[speed0mania]

Hi guys, finally putting up a thread on my final year engg. project! A year later as i didn't get the time right after it due to exams!
The background! Sorry mods gonna go a little off topic here!

My idea was to keep everything as simple as possible! Spoke to a few guys from the reputed colleges of India who had taken up such projects, and made nothing but a dual powered fancy looking four-wheeler, upon asking why they didn't make it a true hybrid and use both sources of power in the same drive cycle, i was told " You need a torque coupling for that and it costs lacs, would've messed the budget up big time"

I wanted to laugh on the guys face even though i didn't have a solution to it then and my project was nothing but lots and lots of ideas in my head, i knew there had to be a simpler solution, if nothing solenoid actuated clutches(not the best option but yeah wouldve done the job.

Now after me and my friends decided that it had to be a very basic vehicle with maybe a ladder chassis. then came the first eureka moment for me, why not make a proper gokart, its fun and solves our purpose beautifully!

Then we set out on a search for parts for the same and visited go kart tracks in NCR, collecting little knowledge and contacts for parts.
Then one fine day I reach college and see my friends in deep discussion, i was glad to see them probably working on something related to the project, but was sadly informed that they were all backing out and wanted to go buy a project instead as they said they didn't get what was going on and i was being toooo optimistic with only 2 months left for submission and exams right after that!
I don't think i was this upset even after my 1st GF left town! lol
Well my dad being my pillar of support and sharing my passion came upto me and asked me if I can do it alone? and how much would it cost? i told him Im sure i can do it! But the only issue is spending around 60K on my college project sounds crazy and my college isn't willing to sponsor the same, they were too reluctant as they were already sponsoring an ATV project.
I was given attitude like "Complete it and then we'll consider it"!
Well my dad was supportive and kind enough to fund it!

So began the journey!!
Well after having finally found a guy who had made a few lots of gokarts, replicas of one he had imported, I bought an old briggs&straton 6HP engine, centrifugal clutch wheels, steering seat rear axle, etc.
I started welding together the chassis!
Still thinking of a better idea for the switchover of power. then it came to me literally a bell rang, it was the bell of a cycle, I ran downstairs and checked out a cycle, that was it, A freewheeling hub ! thats all i required! Eureka moment 2 ;p

It cuts off the DC motor when the engine rotates the axle faster than the motor is! much like peddling slowly while coming downhill on a cycle!

Well the CAD drawings and search for a decent freewheel ensued, finally settled with a cycle rear sprocket itself!

Well thats the begining pics and progress follow:-

[speed0mania]

Targets:

· To build a working model to show how hybrid technology works.

· To keep the design simple and cost effective.

· To make the electric system self-sufficient that is, there should be NO NEED FOR EXTERNAL CHARGING of the battery. As external charging merely shifts the fuel consumption from vehicular fuel to power generation fuel.

· To make it possible to run the vehicle on either source of power independently in case of any failure.


Driveline concept:


Two parallel chain drives are used for the transmission of power, one for the engine and the other for the electric DC motor.

[speed0mania]

Engine drive: A centrifugal clutch is used at the engine crankshaft so as to facilitate idling of the engine. The driving sprocket is mounted on the clutch and the driven on the axle. A reduction gear ratio of 4.5:1 (aprox.) is used so as to reduce the speed of the wheels without loosing torque, while maintaining sufficient traction on the wheels and also to ease off switching of power.

DC Motor drive: A reduction gear ratio is used between the motor and axle again to keep traction, but the sprocket on the axle uses a FREE WHEEL to mechanically disconnect the electric motor from the drive when the engine is driving the axle, so as to protect the motor from any undesirable load.

The free wheel is a ratchet and pawl mechanism, which allows the outer wheel to rotate freely in one direction and locks the inner wheel with the outer in the other direction.

This works on the relative motion between the two wheels hence when the inner wheel (axle) is rotating faster than the outer sprocket it rotates freely without any load on the motor, but when the motor rotates the outer sprocket it locks the inner wheel to give the drive to the axle. This mechanism is similar to that used on a bicycle, when forward motion is given to the pedal it rotates the rear wheel in the same forward direction but when going downhill or moving due to inertia of motion there is no load on the pedal.

[speed0mania]

The selection of the power source is preset and is a function of the pedal feed provided by the driver. Initially when the pedal is pressed the DC motor brings the vehicle into motion and accelerates up to a preset pedal position after which the engine is accelerated which leads to the centrifugal clutch connecting the engine to the axle and powering the vehicle for further acceleration.

This is done by leaving the engine throttle wire with slack, for it to have sufficient tension only at the desired pedal position.

A foot pedal dependant system was used as it makes the driver a kind of a feedback system, as, when more power is needed such as on hill climb the driver would press the pedal further until sufficient torque is transmitted to the drive.

[speed0mania]

The chassis was built from chrome-moly alloy steel rectangular tubing; chrome-moly is a high strength steel with Chromium and Molybdenum.


It is specified when strong, lightweight structural integrity is required and is frequently used in the aircraft industry, for racecars, motorcycles, bicycles, and for industrial equipment. This high-strength steel is easily fabricated and welded. It can be subjected to mild hardening and nitriding for additional wear and abrasion resistance. Gauge 10 sheet was used for making the floor base on the tubing frame. It was built in accordance to a tested design, as go kart chassis design is complicated because it has to twist in parts so as to compensate for the lack of suspensions and to facilitate turning. The go-kart chassis is in many ways quite similar to a tractor chassis, it has to incorporate the lack of suspension and facilitate turning, it can be driven without either one of the front wheels.

[speed0mania]

the standard crank pulley used with the alternator (M800) was used after modification for it to fit onto the smaller crankshaft at first but then mounted onto the centrifugal clutch itself due to the failure of the shaft extension made.

A type “A” V-belt is used to transfer motion to the alternator from the crank. A pulley ratio of 3:1 is used to produce sufficient speed for the alternator to give enough current output.

[speed0mania]

After the chassis was built and other parts collected:-
· The assembly of the kart started similar to a normal go-kart.

· The engine was overhauled; the piston rings were replaced, valves ground, oil filled, etc. Once the engine was running it was mounted onto the chassis.

· All steering brake and power transmission parts were fitted.



· A hub for mounting the freewheel on the rear axle was fabricated on the lathe, giving a keyway to transfer rotational motion.



· The driven sprocket was fitted onto the freewheel with the help of a disc again fabricated on the lathe.

· The Dc motor was mounted on the right side right behind the seat, care was taken to keep the shaft parallel to the axle and the motor fixed firmly in its place.

[speed0mania]

The DC motor used was a 1Hp starter motor from an ambassador!
The alternator is a Maruti 800 alternator!
The speed controller was chucked due to high failure rate and a constant speed was chosen with a relay!

Finally achieved it in time !
My college wanted to sponsor it once it was ready and done with but I had decided, that I'm going to keep this with me! ITs my TROPHY, my accomplishment, my pride, my statement to all those who doubted me through the journey!

[gd1418]

Can you post a full pic of the creation?

[speed0mania]

sorry forgot that!! lol
here you go! its tooooo dirty in the 1st one!! got it out of the garage after 4 months and got it running!

[naveen.kk]

Great Effort....

Atlast you have done what you had in your dream.

That would be better if you can add more spec, and advantages of the project.

[srijit]

Wow, Dhruv. This project is amazing. To think that you spent only about 60K and made a fun go-kart.
Thank you for sharing the details.

[gd1418]

More than a Go-kart, almost looks like a F1.. So it is a rear wheel drive. Since I don't see any pedals, all controls are hand operated?

Dhruv, are you from DCE or IIT-D? Just wanted to know if the entire fabrication of your project was done in-house or certain things were fabricated outside the campus?

[phamilyman]

Awesome project man. You've surely done justice to a final engg project unlike 99% of us!

[speed0mania]

thanks guys! @ gd1418 buddy it does have pedals like any other go kart, one accelerator and one brake.
I'm not from either of those esteemed colleges unfortunately and thats one of the reasons why it was such an uphill task!
All fabrication was done outside!!! no help from college, I travelled from NOIDA (the only decent machine shop i found) to Chhatarpur everyday!! my car was a parts store!
My friends used to make fun saying that theres enough stuff in this car 2 build another one if it broke down!! lol
True though

As for the specs let me compile them:-
IC engine: 6Hp Briggs&straton
DC motor: 1Hp TVS-Lucas starter motor.
Brakes: Single Disk on rear axle.
Steering: basic linkage type steering (ackermann geometry)
Total weight: 150Kg aprox never really weighed it.
Battery: Bosch 50Ah.
Limit switches used to start and cutoff DC motor at pedal positions.

The car starts to move on the DC motor and when more power is required the engine takes over.
Transition is smoother than i expected no jerk at all!!
All in all its a fun Drifter ! love drifting around on it , just wish it had enough power to do donuts