2010 Lexus HS 250hPosted on May 26th, 2009
Hybrid sedan fills out the entry luxury line-up
By Nina Russin
The HS 250h is Lexus’ first dedicated gasoline-electric hybrid. The sedan, that rolls into dealerships this August, is the third pillar in an entry luxury strategy that also includes the comfort-focused ES, and high-performance IS models.
Power comes from a 2.4-liter four-cylinder Atkinson cycle engine and two electric motors, mated to a continuously variable automatic transaxle. A compact inverter converts direct current from the car’s nickel-metal hydride battery into alternating current for the motors. The battery is located between the car’s rear seat and trunk.
An electric power steering pump, similar to the design on other Toyota and Lexus hybrids is lighter and more fuel efficient than a hydraulic mechanism. The electric pump eliminates parts that would traditionally wear out and require replacement during the car’s life cycle.
A fully-independent suspension includes a front stabilizer bar to keep the chassis flat while cornering. Buyers who purchase the base model can upgrade from standard 17 to 18-inch wheels by adding a touring package. The option group also includes heated front seats and a sport suspension.
Eighteen-inch wheels are standard on the upscale premium model. All cars come with all-season radial tires.
Four-wheel disc brakes with four-channel antilock braking are standard, as is traction and vehicle stability control. Standard hill start assist keeps the car from sliding backwards when accelerating from a stop on a steep grade.
Green inside and out
Lexus builds the hybrid powertrain at a dedicated facility in Kokura, Japan. The inside of the plant is temperature and humidity controlled. An enclosed loading dock and carefully controlled air current through the plant create a particle-free environment. The sedan itself is assembled at the automaker’s facility in Toyota Motor Kyushu, Japan.
Infrared-cut glass used on the front windshield reduces infrared rays entering the cabin to reduce air conditioning load and improve fuel economy. Thirty percent of the interior and luggage area trim is made from plant-based plastic that is almost carbon neutral.
The hybrid powertrain is SULEV certified: the most favorable emissions rating a gasoline-electric hybrid can achieve. Average fuel economy is 35 miles-per-gallon according to EPA estimates.
Driving the green machine
I had the opportunity to get behind the wheel of the new Lexus hybrid at a recent media event in Southern California. Based on my recent test drive of the 2010 Toyota Prius, I had high expectations for its Lexus sibling.
Unfortunately, those expectations weren’t met. In this writer’s opinion, the Prius’ performance and interior ergonomics far outshine the HS 250h.
One of the car’s most obvious faults is its weight: it feels like a heavy car. Acceleration, even in power mode, seems sluggish.
According to the manufacturer, the sedan accelerates from zero-to-sixty in 8.4 seconds, which is fairly quick. On the other hand, quarter-mile acceleration is a disappointing 16.6 seconds. Our average fuel economy during the test drive was between 27 and 28 miles-per-gallon, well below the EPA estimates, and about half that of the current-generation Prius.
While it isn’t unusual for Lexus hybrids to feel slightly more nose-heavy than their gasoline-powered counterparts, the HS 250h is even more so. Front-to-rear weight balance is 61/39; the sedan’s relatively short wheelbase when compared to its 60.4-inch track doesn’t help.
The electric power steering, which works exceptionally well in other Toyota and Lexus hybrids, yields poor steering response in the HS 250h. As a driver, I felt disconnected from the wheels. Compounding the problem is poor visibility to the front due to the optional navigation screen, and to the rear because of thick B and C pillars.
In order to see the front end of the car I had to raise the seat until my head was almost touching the headliner. In that position, the gauges were obscured by the large black hood over them.
The sedan will run in pure electric mode at very low speeds: under about 20 miles per hour. The EV mode is a great way to save fuel in extremely congested traffic, or when weaving through large parking lots. When the driver accelerates beyond its range, the powertrain automatically shifts into ECO mode.
Wide view front monitor makes parallel parking easier
A new optional wide-view front monitor is one of the sedan’s best available features. When the car is stopped or moving at very low speeds, a camera in front projects an image to either side of the front wheels. Considering the sedan’s limited forward visibility, it makes the car much easier to parallel park. Ditto for the optional rearview camera.
An available heads-up display projects speed, fuel economy, dynamic laser cruise control warning, an image of the steering wheel-mounted controls and turn-by-turn directions in the lower part of the windshield. The display is well designed: it’s easier to read than some competitive systems, without interfering with the driver’s forward vision. A button on the instrument panel turns the display off.
Intelligent high beams automatically dim to avoid blinding cars in the oncoming lane and behind the sedan. Optional adaptive lighting swivels the headlamps according to steering input to better illuminate turns in the road.
The sedan’s interior is loaded with advanced electronic devices, including a mouse that interfaces with the audio, climate control, navigation and information systems. The mouse itself is extremely well designed and easy to reach from either the driver’s or front passenger position.
Unfortunately it’s mounted to the base of a center stack that protrudes between the driver and front passenger, reducing legroom in the front cabin. I don’t consider my legs to be especially long, but my knees were right up against the bulkhead on both the driver’s and front passenger sides.
Although the HS 250h rides on a shorter wheelbase than the IS or ES sedans, the distance between the front and rear seats is wider. Designers maximized rear legroom by using slimmer, contoured front seatbacks.
As a result, second-row passengers have more legroom than in competitive products of similar size. Since there is no floor tunnel, three small adults should be comfortable sitting in the second-row seats.
The gearshift device is the same one used on the Prius: a small knob that the driver uses to shift between neutral, drive and reverse. A brake mode replaces low gears in a conventional gasoline car. Park is a separate button.
For those who don’t want to use the mouse, redundant audio and climate control buttons are located beneath the navigation screen. The steering wheel has redundant audio and Bluetooth interface controls. All models come with a standard USB port for flash drive or iPod connectivity. Two standard 12-volt power points recharge portable electronic devices.
Both front and rear passengers have plenty of access to small cubbies, cup and bottle holders. A vent behind the center console circulates air through the back.
The trunk, while functional, is rather small: a common problem with hybrid sedans, due to the large battery pack. It has plenty of room to hold the weekly groceries, a couple of golf bags or a weekend’s worth of luggage. But it isn’t large or versatile enough for extremely long on odd-sized cargo.
New Lexus Enform adds an extra measure of safety
The HS 250h will be the first Lexus to feature the automaker’s new telematics system. While it functions in a similar manner to GM’s OnStar, there is no relationship between the two systems. There are two separate Enform formats: one standard on the base model, and a separate system for cars with the optional navigation system.
The safety connect system includes automatic dispatch of emergency services after a collision, stolen vehicle location, an emergency SOS button and 24-hour roadside assistance. Vehicles equipped with navigation also get two premium services: push-button live operation destination assist, and eDestination: an online destination management system capable of storing up to 200 entries.
All cars come pre-wired for XM satellite radio. Vehicles with navigation can get real time traffic, weather, sports and stock updates on XM.
All models come with ten standard airbags, keyless entry and start.
Lexus will announce pricing for the HS 250h closer to its late-summer roll-out.
Likes: An entry-level luxury sedan that features the automaker’s most innovative hybrid and green technologies, including an EV mode that should yield considerable fuel savings in thick traffic.
Dislikes: Poor steering feedback, limited forward and rear visibility. The center stack reduces legroom for the driver and front passenger.
Model: HS 250h sedan
Base price: N/A
As tested: N/A
Horsepower: 147 Hp @ 6000 rpm
Torque: 138 lbs.-ft. @ 4400 rpm
Zero-to-sixty: 8.4 seconds
Antilock brakes: Standard
Side curtain airbags: Standard
First aid kit: Standard
Bicycle friendly: No
Fuel economy: 35/34 mpg city/highway.
Leave a reply