it's all about gears!
 

Drove my gf 2011 Lexus RX 350 for several days this week.
It has an 8 speed automatic transmission.

What a difference compared to the Kia's 5 speed automatic tranny.

Given my personal experience w/ upsizing to lower rpm and the joy of driving an 8 speed, I can't understand why the industry has been so slow in increasing the gearing in their eco-models.

I remember the 1984 corvette had the first 6 speed and got 27mpg on the hwy all day long.

I really thing 6-8 speed auto trannies are the secret to improving mpg.:thumbup:

Auto's have come a long way, that is for sure. My gf's 1999 Sunfire has a 3-speed automatic for crying out loud. That thing is terrible.

You don't need all those gears to get good MPG. The reason they keep adding gears is because the more gears you have to use from 0-70 mph, the less RPMs have to build up to satisfy the average driver's need for acceleration. Lower RPM = higher MPG. It all comes down to building technology that forces drivers to improve their driving techniques.

Why 6-8 gears?

A stout, reliable CVT would have infinite-gearing possiblities, so would (theoretically) be better. Take your pick: cones, belts, planetary gears, etc.

Despite being a BIG Infiniti guy...I know nothing about the cvt trannies:o

I'm with you on the CVT. I love driving the wife's Civic Hybrid. No jerky shifts, when I'm cruising it never goes above 2k rpm except up hills and I think they are just plain fascinating. I don't know why more companies aren't using them.

CVTs basically are two pulleys with a connecting belt. Both pulleys are adjustable as far as width. One pulley gets wider as the other gets narrower thus changing the ratios. Although the ratios are infinite between the two extremes there is a limit as to how low and high the ratios can be.

My invention is much closer to an infinitely variable transmission. Theoretically the top ratio could be almost infinite, then zero (neutral) and reverse, by changing the stroke position alone, no clutch or torque converter, your start in a super high ratio then reduce the ratio (in milliseconds) to get moving and reverse the stroke, which has to go past neutral to reverse which reverses the flow of fluid in the high pressure circuit and is captured for future acceleration events.

US#7677208 the full document is on the web.

http://www.google.com/patents/US7677208

regards
Mech

8?!?!?!? And I hated 4 speeds as they often hunt between 3/4.

+1 on the cvt and ecvt. I never find myself between a gear too high or gear too low. I also like puzzling my passengers as to why my car never shifts gears. :eek:

remember it is an automatic.
It actually shifts effortlessly. and when I'm on the freeway and need power....it just goes!!!!
never feel the downshift.

reading a review about the new Cherokee with teh 9 speed. they said they never saw it engage 9th and that it doesnt even come into play on the EPA cycle (has to be down hill, low throttle above 70mph or something rediculous)

so maybe we've hit the limit of # of gears?

To be HONEST, I was (previously) NOT a CVT fan, however, since getting our '14 Prius with eCVT, I've sudden had to learn MORE about them, and, in-the-process, have become to believe they're definitely OK...especially, the eCVT, in this Prius.

Instead of the normally thought-of dual "cones & belts" CVT, the eCVT is actually a planetary (ring, idler, and sun) gear arrangement, so the gear 'teeth' are ALWAYS engaged...so, unlike the "cones & belts" system, physical "slippage" is totally NOT possible, unless something is broken.

The PriusChat (PC) forum has a neat animated illustration of *how* the eCVT works:

• PC thread: http://priuschat.com/threads/toyota-...ission.127864/

• animation: http://eahart.com/prius/psd/

• CVT history: http://groups.engin.umd.umich.edu/vi...Miller_W04.pdf

Compared to my parent's RX350 which is really good at shifting their older 4Runner with a 4-spd is sluggish at slow speeds trying to shift. It just sounds terrible when it soudns like it's trying so hard to get into 2nd or 3rd I wish it wold just shift sooner.

Fewer gears + better ratios FTW.

"2-speed slush-boxes" and "3-on-the-tree" for the nostalgia (FTN)!

No- fewer gear meshes for lower transmission friction losses.

Dynaflush/PowerGlides be damned!

Drove Chevy 2 speed autos for years. Of course gas was about $.25 back then...

OK, Powerglides were not what I had in mind.

A two speed Lenco then?

Sounds like aero mods would REALLY help it out. Lower drag and a higher gear.

You can trick the transmission into shifting earlier, and thereby reduce the high revving by momentarily backing off of the throttle.

I've found the minimum speeds at which the Camry will cruise in a tall gear, and when I approach these speeds, I cut the throttle to about half and the car upshifts. This all takes about 1 second, and then I get right back on the throttle to continue accelerating at about 85% load.

The '98 Camry I'm driving seems to have 4 gears with a lockup TC at the top end. It's far and away more efficient at cruising than the 6-speed manual on my Acura. The Toyota does 2000 RPM at 55mph compared to the Acura's 2400 RPM.

More gears isn't necessarily better, and there are diminishing returns on each additional gear. The goal is to keep the car in the ideal RPM range for producing peak torque while accelerating, with a sufficiently tall top gear for cruising at high speed.

The eCVT does appear to be the superior transmission, but even that has some limitations in regards to efficiency when it comes to protecting the MG (motor/generator) unit from over-revving. These limitations cause the plug in Prius to have a top electric-only speed of 62 MPH.

I also consider the CVT a good option, but finding one suitable to a high torque load is not so easy.

You are showing your age now :)

Mom @ 75 remembers the days of filling her 1965 Buick Wildcat Convertible with Hi-Test at .29 a gallon :)

Since a Lenco is based of a GM TH400 setup...

My mothers parents own a gas station/ inconvenience store near the NC/VA boarder. She paid 0 for gas as her parents gave it to her. :D She also had every muscle car you see on the power block tv show on spike. To her it was just a car to get from point a to b and once it hit 100 thousand miles she sold them for a few hundred of dollars and daddy took her to get another NEW CAR. She even owned the el camino as well as the dodge version. Cant remember the name. Frequently as I watch power block, fast n loud and other car shows she tells me she had one like that, but it had duck fins or something. :confused:

If you knew where to go, you could find .19 gas just out of town...and every kid knew where :)

Also transmission efficiency...mechanical CVTs have pretty big losses. I love how CVT cars drive though, no surprise shifts, put your foot down and it goes to the optimum rpm instantly.

I don't understand why some people here don't like more gears. I think 7 is the perfect number, more than that is a little strange. On a Yaris/Fit you have extremely wide spacing for 5 gears, but the cruising rpm is unacceptable and taking off in 1st would be horrendously difficult on a hill if you were to decrease the final drive ratio 20%. With 6 gears and a small engine you can get a good cruising rpm, but engines over 2.4L you would want another gear as can be seen with 6 speed Accords and such.

The 2.7L Porsche 9A1 engines connected to a PDK can get over 40mpg cruising in 7th gear at 65mph, where the engine is only spinning at 1850rpm. Gears 1-6 are like an older "sport" transmission in terms of gearing range except you have 6 speeds instead of 5. If you were to do this with 6 speeds keeping the cruise gear you would have an extra 2 big rpm drops between gears which is unpleasant if you're driving stick.

This a new system I would love to see in the our future vehicles.:thumbup::thumbup:http://oi55.tinypic.com/34sh3cm.jpg

1
Description

This invention relates to an improved method of converting input torque to output torque in a multi stepped gearbox and recovering energy from and applying energy to a power train.

The unit can be part of a conventional power train, a hybrid power train a kinetic energy recovery system or a full electric power train.

Conventional hybrid power train systems and kinetic energy recovery systems use a gearbox to transfer torque from the main input source, which is usually an internal combustion engine, to the output, torque from the gearbox goes to the drive axle or axles and additional gearing, transmissions, shafts and clutches connect a variety of electric engines and torque multipliers to this primary power train to harvest and apply electrical energy. The electric shift energy recovery unit (ESERU) here described needs no additional external components; with an electric control unit and an electric energy storage device it comprises a complete hybrid system or a kinetic energy recovery system.

The ESERU is a multi ratio stepped gearbox, suitable for vehicles and other torque transfer devices, comprising a number of gear sets
Figure: 1 (1-6), which can be selected independently or in combination, gear changes are made using electro magnetic energy eliminating the need for mechanical, hydraulic or pneumatic clutches and synchronizing assemblies.

The outer component of each gear set operates as a rotating part of an electric engine, using magnets embedded in the outer circumference of the gear set components (1-6) and the static parts of the electric engines (7) which are built into the gearbox casing (16). Electric energy is used to accelerate, decelerate and position components in the gear sets, to allow them to be unlocked or locked with electronic lockers (13), to facilitate the conversion of input rpm to output rpm, controlling the timing of the application of electrical energy and the force, produces a constantly variable and efficient transfer of torque from input to output of each gear set, giving a true seamless shift between a ratio of 1:1 of any locked gear set and the mechanical ratio of the gear set unlocked.






2
The electrical engines recover electric energy to storage from the power train during deceleration and apply electric energy from storage to the power train during acceleration and cruise and/or when electrical power transfer is demanded, eliminating the need for extra gearing between the electric engines and the power train in hybrid, KERS or electric applications and supply the required electrical power for gear changes in all configurations including conventional or full electric application.

Initial transfer of torque, to achieve propulsion and establish inertia in either rotational direction of the single output shaft (14), is achieved by applying electric energy to the electric engines of the gearbox, if another external engine is required to apply torque to the power train after inertia is established, the outer component of the first gear set (1), is brought to stationary using electro magnetic energy and electronic lockers (13), lock this component to the gearbox casing (16), the external engine is then capable of applying torque through this gear ratio to output.
Gear changes between gear sets is achieved by unlocking the engaged gear outer component from the gearbox casing (16), accelerating the outer component using electro magnetic energy, established component inertia and control over the input torque source, to bring the complete gear set to a common shaft rotational speed, locking this gear set, unlocking the next selected gear set, decelerating the outer component of this gear set to stationary, using electro magnetic energy and locking this component to the gearbox casing (16). A wide range of gear ratios and ratio combinations is made available using this operating method and torque application to the power train from both the gearbox electrical engines and an external engine is made available to output over a wide and efficient range.

The ESERU gear train comprises a variable number of planetary gear sets Example: Figure 1 (1 – 6), any one of the three components comprising the gear sets (8,9,10), can be chosen for torque input, any one for torque output and the remaining component locked stationary, giving a wide range of available ratios from a wide range of possible configurations.
The casing lockers engage with slots (18) on the outside of each gear set and the lockers within the gear train engage with corresponding slots in adjacent components. When a sun gear needs to be locked to the casing to achieve a gear ratio, a locker within the static support tube (18) is used.

3

The static tube is an extension of the gear case (16) and forms the main gear train support.

Example of engaged gear set Figure 1: Input from engine (12) through input shaft (11) and first gear sun gear (10), drives planet gears (9), which are forced to ‘walk’ around crown wheel (8), which is locked to the gear casing Figure 2 (16) by lockers (13), the output of the first gear planet gears (9) drives the input sun gear of the second gear sun gear (17) via the first gear planet carrier.

When not selected for use, the gear sets are locked together as one unit with no relative gear motion, giving zero gear torque loss at a ratio of 1:1 input to output, in direct top gear the complete gear train is locked at a ratio of 1:1 input to output, producing no gear torque loss from the complete gear train, the torque output shaft Figure 1 (14) drives the vehicle through a drive axle (15), or other torque transfer device in all gear combinations.

A sliding locker Figure 3 (19) is provided in most configurations, to allow the selection of disengaged gear train neutral.





4 CLAIM

1. A stepped ratio gearbox without hydraulic, pneumatic or mechanically operated clutches, synchronisers or ratio changing mechanism.
2. An energy recovery and application unit, being an integral part of a gearbox that eliminates the need for additional gear sets and the associated control and installation systems.
3. The electro magnetic operation of a gear set producing a seamless constantly variable change of gear ratios, while maintaining a smooth constant transfer of torque from input to output.
4. A method of torque application that eliminates the need for a direct engagement clutch, by establishing the vehicle or output device inertia prior to connecting a separate torque input device.
5. A gearbox without any relative gear movement in gear sets not ratio selected and in the whole gear train when direct top gear 1:1 ratio is selected, resulting in very low torque loss in use.
6. A hybrid gearbox unit that can be configured to replace most current conventional vehicle transmissions to form the basis of a more efficient, compact and lighter hybrid system.
7. A racing car gearbox including integral energy recovery and apply components, without the need for external gear units or electrical engines, making the unit lighter, more compact and more efficient for KERS applications and installations.




5


Abstract

Electric Shift Energy Recovery Unit

A gearbox unit including integral electric engine components 1-7 which are used for operating gear changes and for recovering electric energy from and applying electric energy to a gear train

Figures 1, 2 and 3 to accompany abstract[/quote]

Source autogyro's Transmission Concept - Forum - F1technical.net

During the Eisenhower administration I remember 12.9 cents a gallon at an ESSO station, a few years before I got my learners permit at 15 years 8 months in 1966. Our telephone number was PA 33471. 19 cents was best price after I got a license.

regards
Mech

I can remember gas wars in the 60's just outside of town prices got down to 11.9 Cents a gallon, lowest I ever saw it that I can remember. It was usually 18 to 22 cents a gallon, fill-up for 2 to 3 bucks. :thumbup:

I think three or four gears in a manual box, with top "gear" being direct drive feeding to a final drive tall enough to negate the need for any overdrive ratios is perfect- as I've said before, fewer gear meshes = less transmission losses. But then I'm a flatlander who's not particularly concerned about extracting maximum acceleration from my vehicle.

so true mcrews
 

I'm so much thinking the same way about gearing!! upsized tires on my car 1.5 inchs higher than stock enjoying the lower rpms on my drives.

In 1968 my 59 AH Sprite was good for a penny a mile. Today the bike is 4 pennies a mile.
84 sentra diesel 4 speed epa was better than the 5 speed.
regards
Mech

I loved my GTO's 6 speed manual. 1st-4th were meant as the power gears, 5th and 6th for mileage (both were overdrives). 4th could go up to 130MPH, and 6th would do 75MPH at under 2000RPM and still pull quite nicely.
I don't really care how many gears there are, just as long as they provide adequate acceleration and a top gear that is as high as the engine can reasonably handle.

The problem is that nowadays the manual transmissions are getting the ratioes too close, more focused on a "sporty" feeling than in an overall efficiency. But who says a 4-speed would gonna be less "funny" than a 6-speed, right?

Anyway, less gears with better ratioes actually improve both the reliability and the fuel-efficiency, since there would be less clutch wear (due to a lesser amount of gear changes required for the engine to operate in a reasonable speed), less internal frictions in the transmission, and a little lighter weight. What would be so bad about a 4-speed in, let's say, a Corolla?

don't mean to get snarky.....but what you just said flys in the face of what the industry is doing.
And even though the industry is full of untrained and uneducated idiots, could you please show some FACTUAL PROOF of what you are saying....


(because an 8 speed Lexus automatic transmission is good for 150-200,000 miles)

more idling gear meshes is an issue w/constant mesh transmissions, true, though with computer precision doing the actual engagements, I think sliding mesh should be revisited.

more gears=more clutch wear? nah. If you get a lower first gear out of the deal you will actually save more clutch as getting rolling is where the wear is at normally (and where %100 of the wear is at if it shifts automatically).

Exactly, gear changes are extremely easy on the clutch compared to starts and closer ratios could mean less clutch wear per shift.

I think the idling gear meshes could be mitigated with smarter oiling. As I understand a lot of transmissions have the gears completely bathed in oil. Even if that's wrong, I don't think idling gears consume much power, and the weight penalty isn't even that bad. The Toyota C60 for example is only 10 pounds more than the C5x transmissions, which is less than the weight of the extra clutch packs and pumps of an automatic transmission alone or solenoids in a DCT/SMG.

My driving is half city/stop and go, half highway cruising so I value closer ratios, but people who live further from cities and do more constant speed driving would understandably not mind having less gears as long as the highest gear is good.

Gears are a gimmic, sort of like adding mystery oil to your gas, they have their purpose, especially in terms of lame brain automatics but the reality is that the gains in MPGs that I see between historic WELL BUILT 4 speed OD Autos and these 7,8,9 speeds is that there has been little or no gain. There is obviously a gain but generally the transmissions are coupled with even larger, heavier options. Only place I see this as being good is around town but only if the car will upshift as high as possible.

The key to understand is that what is MOST EFFICIENT, AKA a direct drive manual transmission with few moving parts, is NOT the most efficient at all loads and would also affect acceleration and performance in various bands.

All this said I like having a well designed 5 speed manual with a WIDE set of ratios, a 4 would likely work as well.

I fail to see how that is "good" or applicable to this conversation, all autos I've owed excluding ones that "needed replacement" on purchase of said vehicle have lasted that long, but then again I avoid Dodge and Ford and 80's chevy OD XMSNs.

Lately I won't own autos, exception would be a Prius or a Volt where there is not alternative.

I think it's not a gimmick though. Toyota is pairing the 1NR-FE with a wide ratio 6 speed in non-US markets, and that thing only has barely over 100hp. 5 speeds I can see being okay with a 1L engine or something like that, but a 6 speed makes a lot of sense for basically all US market engines and a 7 speed makes sense for sporty cars with potent engines (e.g. Honda S2000 cruises at 4000rpm, even if you spaced out the gearing like an eco car you would not be running very reasonable rpms).

Obviously this is a fuel economy forum but closer ratios in a manual transmission does make it easier to shift and more enjoyable to do so, and it is also good for performance. More gears is better, if you're talking stick shift. Automatic, I don't really care because I'd rather have a Toyota Hybrid eCVT, or series hybrid, but if the industry thinks 8 speed autos aren't hard to make and are worth it then they're worth it.

I have seen it in some Fiat and Volkswagen compact cars, including the U.S.-spec Fox which retained the same 4-speed gearbox of the earlier versions of the Volkswagen Voyage on which it was based, also retained by the cargo versions of the Gol due to reliability until they were phased out in '96. During the 80s the fuel-saver transmission for the local Volkswagens back here was the 4-speed, in spite of a 5-speed being available at least since '85 for the front-engined ones.