2010 Honda Insight - Powertrain
A balanced approach to power, compactness and efficiency
Now in its fifth generation since debuting on the original Insight in 1999, Honda’s Integrated Motor Assist (IMA) is a parallel hybrid powertrain that increases efficiency through power assist, energy regeneration and idle stop capabilities. The system consists of a low-friction 1.3-liter SOHC 8-valve i-VTEC 4-cylinder engine that serves as the primary power source; a 10-kilowatt, lightweight, ultra-thin electric motor that provides additional power and electricity generation; a lightweight and compact battery; and a continuously variable transmission. The combined output and overall torque of the engine and motor (max. output 98 hp @ 5,800 rpm, max. torque 123 lb-ft. @ 1,000–1,500 rpm) allow for responsive acceleration in the city and confidence-inspiring performance on the highway. The IPU of the new IMA is 19 percent more compact than that of the fourth-generation system, contributing to spaciousness and utility, while the powertrain’s efficiency is the key to the Insight’s exceptional fuel economy: Honda estimated EPA combined fuel economy of 41 mpg* and a 10.6-gallon fuel tank deliver a maximum range of over 400 miles.
- Fifth-generation Integrated Motor Assist (IMA) hybrid system
- 1.3-liter SOHC 8-valve i-VTEC 4-cylinder engine
- High-power, lightweight, ultra-thin electric motor
- Lightweight, compact, durable battery
- Standard continuously variable transmission (CVT)
- Regenerative braking
- Drive-by-Wire™ throttle control
High-efficiency, lightweight, low-friction 1.3-liter SOHC i-VTEC 4-cylinder engine
The heart of the Insight powertrain is the i-VTEC engine, which combines responsive performance and excellent fuel efficiency as a result of its lightweight, low-friction and efficient design. Rated output is 88 hp @ 5,800 rpm, and rated torque is 88 lb-ft. @ 4,500 rpm. Key features of the engine include the following:
The i-VTEC valve control system employs a dual-rocker configuration that supports both normal valve timing and cylinder idling to achieve a broad power band combined with excellent fuel efficiency.
The lightweight engine block incorporates a thin-sleeve construction, while friction-reducing measures include plateau honing, low-friction pistons, low tensile-force piston rings and an offset cylinder bore. The surfaces of the high-strength forged steel connecting rods have been hardened with a special carbon process for a more lightweight design.
The Programmed Fuel Injection (PGM-FI) is a lightweight, compact system that ensures optimal air-fuel ratio by monitoring throttle position, engine temperature, intake-manifold pressure, intake-air mass flow atmospheric pressure, exhaust-gas oxygen content and intake-air temperature to control fuel delivery via multi-holed injectors mounted in the intake port of the cylinder head. The intake manifold is made of lightweight, composite resin instead of aluminum for further weight savings.
Intelligent dual and sequential ignition with two spark plugs per cylinder facilitates an intense, rapid combustion process for increased power and reduced fuel consumption and emissions.
A subframe torque rod damper system reduces rocking and helps isolate powertrain noise and vibration from the passenger compartment. Hydraulic engine mounts and reinforcements in the engine compartment help further reduce engine noise and vibration for a more comfortable ride.
During deceleration, Variable Cylinder Management (VCM) virtually eliminates the pumping action of the cylinders, decreasing resistance to allow the motor/generator to more efficiently generate electricity with which to charge the battery.
*Based on 2010 EPA mileage estimates, reflecting new EPA fuel economy methods beginning with 2008 models. Use for comparison purposes only. Do not compare to models before 2008. Your actual mileage will vary depending on how you drive and maintain your vehicle.
High-power, lightweight, ultra-thin DC brushless electric motor
The motor contributes up to 13 hp (10 kilowatts) @ 1,500 rpm and 58 lb-ft. of torque @ 1000 rpm to the Insight’s powertrain, assisting in acceleration and some steady state cruising situations at low-to-mid vehicle speeds (depending on conditions). The motor also acts as a generator during braking, steady cruising, gentle deceleration and coasting to capture kinetic energy and recharge the battery. The ultra-compact electric motor is located between the engine and transmission.
Notable: When driving on a flat surface at steady speed in the low 30 mph range, for example, it is possible for the driver to determine that the vehicle is being propelled exclusively by the electric motor when the IMA System Power Flow Indicator on the Multi-Information Display shows that only the battery is providing power.
Lightweight and compact Intelligent Power Unit (IPU)
The Intelligent Power Unit (IPU) controls the power of the IMA system. The IPU contains the energy storage module (battery), Power Control Unit (PCU), motor Electric Control Unit (ECU), and a compact cooling system. The IPU is located beneath the rear cargo area for minimal impact on interior space.
The nickel metal hydride (Ni-MH) battery system consists of seven modules that serve power to the electric motor as it assists the engine. It also stores the electricity when the motor generates electricity during regenerative braking. The seven-module battery system is comprised of 84 individual “D-sized” 1.2 volt cells for a total battery system output of 100.8 volts and a capacity of 5.75 ampere-hours.
Compared to the fourth-generation IMA battery technology in the 2006 Civic Hybrid, power output per module is 30 percent higher, allowing for a decrease in modules from 11 to 7. The changes allowed the overall IPU size to be reduced by 19 percent and overall weight by 28 percent. This decreased size and weight along with the corresponding reduced use of materials have also resulted in a battery with a lower lifetime environmental burden.
Continuously variable transmission (CVT)
The CVT offers smooth and predictable transitions and excellent low-end acceleration and low-rpm cruising. By helping the engine and IMA motor stay in their most efficient operating range, the CVT provides a fuel efficiency benefit superior to that of a conventional automatic transmission with gears, and it allows for greater efficiency during regenerative braking by smoothing deceleration. The use of a lower gear ratio results in quick-reacting initial acceleration performance. The start clutch control is redesigned to take full advantage of the features of the IMA system, engaging at lower rpms to enhance initial acceleration and contribute to fuel efficiency.
The Insight’s regenerative braking system intelligently apportions braking power between the hydraulic brakes and the electric motor to extract even more electricity from the vehicle’s kinetic energy. Less reliance on the traditional braking system and reduced engine pumping losses translate into greater electrical regeneration and improved fuel efficiency. During braking, a braking pressure sensor sends a signal to the IPU, which maximizes the level of regenerative braking.
Automatic idle stop
The Insight automatically turns off the gasoline engine during complete stops under normal operating conditions. This feature allows the vehicle to use even less fuel and emit fewer emissions than a conventional automobile. The system uses the IMA electric motor to restart the engine.
Drive-by-Wire™ throttle control
Continuously optimizing the ratio of movement between the throttle pedal and the throttle butterfly valve in the intake manifold, Drive-by-Wire optimizes engine response and IMA operation to match driving conditions and driver expectations for throttle input response. The system uses a highly responsive DC motor to change the throttle position quickly and precisely.