If Honda’s dual clutch, which will debut on the new VFR, got your attention, how about a V4 with unequal front and rear cylinder spacing plus cylinder deactivation? These Honda patent drawings show the layout of their new engine with the front cylinders widely spaced and the rear closer together. The connecting rods are mounted to the crankshaft with the rear cylinders both connected to the inner side of each throw, the front cylinders both mount on the outside.
According to the patent, turning cylinders on and off causes a number of problems with temperature cycling and engine vibration.
This part is a bit confusing, is there a space between the front cylinders?
When the cylinders in the front bank are arranged on the opposite end sides of the crankshaft, running wind can be made flowable rearwards from a central part of the front bank so that the running wind is also allowed to flow to the cylinders in the rear bank located rearward.
Say again? It seems there’s a gap and they want the air to flow to the rear for cooling. Of course, I could be way off base, here, I’m just trying to understand what they said.
Update: Just found this:
Although the full-time operating cylinders are arranged in the rear bank Br in this embodiment, the arrangement of the opening 9 in the front bank Bf as in the first embodiment makes it possible to also feed cooling wind to the rear bank Br. It is, therefore, possible to reduce thermal loads on the full-time operating cylinders while keeping vibrations low. This embodiment is also advantageous in that, when the front bank Bf is provided with the opening 9 as in the first embodiment, running wind is allowed to flow from the opening 9 to the full-time operating cylinders located in the rear bank Br and to cool the rear bank Br.
Wow, got that? Who taught these guys to write?!!
The 2 rear cylinders are more easily balanced if inboard when running as a parallel twin, than if they tried to fire the 2 widely spaced fronts. The front cylinders are shut down by deactivating the valves.
According to the rpm map, it looks like the engine can run with 2, 3 or 4 cylinders depending on rpm and throttle opening. Running on partial throttle and 2 cylinders, fuel economy would certainly increase while all four cylinders are ready and waiting when needed or desired.
Honda certainly keeps their engineers busy. The new VFR is going to be a pretty impressive bit of high tech wizardry. This has the potential for high performance and high mileage. What’s not to like?
nortley says
This sounds like an air cooled engine from the description, is that really so? Not necessarily a retrograde step, but curious in this era.
kneeslider says
From the specific wording used in the patent, it just looks like they’re using all available methods to keeps things cool, even liquid cooled engines benefit from extra airflow. The more I read the patent language, though, the more confusing it gets.
Paul says
Interesting stuff, but it raises another question: why are companies so willing to pay for engineers and computer people, but totally unwilling to hire a decent writer to communicate the ideas and technology that the tech people are creating? From a marketing viewpoint alone, having someone write a legible description of your product would seem like a fundamental first step.
Honda has a well-deserved reputation for technical excellence – too bad it doesn’t extend to the clarity of the writing in their patents. Fortunately, the owner’s manuals for my various Honda motorcycles seem to have been written by someone with a better grasp of the skills necessary to communicate via the written word.
kneeslider says
Actually, most patents sound the same. It helps hide them from casual searchers and makes it unclear what you’re looking at if you stumble on to something they want to hide but need to patent.
Art says
So many theoretical angels dancing on so many technical heads of pins. But then this is the same company that brought us the CX-Turbo, the CBX, oval pistons and the RC166. Plus CVCC and VTEC on the car side. Some ideas translate from theory to practice better than others. But in the end, the KISS principle seems to eventually win out even at Honda. This doesn’t seem simple or elegant solution to fuel economy.
If I recall from college thermodynamics/physics, one of the tricks to maximum fuel burning, hence fuel economy is to keep the combustion chamber at the optimum temperature to allow the leanest mixture without causing other issues. A cylinder which is not being run would cool below this optimal temperature, especially if it is in the front of the engine where airflow is greatest. So at least some of the gains would be lost when re-starting each cylinder as the mixture would have to be richer than optimum to induce firing.
And if this idea controls the cylinders by closing the valves, would it be best to do so at 1/2 stroke so the compression/vacuum cycles would even out, minimizing losses, reducing oil draw past the rings and I’m sure a host of other unforeseen glitches?
To me this looks like a patent designed to cover remote possibilities, rather than lock-up breakthrough technologies, solve any real-world requirements or end up in production any time soon. That might help explain the confusing language, an often-used patent-filing tactic to try for the broadest interpretation if making a “prior-art” claim on another manufacturer down the road.
Chris says
So lemme get this straight (and this sort of goes along with Art’s comment): if I build a V-four that has wider-spaced cylinders in the front, I can’t actually sell it for the next 17 years because Honda has patented that design?
I trust Honda to get the cylinder deactivation thing right, since by most accounts it was pretty much transparent on the Accord Hybrid. It’s not like they had no experience with this sort of technology before. This new VFR is shaping up to be a fairly interesting motorcycle from a technological standpoint. I’ll be very interested to hear what the bike rags have to say about it after riding one.
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todd says
I always hear bikes running around with low-tech cylinder deactivation – it’s called bad plugs, maladjusted valves, unsinc’d carbs…
Patent language is an art. It is designed to be so ambiguous that any bit of it can cover something you didn’t think about in a future infringement suit.
The cylinder spacing concept is interesting. Yes, you will experience less vibration and crank flex when your connecting rods are closer together. BUT the ones that are closer together are the ones that run at partial / low throttle applications where there is less force available to flex the crank and cause the vibration to begin with. Then the other two, widely spaced, cylinders are the ones that come on under hard acceleration; the very two causes of crank flex induced vibration…
Art, with modern fuel injection and extremely high atomization of the fuel ideal ignition temperatures span a wider temperature range. Likely, Honda will run the coolant through the rear cylinders first allowing it to help keep the front two up to more ideal temperatures.
The cooling air is used primarily for the cam covers, not the cylinders.
This is interesting technology. Sure, it adds a ton of complexity and cost but as Hoyt points out, it adds that to a bike I wouldn’t buy in the first place. To me, the best way to get to increased efficiency is to ride bikes that run closer to their peak torque output at your desired speed.
-todd
Joe says
if they’re so keen on the idea of cooling the rear cylinders, why not just flip the engine around and have the new “front” run all the time? You still get a closely spaced parallel twin up front, with some extra cylinders along for the ride. The rear ones run less, so need less extra cooling. And besides, with that original setup, there’s no place for that incoming air to go. It seems like it would just sit in a hot eddy between the front cylinders, trying to escape, but being blown back in, defeating the whole purpose of that stupid gap.
kevin says
I’ve heard this system in action! Cornerworking turn 2 at Laguna Seca for the 2008 AMA Superbike races one year ago, I was baffled at the sound of the two factory Honda CBR100 superbikes. As they were entering the turn with throttles closed, they sounded just like the Ducati! As soon as the trottles were opened mid-corner, the familiar 4-cylinder wail returned.
I knew they were doing more than just killing spark & fuel on decelleration, that makes the bike sound like crap, not like a ducati.
How do they de-activate the valves?
Simon says
When deactivating the cilinders they probably close the inlet and open the exhaust. You don’t want compression in the ones you’re not using. The same principle works quite well in cars, GM uses it in some of their engines.
A friend has a Chevrolet Avalanche, which gives a quite respectable milage for the size and power of the car.
In superbike racing they might do it to get less engine-braking, that way you don’t need to burn the clutch while braking. Slipper clutches aren’t the most elegant solution.
Paulinator says
Cylinder deactivation thru fuel, spark and valve manipulation still causes sucking and blowing losses, along with sliding friction from the rings. Has anyone watched an Iron-Worker (punch-press) couple and de-couple its flywheel on demand for every hit? I’m thinking about the Ariel Square-four x 2.
Niki says
Slightly off topic but.. I often read about a patent that somebody has spotted. How do you discover what is being patented? How can you search to find a patent under application?
MikeC says
Niki,
I once had a job searching newly released patents for interesting ideas, which we could then develop and market. Searched 8hours/day 5 days a week for 7 months. Found all sorts of interesting things. Most not practical for commercialization.
Remember, just because someone patented something, doesn’t mean they will capitalize on it, or even maintain the patent. If the patent isn’t maintained (ie: paid for yearly) it goes dormant. If the fees are not paid, it can be bought by someone else. If no one else buys it and depending upon the jurisdiction it will turn open, or public information. As for patent pending, again depending upon jurisdiction, it is safe from publication, hence not public until it is issued as a patent, or 18 months, whichever is lesser.
Shawn says
Honda has typically run cylinder deactivation on its econo car engines using the methodology of keeping all valves closed (as does Mercedes and a few other marques).
By keeping all valves closed, you eliminate pumping losses. The air in the cyllnders acts kind of like an air spring. It takes energy to compress (and there are thermal losses in the process), but returns much of that energy pushing the piston back down. It also helps keep the cylinder temps up to address the efficiency issues someone else mentioned.
George Catt says
Honda and other companies have been doing cylinder shut-down tech. for years. Cadillac had the first production version (remember the 4-6-8?) It wasn’t successful but the basic process remains the same.
I trust Honda to get it right on a motorcycle and I’m anxious to see the finished product.
Scotduke says
I expect the technology is a whole lot better now than when Cadillac tried the cylinder shut down feature in the 80s. BMW has been offering it for some years on its cars.
Paulinator says
Thx for the explanation Shawn, et al. I would suspect that they blip the valves a bit to keep slightly positive pressure. Otherwise I think that oil would migrate to the wrong side of the rings to foul plugs and play havoc on emmissions.
I watched a show the other night, about a high-tech diesel ship that could shut down individual cylinders and change them out in 6 hours – on the fly.
Hugo says
One of the biggest advantages of the rear cylinders is they are much smaller then a “normal” V4 so the frame will be smaller at the place where it counts the most, around the knees of the riders. The whole bike can be smaller (almost like a V-twin) creating a smaller frontal area hence a higher top-speed (and maybe better controllable) It is funny the idea hasn’t been used before…
Art says
Niki, there used to be an US-gov’t contracted online facility that allowed free look-up of granted patents, and at one time even some applications not yet granted. I haven’t looked at it in a few years and the specific providers had changed a couple times in the five or so years before that. And yes, writing patents is as much artform as about technical knowledge. Sometimes leaving out details can help you defend a patent by widening the scope, sometimes defeat your defense by not being comprehensive enough. But in any case, it takes big money to defend a patent, and you must defend against all infringements withing the jurisdiction to maintain control. There is an entire business model based on scooping abandoned or poorly/inconsistently defended patents.
But back to this “economizer” embodiment, seems a lot of complication for what is most likely a small percent reduction in fuel consumption. It may be that Honda is actually looking at power delivery/rideability advantages as much as fuel savings, an extension of traction control technology?
Rat says
You ask “Who taught these guys to write?!!” I’m assuming it made sense in the original Japanese, but when translated to English it turned into gobbledygook. Doesn’t matter, even if the patent narrative doesn’t translate well, I think the power and performance of the V4 will speak to riders regardless of language.
Niki says
Mike C and Art, thanks for your comments.
Patenting certainly does see to be a funny affair. Sounds like a minefeild to cover something.
Tim says
Just ref the choice of wording, please note its a patent document, not a marketing document. They are all written in that confusing lawyerish way, and its done to provide as much coverage as possible in the description of the idea.
Unless you have read a few before, everyone has a hard time understanding them. They are also usually written by patent attornies too, not engineers.
tim says
wait, whut? Has it got a front mount rad? if so how does “Cooling air” get to the rear cylinders. Unless it has side mount rads like an RC-51?
Bob Nedoma says
I wonder, has anyone patented the wheel yet.??….
So, what will happen to this motor after running in city traffic (year round) 85% of the time in the two and three cylinder mode?
The Phantom says
Hugo writes: “The whole bike can be smaller (almost like a V-twin) creating a smaller frontal area hence a higher top-speed (and maybe better controllable) It is funny the idea hasn’t been used before…”
Hugo, throw a leg over a VFR750 or VFR800 – they don’t make the most of the two-cyclinders-wide layout, but they are a lot narrower between your knees than your average I4 (MV’s F4 doesn’t count as it’s as narrow as a 916!).
That V4 layout looks to me like what might be inside the RC211V’s 990cc V5 – rumoured to have one cylinder smaller than the other four which were the same size. That V5 itself was largely based on the RC45 power plant. Which, to round things off, became the 1999 VFR800 motor after they swapped the 360 degree crank for a 180 degree crank.
In a nutshell, Honda has a fair idea of what they are doing here.
Nicolas says
If you space out the 2 front cylinders a little bit more, you can even fit the 2 rear cylinders in between … and get a 4 in-line 😉
sirboomdotcom says
They write them confusing because then it’s easier to hang up in court in a patent suit.