The 2018 Clarity Plug-In Hybrid's utilizes the second generation of Honda's Intelligent Multi-Mode Drive (i-MMD) two-motor hybrid system. This highly efficient powertrain selects the optimal drive operation under a wide range of driving conditions to combine fun-to-drive performance with outstanding efficiency.
Power comes from a 181-horsepower electric motor producing 232 lb.-ft. of torque and drawing power from both the gasoline engine and a 17-kilowatt hour (kWh) battery pack. A recharge time of just 2.5 hours using a Level 2, 240 volt (32 amp) charger allows for easy charging.
The Clarity Plug-In Hybrid powertrain utilizes a 1.5-liter Atkinson-cycle engine that is paired with two electric motors – a traction motor and a generator/starter motor.
Detailed energy management for each component, controlled by the Power Control Unit (PCU), enables the 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 exceptional EPA fuel economy ratings.
To help maximize efficiency on the road, the Clarity Plug-In Hybrid seamlessly shifts between three distinct drive operations: EV Drive, Hybrid Drive and Engine Drive, utilizing power from the Atkinson-cycle i-VTEC® 4-cylinder engine and electric motors to actively adapt to current driving conditions.
Two-Motor Hybrid Powertrain
Emissions/Fuel Economy/Range Ratings
- Peak total system output: 212 horsepower
- 1.5-liter, DOHC, i-VTEC® Atkinson-cycle inline-4 cylinder engine
- Engine output: 103 peak horsepower (SAE net) at 5,500 rpm
- Engine output: 99 lb.-ft. peak torque (SAE net) at 5,000 rpm
- i-VTEC® (Variable Valve Timing and Lift Electronic Control) + Electric VTC
- Computer-controlled port fuel injection with multi-hole fuel injectors
- 13.5:1 compression ratio
- AC synchronous electric traction motor
- Propulsion motor peak output: 181 horsepower and 232 lb.-ft. of torque
- Integrated starter/generator motor
- Maintenance Minder™ system optimizes service intervals
- 100,000+/- miles engine tune-up interval
- Regular Unleaded fuel recommended
- 17 kWh lithium-ion (Li-Ion) battery
- Electric-servo regenerative braking system
- Full charge in 2.5 hours using a Level 2, 240 volt (32 amp) charger
- Emission warranty: Eight-year/100,000-mile or ten-year/150,000-mile Li-Ion battery limited warranty, depending on the state of purchase/registration
- 47 mile EPA all-electric range rating1
- 110 MPGe all-electric combined (city& highway) EPA fuel economy rating1
- 44/40/42 MPG (city/highway/combined) EPA fuel economy rating1 (gasoline-only)
- Meets LEVIII SULEV20 emission standards
The Clarity Plug-In Hybrid's key powertrain components are arranged for maximum packaging efficiency, affording the Clarity Plug-In Hybrid a roomy and accommodating 5-passenger interior. The lithium-Ion batteries are packaged beneath the passenger compartment to keep the center of gravity low for optimum handling without intruding on passenger or cargo space.
1.5-liter Inline 4-cylinder Atkinson-Cycle Engine
The 1.5-liter DOHC i-VTEC 4-cylinder Atkinson-cycle engine develops a peak 103 horsepower (SAE net) at 5,500 rpm and 99 lb.-ft. of torque (SAE net) at 5,000 rpm. Advances in engine control tuning together with other technologies combine to create excellent power characteristics, exceptional fuel efficiency and very low exhaust emissions. This clean-running engine meets LEVIII SULEV20 emission standards.
Since the gasoline engine can be decoupled from the rest of the hybrid powertrain, it only operates as needed. Depending on the battery's state of charge and other parameters, the engine will automatically shut off during deceleration, or when the vehicle is at a stop. When needed, the gasoline engine restarts automatically, without action from the driver.
However, when the driver desires extra power in situations such as highway passing, even higher performance can be invoked by depressing the throttle pedal through a resistance point, or "click point," toward the end of the pedal travel, bringing the full power of the engine and electric motor together for maximum acceleration, regardless of driving mode.
Engine Block, Crankshaft and Pistons
The engine has a displacement of 1,498 cubic centimeters. Cast-in iron cylinder liners provide long-lasting durability. Each journal on the forged-steel crankshaft is micro-polished to reduce internal friction.
The 1.5-liter engine has cylinder bores are offset 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.
Cylinder Head and Valvetrain
The 1.5-liter engine has a lightweight cylinder head made from pressure-cast aluminum alloy. A silent chain drives dual overhead cams and four valves per cylinder. The cam drive is maintenance free throughout the life of the engine.
A high tumble-effect intake port design combined with a narrow valve angle decreasing the surface-to-volume ratio helps create a flatter, more compact combustion chamber that improves combustion efficiency while reducing unburned hydrocarbon emissions. This combustion chamber shape and the precise control enables a high compression ratio of 13.5:1, yet the engine still operates on regular unleaded fuel.
i-VTEC Valve Control System
The engine uses an advanced valve-control system to combine high power output with high fuel efficiency and low emissions. The system combines E-VTC (Electronic Variable Timing Control), which continuously adjusts the intake camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes the lift profile, timing and duration of the intake valves' operation.
High-Efficiency Dual Bed Catalytic Converter
A key contributor to the Clarity Plug-In Hybrid's emission performance is the combining of a close-coupled catalytic converter with an under-floor catalytic converter. The close-coupled converter mounts directly to the rear of the cylinder head for fast activation after the engine is started. It is followed by a second catalytic converter located under the floor. They combine to help the Clarity Plug-In Hybrid meet stringent LEVIII SULEV20) emission standards.
100,000+/- Mile Tune-up Intervals
The Clarity Plug-In Hybrid's engine requires no scheduled maintenance for 100,000+/- miles or more, other than periodic inspections and normal fluid and filter replacements. The first tune-up includes water pump inspection, valve adjustment, and the installation of new spark plugs.