that can impact combustion efficiency, using time-honored ways to control the burn might not be insufficient. There is reason to believe we may now be at that stage of measuring and evaluating combustion efficiency in the general populace of racing engines.