The father of Honda’s hybrid system

Hiroo Shimada, Chief Product Engineer, is known inside of Honda Motor Corporation as the father of Honda’s hybrid system. Shimada-san talked to Lou Ann Hammond, CEO, www.drivingthenation.com about the 2014 Honda Accord Hybrid engine, modes and motors.

Overview

The 2014 Honda Accord Plug-in Hybrid (PHEV) and Hybrid (FHEV) Sedan versions are powered by a new 2.0-liter 4-cylinder Atkinson, 87 octane rated, combustion engine with two electric motors. Honda’s new engine management, Intelligent Multi-Mode Drive (i-MMD) integrates three power train modes, (1 internal combustion motor, 2 electric motors) mated with their also new “Electric Continuously Variable Transmission (E-CVT)” implementation. The difference between the Accord Plug-In and Accord Hybrid is the battery size and the in-vehicle charging system for the Plug-in Hybrid. The Accord Hybrid’s  1.3 kWh lithium-Ion battery and DC-DC converter is packaged behind the rear seat of the vehicle.

Engine medley

Honda’s power trains, (1 internal combustion motor, 2 electric motors) are designed for different speeds for either the Accord Plug-in Hybrid (PHEV) or Hybrid (FHEV) Sedan. The electric motors drive the front-wheel-drive Accord from zero to midrange speeds while the gasoline engine drives the front wheels at high speeds. For low to midrange speeds, the new 2.0-liter 4-cylinder Atkinson gasoline engine acts as a generator charging the two electric motors which drive the  Accord. The interaction of these three motors through Honda’s “i-MMD” management software is what Honda calls their  “two-motor hybrid approach” for propulsion.

Propulsion modes
EV Drive

Whether the Accord Plug-in or the Hybrid version, the vehicle is powered by Honda’s two electric motors connected to the front-wheel-drive Accord from zero to midrange speeds.

Hybrid Drive

Literally a combination of Electric drive, EV, or the new 2.0-liter 4-cylinder Atkinson engine.

Engine Drive

The 2.0-liter 4-cylinder Atkinson combustion engine drives either the Accord Plug-in or Hybrid version at high load and speeds.

How the Power is moved

The integration of the three power modes connects to the front-wheel-drive Accord through Honda’s all-new Electric Continuously Variable Transmission (E-CVT) process. This is not a Continuously Variable Transmission, CVT. Honda’s E-CVT has no torque converter, (essentially adding or subtracting work of the engine that moves your vehicle) or any traditional belts and pulleys that permit a CVT to find the optimum gearing with the amount of torque need for the load.

Honda digitally, (software) coordinates the two electric motors and the new 2.0-liter 4-cylinder Atkinson to find the required torque load for the Accord. This “lock-up clutch” of Honda’s E-CVT directly connects to their “two-motor hybrid approach” for propulsion.

In EV mode the E-CVT clutch disconnects from the gasoline engine, while in midrange to high speeds the E-CVT clutch connects the “drive motor to the generator motor to transmit engine torque directly to the drive wheels.”

Honda’s “Automatic Modes” of their new E-CVT have two different settings. “D” mode for normal driving while “B” (brake) that increases the regenerative braking and charging of the battery that powers the two electric motors. Behind the shifter is an “EV” button that selects a fully electric operation but is canceled when the battery is depleted triggering the gasoline engine to recharge the battery.