For off-road enthusiasts, off-road vehicles with fewer electronic systems and simpler mechanical structures are reliable. Toyota Land Cruiser and Nissan Patrol are evergreen trees in the off-road circle. Although they are hard-core off-road vehicles with girders, the comfort of road driving is worrying. A long time ago, people commented on these two cars-the suspension was soft, the cornering roll was severe, and it even made people feel that the car was about to roll over.
In order to improve road performance, Toyota developed the KDSS (Kinetic Dynamic Suspension System) variable dynamic suspension system, and Nissan also introduced a more complex HBMC (Hydraulic Body-Motion Control system) hydraulic body motion control system. KDSS first appeared on the Lexus GX470, and HBMC followed the front and rear double-wishbone suspension of the Y62.
These two systems improve the roll problem on the road through passive adjustment. So what are the similarities and differences between them, and what are their advantages and disadvantages? Let me analyze it for you.
Toyota Believes: Simple is Best
Like most cars that focus on road performance, Toyota has added a thick anti-roll bar to the Land Cruiser to suppress roll. The thick anti-roll bar gives it a good anti-roll ability in corners. Then, the engineer installed a hydraulic cylinder on each of the front and rear anti-roll bars, and the two hydraulic cylinders communicated with each other. It’s these two hydraulic cylinders that break the sway bar’s grip on suspension travel off-road.
The upper and lower hydraulic chambers of these two hydraulic cylinders communicate in parallel, and there is a pressure accumulator similar to a switch in the middle. When off-road, one stretches and the other shrinks. The hydraulic cylinder improves the freedom of movement of the anti-roll bar at this time, especially in the case of “cross-axis” that makes the stretching and compression actions of the front, rear, left, and right suspensions completely opposite (effect As shown below).
When driving on the road, the main anti-roll function is the anti-roll bar, but at this time, the front and rear hydraulic cylinders will be compressed or stretched at the same time, and the hydraulic device will have excessive pressure. At this time, the pressure accumulator sandwiched in the middle of the pipeline is used. The ECU of the vehicle can automatically control the opening and closing of the pressure accumulator according to the vehicle speed and the lateral acceleration of the turn to relieve the pressure of the hydraulic cylinder. Of course, the hydraulic cylinder will also assist the anti-roll bar to increase support for the body on the road.
The Nissan HBMC system installed on the Patrol Y62 can only be realized by relying on the front and rear independent suspension system of this car. In fact, it is to install a hydraulic device on each of the four suspensions, and the four are connected to each other. Compared with Toyota’s KDSS, this hydraulic system splits the front and rear hydraulic cylinders into two small left and right hydraulic cylinders.
On the road, when the hydraulic cylinder on one side is compressed by the rolling force, it will drive the hydraulic cylinder on the other side to compress passively, thereby suppressing the rolling tendency of the entire vehicle body, which is the same as the principle of the anti-roll bar. On off-road roads, its principle is basically the same as Toyota’s KDSS, but because it is four independent hydraulic cylinders, it is more flexible to adjust. The picture below is a schematic diagram of how the HBMC system works as an anti-roll bar when turning on the road.
Tourle is comfortable on the asphalt road, but a bit timid off the road
For off-road enthusiasts who need to modify, the problem with the Touley62 is that as long as the shock absorber is replaced, the HBMC will lose its effect. However, the suspension travel of the original car is not large. After all, the four-wheel independent suspension takes into account the comfort of road and daily driving. Compared with Lu Xun LC200, the rear overall axle structure has a larger suspension stroke and stronger off-road performance.
In general, Touley62 is more suitable for friends who need large space and comfort, but do not need high-intensity off-road.
