Subaru Patented Technology

[b3lha]

I've been browsing around on www.patentstorm.us searching for patents filed by "Fuji Jukogyo Kabushiki Kaisha" (aka Fuji Heavy Industries, parent company of Subaru) around the time that the SVX was being developed, approx 1988-91.

Many of them come from other branches of FYI, relating to trucks, trains, aircraft etc. But there are some that seem to relate specifically to the SVX.

One that particularly caught my attention is 5018594 "Rear-wheel steering system for four-wheel steering vehicle". I reckon this provides probably the best description we will ever find in english for how the 4WS works on the version L.

There are several relating to the specific parts of the engine and AWD system and even some relating to "active suspension" and the "anti-frost windscreen" that were supposedly seen on the SVX concept car.

Interesting stuff, if only they were a little easier to comprehend.

[nutshell]

Hey Phil...Hunting along your lines gave me this one: http://www.patentstorm.us/patents/se...=fuji+steering

Lays it all out neatly...even if Jinglish is the language of choice.
They worked on it for a few years - pity they gave up so easily.

Mind you - it took my local service guys three attempts - they were just one tooth out on the rack - before they got it right.

It is great to find background info to support the contention that the 4WS SVX is the most nimble vehicle ever made...no arguments. :-)

Many thanks.

[b3lha]

Nice work! The second one on your list gives some clues about how to recalibrate the steering angle sensor after the steering rack has been worked on.

5065324 Method of detecting absolute steering angle of steering angle sensor for vehicle

Subsequently, in the servicing work of the vehicle, for example, the power supply (main power supply) of the microcomputer may be once cut off by disconnecting the storage battery terminal. As a consequence, the stored memory of the absolute steering angle of the microcomputer would be erased. Thus, detection of the absolute steering angle would become impossible. According to the present invention, however, the value of the deviation Δθ of the actual straight-ahead position B relative to the reference position A is stored in the non-volatile memory or the memory with the backup power supply as described hereinbefore. The storage of the deviation Δθ is not erased even if the power supply of the microcomputer is once cut off. For this reason, in the case of loss of the stored memory of the absolute steering angle as mentioned above, the detection of the absolute steering angle becomes possible again merely by resetting the reference position A after resumption of the power supply.
More specifically, a maximum number of turns or rotations of the steering shaft 6 is generally designed between two rotations and four rotations. Therefore the photointerrupter 5 detects the neutral position mark 3 during steering operation from a maximum right steering limit to a maximum left steering limit at a total of three points, namely, the true reference position A and, additionally, positions A' and A" which are angularly spaced respectively 360° left and right from the position A as indicated in FIG. 5. Therefore after supplying the power to the microcomputer by connecting the battery terminals, the microcomputer starts resetting the reference position A. Further, the microcomputer may enable to start the resetting responsive to the operation of a resetting switch. Then the three positions A', A, A" are detected by turning the steering wheel 20 in one direction from the maximum right steering limit to the maximum left steering limit. By this procedure, the median detected position among the three detected positions is recognized and set as the reference position A.

[Zandar]

Did any USDM cars see active or passive 4WS?

[maxg765]

Originally Posted by Zandar

Did any USDM cars see active or passive 4WS?

From what I have read no, but would have been nice to have.

Max

[Zeppelin]

Originally Posted by Zandar

Did any USDM cars see active or passive 4WS?

That's a can of worms that has been opened many times, just search for it.

Hello Eddycat? Aredub?

[Hocrest]

My SVX has passive 4WS










We all do... This hasn't been debated for a while...

[Zandar]

Originally Posted by Hocrest

My SVX has passive 4WS

We all do... This hasn't been debated for a while...

That's what I've heard, but I haven't had it confirmed. I have actually looked into the subject on this forum and t3h int3rw3bZ, but I haven't found anything conclusive. It's a lot of, "yes we do," "no we don't" type arguments.

So passive 4ws for USDM and active for JDM? Any way to add active 4ws without spending $10k?

[Trevor]

Originally Posted by Zandar

That's what I've heard, but I haven't had it confirmed. I have actually looked into the subject on this forum and t3h int3rw3bZ, but I haven't found anything conclusive. It's a lot of, "yes we do," "no we don't" type arguments.

So passive 4ws for USDM and active for JDM? Any way to add active 4ws without spending $10k?

If you wish to argue in this direction, so did all cars of old, which used for and aft leaf springs, with a shackle front OR rear. Ask MR Buggati which way was correct.

[b3lha]

Originally Posted by Hocrest

My SVX has passive 4WS
We all do... This hasn't been debated for a while...

Yes. In the sense that "passive 4WS" is a marketing term meaning "2WS".

[Trevor]

Originally Posted by b3lha

Yes. In the sense that "passive 4WS" is a marketing term meaning "2WS".

Absolutely spot on.

[STeeL25T]

A couple Nissans in the early 90's came with Super HICAS 4 wheel steering, and I believe most people with it hate it and remove it. Wonder how it's different, aside from being on a more powerful AWD car.

[crazyhorse]

IIRC the Super HIcas setup was a hydraulic cylinder that moved the rear subframe. The system on the Stealth/3000GT was similar
Honda's was a pure mechanical system, with a shaft running to the back, which had it's own rack & pinion.
The SVX system, which is well detaled elsewhere, was an electric system with a motor that moved the "toe" links via a bell crank.

Personally I'm sort of glad we did without 4ws. The added complexity & weight would be a downer on a higher mileage car.