Compared to the first-generation Genesis, which debuted at the 2008 North American International Auto Show (NAIAS), the latest iteration has “elevated our game even further, on every level,” said Hyundai Motor America’s new CEO David Zuchowski at this year’s NAIAS in Detroit.
The rear-wheel-drive luxury sedan embodies the first realization of Hyundai’s new design direction—“fluidic sculpture 2.0”—that was previewed last year with the HCD-14 Genesis concept (http://articles.sae.org/11727/). Beneath the “clean,” flowing exterior panels, the 2015 Genesis features a redesigned platform to accommodate a new available HTRAC all-wheel-drive system.
“We began with a clean slate and created an all-new platform and body structure solely for the Genesis,” which is composed of more than 50% advanced high-strength steel, said Mike O’Brien, Vice President of Corporate and Product Planning, Hyundai Motor America. “Every element of the body and chassis was optimized for stiffness, crash performance, and weight, with not a single part carrying over from the previous chassis.”
The new Genesis has 16% greater torsional rigidity and 40% greater bending rigidity compared to its predecessor. “Each of these [figures] bests the current BMW 5-Series,” O’Brien claimed.
(Go to http://video.sae.org/11792/ to watch O’Brien point out for Automotive Engineering many of the new technologies using a technical cutaway of the Genesis luxury sedan.)
High-pressure die-cast aluminum shock towers, hot-stamped and laser-welded side members, and a diamond-shaped strut bar are a few of the elements that contribute to the stiffer structure and enhanced steering responsiveness and NVH characteristics.
NVH reduction was a major goal of the vehicle program. Among other efforts, the doors were thickened, sunroof articulation reshaped, and cowl bulkhead insulation and sealing improved. The total weight of the sound insulation package used on the Genesis is 84 lb (38 kg).
Hyundai engineers also developed new suspension, steering, and braking systems. The fully independent, five-link front and rear suspension designs have increased stiffness compared to the original Genesis, with increased front and rear suspension travel for greater wheel articulation and bump absorption. A Continuous Damping Control (CDC) suspension, available on the Genesis 5.0, helps increase control of body motions and body roll.
The company claims that the reduction in camber angles when turning at speed results in improved steering feel, 23% less tire tilt, and increased lateral grip. Rack-mounted motor-driven electric power steering (R-MDPS), with a Variable Gear Ratio (VGR), reportedly helps with high-speed stability and more direct feel at low and medium speeds.
The car has 52:48 front:rear weight distribution.
Hyundai engineers collaborated with top dynamics consultants such as Lotus Engineering to validate the performance capability of the Genesis, O’Brien said.
The new HTRAC AWD system uses an electronic center coupling with active torque control. “What makes it unique is its multimode feature,” he said.
In addition to driver-selectable Normal, Eco, and Snow modes, a Sport setting transfers up to 90% of the torque to the rear wheels for a more dynamic rear-drive feel. The system, which weighs 165 lb (75 kg), also can direct more available torque to the rear wheels during steady-state highway cruising for reduced drivetrain frictional losses and noise.
Both the 5.0-L Tau V8 engine, which produces 420 hp (313 kW) at 6000 rpm and 383 lb·ft (519 N·m) at 5000 rpm, and the standard 3.8-L direct-injected Lambda engine, generating 311 hp (232 kW) at 6000 rpm and 293 lb·ft (397 N·m) at 5000 rpm, were re-engineered with a new induction and exhaust system.
“Both engines now have improved low-end response along with better efficiency and NVH,” said O’Brien.
The Tau V8’s compression ratio was bumped from 11.5:1 to 11.8:1. The engine also benefits from an optimized intake runner length, enhanced timing chain for reduced friction and NVH, low-torque exhaust manifold, and upgraded multiple-injection mapping. Other features include Dual Continuously Variable Valve Timing (D-CVVT), a tuned variable induction system, and low-friction coatings on piston skirts.
The 3.8-L engine includes a three-stage variable intake system, triangular-pattern fuel injector for improved combustion, an air-gap exhaust manifold for better NVH, and an upgraded cylinder block with a variable-vane two-stage oil pump for reduced parasitic losses. It has a compression ratio of 11.5:1, and also features D-CVVT and variable induction.
Both engines are linked to an eight-speed Shiftronic transmission with improved gear change speed, sport-mode mapping, and paddle shifters as standard equipment.
To help with NVH reduction, the engine support brackets were moved further apart for greater stiffness, and transmission and subframe mounts were stiffened by up to 100%.
O’Brien told Automotive Engineering that the new Genesis weighs about the same as the previous generation, largely due to crash-safety requirements.
“Keep in mind, for a front-engine, rear-drive car with a North-South engine orientation, it is very hard to achieve the offset-barrier top safety rating; that requires a lot of structure, because so much energy is in an area where there’s no powertrain [to help absorb that energy],” he explained. “For that reason, our weight is about the same” between the first- and second-generation cars.
The goal for the new Genesis is a Top Safety Pick+ rating from the IIHS (Insurance Institute for Highway Safety), O’Brien added. “We’ve done our own simulations many times, so we’re confident we’ve done everything we can to ensure the top rating. Now it’s up to the testing agencies to test it.”Continue reading »