The street sports suspension kit (SS kit) has received many inquiries since the release of the tuning kit "KG-8" for the CX-06.This time, I will tell you about the development progress.
Among the many suspension parts, the SS kit has a high degree of freedom in design because springs and dampers can be developed together, and it is a part that can pursue the "street best ride" that we are aiming for.First, I will explain the ride quality using a graph.

The figure is the "damping ratio / damping force graph" that appears frequently in our catalogs and websites, and the damping ratio curve (damping ratio curve) in it.Red line) Is not an exaggeration to say that it is a "blueprint" for the best street ride.
This is because we use this "damping ratio curve" as an index to consistently design SUVs, sports cars, and compact cars.By the way, this curve is called "Chinese Ankou" in our company.It's similar to the "Chinese Ankou" seen from the side ... (sweat)

The "damping ratio" is like the balance between the hardness of the spring and the damping force of the damper.In other words, how much the damper works with respect to the hardness of the spring, so it is expressed as "%".

The graph isBlue belt"Initial roll area" has the highest damping ratio,Yellow belt"Ride quality / protrusion area" →Red beltYou can read that it is going down according to the "bad road area".The aim is to steer the steering and strengthen the damper's effect on the springs when the vehicle body begins to roll, creating a sense of stability.

After the "ride comfort / protrusion area", the ride quality and running performance are taken into consideration by suppressing the rise of damping force so that the damper does not stretch too much.・ ・ ・ If it gets too long, it will be difficult to read it, so if you want to know more about it, you can use the suspension.Concept.

Now, let's take a look at the CX-8 development report.
The basic specifications can be calculated on the desk based on the weight and dimensions of the car.
First is the spring design.Since the hardness of the spring determines the maximum roll amount, we will prototype a spring with 110 to 130% of the mass production.
The damper sets the total damping force (damping force that totals contraction and elongation) for the prototype spring based on the damping ratio.
From there, it is divided into "shrinking side" and "stretching side".The standard for sorting is to design a prototype damper so that the damping force on the "extending side" is increased so that the total damping force does not decrease, while the "shrinking side", which has a large effect on riding comfort, is conservative.

This is the end of what you can do on your desk.
From here, we will install the prototype on the actual vehicle, run it on the usual test course, and move on to the driver's sensitivity evaluation by repeatedly changing the combination of "run" → "evaluate" → "replace" → "run" → ..

How does the driver feel about the actual movement of the car?Whether it is pleasant or unpleasant ... Human sensibilities have the ability to detect even the slightest difference, so the final specifications are determined by analog.This alone may be difficult for both a good supercomputer and AI.

So, the following are the specifications of the spring and damper that remained until the final selection after the desk calculation → sensitivity evaluation.

<Details of prototype suspension>* Final selection
・ Spring constant (compared to mass production): S1 = approx. 110% S2 = approx. 125%
・ Damper damping force (compared to mass production): D1 = slightly higher D2 = higher

<Sensitivity evaluation of development driver>
[Test ①]Before and after: S1 + D1 → The roll amount is smaller than that of mass-produced cars, but I want to reduce it a little more.In addition, the harshness (slight vibration) is strong, and the ride quality is generally uncomfortable.

[Test ②]Before and after: S2 + D1 → The amount of roll has decreased due to the increase in spring constant.However, Harshness has not changed.Speaking of the graph above, the cause is that the damping force near the initial roll area to the riding center area is too high.Prototype damper D3 (lower than D1) is available.

[Test ③]Before and after: S2 + D3 → Harshness has disappeared and the ride quality has improved.However, the convergence on the front side is poor, and it is agitated and restless.

[Test ④]Front: S1 + D3 Rear: S2 + D3 → In all areas, the amount of roll was suppressed, giving a moist feeling to the ride.

So, it was decided to the specifications of test ④. I am proud that it has become a "street best ride", with a sharp ride and ride quality that does not make you feel the height of the SUV.

If it is a damper, it can be disassembled on the spot and the damping force can be tuned, but if the spring is the cause, it will take more than two weeks to make a prototype.This directly affects the release date, so it can be a lot of pressure.
So, the street sports suspension for CX-8 is currently in preparation for mass production!Release is scheduled for May.
I think the finished product is a "foot" suitable for "The Sports Limousine".Please stay tuned.

Posted by J.Inazumi