# US 12,768,321 B2 · Fuel reforming system for vehicle

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- Number: US 12,768,321 B2
- Document ID: US12768321B2
- Status: Granted
- Kind: B2
- Application number: 19/046,570
- Filed: 2025-02-06
- Published: 2025-08-21
- Granted: 2026-10-20
- Earliest claimed: 2024-02-15
- Assignees: Mazda Motor Corporation
- Applicants: Mazda Motor Corporation
- Inventors: Chikara Iname; Yuji Harada; Hirotsugu Matsuda; Kenji Uchida; Masahiro Horikoshi
- Web page: https://patentgrep.com/patent/US12768321B2

## CPC

- F02M 21/06: Apparatus for de-liquefying, e.g. by heating
- F02B 75/021: {having six or more strokes per cycle}
- F02M 21/0209: {Hydrocarbon fuels, e.g. methane or acetylene}
- F02M 21/0239: {Pressure or flow regulators therefor}
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)

## Abstract

A system and method can include a decomposer to decompose hydrocarbon fuel into carbon and hydrogen gas by using heat and a pressure of combustion gas produced in a combustion chamber, and to separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane. The decomposer can be adjacent to an intake port in a state of communicating with the intake port via the hydrogen permeable membrane, and can be configured to be able to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port.

## Claims

### Claim 1

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port, wherein
the decomposer includes:
a case that installed along the intake port;
a reformer accommodated in the case so as to extend along the case; and
a closed pipe passage in a central portion of the reformer and having an open end which communicates with the third port,
a second injector to inject the hydrocarbon fuel from a closed end side of the closed pipe passage toward the closed pipe passage attached to the decomposer, wherein
the fuel reforming system is configured to, in a first half of the recompression stroke, inject the hydrocarbon fuel from the second injector in an open state of the third port.

### Claim 2 (depends on 1)

The fuel reforming system according to claim 1, wherein the third port is in the open state during the re-expansion stroke.

### Claim 3

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port,
further comprising:
a first injector to inject the hydrocarbon fuel inside of the third port is attached to the third port, wherein
the fuel reforming system is configured to, in a latter half of the recompression stroke, inject the hydrocarbon fuel from the first injector in an open state of the third port, and wherein
the third port is in the open state during the re-expansion stroke.

### Claim 4

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port, wherein
the decomposer has a communication passage therein, the communication passage communicating between the third port and an intake supply located on an upstream side of the intake port, and
a regulation valve configured to block a flow from the third port side toward the intake supply side is between the intake supply and the communication passage.

### Claim 5

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port,
further comprising control circuitry configured to control the fuel reforming system according to the six-stroke cycle, including selective opening and closing of the third port.

### Claim 6

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port,
further comprising:
the third port, wherein
the decomposer is fluidly between the third port and the intake port.

### Claim 7

A fuel reforming system for a vehicle on which a reciprocating engine is mounted, wherein in the reciprocating engine, a combustion chamber where combustion occurs is partitioned in a cylinder in which a piston reciprocates, the reciprocating engine being configured to perform a six-stroke cycle including:
an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
a recompression stroke in which combustion gas is compressed by raising the piston;
a re-expansion stroke in which the piston is lowered; and
an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, the fuel reforming system comprising:
a decomposer configured to communicate with the combustion chamber via an openable/closable third port, decompose hydrocarbon fuel into carbon and hydrogen gas, and store the carbon; and
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer, wherein
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane,
the decomposer is in fluid communication with the intake port via the hydrogen permeable membrane,
the decomposer is disposed adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port, wherein
the decomposer includes a catalyst to decompose the hydrocarbon fuel into the carbon gas and the hydrogen gas based on the heat and the pressure of the combustion gas produced in the combustion chamber.

### Claim 8

A fuel reforming method using a fuel reforming system for a reciprocating engine having a combustion chamber where combustion occurs partitioned in a cylinder in which a piston is operative to reciprocate, the method comprising:
controlling performance of an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
controlling performance of a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston;
controlling performance of an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
controlling performance of a recompression stroke in which combustion gas is compressed by raising the piston;
controlling performance of a re-expansion stroke in which the piston is lowered; and
controlling performance of an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, wherein
the fuel reforming system includes:
a decomposer in fluid communication with the combustion chamber to decompose hydrocarbon fuel into carbon and hydrogen gas,
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer,
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane of the decomposer,
the decomposer is adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port, wherein
the decomposer includes:
a case that installed along the intake port;
a reformer accommodated in the case so as to extend along the case; and
a closed pipe passage in a central portion of the reformer and having an open end which communicates with the third port,
a second injector to inject the hydrocarbon fuel from a closed end side of the closed pipe passage toward the closed pipe passage attached to the decomposer, wherein
the fuel reforming system is configured to, in a first half of the recompression stroke, inject the hydrocarbon fuel from the second injector in an open state of the third port.

### Claim 9

A fuel reforming method using a fuel reforming system for a reciprocating engine having a combustion chamber where combustion occurs partitioned in a cylinder in which a piston is operative to reciprocate, the method comprising:
controlling performance of an intake stroke in which at least intake air is introduced into the combustion chamber through an intake port by lowering the piston;
controlling performance of a compression stroke in which air-fuel mixture containing fuel supplied to the combustion chamber is compressed by raising the piston:
controlling performance of an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture;
controlling performance of a recompression stroke in which combustion gas is compressed by raising the piston;
controlling performance of a re-expansion stroke in which the piston is lowered; and
controlling performance of an exhaust stroke in which exhaust gas is discharged through an exhaust port by raising the piston, wherein
the fuel reforming system includes:
a decomposer in fluid communication with the combustion chamber to decompose hydrocarbon fuel into carbon and hydrogen gas,
a hydrocarbon fuel supply to supply the hydrocarbon fuel to the decomposer,
the decomposer is configured to decompose the hydrocarbon fuel into the carbon and the hydrogen gas using heat and a pressure of the combustion gas produced in the combustion chamber, and separate the hydrogen gas by causing the hydrogen gas to permeate a hydrogen permeable membrane of the decomposer,
the decomposer is adjacent to and in fluid communication with the intake port, and
the fuel reforming system is configured to supply the separated hydrogen gas as fuel to the combustion chamber through the intake port, wherein
the decomposer has a communication passage therein, the communication passage communicating between the third port and an intake supply located on an upstream side of the intake port, and
a regulation valve configured to block a flow from the third port side toward the intake supply side is between the intake supply and the communication passage.