The crude oil engine is a type of internal combustion engine similar to the hot bulb engine.
 A crude oil engine could be driven by all sorts of oils such as engine waste oil and vegetable oils.
 Even peanut oil and butter could be used as fuel if necessary.
 Like hot bulb engines, crude oil engines were mostly used as stationary engines or in boats.
 They can run for a very long time; for instance, at the world fair in Milan in 1906, a FRAM engine was started and ran until the exhibition was over one month later.
 A crude oil engine is a low RPM engine dimensioned for constant running and can last for a very long time if maintained properly.
 It was later replaced by the diesel engine.
St Vincents Hall, Grantham, is a Gothic Revival mansion built in 1868 for the industrialist Richard Hornsby who founded Richard Hornsby & Sons, engine and machinery manufacturer.
Tsimiroro is a large oil field in the onshore Morondava Basin of Madagascar found south of the Bemolanga ultra heavy oil field and south of the town of Morafenobe.
 It is estimated to contain as many as 9.3 Goilbbl of heavy oil with 14° to 16° API gravity.
 The oil is found in the Isalo and Amboloando formations.
The Associated British Oil Engine Company (ABOE) was a British engineering company.
 It started life as a combine, similar to Agricultural & General Engineers.
 Petters Limited joined ABOE in 1937.
 J&H McLaren & Co. was sold to ABOE in 1943, although it may have been a member from an earlier date.
 In 1945 Mirrlees, Bickerton and Day joined the group followed by the National Gas and Oil Engine company in 1950.
Gear oil is a lubricant made specifically for transmissions, transfer cases, and differentials in automobiles, trucks, and other machinery.
 It is of a higher viscosity to better protect the gears and usually is associated with a strong sulfur smell.
 The high viscosity ensures transfer of lubricant throughout the gear train.
 This is necessary since the devices needing this heavy oil do not have pumps for transferring the oil with only a portion of the lowermost gears bathed in an oil sump.
 This heavy oil can create viscous drag leading to inefficiencies in vehicle operation.
 Some modern automatic transaxles (integrated transmission and differential) do not use a heavy oil at all but lubricate with the lower viscosity hydraulic fluid, which is available at pressure within the automatic transmission.
The Hornsby-Akroyd oil engine was the first successful design of internal combustion engine using "heavy oil" as a fuel.
 It was the first to use a separate vapourising combustion chamber and is the forerunner of all hot-bulb engines.
<nowiki> </nowiki>Fuel oil, (also known as heavy oil, marine fuel or furnace oil) is a fraction obtained from petroleum distillation, either as a distillate or a residue.
 Broadly speaking, fuel oil is any liquid fuel that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash point of approximately 42 °C and oils burned in cotton or wool-wick burners.
 In this sense, diesel is a type of fuel oil.
 Fuel oil is made of long hydrocarbon chains, particularly alkanes, cycloalkanes and aromatics.
 The term "fuel oil" is also used in a stricter sense to refer only to the heaviest commercial fuel that can be obtained from crude oil, i.e., heavier than gasoline and naphtha.
Richard Hornsby & Sons was an engine and machinery manufacturer in Lincolnshire, England from 1828 until 1918.
 The company was a pioneer in the manufacture of the oil engine developed by Herbert Akroyd Stuart, which was marketed under the "Hornsby-Akroyd" name.
 The company developed an early track system for vehicles, selling the patent to Holt & Co. (predecessor to Caterpillar Inc.) in America.
 In 1918, Richard Hornsby & Sons became a subsidiary of the neighbouring engineering firm Rustons of Lincoln, to create "Ruston & Hornsby".
Morondava Basin is one of the major sedimentary basins of Madagascar.
 It encompasses the large Tsimiroro heavy oil field and giant Bemolanga ultra heavy oil field.
Herbert Akroyd-Stuart (28 January 1864, Halifax, Yorkshire, England – 19 February 1927, Halifax) was an English inventor who is noted for his invention of the hot bulb engine, or heavy oil engine.

Question: Who was the English inventor who invented the heavy oil engine manufactured by Richard Hornsby & Sons?
Answer: Herbert Akroyd-Stuart