Honda outlines technology for fuel efficiency push; engines, transmissions, hybrid, plug-in hybrid and electric powertrains
|Newly developed 2.4L-class gasoline engine. Click to enlarge.|
In Tokyo, Honda Motor Co., Ltd. outlined its plans for next-generation automotive technology—which it is labeling “Earth Dreams Technology”—comprising a series of measures to improve the efficiency of gasoline and diesel engines, transmissions, hybrid and plug-in hybrid systems and electric powertrains.
Through applications of the new technology first in the mini-vehicle N BOX—the first model of the new mini-vehicle N Series—and gradually in other vehicle models, Honda is targeting top-of-industry fuel efficiency for every category within three years, while simultaneously setting a timeline of 2020 to reduce by 30% CO2 emissions for all products sold worldwide, relative to emission figures for 2000.
Key elements of the new technology initiative are:
- New gasoline engines which realize top-level driving performance and fuel efficiency.
- A compact diesel engine which realizes the world’s lightest body, top-of-class acceleration performance and fuel efficiency.
- A new line of continuously variable transmissions for improved fuel efficiency and driving fun.
- A two-motor hybrid system (earlier post) that can be applied in a conventional or plug-in hybrid.
- A high-efficiency, high-output electric SH-AWD hybrid system.
- A compact, high efficiency electric powertrain for EVs.
Gasoline engine. By enhancing Honda’s original VTEC (Variable Valve Timing and Lift Electronic Control System) technology to thoroughly improve thermal efficiency and minimize friction, Honda achieved a combination of high output and fuel efficiency. It developed a new engine series employing a new structure for higher expandability. A wide range of engine classes including the 660cc, 1.3L, 1.5L, 1.8L, 2.0L, 2.4L, and 3.5L classes will feature the technology.
660cc class engine. This uses DOHC and VTC (Variable Timing Control) to improve intake efficiency. Further, the compact combustion chamber realizes high thermal efficiency. By shortening the bore pitch compared to the present engine models and reducing the thickness of the cylinder block and camshaft, engine weight is reduced by 15% and fuel efficiency is improved by 10%.
1.3 to 1.5L class engine. This uses VTC, direct injection technology and the Atkinson cycle using the DOHC, VTEC technologies as the base. Extensive friction reduction measures are implemented.
1.8 to 2.0L class engine. This employs direct injection technology and the Atkinson cycle using the DOHC, VTEC technologies as the base. Further, implementation of VTC and high-capacity EGR (Exhaust Gas Recirculation) to both the intake and exhaust ports realizes significantly reduced friction.
For the 2.0L class hybrid vehicle engines, use of an electric water pump eliminates the need for a belt in the auxiliary device and contributes to a reduction in friction. The VTC system allows fuel-efficient driving in various driving styles.
2.4L class engine. Based on the DOHC and VTEC technologies, it employs VTC and direct injection technology and implements extensive friction reduction measures. The standalone engine features 5% improvements in fuel efficiency and output as well as a 10% improvement in maximum torque compared to the previous engine.
3.5L class engine. This employs new valve train mechanisms and direct injection technology in the SOHC, VTEC, VMC systems to improve fuel efficiency by more than 10% and output by 5%, relative to the present standalone engine model.
Diesel engine. Through optimizing engine rigidity and combustion pressure, an aluminum open deck for the cylinder block was enabled in this lightweight 1.6L class diesel engine.
By downsizing from the present 2.2L engine and extensively reducing mechanical friction in each section, a friction level equivalent to present gasoline engine models was achieved.
The engine features an optimized thermal management system due to improvements in the cooling system. A compact, high-efficiency turbocharger and weight reduction in the reciprocating sliding section realizes a sporty and nimble ride, according to Honda.
CVT. Honda has developed three CVT structures for mini, compact, and mid-size vehicle classes to be adopted for a variety of engine models. The transmissions feature a reinforced belt to realize a structure for which a wide ratio range can be set.
Implementation of analysis technology over the contact behavior between the belt and pulley and a high-precision hydraulic control system allow for continual optimization of hydraulic pressure to the pulley under a variety of driving conditions, contributing to improved fuel efficiency.
An electronic oil pump helps to realize an idle stop system with high response that contributes significantly to improved usability and fuel efficiency.
For the mini-vehicle class, the transmission features a control mechanism and innovations in axle placement to reduce the engine size lengthwise, while a reduction in parts by simplifying the transmission casing structure helps realize a lightweight and compact body.
For the compact and mid-size classes, in addition to the reductions in size and weight, transmission efficiency was greatly improved by expanding the ratio range to achieve fuel efficiency improvements of 5% and 10% compared to the conventional CVT and comparable 5ATs, respectively.
Two-motor hybrid system. Honda’s new two-motor hybrid system features a lithium-ion battery and charger to enable mounting on plug-in hybrid vehicles. Mid-sized vehicles equipped with this system are scheduled to begin production starting with a plug-in hybrid model in 2012 and a conventional hybrid model in 2013.
The two-motor system offers three driving modes: an “EV driving mode” for urban environments; a “hybrid driving mode” using electricity generated by the motor; and a “engine-connected driving mode” where the engine and tires are mechanically connected during high-speed cruising.
Electric SH-AWD hybrid system. The new electric SH-AWD hybrid system was developed for large-sized vehicles. By combining a 3.5L, V6 engine with this hybrid system, acceleration equivalent to V8 engines, as well as fuel efficiency equal or superior to in-line 4-cylinder engines were realized, Honda says.
The system includes an electric 4WD system with independent 20+ kW motors on both sides for the rear wheels; a 7-speed dual clutch transmission system with a built-in 30+ kW high-efficiency motor with the engine.
By mounting two independent motors in the rear and employing a newly developed bilateral torque adjustable control system, tight cornering just like driving “on-the-rail” is realized, Honda says. With this mechanism, Honda strives to provide a stable ride for various driving environments.
Electric powertrain. Featuring a high efficiency coaxial motor, low-friction gearbox and electric servo brake system, the electric powertrain has a consumption rate of 29 kWh/100 miles (116 MPGe). A high-capacity Li-ion battery supports a range of 123 miles (198 km) in LA-4 mode, unadjusted, or 130 miles (210 km) in JC08 mode.
Full charge takes less than 3 hours using a 240V source. The vehicle offers three driving modes (Sport, Normal and Econ).