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Nailing Ram’s Aerodynamics And MPG

Posted in News on April 18, 2014 Comment (0)
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Nailing Ram’s Aerodynamics And MPG
Photographers: Courtesy of Chrysler

John Trame’s full title is Senior Manager of Aero Thermal for Chrysler Group. About all we understood from that sentence was “John Trame” and “Chrysler Group.” Now, we already knew a bit about Chrysler’s Scientific and Environmental Labs—they deal with controlled safety and fuel economy testing conditions. We also knew we wanted to play with some of the toys housed there: a $37.5 million aero-acoustic wind tunnel, a climatic test center, and a $300 million powertrain test center. However, we weren’t entirely sure what went on behind the closed doors. Therefore, we jumped at the chance to ask John what the heck it is he does for a living and about his team’s influence on the Ram.

Four Wheeler: You handle aero thermal. Explain yourself.

John Trame: I have aero thermal integration responsibilities for Chrysler Group. What does that mean? Aero is just what it sounds like, aerodynamics. My team works with the design office to make sure a vehicle goes smoothly through the air. We’re responsible for the amount of drag that the car produces, both from the underbody to the top surface. This is referred to as coefficient of drag, or just drag, or Cd. We don’t design the exterior, but we provide guidance to the PDO [product design office] to make adjustments to ensure the vehicle meets the aerodynamic drag requirements.

Now, the flip side, I also have responsibility for thermal development. So, what does that mean? From the start of the program when an engine is selected, we have to manage the thermal energy that the engine produces within a given vehicle environment and loading conditions. However, our objective is not just to manage the energy—it is to optimize the energy to ensure that our vehicles are thermal efficient, thus increasing propulsion efficiency and vehicle fuel economy. In short, we make sure that we dissipate the heat or “cool” all the underhood and underbody systems in the most efficient way.

FW: The Ram’s design is hot. No pun intended. The grille serves more of a purpose than to seem intimidating?

JT: My team directs the exterior design only in an effort to improve the Cd and then balances the drag produced by the opening size in the grille with the thermal requirements needed to optimize the system. In the Ram, we use active grille shutters to strike a better balance so that we can improve airflow when the vehicle is under heavy load or reduce drag when the vehicle is under normal driving conditions.

FW: What did you want to be when you grew up?

JT: I always wanted to design cars. When I was a young teenager I liked designing new exterior shapes and styles. I took courses in high school, like mechanical drawing, which enabled me to design cars during school. I first started on a drafting board and then learned to do drawing in CAD. At the same time my father worked in the HVAC industry. He started, owned, and operated his own heating and air-conditioning company that serviced commercial buildings such as Kmart and other retail stores. When I was 16 years old, I started assisting the technicians on service calls-replacing compressors, changing out HVAC units and so on. Since I had learned CAD in high school, I also started drawing and designing commercial HVAC systems. So, from a very early age, I had a lot of involvement in thermal-dynamic based work and had a love of cars.

FW: What was your first gig at Chrysler in Detroit?

JT: I was in vehicle integration—my responsibility was to establish functional objectives based on the customers’ wants and needs and translate the needs into technical specifications. It also included Human Machine Interface, or the ergonomics of the vehicle. Put another way, it was the touchy-feely aspects of what the customer experiences in a vehicle.

FW: So how does your job in aerodynamic and thermal systems work?

JT: It starts at the very beginning of the product life cycle when we are first investigating different exterior concepts. My team conducts aerodynamic sensitivity analysis to assist in guiding the exterior design. At the same time, we start conducting thermal simulations to ensure that our engines and new technologies have the proper functional objectives to meet the vehicle performance requirements. My team then conducts extensive virtual analysis to verify that the designs meet the requirements before the designs are tooled and parts are assembled into vehicles, followed by vehicle validation to ensure that all thermal and aerodynamic objectives are achieved. If a problem is detected we develop solutions, which could include upgrades to materials, increasing clearance to the heat source, adding thermal shielding, and/or reducing the temperature of the component producing the heat.

FW: The testing process must be pretty cool. No pun intended.

JT: We conduct thermal testing from temperatures ranging -40 degrees F to 130 degrees F and humidity levels ranging from 20-95 percent. We also have the ability to apply different loading characteristics for both two- and four-wheel-drive vehicles so we can duplicate both extreme and normal driving conditions. We even have the capability of making it snow.

Testing utilizes both onboard diagnostics equipment as well as added instrumentation to measure thermal temperatures, fluid flow, airflow, and so on. The aerodynamics testing uses a state-of-the-art aero acoustic wind tunnel, which has a 26-foot-diameter blade and a 6,200hp motor, capable of wind speeds up to 140 mph. This tunnel has capability to measure lift, drag, side forces, and movements. It also is used for confirmation of vehicle frontal area and detailed wind noise measurement.

FW: What’s the best part of your job?

JT: My favorite part of the job is that every day is different. One day we are working on the aerodynamics of a new vehicle concept and making adjustments on exterior surfaces. The next day or next hour, I’m working on a brand-new powertrain and we’re designing the underhood environment and determining the required amount of airflow needed to cool the engine while still optimizing for fuel efficiency.

I also love the differentials, complexity, and interdependency of all the systems. You can’t just consider one aspect to solve a problem, because it has influence on 10 or 12 other objectives. We have to take all the variables into consideration and make sure we have a balanced equation so that we get the right answer. It’s very complex and technical, which is what I enjoy. I like to solve problems people haven’t solved.

FW: And the worst part?

JT: Probably the worst part is paperwork. I think many engineers may dislike paperwork. Obviously, there’s a fair amount of paperwork that falls into most jobs. Appropriate documentation is not only important, but at times, is required because of the complexity of our systems and to ensure that we follow a process. It is also important because without paperwork some details might be missed, and details matter.

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