Why ‘Vehicle Energy Efficiency’ holds more meaning than just ‘Fuel Efficiency’.
We often see the word 'fuel efficiency' being thrown around in our day-to-day life in places like pamphlets, brochures, or even advertisements. Just how important is fuel efficiency, and what pushes the automotive industry to strive towards greater fuel efficiency?
To understand this, we need to define a broader term ‘Vehicle Energy Efficiency’. Fuel Efficiency is generally described as a ratio of distance traveled per unit of fuel consumed (source: Wikipedia). Since fuel is a form of energy anyway, this term applies to fuel efficiency as well, albeit in a broader sense. When we consider the vehicle’s energy efficiency as a whole, other factors such as carbon dioxide emissions, output energy over a drive cycle, amongst others, come into play. Let’s face it, owning a car is a luxury and a privilege, irrespective of the number of arguments we stack up to defend such a statement. “I need the car to pick up and drop off the kids every day”, “Without the car, my wife and I would find it increasingly difficult to manage both our busy schedules”, some would say. Increasingly demanding, yes! But not impossible. Because here’s the thing with cars: THEY LEAVE SOME SERIOUS CARBON FOOTPRINT BEHIND!
According to the European Union official website, passenger cars account for around 12% of the total EU emission of carbon dioxide. There is thus, a dire need for more stringent regulations for the emissions of passenger cars. This primarily motivates the auto industry to focus more on “energy efficiency” to meet the target requirements of each new year. Having worked on an assignment at Volvo Cars within the Vehicle Energy Efficiency team helped me gain a deeper understanding of how the reduction of emissions and setting stricter targets every year is crucial in the long run to contribute positively toward a cleaner environment.
A typical workday would go on like this: ensure that the correct vehicle models were received to be simulated and to verify if the road load coefficients matched the models received. Once all the vehicle models with all the necessary parameters were obtained, then came the main and the most crucial step: running the simulations to obtain results for Fuel Consumption, CO2 emissions, and other relevant parameters which give us an idea of how much emissions each vehicle model belonging to a fleet or market was releasing. Sometimes, a part of the job description also included something called “Correlation Analysis”. The main goal of such an analysis was to “correlate” the results from the virtual tests we’d performed (via simulations) to the results of the physical tests carried out in the testing lab. This was primarily done using Sympathy For Data, Combine’s internal tool for data processing, and data visualization.
Anyway, the results of the simulations run, as well as the correlation analysis, were then presented to the Attributes Realization Engineers, who would then draw a comparison of the models to see which did and which did not meet the emission certification standards required. Keeping the fierce spirit of competition in mind, it was thus a no-brainer that the emission numbers of other auto manufacturers were compared. What possible tuning of parameters could lead to better numbers was discussed.
The goal of reducing emissions is of such a high priority to these automakers that there is even a comparison of emission numbers for vehicles of the same model but having a small difference in components for eg., in my case, it was generally a comparison between a vehicle having a 7-speed gearbox and a similar vehicle having an 8-speed one. While this change might seem insignificant and small, a different gearbox introduces a change in the vehicle mass, the gear ratios become entirely different, and of course, the gear shifting RPM changes as well, all thus directly or indirectly contributing to minute change in fuel economy per drive cycle or road trip.
Thus, the underlying goal remained the same: if there was any way, any way at all the emissions of the vehicles could be possibly reduced, go for it! Of course, the actual numbers I cannot mention here as such information is generally considered “hush-hush”. But I’m assuming you get it: Cars are something which people will only keep buying and buying either for their convenience or even indulgence. And because vehicles, in general, have become so embedded into the web that we like to call life, to think that we will, on a fine Saturday morning, reduce or possibly even stop the usage of passenger cars altogether is a farce. Even the new Electric Vehicles (EVs) currently available in the market have almost twice the carbon footprint during the manufacturing phase compared to conventional ICE vehicles even though their subsequent emissions during usage are practically negligible. And for the entire world to embrace EVs would still take a significant amount of time, especially the developing and the under-developed countries. This, in turn, means the pressure is back on the manufacturers of conventional ICE (and hybrid) vehicles to amp up their technologies to produce less damaging cars to the environment.
I guess what I’m trying to say is this: In a corporate world, where the general impression of people working in the auto industry, put forth by pressure groups, is that of a person who’s “sold their soul”, it is heartening to know that engineers like us, directly or indirectly, are making whatever minuscule efforts we can, in our capacity, to bring about a positive impact as far as the environment and the struggle of achieving climate-change goals is concerned.