Since the Accord's launch as a compact hatchback car in
1976, it has
earned widespread acclaim as a leader in smart design, superb
quality and world-class
efficiency. In its 28-year history, the Accord has constantly
going from that original compact hatchback to today's premium
sedan and coupe. The seventh-generation Accord V-6, released in
2003, once again
raised the bar for performance, safety and value in the
mid-sized segment with
a highly efficient and powerful 3.0-liter, 240-horsepower, SOHC
VTEC V-6 engine,
4-wheel disc brakes and a standard anti-lock braking system
(ABS) on all models,
along with standard features such as air conditioning, power
and door locks, and an AM/FM/CD stereo system. In addition, the
Accord was one of the first mid-sized sedans to bring luxury
features such as
a voice-activated navigation system, XM satellite radio and
side curtain airbags
to the premium mid-size segment.
In 2005, the Accord further establishes its role as a
and efficiency leader with the introduction of the Accord
Hybrid, the world's
first V-6-powered gasoline-electric hybrid vehicle. Boasting
the highest fuel
efficiency for a V-6-powered automobile, Accord Hybrid utilizes
the third generation
of Honda's exclusive Integrated Motor Assist (IMA) hybrid
new Variable Cylinder Management (VCM) technology. By combining
V-6 engine and IMA with VCM, the Accord Hybrid Sedan provides
even more power
- 255 hp versus 240hp in the regular Accord V-6 Sedan - while
fuel efficiency to an estimated 30 mpg city / 37 highway -
virtually all 4-cylinder mid-sized sedans and similar to that
of the compact
class Civic Sedan, already a benchmark for fuel efficiency in
the compact car
Car and Driver's 10Best List - The sixth and seventh
of Accord have a current streak of 5 consecutive years on the
annual review of new cars. In total an Accord has been named to
in 18 of 21 years the magazine has compiled this list, the most
car in over two decades of the magazine's award.
50 Hottest New Cars (2003)
Perfect 10 (1996) - One of 10 most significant cars between
2003 - Best Overall Value, Mid-sized Car under and over
2000-2002 - Best Overall Value, Mid-sized Car under and over
Maxim Magazine 2004 Car of the Year - Accord
Consumer Digest 2004 Best Buy, Family Car
Best Family Car (Comparison Test, 1/2003)
2004 Consumer's Most Wanted - Sedan under $25,000
The Honda Accord Hybrid Sedan is designed to show that a
can be an important component in the mainstream of America's
landscape that provides exceptional fuel economy while still
performance and comfort.
With the introduction of the 2000 Insight - America's first
car and still the leader of the EPA's annual fuel economy
Honda has been at the forefront of hybrid technology. The
company followed up
the Insight with a hybrid version of America's best-selling
the Civic Hybrid, introduced in March 2002 as the first truly
and the first application of hybrid technology to an existing,
high volume vehicle.
With the addition of the Accord Hybrid, Honda becomes the only
car company in
the United States with three hybrid models available to
While using a more powerful and efficient version of Honda's
the Accord Hybrid Sedan also incorporates new, leading edge
engineers are also applying to Honda's main line of cars and
Among these advanced technologies are its Variable Cylinder
system that allows for deactivation of three of the engine's
during cruising. The system also features an Active Control
Engine Mount (ACM)
an Active Noise Control (ANC) system to eliminate the potential
effects of three-cylinder
operation on cabin noise and engine vibration. This same
technology is also
being applied on the all-new 2005 Odyssey minivan equipped with
i-VTEC engine. In addition, the Accord hybrid utilizes a dual
air conditioning compressor that is both belt (engine) and
electric motor driven,
allowing for more efficient operation of the Accord Hybrid's
automatic climate control system even when the engine is in
idle stop mode.
Combined, these technologies along with improvements in
aerodynamics and weight
saving features like an aluminum hood, allow the Accord Hybrid
to achieve an
estimated EPA fuel economy rating of 30 miles per gallon in the
city and 37
mpg highway, up from an EPA-rated 21 city / 30 highway for the
Accord EX V-6
Sedan - a fuel economy gain of 43 percent and 23 percent,
The Accord's Integrated Motor Assist System (60%) accounts for
the gains in city fuel efficiency, while Variable Cylinder
and idle stop (25%) is responsible for the rest. During highway
VCM system (57%) provides the majority of the increase, while
IMA (38%) and
a lower drag coefficient and greater aerodynamics (5%) also
Accord Hybrid Highlights
3rd-generation Honda Integrated Motor Assist (IMA)
3.0L i-VTEC V-6 engine
Intelligent Power Unit (IPU) - Power Control Unit (PCU),
(NiMH) battery pack, internal cooling system
Variable Cylinder Management (VCM)
Active Control Mount (ACM) engine mount system
Dual Zone Hybrid Automatic Climate Control System
Unique Accord Hybrid Sedan Features
Standard rear decklid spoiler
Unique front grille
Exclusive, lightweight 16" alloy wheels with larger 215/60
New combination AM/FM/XM radio antenna
Exclusive IMA digital readout
Active Noise Control (ANC)
New, illuminated steering wheel-mounted switches
3.0L i-VTEC V-6 engine
More powerful IMA system
255 hp @ 6000 rpm
232 lb.-ft. @ 5000 rpm
Hybrid Idle Stop
Variable Cylinder Management(TM) (VCM(TM))
Dual scroll hybrid air conditioning compressor
Active Control Engine Mount (ACM) system
Modified 5-speed automatic transmission
Electric Power Steering (EPS)
Enhanced Traction Control System (TCS) with creep aid
Instant mobility flat tire repair system (IMS)
Unlike previous hybrid vehicles from Honda and other
the focus for the Honda Accord Hybrid is not entirely on high
but also on high performance. The use of Honda's new Variable
Management (VCM) system that deactivates the three of V-6
to save fuel during cruising and deceleration allow Honda
engineers to maximize
fuel economy while the hybrid IMA system helps to increase peak
power by 15
hp and 20 lb.-ft. of torque over the current Accord EX V-6. The
Sedan improves on the current Accord V-6's 0-60 mph time by
half a second
(7.5 sec. vs. 8.0 for an Accord EX V-6). In addition, peak
torque of 232 lb.-ft
@ 5000 rpm is now spread out over a much flatter curve, which
makes 90 percent
available at engine speeds less than 4000 rpm.
Major Accord Hybrid
Accord Hybrid Sedan
Accord EX V-6 Sedan
Change from EX V-6
Engine displacement (cc)
144V, 6.0 Ah
Horsepower @ RPM
255 hp @ 6000
240 hp @ 6250
+ 15 hp (6.3%)
Torque @ RPM
232 lb.-ft. @ 5000
212 lb.-ft. @ 5000
+ 20 lb.-ft (9.4%)
New 5-speed AT
Lighter, more compact
Passenger volume (cu. ft.)
+ 5 cu. ft.
Cargo volume (cu. ft.)
- 2.8 cu.ft (18.6%)
EPA Fuel Economy (mpg city / highway)
30 / 37 (estimated)
21 / 30
+ 9 mpg city (42.9%)
+ 7 mpg hwy (23.3%)
Driving range (based on hwy mileage)
+ 120 miles (23%)
When planning the current Accord Sedan, engineers were looking to put traditional
Accord quality and reliability into a new package filled with more emotional
appeal, and to employ sedan styling similar to popular luxury European sport
sedans. The 2005 Accord Hybrid Sedan adds to this foundation design cues intended
to help it achieve top-of-class fuel economy and to improve the car's
aerodynamics and reduce its drag coefficient to a slippery 0.29. These additions
include a rear decklid spoiler, lightweight 16" aluminum alloy aerodynamic
wheels. Additionally, lightweight aluminum was used in the Accord Hybrid's
hood, bumper frames and rear suspension knuckles, helping reduce overall weight.
In balancing the seemingly contradictory goals of high fuel efficiency and
high performance, Honda combined the 3rd generation IMA system with the all-new
Variable Cylinder Management (VCM) system that alone generates substantial fuel
savings when full engine power is not needed (as in highway cruising and deceleration).
Working together, the two systems provide exceptional fuel efficiency benefits
when the engine is not at full capacity, but mid-sized class-leading power when
the car is at full throttle. Overall, the VCM system helps to maximize highway
fuel economy while the IMA system helps to maximize city fuel economy.
The engine used on the Honda Accord Hybrid Sedan is primarily the same as that
of the Accord V-6, but with a few modifications to save weight and to allow
for the use of Honda's VCM system. Foremost among these changes is the
implementation of Honda's advanced i-VTEC system in place of the VTEC
system of the Accord EX V-6.
Without any help from the electric IMA system, this 3.0L engine provides 240
hp and 217 lb.-ft of torque, but utilizes some lighter weight materials than
the original version used in the standard Accord EX V-6.
First introduced to North America in the all-new 2005 Odyssey minivan, Honda's
innovative Variable Cylinder Management (VCM) system has now been engineered
to maximize fuel economy in the Accord's 3.0L i-VTEC V-6 in concert with
the IMA system. It works by monitoring speed and throttle action to determine
if full engine power is required, if not - as in steady cruising or minor
acceleration, the rear bank of three cylinders is deactivated. Further efficiency
is achieved when the fuel injection system cuts fuel to the three active cylinders
when the car is decelerating or braking - a feature similarly employed
in most Honda vehicles.
Additional efficiencies are gained by the use of lightweight magnesium for
certain engine parts, and the Accord Hybrid Sedan's engine incorporates
a new engine head to manage the VCM system. A new airflow sensor and a 2-axis
belt drive with an auto tensioner help to maintain maximum efficiency and prevent
power losses due to friction.
The 3rd generation of Honda's Integrated Motor Assist system -
which incorporates an ultra-thin electric motor (68mm) mounted between the gasoline
engine and automatic transmission - is the largest and most efficient
Honda has produced. The motor produces 10 percent more horsepower assist (12
kW total) than the Civic Hybrid and 26 percent more supplemental torque (100.4
lb.-ft. total). During regenerative braking when the motor acts as a generator
for the IMA's battery pack, the generator also produces 12% percent more
kW of power (14 kW total), and in both cases, the motor is more efficient, transferring
97.5 percent (vs. 94.6% in Civic Hybrid) of the available energy in assist mode,
and converting 95.2 percent (vs. 93.6%) of renewable kinetic energy into electrical
energy in charge mode. In addition, the Accord Hybrid's Nickel Metal-Hydride
battery pack and integrated cooling system are more compact, yet more efficient
than that in a Civic Hybrid Sedan.
A specially modified version of the existing 5-speed automatic transmission
was specified for the Accord Hybrid Sedan. This new transmission is more compact
than that in an Accord EX V-6 Sedan and is specially designed to work with the
IMA's electric motor to maximize the motor's ability to regenerate
electricity during regenerative braking.
The transmission uses a high response lockup clutch torque converter for improved
fuel efficiency while an integrated electric oil pump helps provide smooth and
quick restarts of the engine after idle stops. With a slightly wider range of
gear ratios than the automatic transmission in an Accord EX V-6, acceleration
is quick from the line and the taller 5th gear helps conserve fuel during highway
Though drivers will notice a different experience when it comes to the reduced
frequency of fuel stops, the actual driving experience is virtually identical
to that of a traditional Accord EX V-6. The complex processes that make the
Accord Hybrid the fuel efficient car that it is would go unnoticed if not for
the small IMA display integrated into the car's speedometer.
At startup, the Accord Hybrid's engine runs at idle speed until the driver
increases the throttle to begin accelerating. During acceleration, all six cylinders
of the Accord Hybrid's 3.0-liter engine are active, with the IMA system
helping if hard acceleration is required. If this is the case, the blue indicator
bars in the Accord's IMA display will light to show that the IMA is in
When the driver minimizes accelerator input at cruising speed, a number of
fuel saving operations begin. First, the Variable Cylinder Management (VCM)
system can deactivate the engine's rear bank of three cylinders to effectively
cut fuel consumption in half. At the same time, the IMA's Intelligent
Power Unit turns the IMA motor into a generator to begin regenerative braking
and the IMA display's green bars illuminate to show the level of electrical
energy being created. If, during cruising, power is required to maintain speed,
the IMA motor will offer assist while the rear cylinders remain inactive.
As the vehicle begins to slow and the driver applies the brakes, more electricity
is created through regenerative braking and the VCM system cuts fuel to the
active front bank of three cylinders to further conserve fuel.
As the driver continues to apply the brake, the IMA system can completely idle-stop
the engine when vehicle speed drops below 8 mph. An indicator in the instrument
panel's tachometer flashes to alert the driver that the car is idle-stopped.
When the driver releases the brake pedal, the IMA motor instantaneously spins
the engine back into action with all six cylinders firing at idle speed. Occasionally,
the idle stop feature is disabled when driving on a hot day and full air-conditioning
power is needed by the hybrid air conditioning system. At all other times, idle
stop can be activated once the vehicle speed exceeds approximately 10 mph.
The suspension and steering set up for the Accord Hybrid Sedan is essentially
the same as that of the existing Accord EX V-6, except for the adoption of electric
power steering (EPS) versus a traditional hydraulic power rack and pinion steering
set up in the Accord EX V-6.
The 7th-generation Accord's 4-wheel double wishbone suspension continues
to be one of the most sophisticated arrangements in the mid-sized sedan class.
The front double wishbone suspension ensures accurate tracking at all vehicle
speeds, while the rear 5-link double wishbone suspension mounted to the car's
subframe helps to limit body roll during cornering and also isolates the cabin
from road noise.
Electric Power Steering also contributes to higher fuel economy (engine power
is not needed to pump the hydraulic system). While similar to the performance-oriented
steering systems used in the Honda S2000 and the Acura NSX, the high-mounted
EPS system in the Accord Hybrid is designed to provide complete steering operation
during idle stop mode.
The Accord Hybrid Sedan also employs a similar braking system as to that of
the Accord EX
V-6, which includes ventilated discs in the front and solid discs in the back.
Braking is further enhanced by a standard 3-channel anti-lock braking system
(ABS) and electronic brake distribution (EBD). Accord Hybrid has wider 215/60
R16 tires compared to those on the EX
Continuing Honda's strategy of incorporating hybrid technology seamlessly
into its mainstream vehicles, there are few interior differences between Accord
Hybrid and an Accord EX V-6 Sedan. The main differences are the unique instrument
panel meter display that shows the IMA system's charge and assist status,
IMA battery charge levels, "ECO" light indicating VCM operation,
along with trip and lifetime fuel economy readouts. Less obvious, but much more
significant is Active Noise Control (ANC) - which helps to reduce the
engine booming sound inherently created inside any engine that has cylinder
deactivation, and a new hybrid air conditioning unit that is powered by a combination
of the gasoline engine's drive belt and a supplemental electric motor
depending upon cooling needs.
The Active Noise Control uses microphones in the front and rear of the passenger
cabin to monitor the low-frequency "booming" noise created by three-cylinder
engine operations. It then generates a counter-cycled sound wave through the
car's audio system that effectively cancels the booming noise.
The hybrid air conditioning unit uses two air compressors, one connected to
the gasoline engine and one connected to an electric motor. When full cooling
is needed, as when a car is first started on a hot summer day, the HVAC control
unit relies on both to create maximum cooling power. Under normal conditions,
cooling is provided by either the belt-driven compressor attached to the 3.0-liter
V-6 or the electric magnet driven compressor powered by the IMA battery. This
allows the air conditioning system to work at virtually all times, even when
the car is at idle-stop.
The Accord Hybrid Sedan features a standard leather-trimmed interior with heated
front seats, an AM/FM/XM audio system with 6-disc in-dash CD changer, dual-zone
automatic climate control, power windows, mirrors and door locks and a HomeLink
remote system. The only factory option on the Accord Hybrid Sedan is the Honda
Satellite-linked Navigation System with voice recognition.
The Accord Hybrid Sedan retains all of the Accord's class-leading safety
technology, including dual-stage, dual-threshold front airbags, dual front side
airbags and side-curtain airbags to protect front and rear passengers in the
unlikely event of a rollover impact.
In addition to the advanced passive safety technology of the Accord Hybrid
Sedan, it also utilizes the same active systems as all Accord V-6 sedans. This
includes four-wheel disc brakes with a three-channel anti-lock braking system,
electronic brake distribution, and a 2nd-generation traction control system
New with the Accord Hybrid Sedan is the car's Instant Mobility System,
which replaces a traditional spare tire with a flat tire repair kit. The elimination
of a spare tire provides an extra covered storage compartment within the car's
trunk. The Accord's IMS provides a convenient and quick process to repair
most flat tire situations.
Retail Gas Prices in the United States (August 6, 2001 to Present)
After a brief decline in prices at the end of 2001, retail gasoline prices have
been rising steadily to a peak of 2.02 per gallon of regular (87 Octane), unformulated
unleaded gasoline during the 2004 Memorial Day weekend. This is even more profound
in states like California, where emissions regulations require further refinement
of the gasoline sold. In California, the reformulated regular unleaded gasoline
is currently going for $2.19 per gallon after reaching a peak of 2.33. Though
the gas shortage of the mid-1970's was more substantial on an inflation-corrected
basis, this is the first time in the history of the United States that gasoline
prices have topped $2.00 nationwide.
At current prices in California, using an average of 15,000 miles driven in
a year, Accord Hybrid Sedan drivers would reduce their fuel expense over $350
per year compared to a traditional Accord EX V-6 ($997/year vs. $1,369)*.
* 33 combined mpg (Hybrid) vs. 24 mpg (Accord V-6). SOURCE: US Department of
Hybrid powertrains were developed originally to enhance fuel efficiency, and
the IMA system in the Accord Hybrid is no different in that regard, helping
the V-6 sedan achieve an estimated 30 mpg city / 37 hwy. What sets this iteration
of Honda's Integrated Motor Assist apart from previous systems is the
fact that along with the increase in fuel efficiency comes a marked gain in
horsepower, torque and performance - making the Accord Hybrid Sedan the
industry's first high performance hybrid car, delivering the power of
a high-performance V-6 engine with the fuel efficiency of a 4-cylinder car.
Along with excellent fuel efficiency, the combination of this Accord's
3.0L i-VTEC V-6 engine with Variable Cylinder Management and Honda's 3rd
generation IMA system produces 255 horsepower (+6.3% over an Accord EX V-6)
and 232 lb.-ft. of torque (+9.4%). Internal testing shows the IMA's motor
assist helps the Accord Hybrid improve its 0-60 mph time to 7.5 seconds versus
8.0 seconds for Accord EX V-6 Sedan, with the powertrain producing torque in
a constant, flat manner - 90 percent of peak torque (232 lb.-ft) available
below 4000 rpm.
Accord Hybrid Powertrain Highlights
Peak power: 255 hp @ 6000 rpm, 232 lb.-ft. @ 5000
3.0L V-6 engine
Lightweight, durable aluminum alloy block
Single Overhead Cam (SOHC) head with i-VTEC
Magnesium head cover
Variable Cylinder Management (VCM)
4-valves per cylinder
Programmed Fuel-Injection (PGM-FI)
6500 rpm redline
Active Control Engine Mount System (ACM)
Integrated Motor Assist (IMA) Electric Motor
3rd-generation of Honda's patented gasoline-electric hybrid system
Thin (68mm), brushless DC motor (vs. 65 mm in Civic Hybrid)
Peak assist: 16.1 hp / 100 lb.-ft of torque (vs. 13hp / 46 lb.-ft. in Civic
Peak generation: 14 kW (vs. 12.6 kW in Civic Hybrid)
Maximum electrical current: 120 Volts (vs. 75V in Civic Hybrid)
Intelligent Power Unit - Power Control Unit, Nickel-Metal Hydrid
(Ni-MH) battery pack and Integrated cooling system
Improved 5-Speed Automatic Transmission
3.0-Liter SOHC i-VTEC V-6 engine
At the heart of the Accord's power plant is the same 3.0L V-6 engine
as that in the Accord EX V-6, but with a few modifications to reduce space and
weight and to allow for the installation of the IMA motor and new VCM system.
This 60o V-6 engine is designed to require only minimal maintenance, including
oil changes every 10,000 miles and its first scheduled tune-up at 105,000 miles.
Aluminum alloy block
Like all Honda engines, the 3.0L i-VTEC engine used in the Accord Hybrid is
built around a lightweight and durable aluminum alloy block that provides significant
weight and long-term corrosion benefits over traditional iron blocks. The 60¹
V-6 block incorporates extra brackets to allow the mounting of the VCM's
magnesium composite head cover and the IMA motor.
To further enhance durability, each cylinder contains cast-iron liners, while
the crankshaft and each of the two camshafts are made of forged steel designed
to minimize friction.
i-VTEC Engine with Variable Cylinder Management
One major improvement new to this engine is the implementation of the advanced
version of Honda's variable valve-timing and lift electronic control (VTEC)
system or i-VTEC. i-VTEC adds a level of "intelligence" to the legendary
VTEC system by adding a Variable Cylinder Management (VCM) system that switches
between six- and three-cylinder combustion. When high output is required, such
as during startup and acceleration or when climbing hills, the engine operates
on all six cylinders to deliver superior performance. During cruising and at
low engine loads, the system idles the rear bank of three cylinders for improved
fuel efficiency and reduced emissions. Further, the idled cylinders remain sealed,
alleviating the pumping losses associated with intake and exhaust and giving
fuel economy a further boost.
Variable Cylinder Management helps maximize fuel efficiency by making the Accord
Hybrid's 3.0L V-6 engine effectively run on only three cylinders when
the power needs are minimized, yet it can still seamlessly provide the full
power of all six cylinders during hard acceleration or other high load situations.
When full power is needed, i-VTEC instantly opens the valves and sends fuel
to the three previously idled cylinders. When combined with the IMA motor, output
peaks at 255 horsepower.
The Accord Hybrid's VCM system is similar to the VTEC-controlled Cylinder
Idling System used on Civic Hybrid, but is more sophisticated. Where the Civic
Hybrid's cylinder idling deactivates three of the engine's four
cylinders during deceleration only to help improve regenerative braking efficiency,
the Accord's VCM system, is able to deactivate the engine's rear
bank of three cylinders during a variety of driving situations, including steady-speed
cruising, light acceleration and braking. Thus, improving fuel efficiency, reducing
emissions and making regenerative braking more efficient.
The Accord Hybrid's i-VTEC V-6 engine features a Variable Cylinder Management
(VCM) system that improves fuel economy by idling three of the Odyssey's
six cylinders during cruising and deceleration. VCM deactivates the rear bank
of cylinders by using the VTEC (Variable Valve-Timing and Lift Electronic Control)
system to close the intake and exhaust valves while cutting fuel at the same
The rear bank of cylinders was chosen for deactivation because the front bank
is best positioned for cooling performance. Idling the rear bank also helps
to maintain the temperature of the catalytic converter beneath the cylinder
heads, helping to maintain optimum emissions performance. The Accord Hybrid's
spark plugs continue to fire even when the cylinders are deactivated. This minimizes
plug temperature loss and prevents fouling induced from incomplete combustion
during cylinder re-activation. Further, sparking in air alone results in higher
voltages than in a fuel-air mixture because of the higher insulation resistance.
Therefore, iridium-tipped spark plugs are used for their high resistance to
wear at high voltages.
i-VTEC VCM System Designed for Rapid Switching at Low Engine Speeds
In a conventional VTEC system, hydraulic pressure pushes a single synchronizing
piston, which is in turn pressed back by a return spring. The VTEC system locks
the valvetrain's rocker arms to allow additional valves to open and increase
engine breathing. Such systems require relatively high engine speeds since hydraulic
pressure is used to push the spring. VCM, however, demands switching at low
rpm. This is achieved by creating a hydraulic circuit with two systems, each
capable of providing the hydraulic pressure required to push the synchronizing
piston in the required direction. This design thereby allows switching from
six cylinders to three cylinders in low-speed ranges. To achieve responsive
switching to six cylinders when the driver quickly opens the throttle under
hard acceleration or driving up hill, the system employs a new three-way solenoid
spool valve to control the oil pressure for switching. These enhancements result
in highly responsive VCM switching regardless of engine speed.
VCM monitors throttle position, vehicle speed, engine speed, automatic-transmission
gear selection, and other factors to determine if the vehicle is cruising or
decelerating. During cruising and deceleration, VCM deactivates the three cylinders
on the rear bank of the engine. To further enhance control, the system also
simultaneously determines whether engine oil temperature is suitable for VCM
switching and whether catalytic converter temperature will remain in the proper
range. While idling the cylinders, the system controls ignition timing, and
turns the torque converter lock-up on and off, thereby suppressing torque-induced
jolting during the switch from six to three cylinder operation. The result is
a smooth, seamless switch between three and six cylinder modes that is nearly
unnoticeable to the driver.
For cylinder deactivation operation, the synchronizing piston moves to isolate
the valve-lift rocker arms from the deactivated cylinders' rocker arms.
The deactivated cylinder rocker arms are operated by zero-lift cams that deactivate
the cylinders by closing the intake and exhaust valves.
Active Control Engine Mount System (ACM)
Due to the inherent increase in engine vibration when VCM has deactivated the
rear bank of cylinders, an Active Control Engine Mount system (ACM) is used
to minimize the effects of engine vibration. The system uses sensors that alert
the Electronic Control Unit (ECU) to direct ACM actuators to move in synch with
the vibration, thereby eliminating the vibration being transmitted to the passenger
compartment. Additionally, an Active Noise Control system (ANC) works in cooperation
with the ACM. An ANC controller with front and rear microphones in the passenger
cabin detects the booming noise associated with cylinder deactivation and instructs
the audio system's speakers to emit an opposite sound wave. (See the Interior
section for more information on ANC.)
As with previous versions of Honda's hybrid powered cars, the IMA system
incorporates an idle-stop feature that temporarily turns off the gasoline engine
when the vehicle comes to a stop from speeds over 10 mph. In this situation,
the IMA's ECU monitors the closed throttle, speed and brake pressure to
determine the driver is bringing the car to a stop. The engine is turned off
when the car's speed drops below 10 mph (16 km/hr). When the brake pedal
is released, the IMA's motor restarts the engine and power is available
Unlike the idle-stop feature in the Insight and Civic Hybrid, the Accord Hybrid
system continues to operate even while the car's automatic climate control
system is in use. This is made possible by the introduction of a new hybrid
air conditioning system, which uses air compressors powered by both the gasoline
engine's drive belt and IMA electric motor (see Interior). Idle-stop is
unavailable only when the car is first started on an extremely hot day when
maximum cooling is required.
The 3rd-generation IMA system is the largest and most efficient to come out
of Honda's hybrid development program. As with previous versions, the
IMA system consists of an ultra-thin DC brushless electric motor mounted between
the gasoline engine and the automatic transmission, and an intelligent power
unit (IPU) that stores electric power in a compact battery box and controls
the flow of electricity to and from the electric motor. Also new with this generation
of the IMA is the mounting of a 15cc air compressor to the electric motor which
provides increased cooling capacity to the Accord Hybrid's dual-zone automatic
climate control system (see Interior).
IMA Electric Motor
Providing supplemental power boost to the V-6 engine, the IMA's electric
motor is designed to provide up to 12 kW (16 hp) and 136 Newton-Meters (100
lb.-ft) of additional power and torque to the Accord Hybrid's engine.
Mounted between the engine and the Accord Hybrid's 5-speed automatic transmission,
the IMA motor is an ultra-thin (68 mm) DC brushless design and provides a substantial
amount of low-end torque to aid in hard acceleration and hill climbing.
In addition to providing supplemental motive power, the IMA motor acts as a
generator during deceleration and braking to recapture kinetic energy and recharge
the IMA's battery pack during regenerative braking, and provides power
to the dual scroll hybrid A/C compressor used in the Accord's dual zone
hybrid automatic air conditioning system (see Interior).
For this third generation of IMA motors, a new internal permanent magnet was
designed to increase output density and make the motor more efficient than previous
motors. At startup, the Accord hybrid provides 26 percent more starting torque
than the Civic Hybrid. During driving, the motor provides a 20 percent increase
in horsepower assist and more than doubles peak torque (100 lb.-ft. from 46
lb.-ft) compared with the Civic Hybrid's IMA motor; and it is more efficient,
now converting 97.5 percent (versus 94.6 percent efficiency of Civic Hybrid
IMA) of the available electricity into motive energy in assist mode.
IMA Intelligent Power Unit (IPU)
Power for the IMA system is controlled through the Accord Hybrid's Intelligent
Power Unit. Located directly behind the rear seatback, the IPU consists of the
Power Control Unit (PCU) - or the IMA's brain, a rechargeable Nickel
Metal-Hydride battery module, and an integrated cooling unit.
Power Control Unit (PCU) - Electronically controls the flow of energy
to and from the IMA's electric motor. Using the latest in computer chip
technology, the PCU's response time is quickened over previous versions,
and a new inverter and DC/DC Converter help contribute to the IMA's
overall increase in peak power.
Battery Pack - Energy for the IMA motor is stored in a bank of Nickel
Metal-Hydride cells. This bank of 120 1.2V units stores up to 144 Volts of
electrical energy for the IMA motor, as in previous versions. But a new SANYO
dual module casing reduces weight from previous hybrid battery packs and also
allows it to increase efficiency of the electrical flow.
Integrated Cooling Unit - To offset the heat generated by the constant
flow of electricity to and from the battery pack, an integrated cooling system
is mounted directly on the battery pack's outer box. Interior cabin
air is continually flowed over the battery pack, and recirculated via a small
vent placed on the rear parcel shelf.
A key to the long-term viability of hybrid-powered vehicles is their ability
to recapture kinetic energy via regenerative braking and store this energy as
electricity in rechargeable battery packs. Accord Hybrid is no different, as
its IMA electric motor also acts as a generator to recharge its battery pack
during steady cruising, deceleration/coasting and braking.
Accord Hybrid's efficiency in generating electricity from braking energy
is enhanced by a more efficient IMA motor/generator, the ability of the engine
and transmission to minimize friction through the VCM system and a modified
5-speed automatic transmission. Exploiting these friction-saving features during
electricity generation, the IMA motor is able to convert 95.2 percent of the
available kinetic energy into electricity to store in the IMA's rechargeable
battery pack. This is an improvement of almost two percentage points over the
previous Civic Hybrid's generator efficiency (93.5%).
This greater efficiency is achieved through more efficient cooperation between
the transmission and the IMA motor, and a more sophisticated the idle stop feature
that cuts fuel to the engine and reduces excess friction losses due to engine
5-Speed Automatic Transmission
To increase performance through quicker shifts and a wider range of gear ratios
and to aid the IMA system's ability to recapture kinetic energy through
regenerative braking, Accord Hybrid employs a new 5-speed automatic transmission.
Sixty millimeters thinner than the version of 5-speed transmission used on
the current Accord EX V-6, this transmission contributes to improved fuel efficiency
through a new lockup clutch torque converter that shortens shift response during
acceleration, more immediate startup after idle-stops by using of an integrated
electric oil pump, and smoother ride during hard acceleration. While a new long
torsion damper works with the VCM system to increase the rpm range during which
VCM is activated to further contribute to improved fuel economy.
5-Speed Automatic Transmission,
Final Drive Ratio
Integrated Electric Oil Pump
In order to generate the hydraulic pressure necessary to shift gears through
its torque converter, most automatic transmissions experience a lag between
shifts while the engine spins the drive shaft and the counter-spinning torque
converter spins to create oil pressure. The Accord Hybrid eliminates this lag,
which subsequently improves fuel efficiency, by using an integrated electric
oil pump to constantly pump oil through the transmission's torque converter.
This is particularly important for the Accord Hybrid when restarting after an
idle stop when the gasoline engine is providing no power to the drive shaft.
High-response lockup clutch torque converter
In addition to the electric oil pump which maintains consistent pressure within
the transmission, the torque converter itself employs an advanced, compact design
that improves shift response time to one-third of that in the Accord EX V-6's
automatic transmission. Regardless of gear, or vehicle speed, shift engagement
takes place in less than half a second, which results in smoother acceleration
and improved fuel economy.
In combination with the integrated oil pump, this new high-response lockup
clutch torque converter helps improve city fuel economy by more than 1.5 mpg
Fuel Efficiency Comparison*
(L4 w/ AT)
*Based on 2004 EPA mileage estimates
Internal testing shows Accord Hybrid achieving an estimated fuel economy rating
of 30 miles per gallon in the city and 37 mpg highway, up from an EPA-rated
21 city / 30 highway for the 2004 Accord EX V-6 Sedan - a fuel economy
gain of 43 percent and 23 percent, respectively. The Accord's Integrated
Motor Assist System (60%) accounts for over half the gains in city fuel efficiency,
while Variable Cylinder Management (15%) and idle stop (25%) is responsible
for the rest. During highway cruising, the VCM system (57%) provides the majority
of the increase, while IMA (38%) and a lower drag coefficient and greater aerodynamics
(5%) also contribute.
In the Accord Sedan lineup, the Accord EX V-6 serves as the near-luxury model
for Honda's award-winning mid-sized sedan, offering features such as a
leather-trimmed interior, dual zone automatic climate control, tilt and telescoping
steering wheel, and an AM/FM/XM stereo with 6-disc in-dash CD changer -
features not available or only available as extra-cost options on many luxury
cars, much less any high-volume mid-sized sedan. The Accord Hybrid Sedan maintains
that high level of feature content, and adds even more, making it the most luxurious
and well-equipped hybrid sedan on the market.
Available as a factory-installed option is the Honda Satellite-Linked Navigation
System with voice recognition. Able to pinpoint the vehicle's location
anywhere in the contiguous 48 U.S. states through a system of satellites in
geosynchronous orbit above the earth, the Accord's navigation system's
DVD-based memory system contains maps to U.S. cities and the address/location
to over 7 million points of interest, including gas stations, restaurants and
bank ATMs. And, it responds to over 200 voice commands that control the navigation,
climate control and audio systems.
Some of the most significant features on the Accord Hybrid's interior,
by design, go virtually unnoticed at first glance. A new Active Noise Control
(ANC) system monitors engine noise within the passenger cabin and counteracts
the noise inherently associated with its Variable Cylinder Management to effectively
provide an ultra-quiet interior, and a new hybrid air conditioning system uses
power from both the engine and an electric motor to increase cooling performance
in the car's interior and helps to further reduce fuel consumption.
Key interior features
Exclusive IMA display monitors charge/assist performance, battery charge
and fuel economy statistics
Comfort and Convenience
Active Noise Control counteracts booming sounds during 3-cylinder engine
Honda-exclusive dual zone hybrid automatic climate control system
Power windows, mirrors and door locks
AM/FM/XM stereo with 6-disc in-dash CD changer
Available voice-activated Honda Satellite-Linked Navigation System
8-way power adjustable driver's seat
Tilt and telescopic steering column
Dual-stage, dual-threshold front airbags with a passenger-side Occupant
Position Detection System (OPDS)
Dual front side airbags (seat mounted)
Side curtain airbags (headliner mounted)
Instant Mobility System, flat-tire repair kit
With the Accord Hybrid's IMA intelligent power unit (IPU) located behind
the rear seats, the Accord Hybrid's rear seats are fixed and total cargo
space is reduced slightly to 11.2 cu. ft. (vs. 14.0 in all other Accord Sedans)
- still spacious enough to carry the luggage and equipment carried by
most mid-sized sedan buyers.
As with all Accord Sedans, the roomy interior in the Accord Hybrid puts it
at the top of the mid-size segment and on the verge of a full-sized sedan. With
102.7 cubic feet of total passenger volume, the Accord Hybrid is the largest
and most spacious hybrid car on the market.
Accord Hybrid Interior Specifications
(vs. Toyota Prius)
Headroom (in., front/rear)
40.4 / 38.5
39.1 / 37.1
Legroom (in., front/rear)
42.6 / 36.8
41.9 / 38.6
Shoulder room (in., front/rear)
56.9 / 56.1
55.3 / 53.0
Hip room (in., front/rear)
54.6 / 53.5
51.0 / 51.6
Total Passenger Volume (cu. ft.)
In keeping with the Accord Hybrid's goal of seamless integration of new
technology into the Accord's existing framework, its instrument panel
display is only slightly different from that in an Accord EX V-6 Sedan.
The primary difference is the small LCD display below the speedometer that
shows all of the IMA systems' key statistics, including the level of charge/assist
activity for the IMA motor, overall average fuel economy and an ECO mode display
that illuminates when the car is being driven most efficiently.
During acceleration, when the engine requires extra power from the IMA motor,
the blue ASSIST bars illuminate out to the right depending on the level of assist
needed. Conversely, during regenerative braking when the IMA motor is generating
electricity for the battery pack, the green CHARGE bars illuminate from right
left to indicate the amount of regenerative charging.
The LCD display also includes the odometer and dual trip meter functions of
all Accords and a new exterior temperature indicator. Other key indicators integrated
into the Accord Hybrid's illuminated gauges include a blinking display
in the tachometer to alert the driver when the car is idle-stopped and a battery
charge meter under the fuel gauge to show the level of charge in the IMA's
intelligent power unit (battery pack).
Dual Zone Hybrid Automatic Climate Control System
Unlike previous iterations of Honda's hybrid vehicles, the power generated
from the gasoline engine and IMA hybrid system is used for more than just drive
power. This 3rd generation IMA system also introduces a dual scroll hybrid air
conditioning system that reduces the load of the gasoline engine by using a
combination of engine and electric motor to drive two smaller air compressors.
These compressors can act independently or together as dictated by the cooling
needs of the Accord Hybrid's dual zone automatic climate control system.
On extremely hot days, cooling is provided by both the 75cc belt-driven compressor
attached to the Accord's 3.0L V-6 engine and the 15cc, 144V motor-driven
compressor attached to the a small secondary motor. When the air conditioning
system is forced to use both the gasoline engine and electric motor, the Accord's
idle-stop feature is disabled until cooling needs are reduced.
In all other situations, either of the two compressors cools the interior cabin
individually depending upon cooling needs and the charge state of the IMA's
battery pack. On warmer days, the 75cc engine-mounted compressor acts as the
sole source of air-conditioning, while the 15cc motor-driven compressor is in
action when the climate control is maintaining a steady temperature or the car
Active Noise Control
A feature found in many luxury cars, Honda's Active Noise Control was
specified for Accord Hybrid to counteract the extra noise created by the imbalanced
motion of the car's V-6 engine when the VCM system deactivates the rear
engine bank's three cylinders. In this condition, the booming noise of
the engine is more spread out, and thus more noticeable to the naked ear.
The ANC uses input from the engine's ECU and microphones in the cars
interior - one mounted in the front headliner and one in the rear parcel
shelf - to monitor noise levels in the passenger cabin. When the ECU puts
the i-VTEC V-6 engine in 3-cylinder mode, a control unit synchronizes the booming
noise created with an opposite phase signal sent through the car's audio
system to essentially cancel each other out. The result is an audio signal with
an opposite wave and a very quiet interior. ANC works whether the radio is on
The Active Noise Control is only active when the engine is in 3-cylinder operation,
and operates regardless of whether the audio system is on or off. The microphones
are tuned to only recognize the engine booming noise - passenger's conversation,
the audio system, or excess road noise have no affect on the system.
XM Satellite Radio
XM Satellite Radio and Honda have enjoyed a partnership for the past two model
years, first as a dealer-installed accessory in select Pilot and Accord models,
then as standard equipment on the 2004 Accord EX V-6. At that time, Accord was
the first non-luxury car to offer a model with standard satellite radio. That
continues with the Accord Hybrid, as the standard audio system includes an AM/FM/XM
stereo and 6-disc in-dash CD changer. Consumers are entitled to a three-month
trial subscription to XM Satellite Radio for no cost at time of purchase. After
the trial period, XM will contact the buyer directly to continue the subscription
Honda Satellite-Linked Navigation System with voice activation
When the 7th-generation Accord Sedan debuted in 2003, it introduced an advanced
version of Honda's Satellite-Linked Navigation System that included a
segment first - voice activation. As with most OEM navigation systems
on the market, the Honda version is DVD based, allowing for 6.6 gigabytes of
memory to store 7 million points of interests and detailed maps of all major
metropolitan areas of the contiguous US.
What sets this navigation system apart from the others in the mid-size segment
is the ability to control many functions simply by speaking. This allows the
driver to continually look at the road and keep attention on driving while simply
commanding the system to follow more than 200 different commands that control
not only the navigation system, but the audio and climate control systems, as
Linked to a variety of satellites in geo-synchronous orbit above the United
States, the Accord Hybrid's navigation system is able to pinpoint the
car's location anywhere in the 48 contiguous US. In addition, detailed
maps of all major metropolitan areas are displayed on the 7" screen placed
high in the center of the Accord's dashboard for easy visibility. Progress
is tracked by wheel sensors and a gyroscope, and directions are displayed in
map or in text form (or both via a split screen) with turn-by-turn directions
announced through the Accord's audio system.
In addition to voice control, the navigation system's many functions,
including a "yellow pages"-style directory, control of the AM/FM/XM/CD
audio system and the dual-zone climate control system, can be controlled by
touching the 7-inch screen or a joystick located directly below.
Interior Safety Systems
Already a recognized leader in low-emissions and high fuel efficiency, the
Accord has also become a leader in safety technology in the mid-sized sedan
category. With a full array of both active and passive safety features, 2004
Accord was awarded the top rating, 5 stars, by the National Highway Traffic
and Safety Administration (NHTSA) for driver and front passenger safety in full
The 2004 Accord also achieved a Good rating and Best Pick designation by the
Insurance Institute for Highway Safety (IIHS) - it's top rating
- for 40-mph offset frontal impact protection.
The Accord Hybrid carries over all of the safety technology built into its
traditional Accord EX V-6 Sedan brethren, including dual-stage, dual-threshold
front airbags, dual front side airbags, and a side curtain airbag system.
Instant Mobility System
In another move designed to keep excess weight on the Accord Hybrid to a minimum,
developers opted to eliminate the temporary spare tire from the Hybrid's
trunk. Instead, Accord Hybrid owners will use a new Instant Mobility System
(IMS) that fixes flat tires caused by the most common driving road hazzards.
This system, already in use on certain European Honda models, requires just
a minimum of effort and will fix most flat tires after three simple steps.
The system is composed of a one-time use can of rubber sealant that injects
into the flat tire's valve stem and a small air compressor that is powered
by the Accord Hybrid's 12V accessory outlet. After injecting the sealant
into the tire and inflating it to the appropriate p.s.i., it is recommended
that the car is driven no faster that 50 mph. After 10 minutes, the driver should
stop and check to ensure that the tire has held its inflation.
The Accord Hybrid's IMS is held in a special tool kit underneath the
cargo area floor where a traditional spare would normally be located. If desired,
a temporary spare tire is available as a dealer-installed option.
When the seventh-generation Accord Sedan debuted in 2003, it was designed to
be a more dynamic overall package. The goal was to package traditional Accord
features and value into a new, more sensual design. Now, the Accord Hybrid Sedan
takes that original, tall-sedan style and adds features intended to conserve
weight and better the aerodynamics of the Accord.
Unique aerodynamic features of the Accord Hybrid include 16-inch alloy wheels
and a standard rear decklid spoiler. Unique appearance features include a black
chrome-style front grille, exclusive Accord Hybrid badging and a roof-mounted
AM/FM/XM radio antenna.
The Accord Hybrid also makes use of lightweight aluminum in its frame and body
panels to further reduce body weight for both efficiency and to maintain the
same dynamic character of the Accord V-6 Sedan.
Key Body and Exterior Features
Rigid, unibody construction
Active Control Engine Mounts (ACM)
Black chrome-style front grille
Standard rear decklid spoiler
Lightweight 16-inch alloy wheels
Larger 215/60 R16 tires
Unique AM/FM/XM roof antenna
Exclusive Accord Hybrid badging
The Accord Hybrid is built from a unibody frame that combines the principal
body panels and platform into one integrated assembly. Greater use of aluminum
in many frame parts, including the entire hood, helps contribute to the Accord's
excellent fuel efficiency but maintains a rigid foundation for a smooth, controlled
ride at all speeds. The Accord Hybrid's unibody continues to incorporate
front and rear subframes that are designed to deform in a controlled manner
in the event of frontal or rear impacts. By doing so, the subframes absorb a
substantial amount of the impact energy before it enters the passenger cabin.
In conjunction with seat belts and the Accord Hybrid's dual-stage front
airbags, the frame is a primary contributor to the Accord's projected
5-star frontal impact rating from the federal government.
Outside of curb weight, there are no measurable exterior differences between
the Accord Hybrid and the Accord EX V-6, which makes it the largest and most
spacious hybrid car on the U.S. market to date. Though the Accord Hybrid's
frame uses more aluminum, the shape and dimensions all remain unchanged from
the traditional Accord Sedan. It continues with a 107.9-inch wheelbase, with
an overall length of 189.5 inches. Front and rear track are unchanged at 61.1
and 61.2 inches, respectively, as is the Accord's 71.5-inch overall width
and 57.1-inch height. By keeping the Accord Hybrid's footprint and dimensions
in line with the traditional Accord Sedan, few changes are needed in the suspension
and steering arenas to keep ride and handling characteristics on par with the
nimble Accord EX V-6.
Extensive use of aluminum
From the top of the Accord Hybrid to its wheels, lightweight aluminum plays
a very important role in helping to reduce weight, but maintaining structural
rigidity and long-term durability. Most noticeable are the lightweight aluminum-alloy
wheels, but underneath the paint, much more aluminum is present. In addition
to many non-structural elements of the Accord Hybrid's frame, the hood,
front and rear bumper beams and rear suspension knuckles are made from aluminum.
With the same basic body frame and design as an Accord EX V-6 Sedan, the Accord
Hybrid is designed to surpass all current government regulations for safety.
With a rigid unibody frame, front and rear crush zones that reduce impact energy
before it gets to the passenger cabin and side impact door beams, Accord Hybrid
is designed to achieve 5-star safety ratings for frontal impact protection by
the National Highway Traffic and Safety Administration. The 2004 Accord Sedan
was awarded 5-star ratings for frontal impacts by NHTSA and was given a good
rating - the highest possible - and designated a "best pick"
by the Insurance Institute for Highway Safety (IIHS) in 40-mph offset frontal
Lightweight alloy wheels
Like all performance cars, Accord Hybrid comes with a set of aluminum-alloy
wheels to keep unsprung weight down and to give the car a distinctive look.
Measuring 16 inches, the wheels on the Accord Hybrid display a distinct 5-spoke
design and are machine finished for a luxurious, yet understated look. They
are accompanied by larger 215/60 R16 tires (vs. 205/60 R16 tires on the Accord
EX V-6) to match the vehicle's increased performance.
Numerous technologies on the Accord Hybrid are intended to help reduce noise,
vibration and harshness (NVH), among them new Active Control Engine Mounts (ACM)
(See Powertrain) and an interior Active Noise Control (ANC) system (See Interior).
Accord Hybrid's frame continues to use hydro-formed steel components
that maximize the effects of high-tensile strength steel. This precise way of
forming steel reduces the manufacturing inconsistencies for the unibody frame
and major subframe components, and creates a stronger, more rigid frame than
previous generations of Accord.
Additionally, special floating rubber mounts that connect the frame and each
of the front and rear subframes, help minimize both road and engine noise. To
insulate the Accord Hybrid's interior from external noises, it uses a
number of sound damping materials and special melt sheets on the cabin floor
to further isolate the interior cabin.
Already one of the more aerodynamically slick sedans in the mid-sized segment
with a 0.30 coefficient of drag (Cd), the Accord Hybrid adds a rear decklid
spoiler and aerodynamic wheels to slightly reduce drag even further. The result
is a .29 Cd, which is similar to many sport coupes on the market today.
As with all Accords, an aerodynamic design translates into greater fuel efficiency
and a quieter interior cabin, virtually void of any wind noise even at higher
speeds. Design details that contribute to this low drag include windshield wipers
that are recessed below the hoodline, side mirror design and distinct A-pillar
design that smooths air flow over the windshield and around the side of the
Three current Accord Sedan colors form the foundation of Accord Hybrid's
color palette - Taffeta White, Graphite Pearl, and Desert Mist Metallic.
A hybrid-exclusive Silver Frost Metallic will also be offered. The new Silver
Frost Metallic and Graphite Pearl will be paired with a leather-trimmed Charcoal
(light gray) interior, while Taffeta White and Desert Mist Metallic will come
with an Ivory-colored interior.
Chassis and Suspension Overview
Based on the same class-leading chassis and suspension design that underpins
the Accord V-6 sedan, the Accord hybrid makes use of an Electric Power Steering
(EPS) system - similar to that in an S2000 and Acura NSX - as opposed
to the hydraulic-powered variable assist rack-and-pinion setup in its gasoline-powered
Accord siblings. The EPS system allows the Accord Hybrid to provide power steering
even when the vehicle is in idle stop mode.
Already recognized as one of the more nimble entrants in the mid-sized class,
all Accords employ a 4-wheel double wishbone suspension. This entirely independent
suspension allows the Accord consistent linear tracking under all conditions,
while minimizing body roll during hard cornering. When combined with the EPS
system, the Accord Hybrid is able to enhance steering response and minimize
torque steer associated with the increased horsepower to provide a very balanced
and stable ride.
4-wheel disc brakes with 3-channel anti-lock braking system (ABS)
Electronic Brake Distribution
Advanced Traction Control System with integrated Creep Aid System
16" alloy wheels with 215/60 R16 tires
Front double wishbone suspension
The Accord's double-wishbone front suspension is designed to maintain
a stable ride under all driving conditions, including hard acceleration, braking
and cornering. With a large lower arm connected directly to the front subframe
and a smaller upper arm positioned high, above the wheel and tire, this suspension
is able to isolate wheel movement and minimize the effects of bumpy roads intruding
into the passenger cabin.
Rear Five-link Suspension
Mounted entirely to the Accord's rear subframe, its rear five-link double
wishbone suspension is meant to keep the vehicle flat during hard cornering
and minimize the amount of roll steer associated with most independent rear
suspensions. By providing precise camber and toe control, this double wishbone
suspension helps to keep a flat tire contact patch between the Accord and the
road. Each of the five tubular steel links is designed to keep the rear wheels
upright through their full range of movement in all conditions, including cornering
at higher speeds.
With a compact design, the Accord's rear suspension was also developed
to minimize the space it takes up behind the rear wheels, and thus maximize
the cargo area in the Accord Hybrid's trunk. With the Intelligent Power
Unit (IPU) of the IMA system mounted behind the rear seats, Accord Hybrid continues
to have over 10 cubic feet of cargo area (11.2), down only 2.8 cu.-ft from a
traditional Accord V-6 Sedan.
Electric Power Steering (EPS)
To allow for power steering operation during idle stop mode and further reduce
fuel consumption while enhancing steering accuracy, the Accord Hybrid employs
a modified version of the Electric Power Steering (EPS) system used in the S2000.
This electric steering rack eliminates the need for power from the gasoline
engine to regulate hydraulic pressure as in a traditional rack-and-pinion setup.
Instead, a high-output motor replaces the oil pump. In addition, the high-mount
design allows for longer tie rods, which reduces the amount of unwanted steering
feedback during bumpy drives.
4-wheel disc brakes
With large, 11.1" ventilated front discs in front and solid disc brakes
in the rear wheels, the Accord Hybrid continues to have one of the most effective
braking arrangements in the mid-sized sedan segment, delivering smooth, linear
and stable braking performance across a broad range of conditions and braking
loads. The braking system is further enhanced by a standard anti-lock braking
system and electronic brake distribution.
The standard Anti-lock Braking System (ABS) from the Accord V-6 carries on
in the Accord Hybrid. This arrangement incorporates wheel sensors at each wheel
and three control channels to modulate braking pressure. With this type of system,
the ABS control unit is able to monitor wheel speed at each wheel and adjust
braking pressure to each of the front drive wheels or both rear wheels jointly.
As such, wheel lockup is avoided in virtually all driving conditions, including
situations where one side of the vehicle has significantly less traction than
the other. This is critical in the Accord Hybrid's ability to maintain
steering control during hard braking in normal and adverse road conditions.
Electronic Brake Distribution
The ABS system is further enhanced by Electronic Brake Distribution (EBD) which
adjusts braking pressure front-to-rear, based on the weight distribution of
passengers and/or cargo. Weight distribution is determined via the relative
difference in rotational speed of the front and rear wheels. Greater braking
pressure, and subsequently stopping power, is directed to the rear wheels when
cargo loads in the rear are heavier. This contributes to a more controlled stop,
and in conjunction with the front double wishbone suspension minimizes "brake
dive" during hard braking.
Traction Control System
An advanced Traction Control System (TCS) has been added to the Accord Hybrid
to help harness the increased horsepower. Similar to previous Honda TCS systems,
the Accord Hybrid's system uses wheel sensors to monitor the rotational
speed of each wheel.
When wheel-slippage is detected at any wheel (higher rotational speed), the
TCS pulses the brakes until traction is regained and all four wheels are again
traveling at the same speed. The Accord Hybrid's TCS system is most effective
at low speeds when the vehicle is accelerating on a split-traction surface.
Specific to the Accord Hybrid's traction control system is the additional
Creep Aid System, which prevents the vehicle from rolling backwards after a
restart during idle-stop. Without creep aid, the brake actuators are released
fully when a driver releases the brake pedal. Thus, slow foot movement from
the brake to the accelerator could allow the vehicle to roll backwards if stopped
on a hill. In the Accord Hybrid, however, the TCS system recognizes the idle-stop
status and upon pedal release slowly reduces brake pressure from each of the
wheels. In doing so, each brake caliper maintains a small amount of braking
pressure until the driver accelerates the car.
The Civic Hybrid and Insight, hybrid-powered cars without traction control,
controlled this rolling situation with a separate creep aid clutch attached
to the CVT transmission. By incorporating the Creep Aid System into the Accord
Hybrid's TCS, Honda was able to save weight and production costs.
Standard wheel size for the Accord Hybrid continues to be 16 inches, but wider
215/60 R16 tires surround each. The wider tires allows the Accord Hybrid, which
weighs approximately 120 pounds more than an Accord EX V-6 and has 15 more horsepower,
to maintain a larger contact patch for handling, steering and traction performance
on par with the regular gasoline-only powered Accord V-6 Sedan.