2001 Honda Odyssey -- Drivetrain
A 3.5-liter, 210-hp (premium unleaded gasoline), 24-valve V-6 engine and 4-speed automatic transmission are standard on both Odyssey models. Exclusively developed for the demands of minivan driving, the Odyssey engine boasts strong low-rpm torque for good off-line and around-town acceleration, fuel economy comparable to a sedan, and low emissions.
The following list highlights the main features of the Odyssey drivetrain:
3.5-Liter V-6 Engine
- 3471-cc displacement
- 210 hp @ 5200 rpm (premium unleaded gasoline)
- 229 lb.-ft. of torque @ 4300 rpm
- 208 lb.-ft. of torque (about 90% of peak torque) available at 2000 rpm
- 0-60 mph acceleration: 9.6 seconds
- 60-degree V-angle helps to minimize engine vibration
- Compact, lightweight engine (98-mm bore spacing)
- Compact cylinder head design
- Lightweight pistons and connecting rods
- Full-floating piston pins minimize piston noise during warm-up
- Cast-aluminum oil pan helps minimize engine noise
- 9.4:1 compression ratio
- VTEC valve train (Variable valve Timing Electronic Control) with rocker arms that incorporate low-friction roller-bearing cam-followers
- 26 mpg highway fuel economy (estimated)
- Meets California's stringent Low-Emission Vehicle (LEV) standard for light trucks
- Electronically controlled EGR
- Air-assist injection system helps lower hydrocarbon emissions and improves driveabiity
- Large-capacity, 130-amp alternator
- Direct ignition system
- Electrically actuated cruise control
- Direct-control automatic transmission is operated by a Powertrain Control Module (PCM) for smoother shifting
- Cruise control is controlled by PCM and automatic transmission ECU for smoother operation
- Minimal gear noise
COMPACT, 3.5-LITER V-6 ENGINE
The 3.5-liter V-6 used in the Odyssey incorporates several innovative features designed to help minimize its size, weight, friction and vibration. For example, in order to keep size and weight to a minimum, the heat-treated, die-cast aluminum-alloy engine block has a relatively short deck height and close (98-mm) bore spacing.
The engine's 60-degree V-angle minimizes underhood space and also helps keep vibration to a minimum. The piston pins are also a quieter, full-floating design that make less noise, especially during engine warm-up.
To further save weight and minimize vibration, the forged-steel connecting rods are a compact, lightweight type, measuring only 19 mm in width. Even the connecting-rod bolts are a lightweight, small-diameter, nutless type. However, despite their smaller size, they have the same strength margins as larger, conventional nut- and threaded bolt-type fasteners, because they are designed to be torqued to the higher clamping forces of the bolt material's plastic-deforma-tion region, instead of its lower elastic region.
The engine's fully counterweighted, forged-steel crankshaft has also been kept short in order to minimize vibra-tion and uses a special dual-mode crankshaft damper pulley.
COMPACT CYLINDER HEAD
The Odyssey V-6's cylinder is the same type as the current 3.0-liter Accord V-6 engine, with a single overhead camshaft installed from the end, instead of being clamped in place from above with bolt-down caps. The elimination of hold-down caps and the use of a single overhead camshaft helps minimize engine height and improves underhood packaging, compared to an engine equipped with dual overhead camshafts.
The camshafts are constructed of ductile iron and flame-hardened to achieve the necessary hardness. The camshafts are turned by a crankshaft-driven, glass-fiber reinforced, toothed belt. An automatic tensioner compensates for belt stress and fluctuation.
The cylinder heads feature efficient pentroof combustion chambers, with 4 valves per cylinder. Four valves per cylinder offer several advantages over 2-valve arrangements, most notably lower reciprocating mass, which allows the engine to safely reach higher rpm and develop greater horsepower. Additionally, valve area is increased with the use of four valves, relative to conventional 2-valve systems, resulting in improved air flow. Valve actuation is via low-friction roller-bearing cam followers.
VTEC VARIABLE VALVE CONTROL
The Odyssey's 3.5-liter V-6 engine uses a special two-rocker version of Honda's VIEC valve system that gives it low emissions and a broad, flat torque curve. (VTEC stands for Variable valve Timing and lift Electronic Control.)
During low-rpm operation, the two-rocker VTEC system used in the Odyssey only opens one intake valve. (The second intake valve does lift off its seat slightly, in order to prevent fuel puddling, which would lead to an excessively rich mixture.) The air/fuel charge drawn through the open intake valve undergoes a swirl effect that creates a stratified charge, with a rich mixture near the spark plug (for good light-oW, and a progressively leaner mixture toward the periphery of the combustion chamber. This stratified charge, combined with the Odyssey engine's precise control of the exhaust-gas recirculation and air-injection system, results in lower emissions (especially during the critical warm-up period) and better fuel economy. The rocker arms are a low-friction, roller-bearing type, which help improve engine efficiency.
At 3300 rpm, the rocker arm of the second (idle) intake valve is locked to the first valve, via electronically controlled, hydraulically actuated locking pins in the rocker arms. The greater valve area of all four valves provides the necessary increase in intake and exhaust flow to meet the V-6 engine's mid- and high-rpm performance needs.
The Odyssey V-6 engine uses Honda-programmed sequential fuel injection. Air induction is via a one-piece, low-pressure die-cast-aluminum intake manifold with individually tuned intake runners, designed to boost low-rpm torque. A tuned plenum and throttle body connect to the upper end of the manifold.
AIR-ASSIST FUEL INJECTORS
The smaller the fuel droplet size delivered by the fuel injectors, the more effectively the fuel mixes with intake air. The result is more efficient combustion, easier starting, better high-altitude and cold-weather driveability (especially during engine warm-up), and lower hydrocarbon emissions. In order to improve fuel atomization, the Odyssey V-6 engine uses an Air-Assist Injector system (AAI). AAI uses an additional injector near each fuel injector that shoots a jet of air into the atomized fuel spray, breaking it into smaller fuel droplets so that it will burn more completely.
MULTI-POINT PROGRAMMED FUEL INJECTION
Honda Multi-Point Programmed Fuel Injection (PGM-FI) is standard on the Odyssey V-6 engine. PGM-FI uses a 16-bit PCM, connected to sensors that monitor throttle position, engine temperature, cylinder-firing position, intake manifold pressure, atmospheric pressure, exhaust-gas oxygen content and intake air temperature. The PCM uses this information to determine the fuel requirements of the engine. It then activates each fuel injector at precisely the right moment for optimum power and efficiency. The result is excellent driveability, smooth torque delivery, reduced emissions and better fuel economy.
An additional advantage of PGM-FI is easier maintenance and repair, since the PCM can sense when various components in the system are malfunctioning and flash a trouble code that tells the service technician where the problem is located.
DIRECT IGNITION SYSTEM
The Odyssey V-6 engine uses individual direct-ignition spark coils, integrated into the spark-plug holder at each cylinder. This design offers several advantages over a more conventional ignition coil and distributor, including greater latitude in spark timing, since there is no need to alter dwell timing to let the coil windings saturate, as well as less weight and complexity.
ELECTRIC CRUISE CONTROL
In place of a conventional vacuum-operated cruise control, the Odyssey uses an electric motor-driven cruise control actuator. Compared to the older vacuum-actuated model, the Odyssey's electric actuator has improved response, more accurate speed control, weighs less and takes up less underhood space.
ODYSSEY AUTOMATIC TRANSMISSION
The Odyssey direct-control automatic transmission features stronger clutches and a larger torque-converter capacity to match the greater torque of its V-6 engine. Additional features of the transmission include precise shifting with reduced shift shock, compared to the automatic transmission used on the previous Odyssey. This new design also boasts less gear noise and vibration, and greater efficiency, and its Grade Logic Control is better integrated into the cruise control system. The transmission is produced at the new Honda Transmission Manufacturing plant in Ohio.
The transmission is a constant-mesh type, with three parallel shafts: input, intermediate and output. Shifting is electronically controlled and hydraulically actuated. Shift management is controlled by a new 16-bit microprocessor. This microprocessor's greater capacity is used to control two linear-shift sole-noids that in turn control hydraulic pressure to the gear clutch packs. Since the new control is more linear, clutch engagement is more progres-sive. The result is smoother shifting under all conditions, whatever the driving style.
A centrifugal hydraulic cancellation mechanism built into the clutch pack further minimizes shift shock by reducing unwanted centrifugal hydraulic pressure. The low-gear clutch and one-way clutch of the previous transmission have been eliminated. The low-gear hold function is now handled by the low-gear clutch.
The use of three support bearings for the intermediate and output shafts helps reduce gear noise, reduces shaft bending and maintains proper mesh even under load.
The lockup torque converter helps minimize fluid-coupling slippage by mechanically coupling the engine to the transmission during certain driving modes, such as steady-state cruising. The benefit is better mileage. The lockup feature works in 3rd and 4th gears, and also maintains lockup in 3rd and 4th gears during deceleration.
Cruise control is now governed by the auto-cruise control ECU in combination with the Powertrain Control Module. The PCM determines when vehicle speed drops below the speed set by the cruise control and initiates the appropriate gear selection, if necessary.
GRADE LOGIC CONTROL SYSTEM
The Odyssey 4-speed automatic transmission uses Honda's Grade Logic Control System. Grade Logic differs from more conventional computer-controlled shift programming in two important ways: It determines certain vehicle driving situations and then, based on stored "shift maps," selects the appropriate shift points for 2nd/3rd- and 3rd/4th-gear upshifts and 4th/3rd-and 3rd/2nd-gear downshifts. This feature is especially useful when driving up and down long grades.