Navigant Research Blog

After a Century, the Era of the Cadillac V8 Is Over

— April 16, 2015

Twenty years ago, the thought of building a flagship Cadillac sedan without a V8 engine under the hood would have been virtually unthinkable. Nonetheless, in the coming months, the all-new Cadillac CT6 will hit the road to take on the likes of the Mercedes-Benz S-Class and BMW 7 Series with only 4- and 6-cylinder engine options to start with plus diesel and plug-in hybrid electric capability in the future. General Motors (GM) has created what it hopes will be a viable competitor to the segment leaders by harnessing a combination of advanced powertrain technologies and lightweighting to achieve both its performance goals and increasingly stringent fuel efficiency and emissions targets.

Cadillac introduced the first mass-produced V8 engine 101 years ago and, until as recently as 2010, every top of the line Cadillac had a minimum of 8 cylinders under the hood. After first being teased in a television ad run during the 2015 Academy Awards broadcast, the CT6 is debuting at the 2015 New York Auto Show and goes on sale later this year.

Bigger, Better, Not Heavier

In order to help meet the often conflicting goals of performance, driving dynamics, and energy efficiency, Cadillac is incorporating all of the major technologies discussed in Navigant Research’s Automotive Fuel Efficiency Technologies report. Despite its significantly larger size compared to the existing CTS sedan, the CT6 is estimated to weigh about the same 3,600 lbs thanks to extensive use of aluminum in its structure.

A combination of stampings, castings, and extrusions accounts for 64% of the mass of the structure and contributes to an overall reduction of 198 lbs compared to a comparable steel version. GM developed new techniques for laser and spot welding of aluminum in addition to the rivets, screws, and adhesives used extensively by Ford in its new F-150 pickup trucks.

Still High Performance

Starting from a lighter platform enables the engineers to utilize smaller, more efficient engines without sacrificing the performance that customers in this segment expect. At launch, the CT6 will be available with GM’s existing 2.0-liter turbocharged 4-cylinder, an all-new 3.6-liter normally aspirated V6, or a twin-turbocharged 3.0-liter V6 producing 400 horsepower and 400 lbs-ft. of torque. All of the engines feature direct injection and variable valve timing. The V6s will be GM’s first overhead-camshaft engines to feature cylinder deactivation with the ability to disable valve actuation and fuel flow on 2 cylinders under light load conditions.

Each power plant is paired with one of GM’s new 8-speed automatic transmissions and has auto stop-start functionality to shut down the engine when the vehicle comes to a stop to prevent wasting fuel while idling. Cadillac won’t reveal fuel economy numbers for the CT6 until later this year, but the new 3.6-liter V6 is expected to increase fuel economy of the midsize CTS by 9% compared to the 2015 model.

V8 86ed

In addition to these advanced gasoline engines, Cadillac plans to add both diesel and plug-in hybrid electric powertrains to its lineup over the next several years. What about the classic V8 configuration? Those are now limited to a pair of niche but still highly profitable segments, the ultra-high-performance CTS-V sedan and the full-size Escalade SUV. The rest of the lineup will rely on fours, sixes, and electrification from now on. It seems that a century after it began, the era of the mainstream Cadillac V8 engine has drawn to a close.

Update: Shortly after this blog was posted, Cadillac president Johan de Nysschen contacted me to confirm that the brand does in fact have a new high-performance V8 engine in development. While V8s will no longer be the volume powertrain, they will remain part of the future Cadillac lineup.

 

Seeking Fuel Economy, Automakers Slim Down

— April 16, 2015

As automakers scramble to stay on track to meet the 54.5 mpg corporate average fuel economy mandate by 2025, weight reduction is expected to be one of the key pathways to hitting that target. During 2015, General Motors (GM) is launching a wide range of new-generation vehicles—from its subcompact Chevrolet Spark up through its flagship Cadillac CT6 sedan, with virtually every new model boasting significant weight reductions thanks to new computer-aided engineering (CAE) processes.

Lightweighting and Global Platforms

In Navigant Research’s Automotive Fuel Efficiency Technologies report, lightweighting is identified along with engine downsizing and engine stop-start technologies as the main vectors for achieving the most cost-effective improvements in fuel efficiency for high-volume vehicles. GM is pursuing all of these approaches, but its weight reduction efforts are among the most notable. Similar to Ford’s approach of rationalizing its product lineup with common vehicles sold in global markets, GM also made a shift to global platforms in the latter part of the last decade.

Designing global vehicles that must conform to often conflicting crash safety standards led to a first generation of vehicles that often turned out heavier than previous models because they were not properly optimized. For GM, the problem was exacerbated by the financial difficulties it faced during the late 2000s leading up to its 2009 bankruptcy reorganization. The continuous effort to cut costs led to a gutting of engineering resources as staff were either laid off or fled for greener pastures in other industries.

Revving Up

Over the last 5 years, as the auto industry has recovered to prerecession sales levels, the once sparsely populated engineering centers at GM, Chrysler, and Ford are now full again and new design techniques are being applied to the next generation of vehicles. We’ve already seen Ford introduce an all-new aluminum-bodied F-150 pickup truck that cut nearly 700 lbs of weight.

So far in 2015, GM has announced the next-generation Chevrolet Volt and Malibu and the new Cadillac CT6 sedan, with a new Chevrolet Camaro and Cruze still to come. The Volt and Malibu will be nearly 250 lbs and 300 lbs lighter, respectively, while the CT6 is projected to have a base curb weight of about 3,600 lbs. The latter is comparable to the midsize CTS sedan, which is 8 inches shorter and 2 inches narrower. The CT6 is roughly 800 lbs lighter than the Mercedes-Benz S550, 700 lbs less than the current BMW 740i, and 400 lbs less than the similarly sized Cadillac XTS.

Optimization

GM has achieved these impressive reductions through extensive application of multidisciplinary optimization (MDO). Traditionally, the development of various aspects of a vehicle was siloed, with teams responsible for specific aspects of the design. The expanded use of advanced CAE and simulations has enabled greater collaboration early in the design process, leading to more granular optimization. Engineers are able to select a wider variety of materials, including aluminum and high-strength steel alloys, to achieve the best balance of weight, strength, manufacturability, and cost.

Just as Ford was able to maintain or improve the payload and towing capabilities of its trucks while shifting to smaller, more efficient engines, GM is able to improve the performance and driving dynamics of its vehicles despite downsized engines. Chevrolet has projected a 7% improvement in combined fuel economy for the base gasoline engine Malibu to 31 mpg, while the new hybrid version is projected to achieve 47 mpg combined. Over the next 10 years, this pattern of weight reduction is expected to continue as other new materials such as carbon fiber composites are put to use, benefiting both electrified vehicles and those that continue with internal combustion engines.

 

Volvo Pioneers Autonomous Vehicles

— March 17, 2015

Volvo has long sold cars that are considered among the safest in the world. Since the 1940s, Volvo has been at the forefront of introducing innovations that include laminated safety glass, crush zones, three-point seatbelts, and more recently, pedestrian detection with automatic braking. As Volvo prepares to launch its first all-new production vehicle since being acquired by China’s Geely Group, the company has announced plans for a test of highly automated vehicles on public roads near its Gothenburg, Sweden headquarters.

Self-Driving Cars a Reality

Self-driving vehicles from automakers, suppliers, and technology companies have become commonplace recently on Silicon Valley roads. However, all of those vehicles are under the control of the engineers trying to refine the complex control software required to make them work reliably. Beginning in 2017, Volvo plans to put a fleet of 100 autopilot-equipped XC90 SUVs into the hands of regular Swedish drivers.

Reiterating its oft-stated goal of achieving sustainable mobility and a crash-free future, Volvo has worked to design the autopilot system it is building into the XC90 to be robust enough to let ordinary drivers give  complete control.

“Making this complex system 99% reliable is not good enough, you need to get much closer to 100% before you can let self-driving cars mix with other road users in real-life traffic,” Erik Coelingh, technical specialist at Volvo, told me. With that in mind, Volvo has recognized the limitations of current technology, so the XC90 will be equipped with a combined array of radar, lidar, ultrasonic, and camera sensors.

Sensor Array on Autonomous Volvo XC90

(Source: Volvo)

Coelingh acknowledges that there are some fundamental problems that cannot be overcome. For example, lidar sensors cannot see through fog or rain and cameras cannot see lane markers that are obscured by snow. In addition to using multiple sensor types, Volvo is taking care in packaging the sensors to minimize the risk of obstruction from the elements such as snow and salt buildup.

The goal is to allow drivers to spend time on secondary tasks without constantly monitoring the system. The vehicles will be able to execute automatic lane changes and enter and exit a limited access highway. Soft degradation of the system will extend the time between the driver being alerted and when they have to take over. If the driver does not respond by taking over control in a timely manner, the vehicle will attempt to pull over and come to a safe stop.

Fully Autonomous vs. Self-Driving

Despite all of that, there is an important distinction between vehicles that are capable of fully autonomous operation and those that are entirely self-driving. The Volvo falls into the former category, with the ability to handle the driving when conditions permit, while reverting to human control in many scenarios. Google’s prototype pod car, which was designed without a steering wheel or pedals, is in the latter category. For the foreseeable future, driverless vehicles are likely to remain restricted to closed environments where they don’t need to interact with traditional vehicles.

As detailed in Navigant Research’s report, Autonomous Vehicles, 40% of new vehicles will have some form of automated driving capability by 2030. The bulk of those are likely to be similar in concept to what Volvo will be testing on Swedish roads in 2017. Although consumer surveys have indicated strong interest in autonomous vehicles, it’s too early to tell how much of that interest will be retained as consumers become aware of the real-world limitations of autonomous technology. Volvo’s test program in Sweden might give the first real feedback on this topic.

 

The New Volt: More Hybrid & More Electric

— March 9, 2015

In a somewhat ironic twist on the original and short-lived advertising tagline for the Chevrolet Volt, when the all-new second-generation Volt goes on sale this summer, it will be both more hybrid and more electric. When the first Volts arrived at dealerships in December 2010, Chevrolet promoted the extended range electric vehicle (EV) with the line “It’s more car than electric.”

That ill-conceived phrase was intended to communicate to consumers that the Volt would function just like any other car, without the range anxiety issues associated with plug-in battery-powered cars. However, the campaign came on the heels of a PR snafu during the media launch, when it became known that under certain operating conditions, the Volt functioned like other hybrid vehicles, sending a blend of torque from the electric motors and the engine directly to the wheels. Throughout the development of the Volt, General Motors (GM) had insisted that Volt wasn’t just a Prius-like hybrid but an electric car with an engine running a generator to provide juice when the battery was depleted. Within a few months, the much-criticized ad campaign was abandoned.

More Alike

When GM CEO Mary Barra revealed the 2016 Volt at the North American International Auto Show in January, she announced that the vehicle’s electric driving range would go up 30% to 50 miles and that range-extending fuel economy was expected to hit 41 mpg, an increase of more than 10% from the 2015 model. Since then, some additional details have been revealed about how the new Volt actually works, and it turns out that part of the mileage boost is achieved by making the electric drive unit work more like other hybrid vehicles.

The original Volt drive unit used two motor-generators, one planetary gearset, and two clutches to provide four different operating modes. In three of those modes, only electric power was sent to the wheels, with the higher-speed, range-extended mode supplemented by engine power, because it actually helped improve overall efficiency. The new drive unit is actually more mechanically complex than the original, although improved integration has enabled GM engineers to reduce the weight by about 100 pounds. In addition to the two motor-generators, the unit now has two planetary gearsets and a third clutch that together enable five operating modes. The new Volt also has three extended-range modes, each of which sends engine torque to the drive wheels in combination with torque from one or both motors.

At the Peak

During its gestation, the original Volt triggered a great deal of controversy among both engineers and the political class. Within months of the debut of the original concept, Toyota proclaimed that the Volt’s series hybrid layout was inferior to the parallel power-split configuration of the Prius. It now appears that GM engineers agree with that assessment. The somewhat more complex mechanism of the new Volt is closer to the way in which Toyota, Ford, and even GM’s discontinued two-mode hybrid systems work. The three hybrid modes provide the controls engineers with greater flexibility to keep the new, more powerful engine in the new Volt operating closer to its peak efficiency at all times while still providing improved performance of the old model.

Until the United States Environmental Protection Agency certifies the results sometime this summer, GM is only able to provide projections of the new Volt’s electric driving range and fuel economy. However, data collected through OnStar indicates that approximately 80% of the trips made with the 73,000 Volts sold in the last 4 years were done on electricity alone. With the electric range projected to go from 38 miles to 50 miles, Volt engineers expect drivers of the new model to complete 90% of trips without burning any gasoline, making it significantly more electric as well as more hybrid when the battery has been run down.

 

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