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Last year marked the introduction of the all-new CT 200h, Lexus’ fifth hybrid vehicle and second dedicated hybrid. As Lexus continues to dominate the luxury hybrid market, the CT 200h premium hybrid demonstrates the brand’s commitment to unparalleled quality, sophistication and technology. In its second model year, the CT features a new Vehicle Proximity Notification System that helps alert pedestrians and cyclists of an oncoming vehicle under certain conditions by emitting a low audible warning sound. In addition, it brings one new exterior color as Nebula Gray Pearl replaces Smoky Granite Mica for 2012.
The CT 200h’s size, packaging, full hybrid technology and ultra-low emissions perfectly meet the requirements of a young, highly discerning, environmentally conscientious customer base. Yet it offers no compromise on the refinement and driving pleasure which hallmark the progressive luxury inherent in every Lexus.
Available in standard and Premium models, the CT 200h boasts remarkably low fuel consumption and has an impressive combined EPA-estimated fuel economy rating of 42 mpg, 43 mpg city and 40 mpg on the highway utilizing regular 87-octane gasoline. Moreover, the CT 200h can be operated in a switchable EV mode which generates zero emissions.
Engine and Hybrid System
The CT 200h’s Lexus Hybrid Drive features a unique energy management system paired with a four-cylinder gas engine. Through the application of brand-specific engineering solutions and software tuning, Lexus engineers focused on enhancing both the environmental and driving performance of the full hybrid series/parallel system, as well as its Ultra-low Noise, Vibration and Harshness (NVH) levels.
Utilizing the most recent generation hybrid system, the CT 200h takes advantage of Lexus’ continuous engineering advances to maximize fuel economy, minimize emissions and deliver driving pleasure. A highly efficient engine design, an exhaust heat recovery system, major efforts to reduce parasitic losses, an evaporative emissions system and driver-selectable driving modes all make notable contributions. Significant efforts were also made to minimize engine noise.
An Atkinson-cycle engine design was chosen for its high efficiency and compatibility with hybrid operation in the CT 200h. The twin-cam engine uses four valves per cylinder and Variable Valve Timing with Intelligence (VVT-i) on the intake side. The engine is undersquare, with an 3.17-inch bore diameter and 3.48-inch stroke, and has a relatively high compression ratio of 13.0:1. Peak output equals 98 horsepower and in combination with the hybrid drive motor, the CT 200h generates 134 total system horsepower. The CT 200h will accelerate seamlessly from 0-60 mph in 9.8 seconds.
Careful design of the intake system reduces engine pumping losses and its twin resonators minimize intake noise. The cooling system uses a modular construction that combines an aluminum engine radiator, hybrid system radiator, A/C condenser and fan into a single assembly for minimal weight. Plus, the electric fan speed is controlled via Pulse Width Modulation to reduce energy consumption and noise. Careful ducting of the cooling system helps prevent hot engine air recirculation that tends to occur at low speeds and while idling, further enhancing efficiency.
One of the keys to lower fuel consumption involves heat. The CT employs an exhaust heat recovery system that captures the heat of spent exhaust gases to speed engine coolant warm-up and allow the hybrid system to stop the engine earlier and more often in the driving cycle when it’s not needed, for example in low power demand conditions in city driving.
Using a two-motor hybrid system, the CT 200h uses an 80 horsepower drive motor that combines with the gas engine. (Note that the sum of the engine and motor power are not equal to the total system power as the operation of the engine and motor cannot be maximized in the same operation range). A second motor in the hybrid system serves as both engine starter and generator to charge the hybrid battery pack.
The efficient two-motor system also uses an Electronically-Controlled Continuously Variable Transmission (E-CVT) that is a model of efficiency, simplicity and compact size with extremely smooth and quiet operation. A motor speed-reduction planetary gear unit helps provide high power output in this small package.
An electric transmission oil pump eliminates another source of parasitic loss to further increase efficiency. Electronic operation allows a control strategy that invokes the oil pump only when needed, and since the oil also flows over the drive motor, overall efficiency of the motor and transmission are improved.
For a fun-to-drive experience, the CT 200h also incorporates a drive-mode selector that allows the driver to toggle between four distinct modes: Normal, Sport, Eco or EV. Each mode changes the rate of throttle opening for a given throttle-pedal angle. Normal mode has an essentially linear throttle response that gives naturally progressive power. Sport mode can be selected when the driver wants a more dynamic experience. In Eco mode, air conditioning settings are adjusted and the throttle response is reduced relative to the pedal angle to emphasize fuel economy. Under certain circumstances, the EV mode can allow the vehicle to be driven short distances using only the electric motors.
Acceleration from 0-to-60 mph is rated at 9.8 seconds. Responsive passing acceleration that benefits from the instant torque of the electric motor and the E-CVT’s ability to quickly find the optimal gear ratio enhance the driving experience.
Source: Toyota Motor Corporation
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