2018 Honda Accord Touring Hybrid – Fun-to-drive Performance with Outstanding Efficiency. 2018 Honda Accord Touring Hybrid – Interior and Exterior.
The 2018 Accord Hybrid’s third-generation i-MMD Two-motor hybrid system is a highly efficient powertrain that selects the optimal drive operation under a wide range of driving conditions to combine fun-to-drive performance with outstanding fuel efficiency. The new hybrid powertrain utilizes a 2.0-liter Atkinson-cycle engine with 40 percent thermal efficiency, up from 38.9-percent in the previous generation Accord Hybrid, and the highest thermal efficiency of any mass-produced Honda engine.
The engine is paired with two electric motors – a propulsion motor and a generator/starter motor. These new motors are the first drive motors in the world to use magnets containing no heavy rare-earth metals, a new Honda-patented design that reduces magnet cost and weight.
Detailed energy management for each component, as controlled by the Power Control Unit (PCU), enables this system to make the best use of both the electric propulsion motor and the gasoline engine to provide seamlessly smooth and responsive performance while garnering top-class EPA fuel economy ratings in the midsize hybrid sedan class.
To help maximize efficiency on the road, the Accord Hybrid seamlessly shifts between three distinct drive operations: EV Drive (100-percent electric motor), Hybrid Drive (electric motor and gasoline engine [driving the generator motor]) and Engine Drive (gasoline engine), utilizing power from the Atkinson-cycle i-VTEC® 4-cylinder engine and the electric motors to suit the driving conditions moment to moment.
The electric propulsion motor alone powers the front wheels, as the gasoline engine (decoupled from the drive wheels) powers the electric-generator motor, which in turn provides power to the battery pack. This allows the gas engine-generator motor combo to supplement the battery by providing added electrical power to the propulsion motor or, alternatively, to charge the battery. In this type of operation, the system works as a “series hybrid.” The electric propulsion motor offers crisp acceleration, and can reach maximum torque almost instantaneously, thanks to electrical power that can be supplied from both the gas engine-powered motor/generator and the battery.
When cruising at medium to high speeds, the high-efficiency Atkinson-cycle i-VTEC gasoline engine provides propulsion via a high capacity lock-up clutch, which connects the generator motor (always linked to the engine) and the electric drive motor, effectively sending motive power directly from the engine to the drive wheels. In this type mode, the system works as a “parallel hybrid” where both the gasoline engine and, when required – for instance upon quick acceleration – the electric propulsion motor, both provide power to the wheels. The i-MMD powertrain operates without the use of a conventional transmission.
The 2018 Accord Hybrid’s third-generation i-MMD system utilizes a 2.0-liter DOHC i-VTEC 4-cylinder Atkinson-cycle engine that develops a peak 143 horsepower at 6200 rpm and 129 lb.-ft. of torque at 3500 rpm. Advances in engine control tuning together with other technologies combine to create excellent power characteristics, exceptional fuel efficiency and very low exhaust emissions. Key contributors to the improved thermal of efficient of the engine include improved exhaust gas recirculation and reductions in operating friction. This clean-running engine meets LEV3- AT-PZEV (SULEV30)/Interim Tier3 Bin30 emission standards, while contributing to the Accord Hybrid’s total system output of 212 horsepower.
Since the gasoline engine can be decoupled from the rest of the hybrid powertrain, it only operates as needed. Depending on the state of battery charge and other parameters, the engine will automatically shut off during deceleration and when the vehicle is at a stop or operating under battery power. When needed, the gasoline engine restarts automatically, without action from the driver.
The engine has a displacement of 1,993cc. Cast-in iron cylinder liners provide long-lasting durability. Each journal on the forged-steel crankshaft is micro-polished to reduce internal friction. To improve smoothness throughout the rpm range and help lower noise levels, the Accord Hybrid is fitted with an internal balancer unit. Consisting of a pair of chain-driven counter-rotating shafts located in the oil pan, the balancing system helps quell the inherent second-order harmonic vibrations that are normally associated with inline 4-cylinder engines.
The 2.0-liter engine has cylinder bores offset by 6.0 mm from the crankshaft to help reduce piston-sliding friction. This gives the connecting rods a more favorable angle during each power stroke, which reduces side loading on the pistons and, in turn, improves efficiency. The lightweight pistons have a carefully optimized skirt design to minimize reciprocating weight, and reduced weight minimizes vibration and increases operating efficiency.