Honda’s reputation as an innovator and technology leader wasn’t earned with the first hybrid brought to the U.S. market or its stubborn commitment to a hydrogen-powered prototype. Honda built its brand on the fundamentals of its most accessible and popular vehicles. Americans admired the simplest solutions to the most complex problems; they respected diligent engineering that set a standard of continuous improvement; and they believed in the company that was consistently one step ahead of the competition.
The company that once sold an affordable compact so clean it met emissions standards without a catalytic converter is hell bent on owning the hybrid market -- small as it may be, Prius be damned, and cost no object. So next year, Honda will add to its crowded stable of hybrids -- CR-Z, Civic, and Insight -- with a mid-size plug-in hybrid.
Not your typical Honda hybrid
Honda’s plug-in hybrid powertrain is far more sophisticated than the simple Integrated Motor Assist system found in Honda’s existing hybrids. It is also significantly different than the configurations used by the Toyota Prius and the Chevrolet Volt. No matter whether the Honda plug-in is relying on energy from its 6-kWh lithium-ion battery or its fuel tank, the wheels are primarily powered by a 161-hp electric motor. A second electric motor functions as a generator to convert power from a 2.0-liter 4-cylinder into electricity for range far beyond the battery’s 10 to 15 miles. If the driver calls for quick acceleration or exceeds 62 mph, the gas engine will also kick on before the battery’s charge is exhausted. Recharging takes about one and a half hours with a 240-volt connection.
The Honda’s unusual trick (all good hybrids have at least one) is that the gas engine can be mated to the front wheels through a fixed gear ratio. While single-speed transmissions are common in electric vehicles, gas engines require multi-speed gearboxes to match the narrow rpm band where the engine is most efficient with the wide range of road speeds. Both the Prius and the Volt use continuously variable transmissions to blend electric and gas power on its way to the wheels. Honda’s single gear ratio has been optimized for low-load highway cruising, such that the gas engine never engages the wheels below 40 mph. An electronically controlled clutch engages the engine when the computer decides to send power directly from the gas engine to the wheels.
A test drive shorter than its electric range
Over an extremely short, city-like loop, we sampled the hybrid powertrain packaged in the chassis of the current Honda Accord. The electric motor is plenty powerful to move at a normal pace without calling on the gas engine. Stomp on the throttle, though, and there’s a slight lag in power delivery and a CVT-like audible awakening as the engine spins up to high rpm and parks itself there. The Honda mule drove with less moaning than a Prius but less engine isolation than the Volt. Maximum acceleration is adequate but not quick.
We were never able to discern if the engine was driving the front wheels, although that doesn’t necessarily mean the system is seamless. It’s possible that the computer simply never saw fit to engage the clutch during our limited test drive. Brakes are easily modulated by hybrid standards.
Honda has committed to production for 2012, but it hasn’t let on if the powertrain will appear in the next Accord or an exclusive hybrid model. If Honda delivers on its claimed electric range of 10 to 15 miles, the mid-size plug-in hybrid will be aimed squarely at Toyota’s forthcoming Prius plug-in, a car that will certainly benefit from instant recognition as a hybrid.
The mysteries that remain
It’s clear that Honda is hoping the more sophisticated powertrain will be a feather in its cap and a step toward reclaiming its reputation as a technology leader. For that to happen, though, buyers will have to respond to this hybrid more strongly than they have to any of Honda’s previous gas/electric cars. While the plug-in hybrid features some genuine innovations, its chance of success depends just as much on unknowns like styling, pricing, and fuel economy.
Honda Motor Co., Ltd. has developed a new SPORTS HYBRID Intelligent Dual Clutch Drive system, a lightweight and compact 1-motor hybrid system optimized for small-sized vehicles. This new hybrid system will be the latest addition to the Earth Dreams Technology series of next generation powertrain technology that realizes both excellent driving performance and high fuel efficiency.
Together with the SPORT HYBRID Intelligent Multi Mode Drive, the world's most efficient1 2-motor hybrid system optimized for mid-sized vehicles, and the SPORT HYBRID SH-AWD® (Super Handling - All Wheel Drive), the 3-motor hybrid system optimized for large-sized vehicles enabling independent control of torque distribution to both right and left rear wheels, the newly developed SPORT HYBRID Intelligent Dual Clutch Drive will constitute the lineup of 3 different Honda SPORT HYBRID systems that accommodate different vehicle characteristics. Honda will continue expanding the application of these hybrid systems based on vehicle characteristics.
SPORT HYBRID Systems Lineup
1-motor SPORT HYBRID Intelligent Dual Clutch Drive
In addition to top-level fuel efficiency in its class2, the fun of driving is realized with acceleration g-force more powerful than that of existing models as well as a rhythmic and linear acceleration feeling. This drive unit combines a newly developed inline 4-cylinder 1.5-liter Atkinson cycle engine with a 7-speed Dual Clutch Transmission (DCT) system with a built-in high-output motor and a Lithium-Ion battery to improve efficiency by more than 30 percent compared to a conventional one-motor hybrid system.
The combination of the 1-motor hybrid system and the engine realizes sporty driving during acceleration and high-speed cruising by using the clutches to engage the engine
Highly efficient electric vehicle (EV) driving is realized during startup and low- to medium-speed cruising by using the clutches to disengage the engine
This system contributes to the improvement of fuel efficiency by increasing energy regeneration using the clutches to disengage the engine during deceleration
2-motor SPORT HYBRID Intelligent Multi Mode Drive / Plug-in:
Through the adoption of high-efficiency/high-output motors, both brisk acceleration with an EV-like driving feel and high fuel efficiency are realized at the same time. This hybrid system realizes the world's highest efficiency1 by combining a newly-developed engine dedicated to hybrid vehicles coupled with two built-in motors and a lock-up clutch, along with a Lithium-Ion battery, and by optimally switching the driving mode among three different profiles depending on the driving situation. This hybrid system, which is also suitable as a plug-in hybrid system, will be available in the North American version of the 2014 Honda Accord Plug-in, scheduled to be introduced to the market in January 2013. The system switches the operation among the following 3 driving modes depending on driving conditions and the battery charge level:
"EV Drive" for driving by the electric motor only, using electricity from the battery and regeneration during deceleration "Engine Drive" for medium-to high-speed cruising with the engine and axle directly connected by a lock-up clutch, with engine power mechanically transferred to the wheels "Hybrid Drive" for urban driving and powerful acceleration using the motor with electricity generated by the engine
3-motor SPORT HYBRID SH-AWD ® (Super Handling - All Wheel Drive):
The combination of a V-6 engine and this high-output 3-motor system realizes acceleration performance equivalent to that of a V-8 engine with fuel efficiency better than that of an inline 4-cylinder engine. A new direct-injected 3.5-liter V-6 engine is installed in the front of the vehicle and combined with a newly-developed 7-speed DCT system with a built-in motor. This unique Honda technology uses 2 electric motors installed in the rear to control torque distribution to the right and left rear wheels.
Using independent motors for the right and left rear wheels, positive torque is applied to the outside wheel and negative torque is applied to the inside wheel, making independent control of torque distribution to the rear wheels possible without relying on engine output
Depending on the radius of the curve, the energy generated by the inside wheel is recovered electrically and applied to the outside wheel to self-generate torque necessary for the vehicle to make the turn
1 Per Honda internal research as of August 2012
2 Hybrid systems for a 1.5L engines
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