Hybrid Car Review

The 2010 RX 450h comes with an updated hybrid drive which has improved fuel economy by 8-12 percent over its predecessor. At the same time, Lexus has also increased the power by 27 hp.

The new EPA rating has gone from 27 mpg city and 24 mpg highway to 28 mpg city and 27 mpg highway. Not exactly a huge gain, but any little bit helps. And it's good enough for a Super Ultra Low Emission Vehicle (SULEV) certification in California (Tier 2-Bin 3).

Both torque and horsepower have been improved, up to 245 hp at 6,000 rpm and 234 lb.-ft at 4,800 rpm.

The 288V DC Nickel Metal Hydride (Ni-MH) battery pack is slotted under the rear seat. It is covered, along with the hybrid-related components up to eight years/100,000 miles.


Press Release Follows:

Lexus has introduced the next generation of its trend-setting RX luxury utility vehicles for 2010, the V6-powered RX 350 and the hybrid RX 450h. Lexus inaugurated the luxury crossover category with the original RX 300 model in 1998 and introduced the first-ever luxury hybrid in 2005. More than one million Lexus RX models have been sold worldwide, making it the most successful luxury utility vehicle. The new RX350, which reaches Lexus showrooms in February 2009 with the RX450h hybrid a few months later, once again raises the bar for design, engineering and luxury innovation in the segment.

Engine/Transmission/Drivetrain/Performance

The 2010 Lexus RX 350 teams a revised 3.5-liter V6 engine with an all-new six-speed Multi-Mode Automatic Transmission. New intake and exhaust manifolds improve engine breathing for enhanced performance and fuel economy. Horsepower is increased to 275 at 6,200 rpm from 270, while Lexus maximized the torque output to better meet the needs of luxury crossover drivers. Ninety percent or more of the 256 lb.-ft. of peak torque is available from 2,300 to 6,100 rpm, an optimal range where torque is most utilized. An insulated engine cover, styled in the shape of two cylinder banks, conceals the new V6 to help ensure a quiet cabin; easy-access points facilitate routine service.

Dual Variable Valve Timing with intelligence (VVT-i) is used to control both intake and exhaust camshafts independently, optimizing engine performance at all speeds and loads. Refinements to the valvetrain, including roller rocker arms and slimmer valve stems, reduce friction and weight to improve fuel economy. Also helping to enhance torque is the improved Acoustic Control Induction System (ACIS), which varies the intake runner length in response to engine speed and throttle position. The ETCS-i (Electronic Throttle Control System-intelligent) softens throttle response during initial acceleration for smoother takeoff and to help reduce wheel spin.

The 2010 RX 350’s new six-speed automatic transmission replaces the previous five-speed. Using miniature high-flow linear solenoids to control transmission-fluid line-pressure, the transmission yields quicker shifting response. The torque converter uses a new low-speed lockup damper to enable lock-up from second to sixth gear to help improve the fuel economy.

When applying the accelerator pedal rapidly during kick-down, the new direct-downshift control allows the transmission to directly shift from sixth to third or fifth to second, skipping the intermediate gears to achieve the quickest response. Under normal kick-down pedal application, downshift control uses the intermediate gears to ensure the smoothest shift is attained. “Shift shock,” which was already commendably low in the previous model’s five-speed transmission, is further reduced.The Multi-Mode Automatic Transmission allows the driver to shift manually when desired by first moving the gated shift lever to the “S” slot and then pushing it forward ("+") to up shift and backward ("-") to downshift. An Artificial Intelligence shifting (AI-SHIFT) control, new to RX, sets shift patterns based on the vehicle speed and throttle position and estimates road conditions and driver input to automatically control the shift pattern. For example, when driving in hilly areas, AI-SHIFT can prevent unnecessary shifting. When descending inclines, the transmission prevents up shifts to achieve more engine braking.

All-Wheel Drive

Lexus again offers its RX 350 and RX 450h crossover models with a choice between front-wheel drive and all-wheel drive. The RX 350 introduces an all-new electronically controlled Active Torque Control AWD system. As in the previous RX 400h, the RX 450h hybrid uses a separate rear electric motor-generator to provide power to the rear wheels when road conditions or throttle response dictates.

The previous RX 350 model’s AWD system used a viscous coupling locking center differential to provide 50:50 torque distribution. In the 2010 RX 350, Active Torque Control AWD uses an electronically controlled coupling ahead of the rear differential to vary torque distribution anywhere from 100:0 to 50:50 front to rear, depending on driving dynamics and road conditions. The new AWD system is 35 lbs. lighter than the previous system and reduces parasitic losses by 30 percent.

When accelerating, or starting off on a low-grip surface, torque is quickly provided to all four wheels. At steady speeds, torque is sent only to the front wheels, enhancing fuel efficiency.

For handling agility and control, the AWD system increases rear-wheel torque when the vehicle’s front tires start to lose traction and decreases rear-wheel torque when the vehicle’s rear tires start to lose traction. On rough or sandy terrain, an AWD LOCK switch provides enhanced traction performance for low-speed maneuvering (if in LOCK mode, the system reverts to AUTO mode when speed exceeds 25 mph). To help prevent a tight corner-braking condition (shuddering) during low-speed cornering, the system reduces rear wheel torque.

Hybrid Powertrain

The 2010 RX 450h introduces an updated version of Lexus Hybrid Drive, featuring a 3.5-liter V6 Atkinson-cycle engine, lighter electric motors, a smaller and lighter power-control unit and other fuel-saving innovations. It offers up performance similar to V8s with better combined fuel economy than the average four-cylinder mid-size sedan. With an EPA-estimated[1] 28 mpg city and 27 mph highway (26 mpg for the AWD), it earns 8-12 percent better fuel economy than its acclaimed predecessor. All this while producing 295 total system horsepower, which is 27 more than the current generation RX400h.

A full hybrid, the RX 450h can operate in electric-only or gas-engine-only modes as well as a mode that combines the power of both. Extended electric-mode operation during low-speed or stop-and-go driving conditions helps reduce fuel consumption. Under certain circumstances, a new driver-selectable EV mode can allow the vehicle to be driven short distances using only the electric motors.

The RX 450h will achieve Super Ultra Low Emission Vehicle (SULEV) certification in California (Tier 2-Bin 3 in other states), producing nearly 70 percent fewer smog-forming emissions than conventionally powered vehicles.

With the Atkinson cycle, the gasoline engine’s intake valves are closed late to delay beginning of compression, resulting in a higher expansion ratio. That reduces intake and exhaust energy losses for more efficient combustion and improved fuel economy. The gas engine alone produces 245 horsepower at 6,000 rpm, up from 208 in the previous RX 400h; torque is 234 lb.-ft. at 4,800 rpm as compared to 212 at 4,400 rpm from the previous RX 400h’s 3.3-liter V6. The Atkinson cycle also reduces exhaust temperature. A new cooled Exhaust Gas Recirculation (EGR) system reduces it further still, helping economy by eliminating the fuel enrichment otherwise needed to help prevent catalyst overheating under high loads.

A 288V DC Nickel Metal Hydride (Ni-MH) battery pack fits neatly under the rear seat and is more compact and lighter than in the previous model. A boost converter efficiently raises voltage to 650V DC, and an inverter changes this to 650V AC for the front-mounted 123-kW electric motor-generator. The boost converter and inverter are enclosed in the power-control unit, which also houses the condenser. The new power-control unit is 17.6 lbs. lighter than the previous unit and about 40 percent smaller. Losses have been reduced by more than 10 percent, enhancing fuel economy.

The RX 450h front-wheel-drive model’s hybrid powertrain employs two motor-generators: MG1, the engine-driven generator, is a starter and can charge the battery pack or power other electric motors as needed; MG2 is the front-drive motor. Power from the gas engine and MG2 is distributed to the drive wheels via a planetary gear-type continuously variable transmission. MG1 controls the output speed of the transaxle through the planetary gear set, without clutches or a viscous coupling. MG2 delivers similar maximum torque as in the previous model, but over a wider range for better response and smoother performance. When the RX 450h is coasting or braking, the electric motors function as generators, capturing energy that would normally be lost as heat through the brakes and transforming it into electricity to recharge the batteries.

The all-wheel-drive RX 450h adds a third, rear-mounted motor-generator (MGR) to drive the rear wheels, eliminating the need for power-transfer gearing or a driveshaft from the front. The hybrid system electronically varies front and rear torque distribution depending on traction conditions.

A new two-step flywheel damper absorbs small torque fluctuations and also the minor vibration produced when the gasoline engine starts and stops. A SNOW mode slows accelerator-pedal response to help reduce the possibility of wheel spin.

Multi-Mode, a feature adapted to the vehicle’s electronically controlled continuously variable transmission, allows the driver to control engine braking for enhanced maneuverability on rough or winding roads. The AI-SHIFT feature, adopted on a hybrid for the first time, selects and holds the optimal range when driving downhill or on inclines, providing a smoother driving experience.

The power-steering pump, water pump and air-conditioning compressor are driven electrically rather than by the engine, reducing parasitic losses.

To enhance fuel economy, a new exhaust heat-recovery system circulates engine coolant through a unit installed in the exhaust pipe behind the catalytic converter. This new feature reduces engine warm-up time, allowing it to stop earlier, more often, and for longer periods, improving both fuel economy and emissions.

Active Safety

The Vehicle Dynamics Integrated Management (VDIM) handling technology is now available on the RX 350 and remains standard on the RX 450h. The VDIM system anticipates loss of vehicle control in virtually any direction. VDIM governs all of the vehicle’s dynamic handling systems – the Anti-lock Braking System (ABS), Brake Assist, Vehicle Stability Control (VSC) and Traction Control (TRAC) – employing them collectively and seamlessly to make corrections while allowing higher dynamic capability. VDIM also interfaces with the electronic throttle control system.

The system’s enhanced VSC function adds steering assist torque to help aid handling on a split-friction surface. The VDIM system also provides a limited slip differential effect. The TRAC and VSC functions can also be switched off, for example, when the driver needs to free the vehicle when stuck in mud or snow.

The new RX adopts Hill-start Assist Control, which uses brake pressure to help prevent the vehicle from moving backward when starting out on an incline. This system does not wait to detect rollback, however. It can be controlled by the driver and works in both forward and reverse. While the vehicle is stopped and the brake pedal is depressed, pushing it further activates the feature. Brake pressure is then maintained for approximately two seconds after the brake pedal is released and the driver switches to the accelerator pedal.

The previous generation RX offered Lexus’ Adaptive Front-lighting System (AFS), which guided headlamps into a turn. The 2010 RX models introduce the new Intelligent AFS, which for the first time on a Lexus is being used for high beams of the HID headlamp equipped models, and for the low beams of the LED equipped RX 450h models. When entering a corner, AFS estimates where the vehicle will be in three seconds, based on the vehicle speed and the angle of the tires, and adjusts the lateral aim of the headlamps. AFS can be switched off by the driver if desired. AFS also includes an auto-leveling function.

Using a camera mounted on the inner rear view mirror, a new available automatic high beam system switches between high and low beams in response to oncoming vehicles and those traveling in front, or when other ambient sources are detected, helping reduce driver inconvenience.

The optional Pre-Collision System (PCS) with Dynamic Radar Cruise Control uses millimeter-wave radar to measure and maintain a pre-set following distance from a vehicle traveling ahead. The radar sensor can detect certain obstacles in front of the car, and a PCS computer with vehicle speed, steering angle and yaw-rate inputs helps to determine whether a collision is highly possible. In such a situation, PCS preemptively retracts front seat belts and pre-initializes Brake Assist so that increased braking will be applied the instant the driver depresses the pedal.

Passive Safety

A high-strength cabin design and comprehensive Supplemental Restraint Systems (SRS) are designed to help provide a high level of crash-energy management. Approximately 42 percent of the entire structure uses high tensile strength sheet steel. The new structure was engineered to help provide collision compatibility with vehicles of varying heights and weights.

The 2010 RX models are equipped with a segment-leading 10 standard airbags, including side curtain airbags, front seat-mounted side airbags, rear side airbags (for the outboard seating positions) and knee airbags for the driver and the front passenger. A roll sensor signals the side curtain airbags to inflate if a predetermined threshold of vehicle tip-up is detected.

The front-passenger airbag is a new dual stage, twin-chamber design that, when deployed, helps provide optimal protection. New active front headrests help to provide whiplash protection in the event of certain types of lower speed rear collisions.

Chassis/Body/Suspension/ Brakes/Tires

Lexus engineered the third-generation RX luxury utility vehicle to provide a more engaging driving experience while also making it quieter and smoother than its predecessor. The overall packaging of the new RX remains similar to that of the previous model. The new RX has a marginally longer wheelbase (+ 0.79 inch) and is 1.38 inches longer; the new model is slightly higher and 1.6 inches wider than the previous RX. To help provide greater handling control, the track is 2.8 inches wider. The engine’s output center has been lowered approximately 0.6-inch, yielding a lower overall powertrain center of gravity to help provide enhanced vehicle agility.

A key factor in the RX models’ sharpened handling agility is the all-new uniquely designed double-wishbone rear suspension, which replaces a strut-based configuration. Another key benefit of the new rear suspension is that the packaging yields greater cargo area room. Despite larger tires and a longer wheelbase, the new RX retains the 38.8turning circle curb-to-curb of the previous model. The front suspension geometry was optimized for the new platform and features a new, thicker stabilizer bar. New inversely wound front coil springs compress in opposite directions, preventing the negative effects of suspension compression on steering.

The new standard electric power steering system contributes to improved agility and steering feel while eliminating the parasitic losses of a hydraulic steering pump. Eliminating hydraulic oil also provides an environmental benefit and reduces maintenance. When the driving conditions involve little steering input, energy consumption is reduced, improving fuel economy by nearly three percent. Steering assist is automatically adjusted in response to vehicle speed, with greater assist at low speeds and greater feel at higher speeds.

The brakes on RX models are enhanced for 2010 with a new two-piston front caliper and larger rotors front and rear. Brake feel is enhanced by optimizing pads, pedal ratio and booster output characteristics. On the RX450h, Electronically Controlled Brakes (ECB2) work closely with VDIM, translating brake pedal stroke speed and pressure to generate the precise amount of hydraulic pressure needed.

The RX models feature new wider standard 18-inch aluminum-alloy wheels, which were designed to appear as if carved from a single block, and 235/60R18 tires. Optional 19-inch aluminum-alloy wheels with 235/55R19 tires are available, with the RX450h hybrid model receiving a hybrid-exclusive design.

Exterior Design

The 2010 Lexus RX models blend a dynamic new version of L-finesse design while retaining the RX identity. The sleek profile is accentuated by broader “shoulders” for a more athletic yet elegant presence. Bright finish side-window moldings follow a subtly concaved line across the A pillars and C pillars, extending at the front and rear ends.

The Lexus design cue of placing the grille lower than the headlights, along with sharper headlight graphics, yields a strong frontal expression. The RX 350 offers standard halogen and optional HID headlights. The plated upper edges of the front grille extend toward the headlights to draw the front features together. The lower edges of the grille form a unique arrowhead design. Subtle surface movement can be seen in the sculpted vertical bars that change shape as they spread upward. The RX 450h’s unique grille features a finer pitch than on the RX 350, creating a fluid-like surface, accentuated by its silver color.

Pronounced front fenders flow into the doors, and integrated rear fender flares neatly sweep around to pull together the taut rear corners of the vehicle. The lower body emphasizes the standard 18-inch wheels. Passenger doors extend below the entry sill, helping keep out dirt and moisture.

Several exclusive design features, including the grille and front bumper, distinguish the RX 450h hybrid from the RX 350. Exclusive optional LED headlights offer a more distinctive appearance as well as longer life and lower energy consumption. Unique 19-inch aluminum-alloy wheels are also available. Lexus hybrid blue is used for the front and rear emblems, hybrid logos, rear combination lights, and headlights.

The RX has a new standard SmartAccess keyless-entry system that uses a touch sensor-type smart switch on the front doors that results in a sleeker, high-tech appearance. A distinctive feature of the door handles is that the surface subtly twists outward from the front to the rear to give a comfortable grip. The side mirrors feature integrated LED turn signal lamps.

The rear spoiler’s primary function is to help lower the vehicle’s Coefficient of drag (Cd), but it also conceals the rear wiper and houses the AM/FM radio antenna and high-mount stop lamp. Nine exterior colors are offered, including the newly developed Cerulean Blue Metallic, while Aurora White Pearl is exclusive to the RX 450h.

Interior Design

Based on Lexus L-finesse philosophy, the dramatically designed interior clearly separates the interior into two distinct zones – the “display zone” to provide information, and the “operation zone” for interaction with controls. The shoulder of the door trim comfortably envelops the occupants, the clear line of the trim beginning inside the cabin and tapering outward toward the exterior. The design imbues a feeling of a continuous line encircling the occupants and defining the controls and displays. Neatly sculpted metallic surfaces, especially on the asymmetrical center stack, showcase a bold contrast of shadow and light.

A new, higher contrast white Organic Light Emitting Diode (OLED) is used for the multi-information display located next to the speedometer. Vibrant white characters are sharply displayed on a high-contrast black background for ease of use and a luxurious appearance. For the RX 450h, blue accented meters strengthen the hybrid image, and a hybrid system indicator replaces the tachometer to encourage driving in an economical manner.

In addition to an Eco Driving indicator light, both the RX 350 and RX 450h models feature a new Eco driving indicator zone that displays current fuel economy using a bar graph and alerts the driver when they are achieving low fuel efficiency.

Lexus employed extensive human-machine interface (HMI) studies to enhance occupants’ interaction with all controls. To help reduce driver distraction and effort, each HMI function in the new RX wastes no movement. The available eight-inch navigation display (or seven-inch audio/HVAC display when navigation is not ordered) is placed at a higher, more distant position, providing a more natural visual angle.

Three innovations to come from the HMI studies include the multi-information switch on the steering wheel, the new Remote Touch console-mounted navigation controller and the available Head-Up Display. The multi-information switch allows the driver to access numerous function settings without taking hands off the steering wheel. It also reduced the number of individual switches, contributing to a cleaner instrument panel. Vehicle settings can be customized according to personal preference, including personal door-lock preferences, interior/exterior light adjustments, driver’s seat easy exit, and window-closure settings.

The new available navigation system on the RX can be controlled using either the Remote Touch device or by utilizing voice command. The Remote Touch allows the user to operate the navigation system, climate, audio, phone controls and more. The screen menus are selected with the controller, eliminating the need to reach out or avert eyes from the road.

The attribute that most distinguishes Lexus’ navigation controller from other devices in other luxury models is its “haptic”-feedback technology, which provides a tactile response to the hand. As the user operates the controller near a screen icon, the cursor is pulled to that icon with feedback from a servomotor in the device enabling the user to feel it “click” into place. The driver or passenger makes a selection by pressing the side thumb button on either side, and the feedback servo is adjustable for sensitivity. The system then confirms the action with a subtle sound. Remote Touch integrates the functions of seven hard switches used with the previous touch screen, helping users to operate those functions with minimal effort and distraction.

The all-new RX is now available with a Heads-Up Display (HUD) utilizing white readouts. High-intensity LEDs project high-contrast white figures onto the windshield, which are easier to read – and easier on the eyes – than the typical green-colored readouts. The HUD offers displays for speed, navigation, and audio. A wedge-shaped windshield interlayer for the HUD projection area eliminates the distracting printed grid pattern seen on some other vehicles equipped with HUDs.

Luxury/Comfort/Convenience

Lexus luxury begins with how the customer first interacts with his or her vehicle. All RX models are equipped with the SmartAccess keyless entry with push-button start. As the driver approaches the vehicle, interior and exterior courtesy lamps illuminate. Opening the door, the instrument panel lighting gradually fades in. When the engine (or hybrid system) is started, the instrument gauge needles and markings illuminate, followed by the multi-information display. After the driver exits the vehicle, the lights fade out at different intervals.

All 2010 RX models are equipped with a power tilt and telescopic steering column. To ease entry and exit, the seat automatically slides two inches rearward and the steering wheel tilts upward and slides forward when the engine (or hybrid system) is switched off. Upon pushing the “ON” switch, the seat and steering wheel return to positions pre-set by the driver using the three-position memory system.

The newly designed, standard 10-way power front seats are shaped to accommodate arm movement when operating the available Remote Touch, while also holding the occupants in place. Both the driver and passenger seats also feature power lumbar adjustment. Also newly available on the RX is a ventilation function for the front seats to help improve comfort on hot and humid days. The shape and texture of the armrests and switches offer an ideal combination of tactile feel and functionality.

The leather-wrapped three-spoke steering wheel features integrated audio controls and a unique cross-section that is designed to provide a more natural grip than a conventional round-section wheel. A leather and wood trimmed wheel is also available for added luxury.

Three seat materials include standard fabric, optional smooth leather or even softer semi-aniline leather. In addition to light gray and black, Parchment is now available as an interior color. The RX 450h also exclusively offers a black and light gray interior with striking black accents. Standard wood trim comes in Brown Walnut matched to Parchment, or Espresso Bird’s-eye Maple matched to gray and black.

The center console box provides enough space to comfortably store CDs/DVDs or the vehicle’s owner’s manual. Even with the owner’s manual, the console box still offers more than 0.75- cu. ft. of storage capacity. The three-part (40/20/40) rear seats can be slid and reclined, and can be folded down using the one-touch levers mounted in the luggage compartment. Compact rear-seat headrests help improve the driver’s visibility. The new double-wishbone rear suspension, due to its compact packaging, yields a larger luggage compartment; the width between the suspension towers is increased by nearly six inches.

The new climate-control system offers quicker cooling and warming and is also quieter. A new high-efficiency compressor detects refrigerant flow in order to optimize engine control and fuel economy. The new system can cool the cabin to about two degrees lower and warm it by about five degrees higher than in the previous RX. An available smog sensor is designed to detect harmful particles (CO, HC, NOx) in other vehicles’ exhaust emissions and automatically switch between fresh air and recirculation modes. A new electric compressor on the RX 450h includes a humidity sensor to help optimize air-conditioner operation, helping to enhance fuel economy.

The new Lexus RX models accommodate a variety of music sources, providing auxiliary and USB inputs, Bluetooth® Audio wireless connectivity and standard XM® satellite radio capability (requires subscription), which is also joined by XM NavTraffic and XM NavWeather. Standard voice recognition and Bluetooth technology allow phone calls to be made and received while driving. When an iPod is attached via the USB port, information such names for the artist, track and album is displayed on the available navigation or audio screen. The large center console storage box easily accommodates a variety of electronic devices while keeping wires out of sight.

The RX continues the tradition of offering the Lexus Premium Audio system as standard equipment, in this case a powerful nine-speaker system with a six-disc changer. Creative placement and angling of the speakers perfectly cross-channels sound to the occupant on the opposite side of the vehicle to transform the cabin into a clear, crisp acoustic environment. A 12-speaker system comes with the optional navigation or rear seat entertainment systems and includes two-rear-door tweeters and a compact, L-shaped subwoofer in the rear-luggage compartment.

The optional 15-speaker Mark Levinson® Surround Sound system allows listeners to enjoy 7.1-channel surround sound. The Mark Levinson system, a Lexus exclusive, features a center channel coaxial speaker, metal-cone midrange speakers, tweeters and a 100-watt amplified subwoofer. A 2.5-inch speaker built into each D pillar provides the right and left surround-sound channels. The diffusion of sound provides each occupant the same level of audio quality.

The available Hard Disc Drive (HDD) navigation system eliminates the need for DVD map discs and offers a unique voice recognition system, which can work using casual-language inputs on certain functions. An optional rear-seat entertainment system includes two high-definition seven-inch screens, one on each of the front seatbacks. Each screen can display video from separate sources. A remote control allows independent control of each screen. Rear-seat occupants can also choose to listen to audio through the wireless headphones instead of vehicle speakers.

The available wide-view side monitor and backup monitor each help provide the driver with a wider range of visibility. The driver can check hard-to-view areas by simply pressing the camera-select button on the steering wheel or, when in reverse, viewing the camera images on the navigation screen. An optional back up camera displays images on the eight-inch navigation screen; systems without navigation have a 2.4-inch display in the rear-view mirror.

Warranty

All new Lexus vehicles come with a 48-month/50,000-mile basic limited warranty with roadside assistance for 48-months/unlimited miles. Powertrain and restraint system coverage is provided for 72 months/70,000 miles. Corrosion perforation protection is covered for 72 months, regardless of mileage. The hybrid-related components, including the HV battery, battery-control module, hybrid control module and inverter with converter, are covered for eight years/100,000 miles.