Although they are not known for it, hybrid engines can actually be used to enhance performance, rather than fuel economy. Given the current climate (and fuel prices!) it’s understandable the more successful hybrid cars (i.e. the Toyota Prius) gets more air time, but there have been some performance hybrid cars out there.
What Makes a Hybrid a Hybrid
But first, the basics. What is a hybrid car and what do I mean they can be tuned for performance? A hybrid car is, once you get down to it, a merger of two engines. Normally, one of the engines is gas (or diesel) and the other is an electric motor. There are other hybrids out there, including fuel cell/electric or fuel cell/gas hybrids, but for the most part when someone says hybrid, they mean gas/electric vehicles.
Now, by mating a gas and an electric motor together, you can actually use the strengths of each to complement each other. For instance, electric motors can give you a very good acceleration, because they provide constant power, while gas engines are less efficient. But in constant road conditions (highway traveling), the power supplied by the gas engine is easier to manage (and it’s a lot easier to refuel with gas). The constant drain on a battery at highway speeds just isn’t as efficient.
In city driving (frequent stop and go), you can recharge the battery pack through regenerative braking. Out on the highway, the gas engine is needed to power the battery pack.
BTW, hybrids tend to have very efficient gas engines, so the myth that says if you have a highway commute you shouldn’t buy a hybrid doesn’t make a lot of sense to me. The Prius gets 45 mpg on the highway. Most people would be ecstatic to get half that.
And so, automakers have used hybrid technology to emphasize the two motors strengths. Electric motor powers the car at low speeds, while the gas engine takes over at highway speeds. Put them together and you get a more efficient vehicle. But efficiency in a car can be taken in other directions. Instead of emphasizing fuel efficiency, you can emphasize power efficiency. And that’s just what Honda did with the Accord Hybrid.
Honda Accord Hybrid Was Built to Perform
The Accord Hybrid took Honda’s Integrated Motor Assist and Variable Cylinder Management technology to to deliver high levels of fuel efficiency from the 3.0-liter Honda V-6 engine, along with highly responsive and powerful performance. The result is an SAE-rated 253 horsepower and 232-foot pounds of torque. Not quite high performance, but you took a V-6 and made it as powerful as a V-8, while still getting the fuel efficiency of a V-6 (or slightly better). (Little known fact: The Honda Accord Hybrid was used as the pace car in the 2006 Indy Racing League IndyCar Series)
The Honda Accord Hybrid was built for performance. It’s features included Electric Power Steering enhances steering response, Drive-by-Wire throttle control enhances acceleration, and a four-wheel independent suspension.
But, in today’s market, performance upgrades (and it was only a little bit of a performance upgrade) wasn’t good enough (specifically, the fuel economy was only 25/34) and the Accord Hybrid is being retired in favor a diesel version.
Hybrid Electric Motors May Not Be The Best Choice
The biggest problem when designing for performance in hybrids comes from the extra weight of a hybrid engine, especially the oversized battery packs that need to be placed somewhere. By adding in the extra weight, you have to make up for that and it’s not easy to do.
Toyota Builds A Better Race Car and Calls it Hybrid
Toyota has decided to work around that problem with their suped up Supra HV-R Hybrid. Toyota modified their Hybrid Synergy Drive and put in three electric motors along with a quick charging capacitor to power them. The four wheel regeneration and drive system includes front in-wheel motors and one 150 kW rear-axle mounted electric motor. Combined, the system can quickly recharge the capacitor in the rapid deceleration and acceleration conditions you would expect in a race.
Using this arrangement, Toyota can recharge the capacitors quickly. In racing conditions, you can imagine the slow downs and quick acceleration is perfect for this type of system.
And it’s also a successful one. Toyota won the Tokashi 24-Hour Race in 2007 and are going to enter the Le Mans in 2008. And the engine was given the Race Engine of the Year Award by Race Engine Technology.
Conclusions
And so, we’re left with a mixed bag. On one hand, you can get more power by using two engines. On the other had, this may not be what people want from their cars these days. With oil prices hopping over $100 a barrel, new laws coming out (see CAFE) and new concerns about where the oil is coming from (see Middle East) consumers are gravitating towards more fuel efficient, not more powerful.
This may change with the onset of lighter batteries (Lithium-Ion rather than the current standard Nickel Metal Hydride) in the next few years. But, given the success of the Prius (Hit number 9 for cars sold last year) and the failure of the Accord hybrid, car makers are more likely to use the more powerful battery packs to further fuel economy.
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