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8th March 1998

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Wheels - By Brian Elias

Converting to LPG - what you should know

Schematic diagram of an LPG system (carburator principle)

Diagram1 Vent line for tank fittings, 2 LPG tank, 3 housing with tank fittings, 4 External filler valve with 80% cutoff, 5 Flow-interrupt valve, 6 Evaporator-pressure regulator, 7 Servomotor for gas control, 8 ECU, 9 Liquified gas/gasoline switch, 10 Venturi mixing unit, 11 Lamda O2 sensor, 12 Vacuum sensor, 13 Battery, 14 Ignition/start switch, 15 Relay.

Conversions from Gasoline or Diesel fuel to LP Gas are becoming increasingly common. We reproduce for the benefit of our readers the following information from the world renowned Manufacturer - ROBERT BOSCH of Germany.

LPG systems

Liquified petroleum gas

Liquified pertoleum gas (LPG) is a mixture of propane and butane. The name is explained by the fact that the gas assumes a liquid state at pressures of 2...20 bar; the actual pressure depends upon the propane/butane ratio and the temperature.

At the start of the '90s, internal-combustion (IC) engines were consuming approximately 8.2 million metric tons of LPG annually (of which 2.5 million tons were in Europe). Should efforts to utilize the gas contained in petroleum succeed, then these figures could increase exponentially. Taxrates on petroleum products exercise a decisive effect on the cost effectiveness of LPG.

Natural gas as engine fuel

Reserves of natural gas are extensive. Together with it being used nowhere near as much as crude oil, this fact makes natural gas a very interesting alternative fuel for automotive applications. Both equipment configurations and emissions would be similar to those for the combination of propane and butane known as LPG (see illustration). Natural gas can be transported in the vehicle either as a high-pressure gas (160...200 bar) or in liquified form (at -160°C) in an insulated tank; the disadvantage of the former mode lies in its limited operating range.

The only real difference between concepts based on natural gas and LPG is the way the gas is transported in the vehicle; actual differences in operating principles are minimal.

Operation on LPG

Any vehicle equipped with an IC engine can be converted for operation on LPG. For the most part, spark-ignition (Sl) engines are re-equipped for dual-fuel operation (system can be switched between gasoline and LPG). LPG-powered taxis and buses are generally set up for single-fuel (LPG only) operation, while regulations require this configuration on gas-powered industrial trucks intended for indoor use. When fuel-injected engines are converted, it should be remembered that these function as naturally aspirated powerplants while running on

LPG (consumption in liters increases by approx. 25...30 % over gasoline, while the figure for carburettor units is 20...25 %).

Exhaust emissions

Because LPG mixes well with air, emissions (of CO2 and other unregulated components such as polycyclic aromatic hydrocarbons) are substantially lower than those from gasoline units, even when the latter are equipped with 3-way closedloop catalytic converters. LPG contains no molecular structures with lead or sulphur. It's very good combustion response is complimented by excellent mixture formation and distribution properties; the resulting benefits become progressively more important at lower temperatures.

Advantages

Extremely economical for drivers who cover large distances.

- assuming the same level of technology (electronic control systems, etc.), emissions from an LPG engine, including CO2, are substantially lower than those achieved with gasoline or diesel fuel.

Disadvantages

- Lower cruising ranges and increased fuel volumetric consumption compared to gasoline (although actual energy use is not higher than with gasoline, lowest with diesel engine).

- Special safety precautions are necessary, as LPG is pressurized.

- Pressurized gas cylinders require a lot of space, as the actual capacity is only 80% of cylinder volume (the remainder serving as expansion room for the gas).

LPG system

In Germany, professional installation of the LPG system in a specialist workshop is followed by a trip to the TUV or TUA German inspection authorities) to secure operating approval. This inspection is based on the "Guidelines for inspecting vehic!es with engines powered by liquified gases" as issued by the Federal Minister of Transportation.

A modern LPG system will incorporate the following components:

- LPG tank,

- external filler valve designed to interrupt refueling at 80% of container capacity,

flow-interrupt valve,

- evaporator pressure regulator with cooling system,

- venturi mixing unit /lnjector,

- electronic control unit (ECU),

- servomotor for controlling gas flow,

- switch for alternating between LPG and gasoline operation.

After emerging from its tank, the LPG flows to the evaporator pressure regulator, where it is vaporized and its pressure reduced. The ECU processes the signals from the Lambda (O2) and vacuum sensors, which serve as references for controlling the servomotor used to regulate the flow of liquified gas to the venturi mixing unit.

The flow-interrupt valve shuts immediately when the ignition is switched off. A gasoline/LPG switch installed in the instrument panel allows the operator to alternate between the two fuels.

LPG tanks

As LPG tanks are used to store pressurized gas, they are subject to the "TRG 380" technical regulations. At the factory, each tank receives official technical approval with certification.

The tanks are equipped with an external filler valve (with a device to limit the charge to 80%) and a solenoid-actuated extraction valve. Tank capacities range from 40...128 litres for passenger vehicles.


Audi comes to stay here

We have gone on "reverse gear" in introducing Audi, said the Managing Director Gerard Fernando and Sales Manager Rajive Fernando on my return to Air Force Base at Katukurunda recently, after a super stimulating test drive on the Audi A 4 (A Motor Car which Champions use).

Senok Automobiles Private Limited has started on the correct foundation in establishing the Audi Franchise in Sri Lanka. They have implemented the UNIQUE MOTORING TRIANGLE.

In reverse to the normal set-up by first having an exclusive Service Station and Parts Warehouse and finally coming to the Showrooms, later.

How the AUDI got its name?

After leaving the Company in 1909 bearing his own name August Horch set-up the rival "August Horch Automobilwerke GmbH" but was forced by the Courts to re name it. He choose a Latin translation of his name: "AUDI" (Listen !!!)

MODEL SELECTION:

1. Audi A8 - In the Preminum Class

2. Audi A6 - For the demanding Owner

3. Audi A4 - Stylish and Stimulating

4. Audi Cabriolet - Winning many hearts.


A view from the hills

The truth is out there!

By Carl Muller

No, this is not a story from the X Files, al though it could very well be. Anyway, it concerns a fox, and a very foxy fellow who foxed a rich Kandy resident, until somebody let the fox out of the bag and it ranged the Maligawa area, long-nosed and bushy-tailed, making nariyas of all the stray dogs.

And no, it is not Fox Mulder, although Colombo Street residents think the aliens may have got the fox. Am I making myself clear? No? Oh well, let's begin again....

A smart and glib fellow from the Mahaweli area brought this rich Kandy resident a pup. Swore that the pup was the finest of breeds. Not just an Alsatian, a Brindled Alsatian. See the ears, how cocky, and the tail... The rich resident was delighted. He shelled out two thousand bucks and the pup was his. He had, he told his neighbours, a Brindled Alsatian. "Only one of its kind, men. Funny way it barks also. Like hooting."

The pup grew fast. Its face got pointier and its ears stuck out like the arches of the Sydney Opera House. It never wagged its tail which graduated from bottle brush to something between a mop and a permanent wave. Then a visitor choked on his tea and shouted, "O, My God! Nariyek!'' and the nariya discovered, bared its teeth and glared.

The resident's wife had hysterics. "Wild animal in the house,'' she moaned and threw things at her husband. ''Take and go and put somewhere. Anyone bring anything and say Alsatian, you'll buy!''

So the fox was dumped, just before the awaited visit of Prince Charles, at the top of Colombo Street. Symbolic, that. Maybe the Prince could do a spot of fox hunting.

Sundry citizens on their early morning constitutionals saw the fox being chased around the block by board members of Stray Dogs Inc. Oh, plenty of strays because, as I was told, it is custom in these hilly parts to dump unwanted animals near temples where they thrive on pilgrims' food and sympathy.

But the fox is no more. Did it decide to emigrate to Kundasale or has it gone under cover? Or is it an alien abductee? The truth is somewhere out there!

Signs of the times

Shop signs and shingles are a great source of amusement in Kandy, but one I stared up at in bewilderment takes the biscuit. It reads, NEW (something) TREADERS, and declares that it has this address in a STEET. So the letter 'r' was dropped in the word 'street' No real harm done. Accidents will happen. But 'Treaders' was something else. Is the company treading, flat-footed, through the tulips? Or does it tread where no man has trod before?

"Treaders" said a puzzled clerk, "you don't know English? We are Traders!''

I left treading on air. Walking past these city signs gives one the feeling of being on a treadmill !

Final Draft

The Children of the Information Age have banded together to produce Final Draft '98 - the magazine of the Young Writers' Association, headquarters in Sarasavi Uyana, Peradeniya. As the editor remarks, "We are a generation who have been told that we are not worth fighting for; who have been told that there is no tomorrow. We have fallen prey even to the traps of formal education, and while away our youth are involved in government strikes and pointless political struggles.''

The magazine contains a medley of stories, poems, essays and bits of sparkling confetti. An achievement to be sure, and something the Ministry of Education should seriously consider distributing to schools everywhere. Let young minds listen and read young minds. Let the wavelength thrum with supercharged creativity.

Final Draft '98 makes excellent reading. And it tells us, helps us understand the youngsters of today. Contact the Young Writers' Association for your copy.

An Avurudu offering

Thilak Palliyaguruge of Digana was adjudged the Best Young Painter of the Year in 1973, and has mounted many exhibitions of his work since 1971. His posters went on display at the International Union for the Consolation or Nature Poster Competition in Athens, and ten of his paintings were selected for display in Washington by the US Association for the Cultural Triangle of Sri Lanka.

Art lovers will be happy to know that Thilak will mount two exhibitions this year, the first at the Alliance Francaise, Kandy, from April 3 to 7, and the other at the Lionel Wendt, Colombo, from July 3 to 7.

The theme will be, broadly, on the Sinhala Avurudda, but he will be also including his studies, sketches, a broad sweep of his excellent interpretations drawn from rural life, Jataka stories, nature and the environment and his own flaring vision of human relations and consciousness.

Birth Defects Research Unit

With the release of a leaflet about ''Having Health Babies'' the Birth Defects Research Unit of the General Hospital, Kandy, marked the start of a National Awareness Campaign directed towards those of reproductive age.

The campaign, according to Dr. Bryan Walker, Director and Voluntary Service Overseas Volunteer, needs a high profile for pre-conception counselling. The BDRU's aim is to reduce defective Sri Lankan babies by 30,000 during the next decade.

The campaign aims to provide information about the avoidance of risk factors for the developing foetus, and a draft of a National Guideline has been prepared out of a workshop where sixty doctors met to discuss the reduction of birth anomalies. The paper will eventually be presented to the Ministry of Health by the College of Obstetricians and Gynaecologists.

The BDRU has also planned a leaflet to be given to every newly-married couple, outlining pre-conception counselling.

A request: The BDRU wants somebody to script a TV drama about the subject. Any takers?


More Plus *  Green light for Expressway  *  Tragedy and bravery

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