A CASE STUDY ON POWER TRAIN IN LJM 01 AND LJM 02

CONTENS

1. History2. Maruthi 800 – As a car3. Engine4. Clutch assembly5. Transmission6. Differential7. Air Filter8. Exhaust9. Radiators10. Suggestions

HISTORYMaruti Suzuki India Limited (MSIL, formerly known as Maruti Udyog Limited) is a

subsidiary of Suzuki Motor Corporation, Japan. Maruti Suzuki has been the leader of the Indian car market for over two and a half decades. The company has two manufacturing facilities located at Gurgaon and Manesar, south of New Delhi, India. Both the facilities have a combined capability to produce over a 1.5 million (1,500,000) vehicles annually. The company plans to expand its manufacturing capacity to 1.75 million by 2013.

The Company employs over 9000 people (as on 31st March, 2012). Maruti Suzuki's sales and service network is the largest among car manufacturers in India. The Company has been rated first in customer satisfaction in the JD Power survey for 12 consecutive years. Besides serving the Indian market, Maruti Suzuki also exports cars to several countries in Europe, Asia, Latin America, Africa and Oceania

Maruti 800 used to be the best selling car in India until 2004; upon its launch the Maruti Alto took that title. It is also exported to a number of countries in South Asia including Nepal, Bangladesh and Sri Lanka, and to some South American markets (as Chile, sold as Suzuki Maruti), and was available in selected European markets between 1988 and 1992, sold as the Suzuki Maruti. In Morocco it is currently sold as Suzuki Maruti (as of March 2008). The car comes in different versions including one with air conditioning and one without. It was launched in December 1984 with almost 100% imported components. The first car to be sold in India was purchased by Harpal Singh, an Indian Airlines employee from New Delhi, who won the ownership rights to the car competing against other prospective owners, through a lucky draw and was handed over the keys of his dream machine by the then Prime Minister Mrs. Indira Gandhi. The original 800 was based on the SS80 Suzuki Fronte, but a modernized version using the body of the second generation Alto (SB308) was presented in 1986.

Maruthi 800 as a car had been a very successful one in India. It has got a very reliable Suzuki engine in it. The company decided to distribute this powertrain to educational institutions valued at Rs 1.5 crore in order to tap the skills of automobile engineering students. The automaker has donated over 40 units of 800 CC engines and powertrain to engineering college students, enabling them to manufacture their own prototype of a Formula car for the four-day SAE India-Maruti Suzuki event at Irungattukottai race track and at BIC. For the initiative, the company has teamed up with Supra SAE India, which would help students focus on developing a prototype of a Formula car equipped with Maruti engines and power transmission.

ENGINE

Since both ljm 01 and 02 uses the same engine and the only difference being the fuel delivery system which is carburettor in ljm 01 and MPFI in 02 there is no comparative study done in this case study.

Technical Specifications

Type: 4 stroke cycle

Displacement: 793 cc

Cylinders: 3

Cylinder configuration: Inline

Valve train: Single Overhead Camshaft

No of valves per cylinder: 2

Cooling: Water cooled

Disposition of Cylinder: R3

Disposition of Engine: Eq

Bore: 68.5mm

Stroke: 72 mm

Compression ratio: 9.2:1

Peak power: 37 bhp@5000rpm

Peak torque: 59Nm@3000rpm

Fuel system: Multi Point Fuel Injection

Fuel type: Petrol

Air/Fuel induction: Naturally aspirated (no turbo and supercharger)

Engine oil: 2.7l

In this engine the fuel is injected in the manifold itself. The injectors are placed strategically so that maximum the fuel to air mixture is homogenous. The firing order of the engine is 1-3-2 such that the engine is well balanced.

Below is the torque curve of Suzuki 800(f8c) engine. This torque curve is generated from the Daewoo matiz hatch back. This car also uses the same engine but with slightly different tuning. This will give a good idea how a maruthi 800 engine power curve will look.

The steep line which goes from 8ps power to 52ps is the power curve of this engine but in a slightly tuned condition. The other curve is the power curve when it is in stock condition. This is not accurate but we can at least get an idea. The above curve goes up to 8000 rpm. But considering the factor of safety supra sae event organisers have limited the engine to 4200 rpm. Thus the engine will never produce its peak power and peak torque. When it reaches 4200 rpm the ECU very sharply cuts off the fuel. But in ljm 01 engine that is not a problem because it does not have an ECU instead it has a carburettor.

CLUTH ASSEMBLYThis power that is produced by the engine is delivered to the gear box by a clutch

assembly. The clutch assembly that is used here is a diaphragm clutch.

TRANSMISSIONTechnical Specifications

Gear Ratios -

1st gear: 3.58

2nd gear: 2.16

3rd gear: 1.33

4th gear: 0.9

Reverse gear ratio: 3.27

Final reduction: 4.35:1

Transmission oil: 2.1l

The 800 powertrain uses a synchromesh gearbox.

This transmission unit comes attached with the engine itself. It has to be filled with separate oil. Engine oil and transmission oil will not mix. They will be present in two different compartments. The gear oil should be changed every 5000 kilometres.

The following tabular column tabulates the torque in each gear when the engine is running at certain rpm. In this tabulation the torque in respective gear represents the torque after the final reduction that happens in the differential.

(Note: All the torque values are in Nm. The actual torque delivery will be slightly less than the calculated values due to frictional losses.)

SNo RPM Torque at crank

Torque in 1st

Gear

Torque in 2nd

Gear

Torque in 3rd

Gear

Torque in 4th

Gear

Torque in Reverse

1 500 24 373.7 225.5 138.9 93.9 341.42 1000 28 436.1 263.1 161.9 109.6 398.33 1500 33 513.9 310.1 190.9 129.2 469.44 2000 37 576.2 347.6 214.1 144.9 526.35 2500 39 607.2 366.4 225.6 152.7 554.86 3000 41 638.3 385.2 237.2 160.5 583.27 3500 43 669.5 404.1 248.8 168.3 611.78 4000 44 685.1 413.4 254.6 172.3 625.99 4200 45 700.6 422.8 260.3 176.2 640.1

The following tabular column tabulates the force at wheel at certain rpm. The force values are in newtons.

SNo RPM Force at wheel in 1st Gear

Force at wheel in 2nd Gear

Force at wheel in 3rd Gear

Force at wheel in 4th Gear

Force at wheel in Reverse Gear

1 500 2430 1412 869 587 21372 1000 2730 1647 1013 686 24943 1500 3217 1941 1195 809 29394 2000 3608 2176 1340 907 32955 2500 3802 2294 1412 956 34746 3000 3996 2412 1485 1005 36517 3500 4192 2530 1557 1053 38308 4000 4289 2588 1594 1078 39199 4200 4386 2647 1629 1103 4008(NOTE: These values are not accurate. Since there are no torque curves available for Maruthi 800 engine Daewoo matiz engine torque curve is used. This is the same engine but has different tuning.)

DIFFERENTIALThis is the unit which delivers the necessary amount of torque to each wheel. The

final torque reduction that happens before the torque is delivered to the wheel is done here. The gear ratio is 4.35:1. This differential acts like a primitive type Limited Slip Differential (LSD) where the slip can be adjusted by changing the oil weightage.

AIR FILTER

Currently in LJM 02 we use Corsworth free flow air filter. The purpose of free flow air filter is to reduce the effort of the engine to suck the necessary air that is needed for combustion. If a free flow air filter is used for a given amount of vacuum pressure created by the engine during the suction stroke more air can rush into the cylinder in less time thus increasing the amount of usable oxygen in the cylinder. This extra oxygen is sensed by the lambda sensor in the exhaust so it signals the ECU to increase the amount of fuel that is injected into the manifold by the MPFI system thus increasing the overall performance. There we can get a better and clean pulling of the car.

But there is not much complication in the case of LJM 01 since it currently uses a carburettor. When we add a free flow air filter to a carburetted engine the air flowing through the carburettor just picks the necessary fuel (in the form of vapour) and comes directly to the cylinder. The inlet air contains the fuel that is to be burnt. There is not much of electronics involves in this type of fuel delivery system. Therefore these engines cannot be limited electronically. Thus these cannot be used in the supra sae event.

RADIATORSRadiators are heat exchangers used to transfer thermal energy from one medium to

another for the purpose of cooling and heating. The radiators that are used in LJM 02 are completely custom made. The capacity of the radiator is 4.5 litres of water/coolant. In LJM 02 we use two radiators that are placed one in each side pod. These two radiators are connected in series.

The radiator which is used in LJM 02 is not like the usual radiators. There are actually two radiators doing the cooling step by step. When the engine is heated up the thermostat

valve opens up and the water runs in the gallery taking out the heat. This heated up water is pumped to radiator 1 with the help of a positive displacement pump. In radiator 1 the water gets cooled to a certain level but the temperature is still very high. Then it is pumped to radiator 2 where it is further cooled. After the cooling the coolant/water flows through the surge tank where the bubbles are taken out by creating swell motion. Then the cold water

flows back to engine gallery again. This cycle is repeated for the continuous cooling of the engine.

SUGGESTIONS1. FORCED AIR INDUCTION - It seems like we will be using 600 cc bike engines for the

upcoming events. As far as my knowledge tells me these bike engines do not need two radiators to cool them. In LJM 02 the side pod design was not good enough to make proper cooling. There is lot of gap between the radiator and the side pod wall so that most of the air could by-pass without flowing through the cooling fins of the radiator. So if we can correct that design flaw we can create proper cooling using a single radiator. Thus making use of only one side pod for the radiator and making the other one free we will have an advantage. The other one can be used as a ram-air intake for the engine. We have to route the inlet manifold to the side pod. In the side pod we should place the air filter. So when the car is moving with a velocity the side pod scoops the air and acts like a forced air induction system. This system will be

effective only in high speeds but it will still make an effect and since we are using only one radiator our weight will be considerably reduced.

2. PROGRESSIVE SPRING – In LJM 02 we are using customised shock absorbers. The shock setting is stiff. My suggestion is we put progressive spring rated springs instead of normal springs. The behaviour of the shocks will differ depending on the bump the car is negotiating. When the bump is small the shocks act softer when they are considerably big they will become stiff. In order to cope up with the soft compound slick tyre which will be using in the future I strongly recommend this idea. Correct me if I am wrong.

3. CUSTOM EXHAUST – In LJM 02 we used a normal exhaust tip. We did not calculate the backpressure that is produced by that exhaust. In Chennai there are places where we can get customised exhaust which suit our specific needs. It will be a free flow one as well as producing less decibel levels. We can work for one if it is affordable.