Automotive Intelligence - the web for automotive professionals and car enthusiasts
September 17, 2008
The Land Cruiser’s six-speed automatic transmission is designed to handle high torque while performing with luxurious smoothness. Fourth gear is direct drive, and both fifth and sixth gears are overdrive gears. The transmission's control unit estimates road conditions to select the appropriate gear ratio for the vehicle's speed and driving conditions. A sequential shift mode allows the driver to select gears manually.
The Land Cruiser’s body-on-frame construction provides ruggedness and durability in extreme driving conditions, plus impressive towing capability and ride isolation characteristics. The front of the frame features a three-stage crush structure so frame damage to other areas of the vehicle is minimized in the case of frontal impact. The Land Cruiser employs a high-mount double-wishbone front suspension system with gas-pressure shock absorbers, a hollow stabilizer bar, and coil springs. The system is designed to suppress alignment change while the suspension travels through its stroke, and maintain an optimal stroke length. This system provides a high level of off-road driving capability and suspension control while maintaining a high level of on-road driving comfort. Approach and departure angles are 30 degrees and 20 degrees, respectively.
At the rear, the reliable and proven four-link, coil-spring with lateral rod format was redesigned to provide a longer suspension stroke for improved on-and off-road performance. The Land Cruiser's rear suspension also features gas-pressure shock absorbers and a hollow stabilizer bar.
The Kinetic Dynamic Suspension System (KDSS) adjusts the sway resistance provided by the front and rear stabilizer bars. KDSS may reduce maximum body-sway angle by as much as 50 percent to help enhance both on-road handling response and off-highway capability. By using hydraulic cylinders acting on each stabilizer bar and linked by a pressure-sensing valve, KDSS reduces the degree of sway stiffness provided by the stabilizer bars in response to changing road conditions and driver inputs.
In off-road driving situations, the KDSS allows the wheels on each axle to move with a larger degree of side-to-side independence, helping to minimize any tendency for wheel lift. During cornering, when both front and rear cylinders are compressed, no fluid is flowing in the system and the stabilizer bars work conventionally to help reduce body roll. When an uneven surface is encountered, one compressed cylinder causes fluid to flow between the front and rear cylinders, allowing the stabilizer bars to move freely. This action increases wheel articulation and travel, as well as helps to equalize wheel loading. By allowing the stabilizer bars to disengage in certain situations, the nominal stiffness of the bars can be notably increased, thereby reducing body roll and improving handling without negatively affecting ride comfort or off-road performance.
The newly-developed JF2A transfer case provides full-time four-wheel drive. This lightweight, compact, chain-driven unit offers a standard 1:1 high ratio for road travel and a low-range 2.618:1 ratio for traversing challenging driving surfaces, such as steep inclines. The system uses a TORSEN® limited-slip locking center differential to distribute power 40:60 front-to-rear, directing more power to the wheels with the best grip should slippage occur. Traction control (TRAC) employs both brake and throttle intervention to help control wheel spin. Vehicle Stability Control (VSC), with a cut-off switch, helps maintain directional control during cornering.
The Crawl Control feature helps make traversing difficult terrain easier and safer. With the transfer case shifted into low range, Crawl Control regulates engine speed and output (along with braking force), to propel the vehicle forward or in reverse at one of three low-speed settings. This allows the driver to maintain focus while steering over very rough level ground or steep grades, without having to also modulate the throttle or brake pedals. Crawl Control includes Downhill Assist Control (DAC), which is designed to augment the low-speed ascending ability of low-range by holding the vehicle to a target speed with no driver intervention. Hill-start Assist Control (HAC) provides additional control for off-road driving by helping to keep the vehicle stationary while starting on a steep incline or slippery surface.
Like all Toyota SUVS, the Land Cruiser comes standard with the STAR Safety System. A new, four-wheel multi-terrain anti-lock braking system (ABS) automatically selects the optimal ABS profile to provide the most suitable brake force for on- and off-road driving surfaces. Electronic Brake-force Distribution (EBD) employs the multi-terrain ABS to properly balance braking forces between the front and rear brakes, while Brake Assist (BA) provides auxiliary force to assist the driver during emergency braking. Active Traction Control (A-TRAC) helps maintain traction during acceleration by controlling engine output and braking forces to the wheel, distributing the drive force that might have been lost to the wheels and tires that have traction. VSC with a cut-off switch, helps maintain directional control during cornering by manipulating engine torque and individual wheel-braking influence if it detects tire slippage.
(Sept. 17, 2008)