I’m Dreaming of a Green Christmas

Between the traveling, the lights, the parties and the gift wrap, Santa’s reindeer aren’t the only ones leaving a footprint. From Thanksgiving to New Year’s Day, household waste increases by 25 percent. This adds an unnecessary strain on your wallet and the Earth!

Reducing waste during the holidays, however, could not be easier with a few simple tips:

1. Switch to LED lights

LED, or Light Emitting Diode lights, require 1/50th of the electricity of conventional lighting and last 20-30 years, as reported by the EPA. You can also lower your carbon footprint by turning off holiday lights when you go to bed or are not at home.

2. Opt for homemade gift wrap

From newspapers to mason jars to maps, it’s easy to make beautiful and original gift wrap using what you already have at home. HGTV, Pinterest and other websites offer an abundance of ideas to help you tap into your inner Martha Stewart, all while saving money and helping the environment.

3. Use and recycle a live tree

While plastic trees are made of petroleum products and are typically discarded after a few years, live trees are grown on tree farms regularly, positively contribute to air quality while growing, and are recycled into mulch almost 90 percent of the time, as reported by Earth Easy.  

4. Recycle whenever possible

According to recycling expert Patrick Morgan, the only wrapping paper you shouldn’t recycle is the paper with plastic or tin foil. Anything else is fair game. At parties, you can promote recycling by placing a box for bottles next to the trash can.

5. Give your house a once-over before traveling

Have you turned off all the lights? Unplugged all the electronics? Closed all the windows and set the thermostat to a lower temperature? Looks like you are good to go!

While it can be easy to get caught up during the holidays, remember that even small changes can make a big difference! 

HEVT hopes you have a safe and happy [green] Holiday!

Mary Cools Off Before Heading to Competition

While DYNO testing at the Transportation Research Institute, we found that our vehicle's power electronics cooling loop was getting too hot, which could be a huge problem at EcoCAR 2 Final Competition.

“If the loop gets too hot, components can get damaged and can hinder us at competition,” said Kelvin Jan, a member of the mechanical team.

In the original model of the vehicle, there was only one power electronic radiator. However, in order to make the vehicle a hybrid-electric vehicle, we added a UQM motor, inverter, a P2 motor, a Rinehart inverter and a DC/DC converter. Quite a bit, huh? These newly-integrated components added too much heat for the stock radiator to handle.

All three electronic radiators in series.

To fix this problem, we needed to find a way to reject more heat from our power electronics cooling loop. First, we used the data we obtained at the Emission Testing Event to do some rough calculations. We determined that two additional power electronic radiators would be needed to do the job.

After checking the CAD model to make sure that there would be enough room for the radiators, Jan designed brackets to mount them. We routed the coolant lines so that the radiators are in a series, moving the original inlet hose to the bottom radiator so that the coolant can flow through all the radiators, while the outlet remains the same. Upon installing the radiators, we ran short tests and found that the coolant loop was running at a lower temperature than it did at the ETE.

“These were just preliminary tests to see if our solution fixed the problem,” Jan said. “Further, more rigorous tests will be conducted in the coming weeks to make sure Mary is competition ready.”

Rear Subframe Redesigned and Ready for Fabrication

We have officially completed the redesigned rear subframe, which now meets the EcoCAR 2 requirements for stress and strength factors of safety.

“The redesigned rear subframe is important for a couple of reasons,” said mechanical subteam member Chris Eaton. “First, it contributes to the overall safety of our vehicle by providing structural strength and stability. Second, the redesigned rear subframe allows us to completely package our rear powertrain which is required for all modes of operation.”

While the redesigned rear subframe is just as stiff as the previous model, it is twice as strong. To achieve this, our mechanical subteam had to first determine which locations on the subframe needed the most support and where they needed to add reinforcements. Next, we had to identify which shape or geography would best fit the design criteria. Finally, we performed the required finite element analysis (FEA) to accurately represent the stress and displacement generated within the subframe while under different types of loading. 

Three stages of the redesigning process.

The finished product includes two major modifications from the original. First, we changed the angles at which the front cross member approaches the rest of the subframe from 90° to roughly 140°. This reduces stress. Second, we added a new arching cross-member, which will assist with load distribution across the rear portion of the subframe.

In addition to successfully developing a redesigned rear subframe that meets both competition and team (HEVT) requirements, this project also provided a great chance to learn.

“I have learned an immeasurable amount about the modeling, drafting, and simulation aspects of computer-aided design (CAD),” Eaton said.

We also learned about how a product moves through the design, fabrication installation phases. While working on the subframe, we reached out to professional engineers at companies like GM and Siemens, which was a great opportunity to learn and network.

With the redesigned rear subframe complete, we can now focus on testing the exhaust system to ensure that it does not leak. We will also be working on the refinement and installation of components associated with our fuel system.

“I look forward to seeing how the rest of the semester unfolds and how we favor during competition this summer. I believe that we can place well in competition if we finish out the rest of the semester on a strong note,” Eaton said.

Do you think our new design will work well at final competition? Let us know in the comments below!

#TransformationTuesay with Mary's Rear Wiring Harness

Mary the Malibu has been busy getting herself dolled up for competition lately. 

The team has been working hard on a new trunk wiring harness. Although the wiring has been functional, it was extremely disorganized and made it difficult to diagnose faults. Since we are in the refinement phase of EcoCAR 2, some of our team members suggested that something be done to clean up the wiring for serviceability, consumer acceptability also weight reduction. 

The majority of the old wiring was 20 AWG (american wire gauge) wire with thin-walled insulation. Most of the wiring in the trunk is used for signal transmission - not power - so a smaller gauge wire can be used for these connections. We purchased seven rolls of 22 AWG thin-insulation wire to replace the signal wires to reduce weight and take up less space in our trunk.

Before and after of Mary's rear wiring harness.

"I created an entirely new harness so that wire lengths could be measured away from the car," said controls subteam member Brandon Nash. "This was so I didn't interrupt the work others were doing with other parts of the car. I then created new pin-outs for every connector in the trunk as well as connectors required to make the harness fully removable." 

Once the pin-outs were up-to-date, we started to lay wire for the new harness. The final result is a smaller, lighter and entirely removable rear wiring harness. As we continue preparing Mary for final competiton, we will be able to add new wires and run them through the loom to keep them organized and as short as possible!

Emissions Testing Event Provides Important Data

The Emissions Testing Event (ETE) was a success!

We were one of the first teams to pass Safety Tech inspection out of the six teams that were at the event. The inspectors were impressed with the work we had done, but were still critical and gave us feedback on areas of improvement. 

With the help of a General Motors technician, we solved two of our biggest issues—starting our engine and fixing our brakes. The engine control module was faulting because we had modified some of the signals (e.g., the 12-volt starter) in order to take control of it. 

Mary testing on the chassis dynamometer.

Before last week, the brakes would hold pressure while driving and it was causing a lot of issues with energy consumption and drivability. We learned that the car had originally been equipped with a hill-start assist feature, which had been compromised when we modified components from the stock vehicle. 

With a running engine, the only thing standing between us and series mode is a fully operational P2 generator motor. Series mode means our engine will be running and use our P2 as a large alternator that will help to recharge our batteries while driving. There are some issues with the interference on our CAN (controller area network) bus that we are trying to work out before we can use the P2 to generate electricity. 

With the help of a Transportation Research Center technician, we were also able to test Mary on a chassis dynamometer (pictured above). We tested the electric vehicle (EV) mode on our vehicle with a few different control strategies and collected some engine starts emissions data. We will be able to use this data to validate our models and have an expectation of how we will perform at competition in June. 

A big thank you to all of the sponsors GM, TRC, Argonne National Labs and the U.S. Department of Energy who were able to help us out at ETE! 

Keep up with our Facebook and Twitter updates, and we’ll be sure to let you know when we’re running in series mode.