Insight into Honda's new hybrid

  • 27-Mar-2009 03:41 EDT
2010 Insight_cropped for Web.jpg
The aerodynamic shape of the new 2010 Insight is aided by an underbody featuring plastic shields under the engine bay, floors, and fuel tank. The result is a Cd reduction of 7%.

Honda usually doesn’t talk about future products, noted company spokesman Sage Marie. But for the past two and a half years or so, there has been much talk about its plans for a new low-cost, dedicated hybrid model, signifying the vehicle’s importance to the Japanese automaker.

In March, the manifestation of all that talk—the five-door 2010 Insight compact sedan—went on sale to U.S. consumers with an MSRP of $19,800—nearly $4000 less than the 2009 Civic Hybrid.

A strong value proposition that would move hybrids even more into the mainstream—that was the goal of the Insight’s development team.

“Comparisons with [Toyota] Prius are inevitable, but our vehicle development and positioning targets are unique in providing customers an attainable entry point into hybrid technology that yet exists,” said William Walton, Manager of Product Planning for Honda cars, at a December media event prior to the car’s public reveal at the North American International Auto Show (NAIAS) in January.

“Honda’s plan for Insight is to match the needs of the [under 30-year-old] age group that has not yet had the access to hybrid technology, mainly due to the affordability or value proposition,” Walton continued, noting that there had to be “a reasonable gap” in pricing between the Insight and the Civic Hybrid.

The initial U.S. sales target for the new Insight is 90,000 vehicles in the first 12 months. In 2008, Honda’s total hybrid sales were 31,495. (In comparison, nearly 159,000 Priuses were sold in 2008.)

“The all-new Insight is the latest symbol of our commitment and what’s to come: a portfolio of hybrids intended to cater to different needs and tastes of today’s consumers,” said Dan Bonawitz, American Honda’s Vice President of Corporate Planning and Logistics, adding that in a couple of years the Insight will be joined by a sporty hybrid car based on the CR-Z concept. “Honda has a clear and defined hybrid story for the next five years.”

“All along we have openly said [that] hybrids don’t make sense yet for the average consumer. They don’t pencil out—unless gasoline is above about $4-a-gallon or you can get the costs down to a much more reasonable level,” said Bonawitz, commenting on why Honda has not placed its Integrated Motor Assist (IMA) hybrid system into more vehicles thus far. “Even though fuel prices are down right now, I don’t think any of us expect them to stay there long term. We think the time is right now to start moving in that direction.”

Asked if the Insight can be profitable in the short term, Bonawitz replied, “We don’t try to lose money on anything we do.” So, yes, he believes the hybrid car can be a moneymaker from the get-go.

Cost a crucial consideration

Responding to why the Insight’s highway fuel economy is slightly down compared to the Civic Hybrid’s, Walton said “we use 11 battery modules in the Civic IMA system, which gives it more battery boost vs. the Insight, which uses seven. A lot of that was cost-related. We had to balance how much technology we could put in this vehicle with the price point that we were targeting.”

Engineers did, however, increase the efficiency of the nickel metal-hydride (NiMH) battery to, in essence, “do more with less,” Walton said. “The overall IMA battery set is 24% more compact than the previous generation in the Civic, but we also increased the efficiency of the battery modules overall by 30%.”

The seven-module battery system is comprised of 84 individual D-sized 1.2-V cells. Module output is improved via thinner separators in the cell and increased electrode plate area. A more corrosion-resistant cathode alloy contributes to a 30% more durable battery. According to Hideharu Takemoto, Powertrain Project Leader, the battery should not need to be replaced for the entire vehicle life cycle.

Rationalized system parts specification—such as unifying the motor electronic control unit (ECU) and battery ECU, unifying the 12-V and high-voltage cables in the subfloor cabling, and soldering the copper plate directly to the semiconductor in the inverter—played a cost-reducing role in the IMA hybrid system as well, while also simplifying manufacturing and assembly.

That delicate balancing act between technology inclusion and cost minimization was indeed the greatest challenge the Insight team faced during development, the car’s Large Project Leader (Chief Engineer), Yasunari Seki, told AEI.

“Executives always told us to make an affordable vehicle; however, it cannot be cheap. Cheap and affordable are different,” said Seki, who was assigned to the new Insight project back in January 2006 when development began.

The fifth-generation IMA system was not the sole source of cost reduction. Component sharing with other Honda vehicles, notably the Fit and Civic Hybrid, was another strategy. “In terms of commonality, the IMA system itself is 97% new—not much is common there,” said Seki. “The engine cylinder block is shared with the Fit; but for the sake of fuel economy, the cylinder head was made new, exclusive to Insight.”

Regarding the platform, the engine frame is based on the Fit, but the front and rear floor sections are newly designed structures to accommodate fuel tank placement under the rear seat and Intelligent Power Unit (IPU) placement under the cargo floor (the Civic Hybrid’s IPU is behind the rear seat width-wise).

The continuously variable transmission (CVT) was borrowed from the Civic Hybrid, and though some front and rear suspension (MacPherson strut and H-shaped torsion beam, respectively), steering gearbox, and other chassis parts were revised, “we basically used the Fit parts,” noted Seki.

“Fit has a large volume, so using its components makes sense,” he said. “It’s very important in terms of cost reduction.”

Material selection, as to be expected, was largely driven by cost considerations, too. That’s one reason why no new “exotic” materials are used in the body structure; the car’s body-in-white is comprised of 54% high-strength steel—the same as on the '09 Fit.

Another reason: “We wanted to make sure that any factory globally could manufacture this car,” said Seki. The new Insight is currently produced at Honda’s Suzuka plant in Japan.

Modifying driver behavior

Admittedly, the Insight development team was not aiming to produce a “hypermileage” vehicle: It wanted to strike a good balance between performance, fuel economy, and comfort.

But along a 16.2-mi (26-km) road course, with flat to slightly hilly terrain and numerous stoplights, this AEI editor was able to post a 68.8-mpg mark in 34 min. On a separate 53-mi (85-km) drive route, not expending as much fuel-sipping effort as during the challenge, 56.0 mpg was still achieved. Both figures are well above U.S. EPA fuel-economy estimates of 40/43/41 mpg city/highway/combined.

Assisting with such economical driving is a new Eco Assist information system that informs the driver when he or she is achieving maximum efficiency—or not—via a multicolored speedometer background: Green is optimal, blue-green is average, and blue is below average. Feedback on current and long-term driving practices is offered via an Eco Guide display.

By pressing the ECON button located to the left of the steering wheel, the driver can choose to enhance fuel economy at the expense of some performance capability. Econ mode initiates a range of functions that increase fuel economy, such as engaging the idle stop feature sooner, operating the air-conditioning more in recirculation mode, optimizing throttle angle input and CVT operation, and limiting power and torque by about 4% (full responsiveness is provided at wide-open-throttle).

The stated EPA fuel-economy figures do not take into account ECON mode. “Based on our in-house tests, the average is about 10% better [fuel economy]” with ECON mode selected, said Takemoto.

“We know there is a wide range of driving habits,” said Bonawitz. “We want to start educating people on better acceleration, better deceleration, as another means of improving overall CO2 reduction and energy use.”

A legitimate concern with such informative graphical elements in the instrument cluster is driver distraction—and Honda engineers gave that prospect much consideration during Eco Assist development.

“That was certainly a lot of the discussion during development of the vehicle, and that’s why [the system] has a couple of levels,” Bonawitz explained. “So the speedometer color change is right in the lower part of your line of sight, something you can see without really taking your eyes off the road. And then the rest of it allows you to, at will, look for a little bit more detail.”

Paired with the IMA hybrid system is a 1.3-L i-VTEC four-cylinder engine, a more efficient unit in its own right. The engine is borrowed from the Civic Hybrid but was tweaked to be about 20% lighter and 2% more efficient in the Insight, Takemoto said. Contributing to the fuel-economy gain are enhanced combustion via high expansion ratio valve timing, reduced engine friction via low-tension piston rings and patterned piston coating, and enhanced catalyzation via high-precision air/fuel ratio control.

The ACE (Advanced Compatibility Engineering) body structure—incorporated in all of Honda’s new products—is now in the Insight, as is a range of safety technologies such as airbags all around, active head restraints, ABS with electronic brake distribution, and a tire-pressure-monitoring system.

Based on in-house crash tests, Honda anticipates receiving all five-star safety ratings, said Seki.

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