2007 Mitsubishi Outlander debuts new-generation V-6 engine and segment-exclusive six-speed Sportronic(R) transmission

The 2007 Mitsubishi Outlander is powered exclusively by an all-new 3.0-liter SOHC V-6 engine (6B31) that combines competitive power with outstanding refinement and fuel economy - all while meeting the nation's most stringent emissions standards. The V-6 engine is teamed exclusively to a new six-speed Sportronic(R) automatic transmission that allows manual shifting by the floor shift or, in XLS model, magnesium steering wheel paddle shifters - a segment first.

The pairing of the efficient new V-6 with the six-speed transmission enables the new larger, roomier, more powerful Outlander to achieve nearly the same highway fuel economy as its four-cylinder predecessor - up to an EPA-estimated 27 highway mpg in the front-wheel drive LS models and 26 highway mpg for 4WD XLS models.

The new 4-valve-per-cylinder V-6 produces 220 hp at 6,250 rpm (213 hp, PZEV) and 204 lb.-ft. of peak torque at 4,000 rpm, running on recommended regular-grade fuel. A combination of the Mitsubishi Innovative Valve Timing and lift Electronic Control (MIVEC) - a variable valve timing and lift system - and a two-stage variable intake manifold ensure a broad torque curve. The Outlander V-6 provides nearly 90 percent of peak torque from just 2,000 rpm. Combined with the optimized ratios of the six-speed automatic transmission, this performance curve gives the new Outlander outstanding response in all driving situations.

The new Mitsubishi V-6 engine (right) uses aluminum for its cylinder block, cylinder heads, oil pan, and resin rocker covers to reduce weight by a significant 55 lbs. compared to the company's previous-generation 3.0-liter V-6. Remarkably, the new Outlander V-6 is only 13.2 lbs. heavier than the 2006 Outlander's iron-block four-cylinder engine (341.7 lbs. vs. 328.5 lbs.).

California P-ZEV Certification

The new Outlander V-6 has also been designed and optimized to meet the most stringent emissions requirements. The Outlander V-6 uses efficient, clamshell-type exhaust manifolds. A catalytic converter housed within the clamshell of each manifold helps improve exhaust emissions performance, particularly under cold start conditions.

The combination of a high-efficiency HC-trap catalyst system and PremAir(R) Direct Ozone Reduction catalyst radiator helped earn the new Outlander Partial Zero Emissions Vehicle (PZEV) certification in California, making Outlander the first PZEV V-6 in the segment. The PremAir(R) catalyst radiator effectively reduces ozone in the air that passes over its coated surfaces by converting ozone molecules into oxygen molecules upon contact. Tests have shown that PremAir(R) catalyst radiator converts as much as 80 percent of the ozone it contacts into oxygen.Federal certification is Tier 2 bin 5.

A sophisticated electronically controlled multi-point fuel injection system ensures precision fuel delivery. The electronic throttle control system (throttle-by-wire) eliminates the mechanical linkage between the accelerator pedal and the throttle plate. Looping the fuel line around the engine improves exhaust gas performance by reducing fuel temperature differences between the delivery pipes, reducing pulsations within the delivery pipes, and suppressing variations in the amount of fuel injected.

Mitsubishi's environmental commitment goes well beyond vehicle emissions. Mitsubishi made a concerted effort to substantially reduce or eliminate toxic substances used in vehicle manufacture. For example, the fuel tank is free of hexavalent chromium and lead.

Mitsubishi Innovative Valve Timing and lift Electronic Control system (MIVEC)

Many engines today employ some form of variable valve control system, which can optimize power and torque by varying valve opening times and/or duration. Some of these valve control systems optimize performance at low and mid-range engine speeds. Others focus on enhancing only high-rpm power.

The Mitsubishi Innovative Valve Timing and lift Electronic Control (MIVEC) system provides both of these benefits by controlling valve timing and lift. Despite its technological complexity, the basic operation of the MIVEC system can be expressed quite simply: MIVEC alters the cam profiles, tailoring engine performance in response to driver input.

In essence, MIVEC serves the same function as "swapping cams," something that car enthusiasts and racers might do when modifying older-design engines to produce more power. However, such swaps come with a compromise - generally yielding either greater low-end torque or more high-end horsepower, but not both.

MIVEC achieves both goals. With MIVEC, the "cam swap" occurs automatically at 4,750 rpm. The cam switch operation is transparent to the driver, who is simply rewarded with a smooth flow of power.

Under low-rev conditions, MIVEC uses a smaller cam profile, yielding medium lift on the intake valves to provide stable idle and lower emissions. When engine speed reaches the switchover point, MIVEC applies longer duration and higher lift to the intake valves, yielding maximum and efficient power and torque over a broad engine speed range.

How MIVEC Works

In the MIVEC system, two distinct cam profiles are used to provide two engine modes: a low-speed mode, consisting of low-lift cam profiles; and a high-speed mode. The low-lift cams and rocker arms - which drive separate intake valves - are positioned on either side of a centrally located high-lift cam.

Each of the intake valves is operated by a low-lift cam and rocker arm, while placing a T-lever between them allows the valves to follow the action of the high-lift cam.

At low speeds, The T-lever's wing section floats freely, enabling the low-lift cams to operate the valves. The intake rocker arms contain internal pistons, which are retained by springs in a lowered position while the engine speed is below the MIVEC switchover point, to avoid contacting the high-lift T-shaped levers. At high speeds, hydraulic pressure elevates the hydraulic pistons, causing the T-lever to push against the rocker arm, which in turn makes the high-lift cam operate the valves.

In summary, MIVEC switches to the higher cam profile as engine speed increases, and drops back to the lower cam profile as engine speed decreases. The reduced valve overlap in low-speed mode provides stable idling, while accelerated timing of the intake valve's closing reduces backflow to improve volumetric efficiency, which helps increase engine output as well as reduce lift friction. High-speed mode takes advantage of the pulsating intake effect created by the mode's high lift and retarded timing of intake valve closure. The resulting reduced pumping loss of the larger valve overlap yields higher power output and a reduction in friction. The low- and high-speed modes overlap for a brief period, boosting torque.

Variable Intake Manifold

Like variable valve timing, variable intake manifolds are a modern interpretation of an idea first used in high-performance engines decades ago. So-called "long-ram" manifolds were once used to provide a longer intake tract, which helped to boost low-end and mid-range torque. In contrast, "short-ram" manifolds helped boost high-end horsepower, but usually at the expense of low-end and mid-range torque. The Mitsubishi 6B31 V-6 engine's aluminum intake manifold uses a resin Induction Control Valve to provide the benefits of short and long intake tracts, automatically switching in response to engine speed.

A flap inside the Induction Control Valve remains closed below 3,600 rpm, forcing the intake charge to take a longer route to the inlet valves. Over 3,600 rpm, the flap opens, providing a shorter tract to the valves to increase power. Positioning the EGR distribution inlet on the upper intake manifold, far from the throttle valve, improves real-world fuel consumption by lowering the temperature entering the EGR distribution passageway.

Premium Level Refinement

When setting standards for minimizing noise, vibration and harshness (NVH), Mitsubishi benchmarked not only Outlander competitors, but premium-level models, as well. This 60-degree V-6, an inherently smooth-running configuration, does not require a balance shaft, yet engineers took extra steps to quell sources of even the smallest vibrations. One example is offsetting the cylinder axis of rotation in the direction of crank rotation, which reduces operating friction.

For the air intake, lengthened ducts and optimized resonators ensure quietness and to reduce weight. A variable-valve main muffler helps reduce noise and vibration. Even reducing the number of exhaust system hangers from six on the previous model to four on the new one helps reduce a source of vibration transmission.

The new Outlander V-6 mounts to the front subframe using a four-point inertial axis system with liquid-filled mounts that help to reduce vibration and enhance ride quality. The pressure-cast aluminum right mounting bracket (engine side) and left mounting bracket (transmission side) have both been made more rigid and lighter, which helps to reduce acceleration noise. A new insulator design for the front and rear mounts has been specially tuned for use with the six-speed automatic transmission, offering a optimal balance of insulation from idle vibration and acceleration shock.

Small Details for Enhanced Durability

Mitsubishi took several steps to enhance engine durability, as well. One example is the use of long-reach Iridium spark plugs. The thinner diameter plug (M12) allows wider valve diameter, and enlarging the water jacket improves cylinder head cooling performance. Another example is the 100,000-mile timing belt, which is quieter than a chain while providing outstanding durability.

The Outlander's cooling system also provided opportunities to reduce parts and weight while enhancing overall performance and durability. The cross-flow radiator is lower than a conventional type, and therefore easier to install and remove if needed. The radiator is installed with one-touch clamps rather than bolts, improving serviceability. The number of parts in the blower and condenser connections was reduced. Compared to the previous Outlander, the new model uses a larger-diameter fan and a higher capacity fan motor.

Six-Speed Sportronic(R) Automatic Transmission

The new Outlander V-6 is teamed exclusively to a six-speed Sportronic automatic transmission, which features a sport mode. As with the new outlander V-6 engine, the new six-speed transmission was designed to impart the refinement expected in premium class vehicles.

Employing six gear ratios instead of five - as most competitors do - helps make the transmission more responsive to a wider variety of driving conditions. In particular, "hunting" between gears over varying road grades is minimized.

Advanced control of the engine and transmission minimizes torque fluctuation during gear changes. The INVECS-II electronic controls match automatic gear changes to both road conditions and individual driving habits. The shift schedule has been optimized to match expectations of the average driver, and the transmission responds to driver input and adapts to an individual driver's style.

Sport Mode enables driver to enjoy more dynamic driving performance by shifting manually. The driver can shift gears manually using the floor console shift handle (forward for upshifts and rearward for downshifts), or a feature more commonly seen on exotic sports cars - and a first for the compact SUV segment - magnesium Sportronic steering wheel paddle shifters in Outlander XLS models. The right-hand shift paddle is for up-shifting, and the left-hand paddle is for downshifts.

The paddles are attached to the steering column and remain in the same position regardless of the steering wheel angle for ease of shifting even in tight corners. The paddle shifters are active during sport mode and automatic mode to enable quick manual shifting at any time. The Outlander can be driven away in second gear under slippery road conditions.