2005 Honda Odyssey Powertrain - Part 1

Overview

The Odyssey powertrain uses the latest innovations to achieve the highest levels of performance, fuel economy and low emissions in the minivan segment. Honda's long and successful history introducing state-of-the-art engine technology continues with the introduction of Variable Cylinder Management on select models and numerous other features for 2005.

The Honda Odyssey's engine is an advanced 3.5-liter SOHC 24-valve 60-degree V-6 aluminum-block-and-head design that is compact, light and powerful. A wide variety of technologies have been engineered to provide 255 horsepower, a broad and flat torque curve, very low emissions, high fuel efficiency, and instantaneous throttle response.

Two engine configurations are available - one with a VTEC valvetrain and one with an i-VTEC valvetrain that includes cylinder deactivation. The VTEC valvetrain and on LX and EX models optimize cylinder filling efficiency across the engine's entire operating range. Additional aids to efficiency include a low-restriction intake and exhaust systems, a 10.0:1 compression ratio, and roller-type rocker arms. New technology includes a drive-by-wire throttle system and a sophisticated engine management system that can determine when the vehicle needs an oil change.

On Touring and EX with Leather models, an "intelligent" i-VTEC valvetrain automatically de-activates three of the six cylinders during cruising to enhance fuel economy. When full power is needed during acceleration and other situations, the engine operates on all six cylinders. Uniquely, Odyssey models with the i-VTEC valvetrain simultaneously provide the highest fuel economy with the most power and the longest driving range in the minivan segment.

The Odyssey's engine also provides excellent environmental performance, meeting California's LEV2-ULEV criteria as well as complying with the Federal Tier 2-Bin 5 emission requirements. High-density catalytic converters are placed directly below the engine's cylinder heads in both banks, boosting performance during cold startups. A high-level of emission control performance is also aided with a third catalytic converter positioned downstream from the two high-density catalytic converters. To further enhance emission performance inside the engine, high-atomization multi-hole fuel injectors are used along with four air-fuel sensors that provide highly precise fuel control and help achieve nearly complete combustion.

The Odyssey's compact 5-speed automatic transmission provides ultra smooth and efficient operation characteristics with the adoption of a direct control shift system that works with the drive-by-wire throttle control.

What's New for 2005

• 255-horsepower (+15 hp) SOHC VTEC V-6 with 250 lb.-ft. torque (+8 lb.-ft.)
• Available 255-horsepower SOHC i-VTEC V-6 with 250 lb.-ft. torque
• Variable Cylinder Management (VCM) system on i-VTEC engine for high fuel economy
• Drive-by-Wire Throttle Control System
• Active Control Engine Mounts and Active Noise Control on the i-VTEC engine minimizes engine vibrations
• Compact engine design with the exhaust manifold integrated into the cylinder head
• Federal Tier 2 Bin 5 emissions, LEV2 ULEV California emissions
• High-flow capacity exhaust system

Odyssey Powertrain Versus the Competition

* Based on 2005 EPA mileage estimates. Use for comparison purposes only. Actual mileage may vary.
Note: All values subject to change.

SOHC VTEC 3.5-Liter V-6 Engine Highlights
(LX and EX models)

• 255 horsepower @ 5750 rpm (+15 hp)
• 250 lb.-ft torque @ 5000 rpm (+8 lb.-ft.)
• New Drive-by-Wire Throttle Control System
• Uses regular unleaded gas
• Federal Tier 2 Bin 5 emissions, LEV2 ULEV California emissions
• Close-coupled catalytic converter
• High-flow exhaust

i-VTEC 3.5-Liter V-6 Engine with Variable Cylinder Management (VCM) Highlights
(EX with Leather and Touring models)
Above features plus:

• 250 lb.-ft torque @ 4500 rpm
• Variable Cylinder Management
• Active Control Engine Mount System
• Active Noise Control (see Interior section)
• Dual-Stage Intake Manifold

Engine Architecture

The Honda Odyssey's engine is a transverse mounted 3.5-liter, SOHC, 24-valve, 60-degree, V-6, aluminum-block-and-head design that is compact, light and powerful. A long list of technologies has been engineered to provide 255 horsepower, a broad and flat torque curve, ultra-low emissions, high fuel efficiency and instantaneous throttle response. The VTEC valvetrain optimizes cylinder filling efficiency across the engine's entire operating range.
The i-VTEC engine further extends fuel economy while maintaining the same power as the regular VTEC engines. Low-restriction intake and exhaust systems, a 10.0:1 compression ratio and roller-type rocker arms also aid efficiency.

Engine Block

The Odyssey's 3.5-liter die-cast engine block is made from heat-treated aluminum to maximize block rigidity and to minimize weight. A deep-skirt configuration rigidly supports the crankshaft, minimizing noise and vibration. Thin-wall, centrifugally-cast iron liners help reduce overall length and weight. Each liner's rough as-cast exterior surface bonds securely to surrounding aluminum during the manufacturing process to increase strength and enhance heat transfer.
Lightweight and Compact Construction
The Odyssey engine features lightweight and compact construction through the use of serpentine belts to drive engine accessories, a lightweight and high-strength timing belt, and an integrated die-cast aluminum exhaust manifold help make the engine more compact and lightweight. The compact and lightweight components contribute to improved packaging and reduced weight for enhanced fuel economy and performance.

Integrated Exhaust Manifold

The exhaust manifold is integrated and unified with the cylinder head. High-density catalytic converters have been placed directly under the cylinder heads on each side, which is a design that vastly reduces combustion-gas heat loss and ensures quick activation of the catalytic converters for better purification during cold starts. An additional catalytic converter under the floor cleanses exhaust gases even further.

Crankshaft/Connecting Rods/Pistons

A forged-steel crankshaft is used for maximum strength, rigidity and durability with minimum weight. In place of bulkier, heavier nuts and bolts, connecting rod caps are secured in place with high-tensile-strength fasteners that screw directly into the connecting rod. Short-skirt, cast-aluminum, flat-top pistons are notched for valve clearance and fitted with full-floating piston pins.

Cylinder Head Construction

The Odyssey utilizes innovative cylinder heads that include tuned exhaust manifolds as an integral part of the casting. Made of pressure-cast, low-porosity aluminum, these lightweight components improve overall packaging, enhance exhaust flow and permit optimal positioning of the close-coupled catalytic converters.

Unlike many minivans, the Odyssey has four-valve combustion chambers, the best approach to optimum performance with excellent fuel efficiency and very low emissions. Valves are clustered near the center of the bore to minimize combustion chamber volume and to provide ample squish area. A 10.0:1 compression ratio helps maximize thermal efficiency, power output, and fuel mileage. A fiberglass-reinforced toothed belt drives one centrally located camshaft per bank. Head gaskets are made of high-strength materials to contain combustion pressures.

Variable Valve Timing and Lift Electronic Control (VTEC™)

Standard on all models, the Odyssey's innovative Variable Valve Timing and Lift Electronic Control (VTEC) is one key to maximizing engine output across the engine's full operating range. The high-rpm induction lobes of the camshaft provide additional valve lift to help increase peak horsepower. Ordinary engines have fixed valvetrain parameters - the same timing of valve lift and overlap whether the tachometer needle is struggling to climb out of the low-rpm range or screaming at the redline. The VTEC approach, however, has two distinct modes so that operation of the intake valves changes to optimize both volumetric efficiency (breathing) and combustion of the fuel-air mixture. In order to achieve the optimum volumetric efficiency in the lower portion of the engine's operating range, rocker arms are programmed to follow cam lobes that provide low lift and reduced duration (shorter time open with less valve lift).

At 4600 rpm, the Odyssey's powertrain control module commands the VTEC system to switch intake valve operation to the high-rpm mode. In response, an electric spool valve opens to route pressurized oil to small pistons within the intake-valve rocker arms. These pistons then slide to lock the three rocker arms provided for each cylinder together. As a result, both intake valves follow a central high-lift, longer-duration cam lobe. The switching process takes place instantaneously and is undetectable by the driver. The extra lift and longer duration provide the added air and fuel the engine needs to produce high peak horsepower and a broader torque band. Instead of a peaky engine, the Odyssey has a powerplant that provides excellent performance at any engine speed.

i-VTEC with Variable Cylinder Management™ (VCM™)

Honda's innovative VTEC technology has evolved once again: the i-VTEC* engine (the "i" is for intelligent) in the 2005 Odyssey features 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 one bank of three cylinders, thus achieving outstanding fuel economy. 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 economy by making the Odyssey's available i-VTEC 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 acceleration or other high power situations. When full power is needed, i-VTEC instantly opens the valves and sends fuel to three more cylinders with output reaching as much as 255 horsepower. Honda's VCM system allows for maximum performance and maximum fuel economy - two characteristics that rarely co-exist at this level of extremes. Other minivans may offer high fuel economy and others may offer engines tuned for horsepower, but only the Odyssey delivers class-leading levels of both.

* Of special note, Honda's 4-cylinder i-VTEC technology uniquely employs VTEC + Variable Timing Control (VTC) for superior performance and fuel economy. Honda's intelligent V-6 technology uniquely employs Variable Cylinder Management (VCM) for performance and fuel economy.