[Aditya]

Mahindra has launched a four-wheel drive version of the Arjun Novo tractor in the India called the Arjun Novo 605 DI-I -4WD.



The 605 DI-I-4WD is powered by a 3,531cc, 4-cylinder diesel engine that puts out 57 HP. It has a 4WD system which distributes power to all four wheels, making it easier for the vehicle to work in all types of soil conditions. It is especially suited for wet land cultivation. It can be used with agriculture implements like tractor-mounted combined harvester, gyrovator, dozer and loader and for primary tillage and haulage applications.

The vehicle also has a synchro-shuttle feature that offers quick forward and reverse movements. A single hand operated lever can reverse the tractor at the same speed. The tractor has a full synchromesh side shift transmission with 30 speed (15 forward + 15 reverse) options. It has a range from of 1.7 kph to 33.5 kph and a lift capacity of 2,200 kg.

The Arjun Novo platform has been designed and developed in-house at Mahindra Research Valley in Chennai.

[jvk84]

I always wondered: why those huge engines with very small power output on tractors and similar machines? what is the advantage?

Why not put a 1.5L engine which can deliver more power, possibly with higher efficiency?

(Anyone know how much torque this motor generates? )

[amit_purohit20]

Originally Posted by jvk84

I always wondered: why those huge engines with very small power output on tractors and similar machines? what is the advantage?

Why not put a 1.5L engine which can deliver more power, possibly with higher efficiency?

(Anyone know how much torque this motor generates? )

Reason for higher capacity engine are:
1) Long Stroke engine required for good torque.

2) Require Good Backup torque of the engine.

Backup Torque= (Max. Torque - Torque at Max. Power rpm)/ Torque at Max. Power rpm

Range of Backup torque is 18-22% Higher the better.

Tractors are normally driven at Constant Throttle position at Max. Power rpm. If the torque requirement is higher than what is available at Max. Power rpm the Engine rpm drops till sufficient torque is available. (Please note here that the torque increases as the Engine rpm drops from Max. Power rpm.) The lesser this engine rpm drop the better its perceived by the farmers. This explains the significance of Backup Torque.

3) For tractor Power requirements are less whereas there is very high importance placed on Torque figures as well as the torque characteristics with respect to Engine rpm.

4) Lower Engine running speeds favor Increased Fuel Economy.

5) Higher the Engine CC higher is the reliability of the Engine as the engine is less stressed.

6) Space requirements for fitment of engine in tractor is not as stringent as a car. So Engine dimensions do not matter much and thus one can go for higher cc engines.

7) Tractors undergo a lot of use and abuse, so the Engines have to be build sturdier and more robust than passenger cars.

[dhanushs]

Im not sure about the Model Number, but a close friend and my neighbor has a 4WD model Arjun tractor bought back in 2011. So, this is not the first and only 4WD tractor from Mahindra.

The tractor is very heavy, not as agile as the 2WD ones (without the trailer), but has solid torque and good road speed. It will pull a fully loaded 10wheeler truck easily provided it has good traction.

[GTO]

Originally Posted by Aditya

The 605 DI-I-4WD is powered by a 3,531cc, 4-cylinder diesel engine that puts out 57 HP. It has a 4WD system which distributes power to all four wheels, making it easier for the vehicle to work in all types of soil conditions. It is especially suited for wet land cultivation. It can be used with agriculture implements like tractor-mounted combined harvester, gyrovator, dozer and loader and for primary tillage and haulage applications.

Brute offroaders, can run through any sort of terrain .

2WD tractors are so capable that I can only imagine what a 4x4 Tractor can do. Torque, big wheels and tyres that just dig mercilessly into the mud. If an offroader gets stuck, the best recovery vehicle is a tractor. Pulls a Jeep out like it's a toy.

[Divya Sharan]

Interesting discussion. I agree that for applications worthy of a tractor, pulling capacity matters more than outright power, but I was expecting huge figures for torque for the 3.5L unit.

Googled about a bit and got some data on another smaller cousin (2WD) from Mahindra.
Mahindra Bhoomiputra 575 DI Tractor - 2.5L, 44 hp and 155 Nm torque @1200-1400 RPM.
Isn't 155 Nm too less for a 2.5L mill? So this 3.5L mill may make 180 or so Nm.

I'd like to know what limits the manufacturers from extracting more power/torque from these machines?
1. Doesn't need more power/torque?
2. Would require bigger engines for achieving the same (keeping reliability in mind)?
3. What are the technical challenges faced exactly, with smaller engines?
4. Do they have the same emission standards as passenger cars?

[amit_purohit20]

Originally Posted by Divya Sharan

Interesting discussion. I agree that for applications worthy of a tractor, pulling capacity matters more than outright power, but I was expecting huge figures for torque for the 3.5L unit.

Googled about a bit and got some data on another smaller cousin (2WD) from Mahindra.
Mahindra Bhoomiputra 575 DI Tractor - 2.5L, 44 hp and 155 Nm torque @1200-1400 RPM.
Isn't 155 Nm too less for a 2.5L mill? So this 3.5L mill may make 180 or so Nm.

Tractors have very high Gear reduction of 100 or above sometimes in lower gears.

This translates to the torque at engine being multiplied more than 100 times before applying it at the wheels. So a lower Engine torque figure should be sufficient for its needs. In lower gears often traction is the limiting criteria not the Torque available at the wheels. Exactly the reason why 4wd Tractors are more preferred over 2wd ones. Its only the cost factor which stops a farmer from going for the 4wd ones.

Lower Torque, Lower Power, Higher CC all help in making a Engine less stressed. The lesser the stress the lesser the need for high strength and costly materials for the engine parts.

Lesser stress also equates to higher reliability.

I think smaller capacity engines will have poor Backup Torque as well as the rpm drop will be too large for the Tractor to work satisfactorily.

Larger rpm drops (as explained in my first post) will lead to inaccuracy in executing agricultural operations.

[Sutripta]

Hi Amit,
I think you need to put in a post about things like side shift gears, planetary reduction in axles etc. And then of course tractor hydraulics. And the range of implements/ attachments available in the tractor world. I think such a post would be appreciated by this forum.

Regards
Sutripta