OVERVIEW
The 3.2 TL is powered by an all-aluminum, 3.2-liter V-6 that uses
24
valves and Acura's innovative VTEC system to deliver 225
horsepower
and 216 lb-ft. of torque. The V-6 in the high-performance TL
Type-S
model builds upon this potent foundation by adding a high-flow,
dual-stage induction system and a free-flowing exhaust - which
help
boost output to 260 horsepower and 232 lb-ft of torque.
In each engine, Acura's patented VTEC system - first unveiled on the NSX exotic sports car - helps provide an exceptionally flat torque curve, enhanced engine breathing, and superb responsiveness at all engine speeds.
Both the TL and the TL Type-S are equipped with an electronically controlled, 5-speed Sequential SportShift transmission. Inspired by the transmissions used on modern Formula One race cars, Sequential SportShift allows the driver to shift the forward gears semi-manually - without the need for a clutch pedal. The transmission also offers the shifting convenience of a conventional automatic.
In keeping with Acura's commitment to the environment, both TL engines meet stringent Low Emission Vehicle (LEV) standards. The California-model 3.2 TL also meets Ultra Low Emission Vehicle (ULEV) requirements.
Powertrain at a Glance
Engine
- 3.2 liter, SOHC, V-6, aluminum alloy engine block and cylinder heads
- 225 hp at 5600 rpm and 216 lb.-ft. of torque at 4700 rpm (TL)
- 260 hp at 6100 rpm and 232 lb.-ft. of torque between 3500 and 5500 rpm (TL Type-S)
- Variable Valve Timing and Lift Electronic Control (VTEC)
- Dual-stage induction system and high-flow exhaust (TL Type-S)
- Computer-controlled Programmed Fuel Injection (PGM-FI)
- Direct ignition system
- 105,000-mile tune-up intervals
5-Speed Automatic Transmission
- Quick-response, 5-speed Sequential SportShift allows semi-manual operation
- Wide-ratio, 5-speed design helps improve performance and fuel economy
- Direct-control, automatic transmission managed by Powertrain Control Module (PCM) for enhanced shifting smoothness
- Grade Logic Control for reduced gear "hunting" when driving in hilly country
Emissions/Fuel Economy
- 3.2 TL/Type-S EPA fuel economy of 19/29 mpg (city/highway)
- 3.2 TL and Type-S meet LEV standards; California-edition 3.2 TL meets ULEV standards
- Electronically controlled Exhaust Gas Recirculation (EGR)
Noise, Vibration, and Harshness (NVH)
- Smooth-running, 60-degree V-angle engine design
- Full-floating piston pins eliminate piston slap during warm-up
- Elimination of separate camshaft holders allows for a more compact, rigid cylinder head
- Lightweight pistons and connecting rods
- Hydraulic engine mounts
- Cast-aluminum oil pan
- High-rigidity cylinder block with additional strengthening ribs for the TL Type-S
ENGINE ARCHITECTURE
The TL features a sophisticated, 24-valve, 3.2-liter V-6 engine. In
addition to its lightweight, all-aluminum construction and
compact,
smooth-firing, 60-degree layout, the engine incorporates such
state-of-the-art technologies as the VTEC system and a
high-flow
induction system to combine prodigious power with smooth,
refined
operation. In addition, the high-performance Type-S V-6 uses a
unique, dual-stage induction system to boost output to 260
horsepower.
ENGINE BLOCK
The compact, aluminum engine block of the TL V-6 is die-cast
and
heat-treated for exceptional rigidity and minimal resonant
vibration.
The engine's iron cylinder liners have their bore pitch set at a
close 98-mm spacing to reduce overall engine size. The
free-revving
TL engine is oversquare with a bore of 89 mm and a stroke of 86
mm -
yielding a total displacement of 3210 cc.
The TL employs an engine cylinder bank V-angle of 60 degrees for improved smoothness and compact size. The block has an unusually short deck height, resulting in an overall reduction in the height and width of the assembled engine.
While both TL models have iron cylinder inserts, the Type-S engine adds unique spin-cast cylinder-wall liners that are cast into the engine block during the initial manufacturing phase. These spin-cast liners are lighter than traditional iron liners - and also improve heat dissipation to avoid engine knocking. Because they require fewer machined surfaces, spin-cast cylinder liners also simplify the production process.
CYLINDER HEAD
The powerful TL engines incorporate pressure-cast, aluminum
alloy
cylinder heads with four-valves-per-cylinder, compact
combustion
chambers, and a generous squish area to promote swirl and
enhance
combustion efficiency. For enhanced flow into the combustion
chamber,
the Type-S engine has specially designed, race-bred intake
valves.
The single overhead camshaft in each cylinder head is installed
from
the timing belt side of the engine, saving weight and complexity
by
eliminating the need for bolt-on cam caps. The cams are driven
by the
crankshaft via a fiberglass-reinforced, toothed timing belt and
use
friction-reducing roller followers to activate the valves.
CRANKSHAFT/CONNECTING RODS/PISTONS
Of paramount importance in designing the TL's V-6 was the goal
of
compact overall engine dimensions. The TL engine uses a rigid,
forged
crankshaft and narrow 19 mm connecting rods to reduce engine
length
and width. Rather than conventional nut-and-bolt type fasteners,
the
connecting rods in the TL V-6 use lightweight bolts (without nuts)
called plastic-region fasteners. The rod bolts thread directly into
the connecting rod allowing the bolts to be smaller while
retaining
the required clamping force and strength margins.
The V-6's compact pistons are made of lightweight, cast-aluminum alloy. A unique dome-shaped design provides maximum combustion efficiency in each combustion chamber. The compression ratio is 9.8:1 in the 3.2 TL and 10.5:1 in the Type-S due to a taller piston dome. The pistons utilize a 3-ring design with the Type-S engine incorporating a unique angled top ring for an improved seal within the cylinder to accommodate the higher combustion pressure.
VARIABLE VALVE TIMING AND LIFT ELECTRONIC
CONTROL (VTEC)
First unveiled on the Acura NSX supercar, the innovative Variable
Valve Timing and Lift Electronic Control (VTEC) system is a key
player in the TL engine's remarkable combination of low end
torque,
high-rpm horsepower, fuel efficiency and low exhaust
emissions.
Unlike engines with conventional fixed-timing intake valves, the TL's VTEC engines automatically optimize the intake valve settings for either low or high-rpm operation. By altering the lift and opening duration of the intake valves depending on engine rpm, VTEC helps the engine produce abundant low- and mid-range torque with no sacrifice in high-rpm power. At high rpm the VTEC V-6 produces considerably more horsepower than other engines of its size.
At low rpm, the VTEC intake valves follow a set of low-lift, short-duration cam lobes with timing that optimizes cylinder filling. In addition, the timing of the intake valves is staggered and their lift asymmetric - creating a swirl effect within the combustion chambers at lower RPM. The result is increased burn speed with improved combustion stability and an increase in allowable EGR rate. As the engine spins through 4400 rpm (4800 rpm on the Type-S), the intake rocker arms transition to actuation by high-lift, long-duration cam lobes designed to optimize high-rpm output.
On the Type-S, high-performance camshafts further increase power output by providing longer intake-valve duration, more valve overlap, and additional lift for the exhaust valves.
DUAL-STAGE INDUCTION SYSTEM
Found only on the Type-S engine, this revolutionary dual-stage
induction system is a major contributor to producing the V-6's
robust
260 horsepower. At its heart, the system uses a large,
two-chamber
intake plenum separated by an electronically actuated butterfly
valve, which opens at 3800 rpm.
At low and mid-range engine speeds, the valve is closed - creating a Resonance Charge condition where pressure pulsations between cylinders banks are separated. In doing so, air filling the cylinders increases with the resonance energy from the adjoining cylinder of each bank (Helmholtz principle).
At mid to high engine rpm, an electric motor opens the butterfly valve and an Inertia Charge condition is achieved. Increased air filling then occurs when the manifold volume is increased and the resonance charge condition is eliminated. This phenomenon utilizes the high flow mass to pressurize the manifold port air, producing a natural "supercharger" effect.
The increased airflow and improved cylinder filling is the fundamental reason for the engine's efficient combustion and increased power. Additional improvements include a larger 64-mm bore throttle body (which reduces air-intake restriction and increases total air flow volume), free flow exhaust, and a low-overall restriction air intake system with a free flow air filter and air flow tube.
PROGRAMMED FUEL INJECTION (PGM-FI)
A Programmed Fuel Injection (PGM-FI) system controlled by a
16-bit,
32 MHz Powertrain Control Module (PCM). The PCM utilizes
position
sensors on the crankshaft and both camshafts to monitor many
variables including throttle position, engine temperature, intake
manifold pressure, atmospheric pressure, exhaust gas oxygen
content,
and intake air temperature. The PGM-FI system controls fuel
delivery
by six injectors mounted in the cast aluminum, tuned-length
intake
manifold.
EXHAUST SYSTEM
The lightweight, high-flow, dual-exhaust system in the 2003 TL is
designed for low-restriction performance with minimal noise and
vibration. The high-output Type-S engine has a larger-diameter
exhaust pipe, an increased-flow, low-restriction catalytic
converter,
and ultra-high-flow capacity dual silencers. The result is a 30
percent increase in exhaust gas flow compared with the 3.2 TL.
The
Type-S also boasts an aggressive, performance-oriented
exhaust note
that settles into a subdued tone at cruising speeds. Both the 3.2
TL
and the TL Type-S meet LEV standards while the
California-edition 3.2
meets ULEV standards
DIRECT IGNITION SYSTEM/KNOCK CONTROL
While proper ignition timing is critical to optimized engine
performance and emission control, proper timing depends on
many
variables and constantly changes from moment to moment. If
there is
not enough spark advance, fuel efficiency suffers. If there is too
much advance, engine knock or even engine damage may
occur. The TL is
equipped with a new-generation knock-control system. Using a
centrally located engine-block sensor that "hears" the onset of
knocking, the system can advance ignition timing to the point of
peak
efficiency - without going beyond. The system is even able to
adapt
if the quality of fuel used is less than the specified unleaded
premium.
The ignition system further benefits from compact and reliable direct-ignition coil units, which are positioned directly in the spark plug access bores.
NOISE, VIBRATION, AND HARSHNESS (NVH)
CONTROL
In addition to power and fuel efficiency, the TL powertrain was
engineered for superb smoothness and noise control. To that
end, the
TL's V-6 engines incorporate such NVH-reducing features as a
rigid
aluminum block with an unusually high resonant frequency, a
rigid
forged crankshaft, die-cast accessory mounts, and a stiff,
cast-aluminum oil pan.
105,000-MILE TUNE-UP INTERVALS
For the first 105,000 miles, the TL engines require only routine
inspections and fluid and filter changes. Thanks to the
roller-follower design of the VTEC valvetrain, friction and wear
are
reduced to the point that the screw-type tappet clearance
adjusters
need not be checked until the 105,000-mile mark. At that point,
the
long-life, platinum-tipped spark plugs are also scheduled for
replacement.
DIRECT-ACTING CRUISE CONTROL
For relaxed highway cruising, the TL is equipped with a
sophisticated
electronic cruise-control system. When engaged, the system's
Powertrain Control Module (PCM) is able to command the
5-speed
transmission directly, summoning downshifts as required to
help
maintain the driver's preset road speed even when climbing
steep
grades. For added convenience, the cruise control is operated
using
buttons on the steering wheel. Using these buttons, the driver
can
adjust road speed up or down in one mph increments or
disengage the
cruise-control system without touching the brake pedal.
5-SPEED, SEQUENTIAL SPORTSHIFT' AUTOMATIC
TRANSMISSION
The TL features a 5-speed automatic transmission with an
advanced
Sequential SportShift feature as standard equipment. Inspired by
the
transmissions found on contemporary Formula One Grand Prix
racecars,
Sequential SportShift allows the driver to choose the
convenience of
a conventional automatic or shift gears semi-manually. To do the
latter, the driver places the gear lever in a special SportShift gate
to the left of the D5 position and then simply moves the lever fore
or aft to shift up or down. The selected gear is displayed on an
LED
indicator inside the tachometer face.
To improve the immediacy and "manual-transmission feel" of the shifting experience in SportShift mode, the transmission computer commands shifts that are firmer and approximately 10 percent quicker than those in automatic mode. At the same time, the SportShift system incorporates built-in safety-override features unavailable with a conventional manual transmission. For instance, the transmission logic will not allow a downshift that would cause the engine to over-rev.
The TL's 5-speed automatic transmission figures heavily in measured performance gains and performance driving feel. Its gear ratio settings closely match the demands of a variety of driving situations. The wide ratio transmission's lower gears provide quick acceleration while the tall top gear ratio results in low cruising rpm's for reduced engine noise and lower fuel consumption.
Thanks to a design that shares the idler and third-gear clutches, the TL's transmission provides five ratios in a unit about the size of a conventional 4-speed transmission. The transmission also incorporates a first gear one-way clutch for smoother shifts, plus an innovative heat exchanger design that moderates transmission operating temperature quickly and without undue complexity.
Linear solenoids provide precise, real-time control of the clutch on/off pressure in the TL's transmission. Thanks to this superior clutch-engagement accuracy, the control logic system operates smoothly under all conditions. For added refinement, a bearing supports the idler shaft.
To manage overall powertrain operation, the PCM interacts with multiple control strategies. For instance, by limiting engine output torque and/or transmission clutch pressure, harsh driveline shocks are eliminated. The system also prevents the engine from exceeding 5000 rpm when the transmission is in neutral or park.
GRADE LOGIC CONTROL
To improve powertrain smoothness and reduce gear "hunting"
on steep
grades, the 5-speed automatic transmission is equipped with a
standard Grade Logic Control system. Using sensors that
monitor
throttle position, vehicle speed, and acceleration/deceleration
the
system compares these inputs with a map stored in the
transmission
computer, determines when the vehicle is on an incline and
adjusts
the automatic shift schedule for improved climbing power or
downhill
engine braking.