Green Cars

December 15 2010 Tom 4 724
MapleSim

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My father’s first car when our family moved to North America was a 1970 Buick Skylark sedan, and the color was a majestic deep green. I was seven years old at the time and this was my first experience with a green car. It’s ironic that my life in North America started with a green car and has come full circle with green cars all over the place as far as my job is concerned. But of course, today’s green car is really about highly fuel efficient cars or cars powered by entirely difference energy sources than with the old Skylark. My first car, incidentally, was a 1973 Plymouth Valiant and it was orangish brown … both the rusted and non-rusted parts. It cost me $300 and it was about as un-green as you can get both in the color and its environmental sensibilities.

 

My first "far from green" car

 

The current interest among automotive engineers for better modeling tools is largely driven by the green auto movement. The reality is, to squeeze every last bit of performance from an internal combustion engine, or to gain acceptably long travel distance from a single charge on an electric vehicle, engineers need to analyze and simulate systems and subsystems that are considerably more complex than with vehicles even a decade ago. With ever-shrinking timelines between model releases, this requires better and more modeling and simulation.

I’ve been amazed at how enthusiastically automotive engineers around the world have received MapleSim. In a scant two years, MapleSim has gone from an engineering curiosity as the new kid on the block, to a legitimate alternative for many aspects of real-world physical modeling. And nowhere is this more evident than in the automotive industry. Correspondingly as more and more engineers begin working withMapleSim, they discover more possibilities to improve the tool. This input has been invaluable to us to grow and mature the product in such a short amount of time.

Some typical green auto applications

HEV
Among the various engineering paths that automotive engineers can take, the Hybrid Electric Vehicle (HEV) seems to be the one that the OEMs see as an effective, immediate option to increase efficiency. With existing engineering and manufacturing techniques, we can significantly increase the fuel efficiency of most vehicles and it does not require major additions to our fueling infrastructure. Many of our users in the auto sector are applying MapleSim and Maple to various aspects of HEV model developments. By definition, the HEV requires a modern systems perspective on the vehicle and the MapleSim component approach is ideal. Already, the MapleSim community is producing HEV models integrating the IC engine with the electrical motor and charging system, are being connected to chassis models, driver models, and various other subsystems.


A MapleSim model of an HEV (model and image from Dr. John McPhee’s research team)

Battery Models
Although it shouldn’t have surprised me, it did. One of the most frequent application contexts that we encounter is that of high-fidelity battery modeling. I always thought that batteries were relatively straight forward components and the real challenge for modeling was all of those complicated moving parts in a car. But of course, in the age of electrified or semi-electrified vehicles, the primary power source is often the battery and any increase in performance or stability and predictability of the battery is critical. Dr. John McPhee of the University of Waterloo, in collaboration with Toyota has been at the forefront of modeling HEV systems and batteries. He’s considered electrical, thermal, and even chemical aspects of battery models using MapleSim or Maple. Once again, the inherent flexibility and openness of these tools are allowing engineers to very quickly deploy high fidelity models of needed new components.

Driveline Models
While various engineering teams in Japan, US, Germany, and elsewhere are busy devising miraculous schemes for powering next generation vehicles, there is still an awful lot of more conventional engineering components that need to be designed. Driveline or transmission models tend to come up a lot. Although such models are not limited to the celebrated green cars, the issues of transferring power from the fuel source in an efficient way to make the wheels turn, are of course, universal. This has resulted in us investigating a whole range of driveline components and getting “down and dirty” with gears and things.

MapleSim model of a ZF 4HP22 Transmission

The common theme running through all of these applications is the real value that the rapid development of accurate models of any automotive system provides an engineering team. The MapleSim and Maple approach often reduces development time by an order of magnitude while maintaining or increasing model fidelity. This extra boost to the modern engineer’s productivity and creativity is the real fuel for a greener future.


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