CN-122029342-A - Internal combustion engine

Abstract

A gas-fuelled internal combustion engine comprising an engine structure defining one or more cylinders, a piston mounted for reciprocating movement in the or each of the one or more cylinders, a crankcase, a gas pressure source configured to deliver gas along a ventilation path to remove blow-by from the crankcase, wherein the ventilation path comprises at least one ventilation passageway having an opening proximate a lowermost extent of the one or more cylinders.

Inventors

• T. P. Randall's
• K. BROWN
• J. Bond

Assignees

• JCB研究

Dates

Publication Date

20260512

Application Date

20240920

Priority Date

20230922

Claims (20)

1. 1. A gaseous-fuelled internal combustion engine comprising: an engine structure defining one or more cylinders; a piston mounted for reciprocal movement in the or each cylinder of the one or more cylinders; A crankcase; a gas pressure source configured to deliver gas along a ventilation path to remove blow-by from the crankcase, wherein the ventilation path includes at least one ventilation passage having an opening proximate a lowermost extent of the one or more cylinders.
2. 2. The engine of claim 1, wherein the opening is at substantially the same level as a lowest extent of the one or more cylinders.
3. 3. An engine according to claim 1 or 2, wherein the engine structure comprises a plurality of cylinders.
4. 4. An engine according to claim 3, wherein at least two of the plurality of cylinders are provided with respective ventilation passages having openings near the lowest extent of the corresponding cylinders.
5. 5. The engine of claim 4, further comprising a manifold arranged to connect at least two ventilation passages.
6. 6. The engine of claim 5, wherein the manifold extends longitudinally along the engine.
7. 7. An engine according to claim 5 or 6, wherein the manifold is integral with the engine structure.
8. 8. The engine of claim 7, wherein the manifold is a linear rail disposed within the engine structure.
9. 9. An engine according to any of the preceding claims, wherein the engine further comprises a gearbox and a further ventilation passage connects the ventilation path to the gearbox.
10. 10. The engine of claim 9, wherein the other vent passage connects the gearbox to the manifold.
11. 11. An engine according to claim 9 or 10, wherein the further ventilation passage is connected to an upper portion of the gearbox.
12. 12. An engine according to claim 3 or any one of claims 4 to 11 when dependent on claim 3, wherein the at least two cylinders are arranged in line.
13. 13. An engine according to claim 12, wherein a wall extends downwardly from the bottom of the cylinder towards the crankshaft journal bearing block intermediate the two cylinders, dividing the lower piston area of the crankcase into two separate compartments.
14. 14. The engine of claim 13, wherein a hole is provided in the wall.
15. 15. An engine according to any one of the preceding claims, wherein the gas pressure source is a pump.
16. 16. The engine of any of the preceding claims, wherein the gas pressure source is configured to draw ventilation gas into the crankcase via the one or more ventilation passages.
17. 17. An engine according to any one of the preceding claims, wherein at least one of the one or more vent passages comprises a nozzle mounted thereto, the nozzle being arranged to direct vent gas towards the underside of a piston adjacent thereto.
18. 18. An engine according to any preceding claim, wherein the or each cylinder has a displacement in the range 0.75 litres to 1.5 litres.
19. 19. An engine according to claim 18, having a maximum power output in the range 10kW to 35kW per cylinder, optionally in the range 12kW to 33kW per cylinder.
20. 20. An engine according to any one of the preceding claims, wherein the engine is a hydrogen powered engine and comprises a hydrogen fuel delivery system.

Description

Internal combustion engine Technical Field The present teachings relate to an internal combustion engine (internal combustion engine ). In particular, the present teachings relate to gaseous fuel internal combustion engines, such as hydrogen-powered internal combustion engines. Background In order to reduce emissions from internal combustion engines, and possibly greenhouse gases, hydrogen has been proposed as a fuel for such engines instead of diesel or gasoline. In addition, other gaseous fuels (such as compressed natural gas) are known as fuels for internal combustion engines and can provide environmental benefits over liquid fuels such as diesel and gasoline. In internal combustion engines, it is common for air and fuel in the combustion chamber of the cylinder and combustion gases formed in the combustion chamber to leak to some extent from the combustion chamber past the piston into the crankcase of the engine. The leakage gas is commonly referred to as blow-by gas (blow-by gas ). In engines powered by gaseous fuels such as hydrogen, the accumulation of the gaseous fuel component of the blow-by gases in the crankcase can cause problems if the ventilation is insufficient. This is because some gaseous fuels have a relatively high flammability range (e.g., a hydrogen gas concentration in air of between 4% and 75%). Unless the blow-by gases are vented such that the concentration of gaseous fuel in the crankcase is below its lower flammability limit, there is a risk that the gaseous fuel in the crankcase may ignite, possibly damaging the engine and its surroundings. The gaseous fuel may then also ignite the lubricating oil in the crankcase, thereby initiating further combustion. Crankcase ventilation systems are known that are configured to vent blow-by gases from the crankcase of a gaseous-fuelled internal combustion engine. Typically, such systems provide a flow path for the blow-by gases to rise from the crankcase and through the engine to an outlet located at an upper portion of the engine (such as a cylinder head or rocker cover). The blow-by gases rise due to their high temperature, but may also float naturally (buoyant) when the gaseous fuel has a lower density than air (e.g., hydrogen). However, there may be locations in the engine where blow-by gases may accumulate and may not be easily diluted by the ventilation system, resulting in an increased risk of combustion in the crankcase. In higher specific output (specific output) engines, this risk may be greater due to more blow-by and due to longer engines (such as in-line six-cylinder or eight-cylinder engines) the ventilation path within the engine may be longer and dilution may therefore be less efficient. The present teachings seek to overcome or at least mitigate the problems of the prior art. Disclosure of Invention A first aspect of the present teachings provides a gaseous fuelled internal combustion engine comprising an engine structure defining one or more cylinders, a piston mounted for reciprocal movement in the or each of the one or more cylinders, a crankcase, a gas pressure source configured to deliver gas along a ventilation path to remove blow-by from the crankcase, wherein the ventilation path comprises at least one ventilation passageway having an opening proximate a lowest extent (lowest extremity) of the one or more cylinders. Advantageously, this arrangement allows ventilation gas to be introduced into the crankcase in the region where the blow-by gas first enters the crankcase, thereby diluting the blow-by gas where it occurs, making it less likely that the ventilation gas reaches its lower flammability limit. Optionally, the opening is at substantially the same level as the lowest extent of the one or more cylinders. Advantageously, this ensures that the ventilation gas is delivered directly to where it will dilute the blow-by gas as it exits the cylinder. Optionally, the engine structure includes a plurality of cylinders. Optionally, at least two cylinders of the plurality of cylinders are provided with corresponding ventilation passages having openings near the lowest extent of the corresponding cylinders. Advantageously, by providing multiple passages on a multi-cylinder engine, the risk of gaseous fuel reaching its ignition concentration is further reduced. Optionally, the engine further comprises a manifold arranged for connecting at least two ventilation passages. Advantageously, providing a manifold provides a convenient way of constructing a ventilation path that ensures that ventilation gas flows into or out of the crankcase in multiple locations. Optionally, the manifold extends longitudinally along the engine. Advantageously, this allows the manifold to be relatively short with respect to the passages to be connected and easy to manufacture. Optionally, the manifold is integral with the engine structure. By "integral" is meant that the rail is integrally formed with the engine structure, for example, in embodiments