What Makes the Perfect Hybrid?

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What Makes the Perfect Hybrid?

For many folks hybrid vehicles have a negative aura about them. Some of that is the fault of poorly executed models over the past two decades, and some is due to the most successful, and arguably best engineered hybrid, the Toyota Prius.

And you can’t blame them. The Prius is tops both in sales and fuel economy. Unfortunately it’s also both odd looking and dull to drive.

It goes without saying then, that while it may be good; the Prius isn’t the perfect hybrid. In fact, we’d go so far to say that an uncompromised, fuel efficient, fun-to-drive hybrid isn’t yet out there, but it’s very close. If we had our choice, here’s what would make up the ‘perfect’ hybrid, which would be fuel friendly and not a bore.

Looking at all the gasoline-electric cars currently on sale, the components of the perfect hybrid are out there. While better performing technology is possible (and available), it would be a good idea to keep the price point around or below the $30,000 mark. Finally, benchmarking one of the most competitive and biggest segments in the industry, we imagine the car to be a four-door mid-sized sedan, something that can be both family friendly, practical and enjoyable to drive.

Hybrid-type: Full-Hybrid, (AC Motor from Toyota Camry)

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While some automakers like Honda and GM still dabble with mild hybrids, those systems still haven’t proven themselves to be impressively fuel efficient, or even that cheap. In fact, the only redeeming factor of a mild hybrid is that you can possibly pair it up with a manual transmission, like Honda does with the CR-Z.

no pluginNo, a mild hybrid wouldn’t be found in our theoretical perfect hybrid. Neither would a plug-in hybrid system. While plug-in technology does do a fair bit to help improve fuel efficiency, it’s quite a bit heavier, more expensive, and can compromise passenger and cargo space. For that reason the perfect hybrid would have to use a standard parallel gas-electric hybrid powertrain.

no-mildhybridWith a permanent AC Electric motor which cranks out 105 kW or 140 hp and 199 lb-ft of torque, like in the Toyota Camry Hybrid, our imaginary hybrid would have ideal acceleration and torque, making the driver forget about any stigma associated with the hybrid powertrain. This setup should also allow for highway speed coasting in EV mode.

Toyota’s setup doesn’t result in the most MPGs in its class, that honor would go to Ford with its Fusion Hybrid netting 47 mpg combined, while the Camry Hybrid gets just 41 mpg, but we think the refinement of the Toyota system will result in a more consistent fuel mileage, instead of a “once-in-a-while it’ll get 47 mpg” rating.

Transmission: eCVT (From Toyota)

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While traditional automatics (even 8-speeds like that found in the BMW 3 Series Hybrid), and DCTs (VW Jetta Hybrid) offer gear selecting for sportier driving, they are often less refined when it comes to coupling the electric powertrain and internal combustion engines, resulting in jerky starts, rough activation and deactivation of the motor and an overall unpleasant experience.

2012 Honda CR-Z InteriorThe goal of the best hybrid is to give the best fuel economy… and the best driving feel. As such, the transmission has to be efficient and smooth, blending the electric motor with the gas engine. For this reason, we’d choose any of the eCVTs from the Toyota/Lexus lineups. Our experience, especially in the Lexus hybrids, is that these systems are eager to give you power when you need it, and fuel efficiency when you are cruising along. The company might use dated nickel metal hydride batteries but its hybrid system and transmission is smooth and flawless.

However, if there’s one thing we’d love to see added to the eCVT are paddle shifters like the one used in the Honda CR-Z, which allows the driver to select one of seven pre-set gear ratios. This will help to keep enthusiasts from complaining about the rubber band feeling of most CVTs. Helping to choose a pre-set gear ratio allows the car to not shift, and stay in its power band during spirited driving.

Battery type: Lithium-Ion Polymer (From Hyundai)

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Our ‘perfect’ hybrid would be nothing without a proper battery making it all work. Batteries are tricky because they have to be strong enough to power the car, while being small enough so they don’t weigh it down.

The nickel-metal hydride batteries that Toyota uses in its hybrids are a bit too dated, and require quite a number of cells. Newer lithium-ion batteries are better, but can be a bit worrying in terms of heat. When lithium ion batteries charge and discharge they expand and contract due to the heating and cooling that occurs. This can ultimately reduce the cell’s ability to hold a charge.

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Look at the technology in the Hyundai Sonata Hybrid, which uses lithium polymer batteries.

“The major difference [between lithium ion and lithium polymer] is that the lithium-polymer batteries come in flat sheets with polymer instead of liquid,” says Hyundai’s resident hybrid expert Miles Johnson. “We use 72 of these sheets hooked together in the Sonata Hybrid, while something like the Tesla Model S (which has an incredibly high-tech electric drivetrain) uses 18,000 lithium-ion cells.”

Lithium-polymer batteries are a more advanced version of lithium ion batteries and don’t experience the same expansion and contraction as other lithium ion batteries, so they’re expected to be extra reliable, helping to coerce anti-hybrid fans with sensibility.

They’re also smaller and more compact. Lithium ion polymer cells are flat, meaning you can stack them on top of each other, taking up the least space possible. The Sonata also enjoys the highest EPA rated passenger cargo space compared to the Fusion Hybrid and Camry Hybrid, thanks to its clever packaging.

Regenerative Brakes: Toyota

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Hybrids use regenerative brakes to capture the energy lost when slowing down. This helps charge the car’s battery. Due to this, many hybrids have touchy brakes, biting hard the moment you tap the pedal. While this does wonders for recharging the battery, it’s not a smooth driving experience. It can turn the average stop-light experience into a something akin to riding a boat in choppy waters, with plenty of rocking motion.

Volkswagen’s regenerative brakes are particularly frustrating, and we find that pedal pressure is inconsistent. BMW’s setup is no better. For those who enjoy a strong bite from the brakes, Ford setup has proven to be strong at initial application, yet smooth all the way to the point of stopping.

Fortunately one car company has refined their regenerative braking technology and features undoubtedly the best brakes available in a hybrid. Toyota’s stoppers in the Prius are excellent, and smooth, and every hybrid on the road should have brakes like these ones. They don’t feel like they’re regenerative brakes, and that’s one of the biggest compliments one can give. Honda hybrids also enjoy solid, consistent braking feel, though that may be due to the fact that the company prefers to use mild hybrids which use a small battery, and don’t require as much regenerative braking energy.

Internal Combustion Engine: Ford

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Now that we have most of the essential electric tech out of the way, it’s time to start thinking about the internal combustion engine that will be paired with our hybrid setup. Like every other hybrid out there, the car has to be fuel-friendly, but it should also be fun-to-drive, and that means it has to be powerful. For that reason alone, dismiss Toyota’s 1.8L four-cylinder motor used in the Prius.

Instead look to the blue oval’s two-liter four-cylinder engine, which is put to work in the Ford C-Max and Fusion hybrid. Making 141 hp from the internal combustion engine alone means that the total combined numbers when paired to the AC electric motor should be somewhere around the 200 hp mark. While there is a more powerful 2.5L engine in Toyota’s hybrids, it can be a bit fuel-thirsty and heavy, and the turbocharged 1.4L engine in the VW Jetta Hybrid is very thrifty, but sacrifices refinement.

As a result, the two-liter engine from ford will make our hybrid powerful when the driver calls for it, and smooth when it comes to cruising. Since the lithium polymer battery tech isn’t too heavy, our perfect hybrid should be enjoyable to drive, and still return excellent fuel economy.

Driving Coach: Ford

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Combining a powerful electric motor with a larger gas motor has the potential to cause issues. Having all that power available could result in lower fuel economy. While, yes, our car is trading electrons and gas for smiles and fun, it should still be capable of savings at the gas pump. With proper coaching, it should be possible to return over 45 mpg in combined driving situations. That would peg it as slightly more fuel friendly than the 41 MPG combined from the Toyota Camry Hybrid.

The eco-coach, which provides feedback and information to the driver, would be the one used in Ford’s hybrid system. By using a meter which shows how much is being asked of the car, the driver can dial out additional throttle input to keep the car in the EV range. Furthermore, the system can show which engine is working, or if the two motors are working in unison to provide maximum acceleration. Ford also has a very good braking coach which helps you recapture any energy lost with braking.

C-Max1The goal is to turn something as boring as getting good fuel economy into a fun video game. Maybe by assigning points and achievements based on your driving habits, drivers could get more involved in how they drive their car. Reached 45 mph without activating the ICE? Bonus! Did you just overachieve the fuel-economy estimates on your third consecutive gas tank? Score!

Perhaps that’s exactly what the hybrid car segment needs, something to quantify your driving experience, via a leaderboard, or social media connection. If corporations can provide perks ala Klout, maybe driving green could help line your pockets or get you goods.

For those not interested in the information overload, Ford has a visual representation of how your driving style is affecting fuel economy, with its “efficiency leaves” display. Gimmicky and unnecessary, this sort of nonsense wouldn’t make the cut.

Overall the driving coaches will cater to any driver, be it those who look for getting the most in every tank, or those who just want to know how to modify their driving style to fit a hybrid.

The Final Product?

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There’s no car out there that combines the very best of every hybrid, but based on this quick analysis of what’s out there, there should be. We’ll gladly leave the rest of the car, including the drive-train, interior-fittings and design up to the automaker, but our choices of tech should help the car stay under $30,000. The most expensive components here are the bigger AC motor from the $26,140 Toyota Camry Hybrid, and the high-tech battery technology from the $25,650 Hyundai Sonata Hybrid.

Of course, engineering challenges are likely what makes this ‘perfect’ hybrid from happening. Making the high-tech polymer battery work with a high-output AC motor and eCVT drive-train with pre-set gear ratios isn’t like bolting an aftermarket air intake to a Honda Civic. Everything needs to mesh in an efficient and safe way, which doesn’t interfere with the weight, practicality and usability of the vehicle. Until that can happen, we’ll keep waiting for the perfect hybrid.

  • Leaf

    Or even better.. get a Leaf!

  • RedDevil (’11 Insight owner)

    A turbo charged Honda Insight G2 makes the CVT deliver real power when it climbs in revs while it stays very economical when the revs are low.
    Road handling in the G2 is already quite good.