4WD Technology

Concern for the Active Life

It was not so long ago that when hearing "4WD" one recalled rough riding, mud splattered off-road use vehicle. Mitsubishi caused a revolution in the public perception of what a 4WD vehicle was in the early 80s with the launch of the Pajero (Montero). It combined go-anywhere capability with the good ride manners of a saloon car. Consumer acceptance was enthusiastic!

The next step was to delve deeper into what advantages a saloon car with 4WD might have? Surer, Safer operation, especially when considering wet or snowy road surfaces came to mind, a real advantage for the active lifestyle of the present day consumer. But some major drawbacks came to mind as well. Fuel economy, convenience and general ride comfort might suffer. Throughout the 80s Mitsubishi engineers addressed these concerns and in the process made many significant advances in 4WD technology. Yet even with the rapid advancement of technology, no single 4WD system could adequately address the spectrum of applications and the diversity of vehicle types. Mitsubishi's approach to this dilemma was to develop a variety of systems, each geared toward a specific vehicle type and the profiled use of that vehicle. The result is that Mitsubishi can boast of one of the most comprehensive 4WD lineup of any manufacturer. Full-time 4WD, part-time 4WD, Super Select 4WD and SS4-i systems make up Mitsubishi's arsenal of 4WD technology today.

Part-time 4WD

 

For general utility, system cost considerations and the anticipated use of the vehicle, Mitsubishi's part-time 4WD system featuring a front free wheel differential offers advantages over auto-free wheel hubs and manual systems. This part-time 4WD system allows the driver to choose the optimum drive mode (2WD, 4WD) according to terrain and weather conditions with ease. The advantage over the other part-time 4WD systems is that the driver need not leave the comfort of the cabin to change the drive mode. To switch from 2WD to 4WD, the driver simply stops and shifts the transfer lever to 4H that locks the free wheel differential. Switching between high and low 4WD range can be done under running operation. To unlock the free wheel differential, the driver simply stops the vehicle, shifts the transfer lever to 2H, stops the engine and then restarts it. The Strada (L200), Minicab and Pajero Mini are models marketed in Japan with part-time 4WD.

Full-time 4WD

 

For passenger cars, with little off-road use anticipated, Mitsubishi's full-time 4WD system featuring a central differential and viscous coupling unit provides several advantages to either a central differential 4WD system or a viscous coupler 4WD system. Mitsubishi's full-time 4WD system provides the positive characteristics of several systems. Excellent starting and acceleration, cornering and straight-line stability of a locked 4WD system is provided. Added to these are the advantages derived from combining both the central differential and viscous coupler systems, such as, low noise and vibration, low fuel consumption, smooth and easy low-speed cornering without torque-induced braking around tight corners. The system is ideal for long-distance driving under all road conditions. The Diamante (Sigma), Galant, Lancer, Mirage (Colt), GTO (3000GT), RVR (Space Runner), Chariot Grandis (Space Wagon), Legnum (Galant Station Wagon), Libero (Lancer Station Wagon), Minica Toppo, Minica (Towny) and Bravo (L10 0) are models currently marketed in Japan with Mitsubishi's full-time 4WD system.

Super Select 4WD / SS4-i

 

The go-anywhere versatility of Mitsubishi all-terrain vehicles is a product of superior technology. Super Select 4WD and SS4-i are prime examples of this cutting-edge engineering. Mitsubishi developed the Super Select 4WD system for the 2nd generation Pajero (Montero) in 1991. In addition, current Challenger (Pajero Sport / Montero Sport) and Delica Space Gear (Space Gear / L400) models employ Super Select 4WD. It combines in a single system the merits of 2WD, full-time 4WD and locked 4WD. Cruising down the highway, maneuvering through heavy city traffic, traveling on gravel country roads, negotiating on wet or snowy mountain roads, the driver decides what level of traction and economy is required and makes an easy shift, even under running conditions.

Based on the tried and tested Super Select 4WD, the SS4-i offers all the advantages of its predecessor, enabling one-handed transfer between 2WD and 4WD at speeds up to 100km/h for example, yet is smaller and lighter. Mitsubishi developed the SS4-i system in 1998 for the
Pajero iO. Both systems allow the driver to choose from four operating modes to optimize traction on all surface conditions.