04.02.2009, 11:23
The mode for everyday driving is, as with Easy Select, '2H'. Here, drive is to the rear wheels only, on the basis that on good road surfaces you don't need anything more.
The first 4WD setting is '4H', which adds drive to the front wheels, and like Easy Select it allows shift-on-the-fly. But one important difference is that you can use 4H on dry roads without fear of transmission wind-up.
Indeed, in 4H SS4-i is in 'thinking' mode, because although you've selected 4WD, power is still only fed to the rear wheels until surface conditions dictate that the front wheels need it too.
This is achieved via a device in the centre differential known as a viscous-coupling unit (VCU), which senses when the rear wheels are losing grip, and instantly feeds drive to the front wheels so that they can help with traction. This could happen when, say, you hit a patch of ice on the road.
The benefit is that the vehicle is only using 4WD when it really has to, and so is always running as smoothly as possible as well as optimising fuel economy.
While the above mode is suitable for driving in a mix of road conditions, '4HLc' is intended for slippery off-road terrain, wet grass for example. When 4HLc is selected, the VCU is bypassed and drive to the front and rear axles is locked up, which takes out any speed differences between the front and rear wheels. Thus, provided all four wheels are still on the ground the Shogun Pinin should keep moving.
The most impressive 4WD system in the Mitsubishi armoury is SS4-II, used in the Shogun. It offers the same four modes as SS4-i, except it overlays an increased level of sophistication, which eases selection and improves on-road driving characteristics.
The 2H function is unchanged over SS4-i, but in 4H the VCU splits the engine torque in the ratio 33/67 front/rear as opposed to the 50/50 distribution in SS4-i. The benefit here is that the bulk of the power going to the rear wheels gives better balanced on-road handling, making the Shogun feel more sporty through corners. However when slippery road or off-road conditions demand, the VCU will automatically split the torque accordingly, from 33/67 front/rear to 50/50 front/rear.
The 4HLc and 4LLc work in the same way as in the Pinin, being the two settings for off-roading. However the driver also has the option of locking the rear differential, for side-to-side locking of the rear axle.