Machine Design

If it ain't broke, don't fix it

Lexus LX 470 captures top honors for second consecutive year.

Lexus LX 470 captures top honors for second consecutive year.

Why change a good thing? This apparently was the thinking of Lexus engineers as there are only minor adjustments to the 2001 Lexus LX 470. Judges agreed, awarding the LX 470 with top honors again this year. As one judge rather eloquently stated, "The German luxury sedans may have heritage that Japanese automakers will never equal, but when it comes to off-road light trucks, Toyota and Lexus have heritage and competence that Mercedes Benz and BMW will have to play catch up to equal."

For a smooth ride, the LX 470 has height-adjustable suspension with computer-controlled shock-absorber damping. The adaptive variable suspension (AVS) has sensors gathering information from acceleration, steering, braking, and road surfaces. The information is used to continuously adjust the shock absorbers and maintain a smooth ride. A suspension-control ECU gathers the vertical relative speed between the body and wheels and then adjusts actuators accordingly. A 51.4% front/48.6% rear weight distribution also aids in on and off-road handling. A double-wishbone independent front suspension uses torsion bar springs for long wheel travel, adding stability.

While the suspension system ensures a smooth ride, vehicle skid control (VSC), brake assist, and four-wheel active traction control (A-Trac) help keep the LX 470 on the road. The VSC system compares actual vehicle movement to what the driver is doing with braking, the throttle, and the steering wheel. A skid-control ECU directs hydraulically controlled solenoids to manage brakes on all four wheels. The VSC detects understeer and oversteer and corrects these conditions by using torque intervention and/or individual wheel brakes. Brake assist cuts stopping distances during panic stops. For example, if the system determines the driver is trying to stop quickly and has applied insufficient pressure to engage ABS, it adds an extra boost of stopping power.

For off-roading, full-time four-wheel drive splits power 50% front and 50% rear. Off-road traction control (Off-Road Trac) engages sensors and actuators from the ABS system, using brake and throttle intervention to control wheelspin. The sensors determine road condition by changes in wheel speed. ABS influence decreases if road surface roughness increases or becomes steeper. Pneumatic-adjustable height control displays current suspension height as well as recommend optimal height during changing road conditions. Switching to high mode increases the approach angle from 30 to 32°, and the departure angle from 23 to 26° to help surmount obstacles. Rack-and-pinion steering and a 39.7-ft turning circle garnered comments such as "nice turning radius" and "easy to handle." All this smooth ride and handling needs power as well. The Lexus LX 470 is powered by a DOHC 4.7-liter V8 providing 230 hp and 320 lb-ft of torque.

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