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Discussion Starter · #1 ·
I've spent several hours reading about EPS (Electric Power Steering) and drive-by-wire systems. I have learned much but my basic question remains unanswered.

Does the current-model CR-V replace the mechanical steering linkage steering with full steer-by-wire technology? If not, how does the RDM "Lane Departure" shake the steering wheel without transmitting that movement to the car?

I've learned that GM and Infiniti have both produced full steer-by-wire car models; I couldn't find specifics on GM but Infiniti has a magnetic clutch coupling that's normally disengaged but slams together to create a physical linkage if there is a component failure or the engine is off, thus enabling steering when the engine is off. Earthmoving and heavy equipment, as well as some heavy road trucks, have used full steer-by-wire for years. (I presume these vehicles are so massive that physical effort wouldn't even register as steering input.) I've learned here's a whole safety certification system set up to certify steer-by-wire road vehicle systems.

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I’m thinking the steering is mechanical linkage with the power-assist being electronic. Now, the lane departure is all done by pure magic. Just kidding.
 

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No, there is no vehicle allowed on the road that does not have a direct mechanical connection between the steering wheel and the wheels. Even self driving cars must have the driver able to control the steering mechanically.

Electronic power steering is nothing new by far, GM and such have been doing for over a decade.

It is nothing fancy really either. All that's involved is no longer using a fluid pump that's driven by the engine. Instead there is an electric motor and gearbox for it either attached to the steering column inside the dash or to the power steering rack itself. When you turn the wheel it turns the electric motor on to provide torque to help you turn the wheel.

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Everything in Moderation
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Infiniti has a steer-by-wire system


It DOES have a mechanical back-up in place, for the present.
 

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Everything in Moderation
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Nissan also has Variable-compression engines!

 

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Nissan also has Variable-compression engines!

Interesting, but yawn ?
ICE engineers spending huge $ on the dawn of the end of ICE’s , trying to milk 0.1 mpg more with more and more minute revisions of the basic concept, not unlike the fanatical details and regurgitated designs of horse carriages during their last 20 years,- impressive engineering for the time.
Now take the gasoline Wankel engine from so long ago...now there’s a genuine “thinking outside the box” ICE, if there was one. ??
 

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So.......as the OP asked, does the current model CRV have electric power assisted mechanical steering or steering by wire? Those videos are nice.


Wow! I luv this forum.....learn something new everyday. Thanks guys for those videos.
 

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Discussion Starter · #8 ·
No, there is no vehicle allowed on the road that does not have a direct mechanical connection between the steering wheel and the wheels. Even self driving cars must have the driver able to control the steering mechanically.
<snip>
Thanks. I have no information to suggest otherwise. But... how does that steering wheel shake work?? Magic, as suggested earlier in this thread? :)

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Thanks. I have no information to suggest otherwise. But... how does that steering wheel shake work?? Magic, as suggested earlier in this thread? :)

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Likely the same system that sends torque commands to the steering wheel for lane keep assist. Projects like comma.ai take advantage of this control to improve the capabilities of the driver assist systems.

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I think you're conflating electric power steering (EPS) with steer-by-wire. EPS replaces the hydraulic rack and pinion motors (HPS) with electric motors. Steer-by-wire severs the mechanical linkage entirely and computerizes the steering. In other words, it turns the steering wheel into a video game controller. HPS felt better than EPS, and from what I've heard, SBW is even more numb than EPS. A few concept vehicles with SBW have been developed but none are currently on the market.
 

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Likely the same system that sends torque commands to the steering wheel for lane keep assist.

I think you're conflating electric power steering (EPS) with steer-by-wire. EPS replaces the hydraulic rack and pinion motors (HPS) with electric motors. Steer-by-wire severs the mechanical linkage entirely and computerizes the steering. In other words, it turns the steering wheel into a video game controller. HPS felt better than EPS, and from what I've heard, SBW is even more numb than EPS. A few concept vehicles with SBW have been developed but none are currently on the market.
Yeah, but how does it shake the steering wheel, but not the tie rods if everything is all connected together? This is the question. I too want to know the answer to this now.
 

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Yeah, but how does it shake the steering wheel but not the tie rods if they are all connected together? This is the question. I too want to know the answer to this now.
It probably uses a separate small motor to shake the steering wheel but a signal is also sent to the electronic steering units to ignore that movement. It's also possible that they can do it with the existing system by creating a larger feedback signal from the motors to the steering wheel. The same feedback that allows you to have a sense of feel for the road conditions. There are many ways it can be done, I am not sure which one Honda is using.


Rob
 

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I just went out to my car and did an experiment. Without pushing the button to start the car I tried turning the wheel back and forth. It felt just like normal old school manual steering. I just learned that there doesn't appear to be any type of steering wheel lock either, which was also an interesting discovery.

I just did some quick google research and came up with info from this website... http://www.car-engineer.com/2017-honda-cr-v-chassis-electric-power-steering/

I don't completely understand all of the technical mumbo jumbo, but here is what it says about the cr-v's steering...

"The Electric Power Steering (EPS) incorporates dual pinion gears and a variable gear ratio (VGR) for enhanced low-speed maneuverability and high-speed stability. Compared to a traditional single-pinion steering system, the dual pinion EPS utilizes the physical steering input from the driver as well as from a supplemental electric motor. A non-contact torque sensor measures the driver’s steering effort and an ECU determines how much electric motor assist to add, with the result claimed to be a seamless, natural-feeling steering in all situations.

The steering ratio is variable over a 20-percent range with a final full off-center ratio of 12.3:1. This provides a 2.3 turns lock-to-lock – significantly quicker than the 2016 CR-V’s 3.1 turns – enabling easier low-speed maneuvering and parking. The variable ratio allows for slower gearing around the straight-ahead position for improved stability at high speeds. Also contributing to the enhanced steering performance and feel of the CR-V are reduced operating friction, a high level of stiffness for the steering mount, and a larger diameter, more rigid steering column shaft (8 mm larger than the 2016 CR-V).
"
 

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I think this will work with any car. Just shake the steering wheel while driving down the highway.

If you shake the wheel fast enough, the tires don't have enough time to respond, and the shake isn't felt in the vehicle.
 

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Dual pinion essentially means there's two steering columns, one on the left and one on the right. In the USA, the right side column is hooked up to an electric motor and the left side is hooked up to the steering wheel. The electric motor detects the amount of effort the driver is putting on the wheel and provides assistance to ease effort.


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Discussion Starter · #17 · (Edited)
Likely the same system that sends torque commands to the steering wheel for lane keep assist. Projects like comma.ai take advantage of this control to improve the capabilities of the driver assist systems.

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But the steering wheel alert shake isn't transmitted to the steering or the vehicle. If there's a mechanical connection, this baffles me.

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AFAIK, Infiniti is the only auto manufacture supplying vehicles with steer-by-wire to North America. As jbeachy mentions above, it's been available for years. There have been reports of failures of Infiniti SBW systems in colder weather (that would be interesting...driving down the highway and no steering...). I strongly prefer a direct, mechanical linkage for my steering...
 

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The Infiniti Q50 appears to have had it since 2014.
https://www.wired.com/2014/06/infiniti-q50-steer-by-wire/
AFAIK, Infiniti is the only auto manufacture supplying vehicles with steer-by-wire to North America. As jbeachy mentions above, it's been available for years. There have been reports of failures of Infiniti SBW systems in colder weather (that would be interesting...driving down the highway and no steering...). I strongly prefer a direct, mechanical linkage for my steering...

According to that article, Infinity hasn't abandoned mechanical steering in any vehicles yet....


"If Infiniti ever has the guts to go for the lobotomy and strip out the mechanical steering system (it left it in there as a backup), it could cut the car’s weight and boost fuel economy."
 
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