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Senarat Paranavitana, the gentleman I knew.



by Raja de Silva

An inevitable change in our social life has resulted from the restriction to our movement caused by the onset of Covid-19. We tend to refrain from visiting friends and relatives, staying in our homes instead; we have more time to think of the past and reflect on those we knew in days gone by. Very recently I had a rare visit from a relative, a medical man who is also an amateur antiquarian. He asked me to relate something about the legendary Paranavitana, whose last living erstwhile assistant I am. Like Hercule Poirot, I consulted my little grey cells and told him old stories, which I now place on record.

1.The interview

The year was 1949 and I had appeared before Paranavitana, Archaeological Commissioner (AC) (1940-1956), who together with Director of Museums, Paul Deraniyagala and the Professor of Chemistry, A. Kandiah constituted an Interview Board at the Archaeological Department. Three of us friends had applied for the post of Archaeological Chemist to be trained in India, and I was the first to be interviewed. Paranavitana commenced his inquisition with the following memorable words.



: Mr. de Silva, we have your biodata with us. Tell me, who was your mother?

RH de S (knowing that the purpose of this question was to find out my caste): My mother’s maiden name was Jayawickrama, Sir.


: Jayawickrama from Kurunegala?

RH de S: No Sir, from the South, in Mirissa.


: Any relation of Francis Jayawickrama who helped to restore the Tissamaharama Mahathupa?

RH de S: Her father, Sir.


(with a gleam in his eye): If you were to join this department it is not impossible that one day you would be able to restore old dagobas in a more scientific manner.

I knew of course that the superstructure of the Tissamaharama Mahathupa was of a most peculiar shape, conical in silhouette, unlike the familiar superstructures of all restored dagobas in Anuradhapura and Polonnaruva.

After a second interview at the Public Services Commission, and being appointed a Probationer I was immediately sent for a two-year period of training by the Archaeological Chemist in India, Dehra Dun.



One day the AC called me and Saddhamangala Karunaratne (SK) Assistant Commissioner, who was appointed a year after me, to his room to speak generally about our duties. His opening move was to slide two tins of cigarettes forward, a Navy Cut and Bristol, the latter of which he used to smoke. I took a Navy Cut and put it in my shirt pocket. SK declined. When we came away, I asked SK why he didn’t accept a cigarette. His reply was, ‘How could I smoke in front of the AC?’ From then on the AC used to offer me a cigarette but none to SK.

Post-luncheon nap

One early afternoon the AC had sent his peon on several occasions to my office requesting me to see him. It was about 2.10 when I appeared in the AC’s office soon after returning to work from my lunch break. The following dialogue took place:


: I have sent for you many times; where were you?

RH de S: I went home to lunch, Sir.


: Where do you live?

RH de S: In Ward Place, Sir.


: Don’t you know the lunch period is 12 to 1? It is now past 2.

RH de S: I know Sir, but I have a nap for one hour after lunch, because my efficiency is then better in the afternoon.


: Is that so?

and the AC told me what he wanted done.

From then on I was allowed to continue this salutary practice. I made a discovery 13 years later, when I moved into the office of the AC, that there was an ante-room provided with a large safe, a small table and chair for having lunch, a wash-basin and a cane easy-chair ideal for reposing in for forty-winks. It served me as it must have done the Old Chief.



At the outset, the AC told me that the Sigiriya fresco pocket had been closed to the public from 1947, and I was to go there often and attend to the paintings, some of which were cracked and in danger of falling off. In 1952/53 I used to occupy room No. 2 at the circuit bungalow, whereas the AC was often in room No. 1, after peering at the ancient writings on the gallery wall. One evening after sundown, he summoned me from room No. 2 where I had taken refuge and told me to get into his Willy’s station wagon. He told his chauffeur to drive us to the Rest House one minute away. Once we were settled comfortably in the verandah, with the waiter standing by, the AC asked me what I would like to drink, to which I replied, ‘A small whiskey and water please’. He ordered a wee whiskey for me and a small brandy and ginger ale for himself. He next announced, ‘You may smoke’, at which I brought out my packet of Gold Flake cigarettes and laid it on the table. The AC extracted his tin of Bristol from his coat-pocket and lit a cigarette, while I gave my Gold Flake a rest. We spent close to half an hour at the Rest House, and I remember what the AC told me, as if it were yesterday. ‘Do not accept anything from those junior officers in the field. They might put king coconuts in your car or offer you cigarettes or soft drinks. Do not take anything’. This was (I believed) in order that I would not become familiar with or beholden to anybody.

Again in 1954, in Anuradhapura, the AC took me out one evening to the Grand Hotel (now Tissawewa Rest House) for a drink. One drink; the same, and I did not smoke. I have no doubt that Driver Grade 1 Dassanaike would have duly reported to the minor staff that the lokumahattaya had given me a drink; my reputation would have gone up through the ceiling.

After about two years work at Sigiriya, I was able to inform the AC that, in my opinion, it was safe to open the fresco pocket to the public, provided that only a few people were allowed in at any one time. This was done in 1954, and the AC was commended in the newspapers.


Barber’s saloon

On the occasion of the retirement of a senior Assistant Commissioner P.H. Wilson Peiris, ARIBA, in the course of the AC’s valedictory speech, he referred to an incident concerning Peiris’s little son who used to roam about exploring the Archaeological Department. One entrance to the AC’s private office had swivel half-doors (as was common in barber’s saloons). The AC related how the little boy pushed open the two flaps of this entrance and inquired of him who had looked up in surprise, ‘Barber saloon ekak the?’. AC had replied, ‘Nää puthè, barber saloon ekak nevey’. The boy had retreated in disappointment. The AC concluded by declaring that we would all miss the intrepid young explorer.


The gourami

In the garden of the Polonnaruva circuit bungalow, Conservation Assistant Shanmuganathan had built a pond rather like the ancient lotus pond in the archeological reserve. It contained water and a gourami fish lived there. The AC on circuit never failed to feed the gourami a crumb or two after breakfast. One day, Hinton (the bungalow keeper) was suddenly informed that the AC on circuit, was arriving at the bungalow to dinner. The resourceful Hinton executed the gourami and served a fish course to the AC. The next morning when the AC looked to feed the gourami, he was aghast to find it missing. On inquiry, Hinton had professed no knowledge of the fate of the fish. A well-wisher who aspired to be the circuit bungalow keeper had ratted to the AC that Hinton was the guilty party. It was common knowledge that Hinton was no more at the circuit bungalow. On a visit of mine to Dimbulagala, ten miles away, I met Hinton who related to me the story of his banishment. Several years later, feeling that Hinton had served a long enough sentence among wild bears, who infested the jungles around the Maravidiya caves, I restored him to the Polonnaruva Circuit Bungalow.


Out of favour

Misfortune had set in. In 1954, certain paintings in one of the Maravidiya caves at Dimbulagala were subject to vandalism by a fanatic carrying buckets of cow-dung and applying it in water over the paintings (ASCAR 1954, 8, para 32). On the occasion of the AC seeing me at the Anuradhapura circuit bungalow, the following dialogue took place one morning.


: I want you to give instructions to Sarath Wattala to clean those paintings at Dimbulagala.

Assistant Commissioner (Chemist): Sorry, Sir, I am unable to do so.


: Why?

Assistant Commissioner (Chemist): He is the Modellor, and he would not know the difference between an acid and an alkali, Sir.


. You do not like him, do you?

Assistant Commissioner (Chemist): Sir, it is not a question of like or dislike. He is just not suitable for the job you wish me to give him. I shall try to clean the paintings myself.

That was the end of the conversation, which I saw had displeased the AC, who left Anuradhapura in continuation of his circuit. However, in a day or two I received written orders from the AC to give instructions to Sarath Wattala to clean the Dimbulagala paintings. I replied, from Anuradhapura, that as explained personally, I regretted it was not possible for me to do as the AC required, but that I would attempt to clean the paintings. All attempts, including an effort by Luciano Maranzi, UNESCO expert, failed. In this connection, Paranavitana later (1958) wrote ‘In caves on the adjoining hill at Dimbulagala, there were, before a fanatic recently obliterated them, fragmentary paintings of the first half of the 12th century.’

The AC was annoyed with me. In February 1956 I was given nine months duty leave by the AC to attend a British Council course in the Preservation of Works of Art. But, the AC arranged for my junior colleague, Saddhamangala Karunaratne (SK), Assistant Commissioner (Epigraphist), to study for a PhD at Cambridge University, for a period of three years on duty leave. For this purpose, the AC had addressed Government stating that “with my imminent retirement, it is necessary to have an officer trained in research work so that he may be equipped to head the Archaeological Department. SK was chosen for such a scholarship abroad. I saw that letter in the file in 1957 when I was senior Assistant Commissioner (detailed to look after administration), while the Acting AC, Claudio Sestieri, was to be free to do field work and train the staff in excavation. SK left for Cambridge in 1957.

It was now my turn to be righteously annoyed. I wanted to show the retired AC that I was capable of research work, and how better than by criticizing one of his own theories?

I published a long newspaper article in the Sunday Observer dated April 4, 1957, criticizing Paranavitana’s theory that the Dakkhina thupa, Anuradhapura, was built on the site of King Dutugemunu’s cremation (See de Silva, Raja 2005, 93 – 103). There was no reply from my old chief, who was by then Professor of Archaeology, Peradeniya University.


Lost ground retrieved

The Government (1959) agreed (on representation made by me) that I should be given the same facility for post-graduate research work abroad as was given to SK. I was to be given a placement at Oxford University, provided that my university professor and my departmental head testify to my good character and capability to undertake research work. The certificates were to be sent to Oxford through the Education Officer, Ceylon High Commission in London. The Chemistry Professor sent his recommendation (on my request) direct to London. I informed Professor Paranavitana of this requirement, and kindly requested that the required certificate be sent to London. Mirabileé dictu, my old AC sent me (for onward transmission) a recommendation that was couched in superlative terms. I realized what a warm-hearted gentleman Paranavitana was, and humbly thanked him for the splendid certificate. I was thus able to be on duty leave in Oxford for a period of three years from August 1959.


Retired AC becomes Professor

After I was appointed AC in 1967, my former AC used to visit me in my office, whenever he came to the Library to refer documents. I would get up, go round to the visitor’s side and sit down to converse about his requirements. To assist Professor Paranavitana in his researches, I was able to obtain the approval of the Ministry of Cultural Affairs to give him all his requirements free of charge. I used to take to his residence rubbings of inscriptions that he wished to inspect; I was once shown on a rubbing the spots where the words Platava (Plato), Alaksandara (Alexander), and Abrasthita (Aphrodite) were seen by him. The Professor used to give me autographed off-prints of his academic papers, which I have safeguarded to this day.

My old chief died in 1972. It gave me satisfaction to persuade a chieftan of the Lake House Press, to bring out from their press, the former AC’s latest book, The Story of Sigiriya, before the date of his state funeral.

Paranavitana was roundly criticized by latter day scholars for his study and publication of later interlinear writings on old inscribed stones. I replied to several of these critics and defended Paranavitana from the insinuated charge that there were no interlinear writings and he was therefore an intellectual fraud. My defense of Paranavitana was titled ‘Paranavitana and the interlinear writings’ in my book Digging into the past (2005: 203-216), where I showed that his peers CE Godakumbure and Saddhamangala Karunaratne had both accepted that there were interlinear writings on stones.

Senarat Paranavitana the scholar, is justly remembered as the greatest Sri Lankan archaeologist of the first half of the 20th century. But not second to him was Paranavitana the gentleman, who was not known to many people outside the Archaeological Department. It was an honour to have known him.

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An air of discontent prevails



We have had a series of “Avurudhu parties” here in Aotearoa. No shortage of Kavum, Kokis, Athiraha, and even Wali Thalapa. Buffalo curd available locally and of course imported treacle in abundance. Yours truly has assumed the role of a fly on the wall during these festivities and gleaned much information, worth talking about.

First to get on to the Pearl, the talk of the botched-up vaccination plan and running out of the second dose of vaccine. Bizarre permutations as to what would happen if the second dose was not available on time and to who would be press-ganged into getting the “dodgier” types of vaccine from China and Russia, etc. The possible repercussions of getting a second dose of another type of vaccine to the original, the speculations of which left me rather glad that the general populace of Aotearoa has not been vaccinated to date. The talk moved on to the Easter bombings and the recent comments by leaders of the Roman Catholic church as to the possible perpetrators of the attack. Some increasingly obvious conclusions as to those responsible for the planning and funding of same are being reached by those other than some of us who dared to voice our opinions over a year ago! This combined with the increasing and very rapid unpopularity of the person they elected to high office hoping he was genie of the magic lamp type, and the possible reverse of Hong Kong that could take shape on the reclaimed land near the Colombo port, does not bode well for an already dubious future. By reverse of Hong Kong, I mean Hong Kong is trying to hold out as a bastion for democracy, whilst the proposed port city seems to be modeled on the opposite!

Moving on to Aotearoa, the rest of the world seems to be praying for a leader such as our own Jacinda Ardern, but the fat cats of Aotearoa are getting rather sick of her. Those who own multiple houses and have been setting off their interest payments against their taxes due to a loophole in the law that has now been plugged are grumbling. The fact that most young people can’t afford to buy their first houses due to rich people and property developers snapping up all available property, happily funded by banks who are only interested in the bottom line, is of no consequence to them. The fact that this could lead to so much discontent that it could even lead to armed insurrection doesn’t bother them. They seem to have forgotten that we have had almost no deaths and hardly any Covid 19 cases in our community when they say that the lockdowns, we underwent were too excessive and how the economy and business sector has suffered. These very people throng the stadia during the rugby and cricket games and enjoy music concerts with gay abandon. Megacorporations are not happy about the restrictions that are coming on with regard to the use of Liquid Petroleum Gas (LPG) due to environmental concerns. To top it all off I had a lecture from my 13-year-old daughter about how I am being “led by the nose” by Jacinda Ardern and her propaganda! Where she got that from could only be from her elder brothers whose get rich quick schemes have seen a setback due to certain leftist policies coming in from the Labour government that is in power with an absolute majority.

I laugh to myself and think about other examples I have seen of self-proclaimed pundits never being content with their lot. My education was in a very large Government school. As a perfect and a member of some sports teams we handled the administration and some of the governance of this school. Later in life when my children were attending a private school I got involved in the Executive committee of the PTA of that school. The “problems” faced by the private school and the vast dramas that were involved in trying to solve those problems were laughable when compared to those faced by even us, senior students (a much lower level in the administration) of the Government school.

It led me to believe that people always grumble. They are never content with their lot and there is always someone plugging their case and trying to sow the seeds of discontent among the populace. If those living in Aotearoa, in the present situation and well aware of the chaos and mayhem that is prevailing in the rest of the world are dissatisfied, when will anyone be satisfied? Everything is relative and one should try to step outside the confines of one’s own situation and look at the broad picture. In the words of learned barristers, I rest my case!

This week’s missive will not be complete without a tribute to the memory of Prince Phillip, the Duke of Edinburgh. He lived through some of the best and worst times of human existence on this planet and conducted himself impeccably. He showed his humanity and his failings, with a few bloopers down the line but most of those had an undercurrent of humor and couldn’t really be construed as offensive, despite the best efforts of the media and others to make them so. He served as consort to her Majesty the Queen with loyalty and aplomb and he leaves behind an enviable legacy in the world of conservation and youth affairs. It is hoped that his heirs will be up to the task for they face a task which in cricketing terms could be classed as coming into bat after the great Sir Vivian Richards had just scored a century, in his prime. Something very difficult to surpass in skill and entertainment value. Unfortunately, the Duke made just 99. May he rest in peace!


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We have much to learn; and emulation is no disgrace



“Imitation is the sincerest form of flattery that mediocrity can pay to greatness.” said Oscar Wilde who, through sharply ironic wit, often proclaimed the absolute truth.

Cassandra quotes him today as she wants to point out how much we in Sri Lanka can benefit by reaping some ideas from the recent royal funeral in Windsor. And she does not excuse herself for placing stress on our mediocrity as juxtaposed with greatness. Nationalists may shout themselves hoarse and bring down a few more majestic trees by decrying the comparison. They can justifiably claim we have a cultural heritage of two and a half millennia but have we remained cultured, following faithfully and correctly the four great religions of the world? A loud NO from Cass, echoed by millions of others. Though Britain’s development of the English language, culture, arts and science was later than our civilization, they outstripped all countries at one time and are again elevated, while we are poised on bankruptcy, with the begging bowl in hand and thugs and thieves as legislators. We in Sri Lanka are mediocre if not degraded against the greatness shown by the Brits in many spheres. This is no Anglophile speaking but a dame who was born when the Brits were leaving us to govern ourselves and grew up with our statesmen doing a jolly good job of it; Sinhalese, Tamil, Burgher, and a few Muslims taking the lead graciously and effectively with complete honesty, to serve the people. They maintained and improved our country so it was admired by others and even some desiring to imitate Ceylon as Singapore’s Lee Kwan Yew admitted. And where are we now? Except the Rajapaksa family from Medamulana, wearing rose tinted glasses or with eyes shut by arrogance, and their followers and throngs of sycophants, others see our country and our people for what it, and the people, really are. No need to elaborate.


The funeral of Prince Philip juxtaposed against customs here

The low-key funeral observing all Covid-19 restrictions was noteworthy for being utterly devoid of bombast and vainglory. It was dignified and moving. Cass wonders how many of her readers watched the funeral on Saturday 17, late evening here. Prince Philip had detailed all arrangements from the Navy being prominent and other Forces joining in plus the substitution of the gun carriage with a jeep he had helped design. The horse carriage he was adept at racing was stationed close by the entrance to the chapel. He has bequeathed it to the daughter of his youngest son and Sophie; the Wessexes having been very close to him and the Queen.

The entire proceedings proved first and foremost that the royal family observed strict pandemic restrictions like mask wearing and physical distancing. There was no one rule for them and another rule for us, thus proving beyond doubt that England (usually), and more so the Royal Family (definitely) are a country and an institution despising double standards. The monarch decreed and abided by the same regulations that have restricted everyone else in the UK, sharing their fate. An anecdote is relevant here. The Queen learned that lesson long ago. She was 14 when her mother said, after Buckingham Palace was bombed in September 1940, that she “could look the East End in the face now.”

Do all our people follow rules common to everyone? Oh! My heavens NO! There are differentiations according to layers in society. Shangri La would host a party for a hundred when only 30 are allowed to gather. During the height of the first wave when restrictions were strict, SLPP electioneering saw hordes thrust together and baby carrying, patting heads and hand clasping mostly by Mahinda Rajapaksha sans a mask. He has a charismatic bond with the masses but that needed to be curbed. Sajith Premadasa’s meetings were strict on physical distancing and mask wearing.

Only 30 were invited to the extremely solemn and yes, beautiful funeral service at Windsor Chapel. This meant eliminating even close relatives of the Family; but it was done. The Queen sat distanced from her daughter and sons and their spouses. Her now diminutive figure seated alone emphasized the loneliness she must be feeling after a close and successful marriage of 73 years.

This brings to mind our First Ladies. Cass steps out bravely to say that Elina Jayewardene was a gracious lady of restraint and dignity, the only perfect consort so far. Cass remembers Hema Premadasa beating her breast (true) and crying over the coffin of her late husband’s remains – in the true sense of the word – at the Prez’s funeral at Independence Square. There is dignity in restraint of even tears over a death in public. Among the women Heads of the country, the mother completely beat the daughter in dignity and ability.

We Sri Lankan women are now much more restrained in our mourning at funerals. Time was when widows even hoarsely wailed their sorrow, coiled and roiled with grief, and begged the dear departed “To look once more; say one word.” Cass in all the expressed grief of such funerals suppressed her laughter with difficulty. How would it be if the corpse obliged?

The choir at the funeral of Prince Philip was just four – one woman and three men. But their singing resounded in the high vaulted, completely majestic, centuries old church. The lone kilted piper within the Chapel evoked much. The service itself was short, just a Reading, prayers and listing of the multitude of honours bestowed on the Duke of Edinburgh, whose medals and decorations were on display beside the alter. The Archbishop of Canterbury, Justin Welby, and the Dean of Windsor, David Conner conducted the service.

To conclude, the Duke of Edinburgh had advised and laid stipulations on a simple funeral with the necessary pomp and pageantry but low key and very unostentatious. The actual funeral was even more low-key with mourners requested not to be on the streets or place flowers. The latter they did in all the residencies of the Royal Family in appreciation of a man who faithfully stood by the Queen and in his own way gave service to the nation.

Coming back to Free Sri Lanka, we seem to stress on that first word Cass inserted to the country name, even in these dire times of no crowds. And the worst is milling crowds are apparently encouraged to boost popularity of certain VVIPs by sycophants and by the preference/orders of the VVIP himself.

Consider the funeral of Minister Thondaman: crowds in Colombo and all VIPs wishing to register their presence before the body, and then the commotion at the actual cremation Up Country. Consider this year’s Sinhala New Year celebrations which were very dignified at the President’s residence but were inclusive of all traditions and a large gathering in the PM’s home, even raban playing by the Second Lady, and milling crowds outside.


Roller coaster ride of the country continues

Cass is relieved she had a topic to write on; namely that we should emulate the manner in which the much admired Duke of Edinburgh’s funeral was conducted, abiding by his stricture of it being low key and the country’s Covid restrictions. Our leaders especially must accept the saying I quoted at the beginning.

The country continues its roller coaster bumpy ride with some crying out the country is being sold to the Chinese, we will be a colony of theirs after they occupy the Port City; and others in remote areas sitting down for days on end, some near 100 days, drawing attention to the human elephant conflict. Much is touted about the Bill relating to the rules to govern the Port City.

Cassandra listens to all, and is somewhat warned and frightened, but cannot comment. However, one matter she speaks about loud and clear. The people must be told the status quo of the pandemic – daily numbers catching the infection and numbers dying. This is not for interest sake or ghoulish appetites; but to know how things are so we relax a wee bit or shut in more stringently. The Covid-19 Task Force, or the Health High Ups (not Pavithra please) should tell the country of the true situ of the pandemic as it holds the country in its grip. We want to know whether the grip is tightening or weakening. Please give us daily statistics. This newspaper announces total numbers. No help. Are we expected to jot down figures, subtract, and give ourselves daily infection and death statistics? No! It goes to prove that other matters – political slanted, ego boosting and economics – are more important than warning, containing the pandemic, and saving lives.

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Do you pump Octane 95 Petrol to your car to get better performance?



If your answer is YES, this article is for you

Dr. Saliya Jayasekara.

Senior Lecturer Department of Mechanical Engineering
University of Moratuwa

Many passenger vehicles, including three-wheelers and motorcycles are fueled by octane 95 gasoline when octane 92 gasoline (petrol) is available at a lower price. 

Otto engine (petrol engine) is an internal combustion spark ignition engine invented by a German engineer Nicolaus Otto in 1876 and used in most of the light weight vehicles including cars, three wheelers and motor bicycles. Otto engines can burn most of the hydrocarbon fuels (including hydrogen and ethanol) that can mix with air by evaporation (low boiling point). But the combustion characteristics of different hydrocarbons are not the same when burned inside an engine. If an Otto engine is designed for a particular fuel, it would not perform similarly with a fuel that has a different chemical composition.

In a well-tuned Otto engine run on gasoline for which the engine is designed, the combustion of the gasoline (petrol) / air mixture will continue smoothly from the spark plug to the piston head by igniting successive layers of the mixture as shown in Figure 1 (a).

If low grade gasolines are used, the combustion of some of the air/ fuel mixture in the cylinder does not result from propagation of the flame front initiated by the spark plug, but one or more pockets of air/fuel mixture explode (Detonate) outside the envelope of the normal combustion front as shown in Figure 1 (b). This detonation can cause severe damage to the piston and the head of the engine while deteriorating thermal performance of the engine (low efficiency)

Gasoline is a petroleum-derived product comprising a mixture of different hydrocarbons ranging from 4 to 12 carbon atoms in a carbon chain with the boiling point ranging of 30–225°C. It is predominantly a mixture of paraffins, naphthenes, aromatics and olefins. Additives and blending agents are added to improve the performance and stability of gasoline. The engine designers learned that straight-chain paraffin have a much higher tendency to detonate than do branched-chain paraffin.

The tendency of a particular gasoline to detonate is expressed by its octane number (ON). Arbitrarily, tri-methyl-pentane, C8H18 (iso-octane) is assigned an ON of 100, while the straight-chain paraffin n-heptane, C7H16 is given an ON of zero. Hence, a fuel sample with the same anti-detonation quality as that of a mixture containing 90% iso-octane and 10% n-heptane is said to have an ON of 90. Gasoline is made up of a mixture of mostly branched-chain paraffin with suitable additives to give an ON in the range 90 –100. It was also learned through experiments that the ON of a gasoline blends (e.g. gasoline and ethanol) can be calculated by using weighted average ON of each compound. Most importantly, the octane number has nothing to do with the heating value (Calorific value) or the purity of the fuel.

Engine thermodynamics show that engines with a high compression ratio offer higher thermal performance than engines with a low compression ratio. These engines having high compression ratio require high octane gasoline (for example octane 95) to avoid detonation. However, using gasoline having higher octane ratings for the engines designed for a low octane rating (for example, 92 octane) would not provide an additional benefit or loss, other than increased fuel cost.

Therefore, it is important to know the designed octane number of the engine before fueling (refer owner’s manual of the vehicle). For example: the minimum ON requirement for two and three wheelers in south Asia is 87 (The World Bank). Most of the Toyota, Honda and Nissan models including hybrid engines recommend 92 octane gasoline.

Dr. Saliya Jayasekara received the B. Sc. degree in mechanical engineering from university of Moratuwa in 2001, and the M.Sc. and PhD degrees in decentralized power generation systems from Royal institute of technology Sweden and the Melbourne University Australia in 2004 and 2013 respectively. He has well over 13 years of national and international experience in design and installation of centralised/decentralised power plants, boilers (utility/package) and heat exchangers. Currently he is serving as a senior lecture at University of Moratuwa, a visiting lecturer and fellow at Deakin University Australia.

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