The future of tractor design

[davehowell]

Check this out....

Cat | D7E Track-Type Tractors | Caterpillar

 

[davrow]

It's kind of sad. I've been driving an EV for 11 years. All that time EV drivers have been battling the misconceptions and prejudice that most people have. But the fact is that electric is better than gas/diesel alone. I will admit batteries are hardly any better than decades ago and are way past due for a breakthrough.

But for tractors the diesel generator/electric drive is a match made in heaven. Unfortunately heaven doesn't export them!

 

[GManBart]

But the fact is that electric is better than gas/diesel alone. I will admit batteries are hardly any better than decades ago and are way past due for a breakthrough.

Right, spend $100K for a new Tesla S with the upgraded 85kWh battery, and you can drive all of 265 miles before you have to let it charge for 8+ hours if you have the right connections, and 50+ hours if you just plug it in a normal house circuit with 120v. I don't see that as being better than gas/diesel.

When they improve the batteries, significantly, maybe they'll be better than gas/diesel.

 

[beemerphile]

Once again, the sustained power requirement does not lend itself to battery driven tractors - at least with current technology batteries. A Diesel-electric tractor or a diesel-hydraulic tractor or a diesel-geared tractor is still a diesel powered device. Whether the diesel engine is used to create hydraulic pressure and flow, electric voltage and current, or direct rotational force does not change that. The tractor needs to turn wheels and operate implements and attachments. In this scheme, past how they move the tires, the geared and hydraulic (hydrostatic) tractors are the same - they use hydraulic power. The Cat D7E uses diesel-electric for the prime mover, but still has significant hydraulic power. The diesel-electric I envision would be different. I am looking for the improvements I saw in the all-electric injection molding machines...

1) Leak free
2) Quieter operation
3) Higher efficiency
4) Faster and more accurate positioning
5) Infinite adjustment of speed, position, and torque
6) Facilitation of enhanced coordination and control capability
7) Higher reliability and uptime (this was quickly observed with all-electric molders)

 

[Fossil Farm]

I believe the "Big Muskie" shovel that removed overburden to get to the coal seams in SE Ohio was electric. At the time, it was the largest shovel in the world.

 

[Danny C]

I am a retired engineer and have spent many years around hydraulic production machinery - particularly plastic injection molding machinery. Towards the end of my career most of the machine companies were tending towards fully electric machines rather than hydraulic. The advantages were numerous. Electric presses can now provide hundreds of tons of pressure. The machines are fast as a cobra and almost totally silent. A conventional molding machine sounds like a hydrostatic tractor. I got to thinking about whether an analogous trend was possible with tractors. Servos replace cylinders. Stepping motor drives replace hydrostatic drives. Transmissions become unnecessary (which was the main objective of the diesel-electric locomotive many years ago). The tractor's motor, rather than turning a large hydraulic pump would be direct-connected to a large electric generator. Individual electric wheel motors would allow computerized differential speed at each wheel during a turn to minimize wheel spinning or turf damage. Four wheel steer, crab-steer, or anywhere from one to four wheel drive are easily implemented. Self-leveling a loader would be done by programmed control. An implement could be programmed to lift or stop during a turn or reverse maneuver. PTO's could run at constant speed, set to any desired speed, or could be programmed to follow ground speed.

Intriguing thought. One that would work. Could one match a smaller engine to generator and produce similar results? Regardless, one could use it to generate electricity when power was out. Easy to fix. Effiecient. Problem is getting folks to change from mechanical machines they understand to a new technology although it's only new in application.

 

[kirkawilson]

Here is the first 'hybrid' ATV/Lawnmower on the market from Lowe's; the Raven. They had to remove it from the market last year due to operational and safety problems. But, I could envision a similar tractor with electric plug-in attachments using high-power electronics and variable speed drive motors for all rotating parts including the wheels. Much of the current development is working to solve the electronic cooling requirements for the power electronics.

Raven mower, rider, and generator at Lowe's (1 of 2) - YouTube

 

[Industrial Toys]

Am I wrong in assuming that the Diesel Electric Configuration in railway locomotives was conceived to control and put a large amount of tractive effort to the rails? What would be the point of this, in a tractor? There is no issue coupling modest amounts of power to a tractors wheels. Do you know how much switchgear and control equipment is in a locomotive? I don't. But I assume it is extensive.

Curious. Does anyone have any experience with those electric, rechargeable push mowers. I always see them at Habitat for Humanity, Restore (Returns from Home Depot). Not a good sign IMO!

 

[GManBart]

Curious. Does anyone have any experience with those electric, rechargeable push mowers. I always see them at Habitat for Humanity, Restore (Returns from Home Depot). Not a good sign IMO!

My father-in-law has one, and loves it....small yard, so I'm not sure that means much.

 

[DeereMann]

Well, the mine haul trucks do that today. There are both mechanical & electromotive variants. What the industry is finding is the electromotive variant has higher total cost of ownership compared to mechanical, so haul truck makers are going back to all mechanical & hydraulic drive. The big reason is contamination - mines are very dusty & dirty. Oil can be changed, motor bearings not so much.

Caterpillar is the biggest player that changed back within the past decade.

Train locomotives are all electromotive - but for other reasons. They not only run in clean environs, but they use the generator as a motor heat sink brake going down mountain slopes. That and infinitely variable torque for acceleration control. That used to be very expensive, but they recently changed over from rectified DC motors to VFD AC motors, and the cost has come down.

I don't see it happening for mobile equipment much for the same reason as mine haul trucks - dirty environments (especially mowing, etc) and high initial cost.