The Cummins L-series engine is a straight-six

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...

designed and produced by

Cummins Cummins Inc. is an American multinational corporation that designs, manufactures, and distributes engines, filtration, and power generation products. Cummins also services engines and related equipment, including fuel systems, controls, air ...

. It displaces , and began production in 1982 as the L10 at the Jamestown Engine Plant in Jamestown, New York. After lengthening its stroke from 136 to 147mm, its displacement was enlarged to 10.8 litres and the engine renamed ISM 11, later M11. The ISL 9 and current L9 engines are not related to the L10 engine, but instead based on the smaller C-series platform with the 135mm stroke of the C8.3 enlarged to 144.5mm, together with 4 valves per cylinder, giving it 8.9 litres displacement. The L10 displaced , and was available in either a vertical form, for upright use in trucks and buses, or horizontal form, for underfloor use in buses and trains. The L10 was Cummins's first competitive offering in the British bus market, as their earlier production had been too large and heavy. However, it had a troublesome introduction to the British market, with high oil consumption and sealing problems. By 1994, it had been developed into the M11, and in 1998, Cummins ceased production of the old L-series engine. After the original L10 evolved into the M11 engine, the new ISL9 engine was introduced to operate in this market segment, yet with a better power to weight ratio, by enlarging the piston stroke of the older C8.3 engine. The Cummins L10 also has a sister engine which runs on

compressed natural gas Compressed natural gas (CNG) is a fuel gas mainly composed of methane (CH4), compressed to less than 1% of the volume it occupies at standard atmospheric pressure. It is stored and distributed in hard containers at a pressure of , usually in cy ...

(CNG). The engine was introduced in 1992 as the L10G before being replaced by the L Gas Plus in 2001 until it became the ISL G in collaboration with

Westport Innovations Westport Innovations (, ) is a company that develops alternative fuel, low-emissions technologies to allow engines to operate on clean-burning fuels such as compressed natural gas (CNG), liquefied natural gas (LNG), hydrogen and biofuels such as ...

in 2008, now based on the C-series engine architecture. The ISL engines were manufactured at plants in Rocky Mount, North Carolina and Darlington, Englandbr>
In 2016 onwards, the ISL9 was simplified to L9, though physically it shares no resemblance to the old L10 engine: The current L9 engine is a stroked version of the C8.3 engine platform, while the current M11 engine is a stroked version of the original L10 engine platform.

Models

Popular power ratings

Diesel-powered urban bus : at 1300 rpm, electronically governed at 2200 rpm : at 1300 rpm, electronically governed at 2200 rpm : at 1300 rpm, electronically governed at 2200 rpm Natural gas-powered urban bus (L Gas Plus, ISL G, ISL G NZ, L9N) : at 1300 rpm, electronically governed at 2000 rpm : at 1300 rpm, electronically governed at 2100 rpm : at 1300 rpm, electronically governed at 2000 rpm ;Firetruck/motorhome/truck : at 1300 rpm, electronically governed at 2100 rpm : at 1300 rpm, electronically governed at 2100 rpm : at 1300 rpm, electronically governed at 2200 rpm

References

External links

Cummins websiteCummins Westport (CNG) website
{{DEFAULTSORT:Cummins L Series Engine Cummins diesel engines Diesel engines by model Straight-six engines