By Christopher A. Sawyer
The Virtual Driver

(February 28, 2016) Don’t look now, but in the near future, your average Pony car will be a hybrid. I’m not talking full-on Prius-style hybridization here (at least not yet), but the sort of light electrification that will keep Mustangs and Camaros from being a big drain on an automaker’s CAFE plans.

The basic system is simple. It incorporates stop-start capability, a compact electric motor packaged in the front end accessory drive to provide a small amount of boost during initial acceleration, and regenerative braking to recharge the onboard battery pack. These simple changes should increase fuel economy by 10%-15%, and add about 2 mpg to the EPA city and highway fuel economy number. The weight disadvantage would be about 100 pounds.

With a little extra work, the technology could be modified or adapted to offer further gains. For example, V6 and V8 motors with variable valve timing would be able to run a more fuel efficient Atkinson cycle in routine driving. True, the engine would be less powerful when running in Atkinson mode, but it would be much more fuel efficient. Plus, it can use the accessory drive-mounted electric motor to fill in any torque troughs.

Then it can switch to an Otto cycle under spirited acceleration, using the electric motor for a mild power boost and torque smoothing. On the other hand, in a performance four-cylinder application some of the electric power could be siphoned off to drive an electric turbocharger. This would give instantaneous boost, improve low-end torque, and smooth torque application between shifts. This adaptation would give V8-like acceleration off the line, as well as smoother acceleration through the gears.

None of these ideas would require adding an electric motor to either the transmission or rear axle as the hybrid effect is minimal. That’s because you don’t need a large battery or the ability to drive on electric power only to get a significant improvement in fuel economy.

However, should that capability become necessary, automakers are looking at a number of ideas to marry performance and hybrid ability. Drawing from the work currently being done on hybrid pickup trucks, automakers are looking at ways to adapt a fully hybridized transmission or axle to a performance coupe. The problem isn’t in making the technology work, it’s in finding the space in which to place the large battery pack necessary for this technology. You can’t place it under the bed as you would in a pickup. And where you put it has a big effect on weight distribution, ride and handling.

Currently, the preferred idea is to integrate the battery pack into the rear bulkhead, just behind the rear seats and above the rear axle. Unfortunately, there are two major drawbacks. First, the weight sits relatively high in the body. Second, unless there is a major increase in battery density, not only will the fold-down rear seat be a thing of the pat, so will anything that can reasonably be called trunk space. That’s even with a limit of three miles of EV-only power.

The level of hybrid technology chosen depends on how well each automaker does in reaching the CAFE standards with its main fleet, and whether or not Congress will extend the compliance window. Exceeding the standard reduces the pressure on each vehicle line to perform at max mpg, and reduces the complexity of the technology deployed and the cost of the product.

It will be interesting to see which technologies are deployed and where, and how purists respond.

The Virtual Driver