Two-stroke engine and four-stroke engine

Patent metadata

Field	Value
Publication number	US-9347366-B2
Application number	US-201113978735-A
Country	US
Kind code	B2
Filing date	Dec 26, 2011
Priority date	Jan 11, 2011
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

An exhaust gas exhausted from a combustion chamber of a two-stroke engine is fed to a turbine of a supercharger. Part of the exhaust gas that has passed through the turbine is extracted as an EGR gas by an exhaust gas recirculation part. The EGR gas is cooled by the heat of vaporization of liquid ammonia ejected from an ammonia ejection part, circulated into a suction gas in a suction path, pressurized by a compressor, and supplied as a scavenging gas into the combustion chamber. This recirculation of the exhaust gas can reduce the amount of nitrogen oxide exhausted from the two-stroke engine into the ambient air. Ejecting the liquid ammonia toward the EGR gas in a recirculation path facilitates cooling of the EGR gas, which is required for circulating the EGR gas into the suction gas.

First claim

The invention claimed is:

1. A two-stroke engine comprising:
a cylinder;
a piston provided in said cylinder;
a supercharger for pressurizing a suction gas to generate a scavenging gas;
wherein said supercharger includes:
a turbine that is rotated by the exhaust gas exhausted from said combustion chamber; and
a compressor for pressurizing said suction gas, using the rotation of said turbine as power;

a scavenging port provided in said cylinder and for supplying said scavenging gas from said supercharger into a combustion chamber that is a space enclosed by said cylinder and an upper surface of said piston;
an exhaust port provided in said cylinder for exhausting gas out of said combustion chamber;
an exhaust gas recirculation part for extracting part of the exhaust gas exhausted from said combustion chamber that has passed through said turbine as EGR gas and circulating said EGR gas into said suction gas or said scavenging gas;
an ammonia injector for injecting liquid ammonia into said EGR gas within said exhaust gas recirculation part.

2. The two-stroke engine according to claim 1 , wherein said EGR gas is circulated into said suction gas or said scavenging gas without needing to be cooled by a cooling medium.

3. The two-stroke engine according to claim 2 , further comprising:
a fuel injector for supplying fuel to said combustion chamber,
wherein said fuel contains liquid ammonia.

4. The two-stroke engine according to claim 3 , wherein
said two-stroke engine is a marine engine, and
the exhaust gas exhausted from said combustion chamber is circulated into ambient air without needing to remove sulfur content with a scrubber.

5. The two-stroke engine according to claim 1 , wherein
said EGR gas is circulated into said suction gas or said scavenging gas without needing to be cooled by a cooling medium.

6. The two-stroke engine according to claim 5 , further comprising:
a fuel injector for supplying fuel to said combustion chamber,
wherein said fuel contains liquid ammonia.

7. The two-stroke engine according to claim 6 , wherein
said two-stroke engine is a marine engine, and
the exhaust gas exhausted from said combustion chamber is circulated into ambient air without needing to remove sulfur content with a scrubber.

8. The two-stroke engine according to claim 1 , further comprising:
a fuel injector for supplying fuel to said combustion chamber,
wherein said fuel contains liquid ammonia.

9. The two-stroke engine according to claim 8 , wherein
said two-stroke engine is a marine engine, and
the exhaust gas exhausted from said combustion chamber is circulated into ambient air without needing to remove sulfur content with a scrubber.

10. A four-stroke engine comprising:
a cylinder;
a piston provided in said cylinder;
a supercharger for pressurizing a suction gas to generate an intake gas;
wherein said supercharger includes:
a turbine that is rotated by the exhaust gas exhausted from said combustion chamber; and
a compressor for pressurizing said suction gas, using the rotation of said turbine as power;

an intake port provided in said cylinder and for supplying said intake gas from said supercharger into a combustion chamber in an intake stroke, said combustion chamber being a space enclosed by said cylinder and an upper surface of said piston;
an exhaust port provided in said cylinder for exhausting gas out of said combustion chamber in an exhaust stroke performed after an expansion stroke in which the gas within said combustion chamber burns;
an exhaust gas recirculation part for extracting part of the exhaust gas exhausted from said combustion chamber that has passed through said turbine as EGR gas and circulating said EGR gas into said suction gas or said intake gas; and
an ammonia injector for injecting liquid ammonia into said EGR gas within said exhaust gas recirculation part.

Assignees

• Fukuyama Masahisa
• Ishiguro Kenji
• Murata Naohiro
• Hitachi Shipbuilding Eng Co

Inventors

• Fukuyama Masahisa
• Ishiguro Kenji
• Murata Naohiro

Classifications

• F02M21/0206

  Non-hydrocarbon fuels, e.g. hydrogen, ammonia or carbon monoxide · CPC title

• F02B37/00 Primary

  Engines characterised by provision of pumps driven at least for part of the time by exhaust · CPC title

• F02B29/0406

  Layout of the intake air cooling or coolant circuit · CPC title

• F02B33/00 Primary

  Engines characterised by provision of pumps for charging or scavenging · CPC title

• F02M21/0275

  for in-cylinder direct injection, e.g. injector combined with spark plug · CPC title