COVER STORY: Engineering the 2017 Honda CR-V
It would be hard to overstate the importance of the CR-V to Honda.
Even though the words “Accord” and “Civic” probably spring to mind when you think of the company—and with good reason, it should be noted, as those two cars have been absolute mainstays of the business for so many years—the CR-V, which is now entering its fifth generation, has been making remarkable increases in the overall business of Honda in the U.S. market.
If you go back to 1997, the first year of the first-generation CR-V, American Honda sold some 800,000 trucks, which represented 13 percent of its overall sales that year.
Walk it through to 2016 and light trucks represent 48 percent of American Honda’s sales. Or approximately 1.6-million units.
To be sure, 20 years ago it was the CR-V. And today there are other vehicles in the truck lineup, like the Ridgeline, Pilot and HR-V. But know that the CR-V has had annual sales of over 300,000 units for three years running. And that it has grown for six straight years. And that since it has been available it has been bought nearly 4 million times in the U.S.
All things that few vehicles from any OEM have achieved.
With the compact SUV (or compact crossover) market being as important as it is for essentially every automaker in the U.S.—or anywhere on the planet, for that matter, as the phenomenon is nothing short of phenomenal—as Takaaki Nagadome, the development leader (a.k.a., chief engineer) for the 2017 CR-V, and his team set about developing the vehicle, they had a real challenge in front of them.
That is, on the one hand they needed to keep the characteristics that have made the vehicle so appealing to so many.
On the other, they had to create something that would have even more appeal in a tough segment.
Nagadome, who started his career at Honda working on the first-generation NSX and who recently served as assistant large project leader (or assistant chief engineer) on the HR-V, uses a word to describe what they were trying to achieve, a word that may be associated with supercars like the NSX but a compact crossover like the CR-V . . . ?
Yes, he says that was the keyword for the development of the vehicle.
He wanted to achieve both ease of use (think HR-V, the subcompact crossover) and premium values (think NSX, which may be a stretch, admittedly). They wanted to achieve a compact crossover that has best-in-class dynamic performance and a degree of sophistication and quality. The dynamics are engineering. The sophistication is based on aesthetics.
Overall, the fifth-generation vehicle is larger than its predecessor. It is 1.2 inches longer (at 180.6 inches) and the wheelbase is 1.6 inches longer (at 104.7inches). It is 1.4 inches wider (at 73 inches) and its height is increased by 0.5 inches (65.6 inches).
Nagadome cites the key attributes that they worked to achieve to realize the dynamic performance they wanted for the vehicle.
They sought sporty and linear handling. This is predicated on steering precision—as in the nose of the vehicle going in the direction indicated by the driver by turning the steering wheel—yaw delay—little lag in the movement of the vehicle in response to a maneuver with the body feeling solid—and easy handling—or proper feedback from the steering wheel.
They sought a “sporty” drive, with linear acceleration.
They wanted there to be low NVH.
They wanted the vehicle to handle changes in road surfaces.
They wanted there to be a flat ride so that the occupants would be comfortable
They wanted stability at high speeds and controllability of the braking at all speeds.
For the steering precision, they are deploying a dual-pinion, variable-ratio electric power-assisted rack-and-pinion steering system. The dual pinion setup is such that there is both physical input from the driver and a supplemental electric motor: there is a non-contact torque sensor that measures the driver’s steering effort then an electronic control unit calculates the amount of motor assist needs to be added.
The variable steering ratio encompasses a 20 percent range; there’s slower gearing when the vehicle is going straight at high speeds. For lower speeds, there are just 2.3 turns lock-to-lock, as compared with 3.1 turns for the previous generation.
As for the handling, there are MacPherson struts in the front and a multi-link setup in the rear. The front suspension arms and hub carrier are steel. The lower suspension arms are connected to the subframe and the body with fluid-filled compliance bushings (the trailing arms in the rear also use them) to minimize vibration transfer to the cabin.
The rear suspension is mounted on a rubber-mounted subframe, which helps contribute to noise reduction. The rear suspension uses stamped-steel arms and cast-aluminum hub carriers.
The stabilizer in the front is tubular; the rear stabilizer bar is solid.
As for the braking, there are four-wheel discs with four-channel ABS. The system features an electric brake booster (EBB). The EBB includes an electric motor-operated booster that is controlled by a microprocessor. The microprocessor monitors the speed of the vehicle and the amount of pressure that the driver is applying to the brake pedal. This helps quickly build hydraulic pressure to provide better braking as required by speed (which is something that vacuum-assisted systems don’t take into account).
A big factor contributing to NVH, safety, dynamic handling and fuel economy is a light, strong structure. For the fifth-gen CR-V, ultra-high strength is used to an extent that massively eclipses the previous vehicle. This is hot stamped 1500 MPa material. It is used for 13.8 percent of the body structure. The 2016 CR-V is 3 percent 1500 MPa steel. But that’s not all of the ultra or advanced high-strength materials used to build the vehicle. There is 11.8 percent 980 MPa steel (none in the 2016 model, FYI), 11.6 percent 780 MPa material and 10 percent 590 MPa steel. Then 3.1 percent of the body structure is made with 440 MPa high-strength steel and 6.2 percent with 340 MPa steel. The remaining 43.5 percent is mild steel, 270 MPa.
One of the other things that’s done to increase the stiffness and the durability in the unibody structure is to closely group the welds in critical areas: while the traditional spacing of the welds is 40 mm to 45 mm apart, in the short-pitch grouping the welds are just 20 mm apart. And before leaving the steel, one of the things they’re doing is to provide “soft zones” in some of the components, such as the rearward ends of the rear unibody frame rails. This is done to provide better crash-energy management. The soft zones are created by selectively tempering the hot-stamped, laser-trimmed components. So, in the case of the ends of the rails, they’re at 650 to 800 MPa while the overall rails themselves are at 1400 to 1700 MPa.
(Speaking of the assembly of these vehicles, they’re being manufactured in three plants: East Liberty, Ohio, Greensburg, Indiana, and Alliston, Ontario, Canada. The engines, which we’ll get to next, are manufactured in two plants: Anna, Ohio, and Alliston, Ontario. The transmissions are made in Russells Point, Ohio.)
Of course, performance is predicated in large part on the powertrain. There are two engines, a 184-hp, normally aspirated 2.4-liter DOHC in-line four and a 190-hp, turbocharged 1.5-liter DOHC in-line four.
The 2.4-liter engine is a carryover from the 2016 CR-V. The 1.5-liter is a higher performance version of the engine available in the 2016 Civic (which produces 174 hp).
According to Toshikatsu Takanohashi, project leader, Powerplant, the improved engine performance is achieved by a new turbocharger impeller design and improved intake and exhaust systems, which allow a reduction in compression ratio (from 10.6:1 to 10.3:1) and an increase in maximum turboboost pressure (by about 6 percent more). The impeller in the turbocharged Civic has 11 blades. That is redesigned for the CR-V: it has a nine-blade turbine impeller. The blades, Takanohashi says, are longer (by about 5 mm) and wider (by about 3 mm) in the CR-V; this help improve the movement of the exhaust.
“It’s not just the turbo,” he says. “We worked on piston cooling. There are cooling channels, grooves, to run cooling oil through the piston head.” This helps improve combustion.
Both engines are mated to a continuously variable transmission (CVT). There are modifications to the CVT depending on which engine is used. For example, there are refinements to the lockup clutch damper and torque converter when used with the turbo, so as to help smooth initial acceleration.
Because it is a “utility” vehicle, there is an available all-wheel drive system. This consists of the front-wheel drive system, a compact transfer case, a prop shaft, a rear differential, an electronically controlled hydraulic pump, a multi-plate clutch, and left- and right rear-wheel drive shaft. This is called “Real Time AWD with Intelligent Control System,” with the intelligence being a control system that manages the electric motor that drives the hydraulic pump that, in turn, actuates the clutch to apportion power to the rear wheels as required by conditions.
As noted, the fifth-generation CR-V is wider than its predecessor. The exterior designers (the exterior design proposal was penned in the U.S.; the interior lead was in Japan) took advantage of providing stronger fenders all around to help accentuate the stance.
While the overall silhouette is similar to the previous generations, there are some notable changes, such as a longer hood and shorter rear overhang, as well as narrower A-pillars. As is de rigueur in automotive design today, there is particular attention paid to the lighting in the front and rear. There are LED daytime running lights on all models, and LED headlights are available on the CR-V for the first time. In addition to which, there are standard wing-shaped LED taillights. Another first-time for the CR-V: the wheels—17- or 18-inches, depending on trim—are all aluminum alloy.
One benefit of having a longer wheelbase is having greater cargo capacity, with there being 39.2-ft3 of capacity with the second row up, or 2-ft3 more than the 2016 model, and 75.8-ft3 with the seats folded, or 4.9-ft3 capacity.
Of course, the human space is larger, as well, with an EPA passenger volume of 105.9-ft3, or 1.8-ft3 more than in the 2016 model.
Honda is expanding the availability of its Honda Sensing tech from one trim level to three. This includes:
• Collision mitigation braking. An automatic emergency braking system that uses a millimeter radar system behind the front grille and a monocular camera near the rearview mirror to scan traffic conditions and, thanks to the camera, pedestrians. The radar and the camera work simultaneously and together and control the vehicle stability assist (VSA) and electric brake booster (EBB) to engage braking when necessary.
• Forward collision warning. This is integrated with the collision mitigation braking system.
• Lane keep assist. The camera on the upper portion of the windshield reads lane markings (lines, Botts’ dots and cats eye) at speeds between 45 and 90 mph. If it is determined that the driver is drifting, the system automatically engages the electric steering system to apply the torque necessary to bring it back into the center of the lane.
• Lane departure warning. If the camera detects the driver leaving a lane without using the turn signal, visual and audible warnings are displayed.
• Road departure mitigation. This works with the lane departure warning setup. If the system determines that the CR-V is leaving its lane, then it can use the electric power steering system to make the required adjustment, and if that is insufficient it activates VSA and EBB to keep the vehicle in its lane or from going off the road.
• Adaptive cruise control with low-speed follow. The radar and the camera determine whether the set speed can be maintained by tracking the distance of the vehicle in front of the CR-V, and signals adjustments to the brakes or throttle as needed. The low-speed follow function allows the vehicle to go to 0 mph. The vehicle resumes travel when the driver uses the accelerator pedal or activates a button on the steering wheel.
In addition to which, the vehicle offers a radar-based blind-spot information system, a driver attention monitor (it tracks the driver’s steering inputs to determine whether the driver might be getting inattentive and in need of a break) and cross-traffic monitor that uses the same radar sensors in the corners of the rear fascia as the blind-spot information system.
Chief engineer Takaaki Nagadome says, “We aimed to create the benchmark for the next generation of SUVs.”
With the fifth-generation CR-V, it seems that they nailed it.
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