Engine device

Patent metadata

Field	Value
Publication number	US-10378461-B2
Application number	US-201615760890-A
Country	US
Kind code	B2
Filing date	May 24, 2016
Priority date	Sep 16, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

An engine device (21) including: an intake manifold (67) configured to supply air into a cylinder (77), an exhaust manifold (44) configured to output exhaust gas from the cylinder; a gas injector (98) which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve (79) configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to another between a gas mode and a diesel mode, a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, and then is controlled by a speed-governing control based on the engine rotation number. The switching threshold value is set based on the engine rotation number or the engine load.

First claim

The invention claimed is:

1. An engine device comprising:
an intake manifold configured to supply air into a cylinder;
an exhaust manifold configured to output an exhaust gas from the cylinder;
a gas injector configured to mix a gaseous fuel with the air supplied from the intake manifold; and
a main fuel injection valve configured to inject a liquid fuel into the cylinder for combustion, the gas injector and the main fuel injection valve being coupled to the cylinder, and
an engine controlling device configured to switch operation modes between:
a gas mode in which the gaseous fuel is supplied into the cylinder; and
a diesel mode in which the liquid fuel is supplied into the cylinder,

wherein, to switch between the operation modes, the engine controlling device is configured to:
calculate a switching threshold value based on an engine rotation number; and
based on a determination that a first fuel supply amount of a first fuel is greater than or equal to the switching threshold value, perform a speed-governing control of the first fuel supply amount.

2. The engine device according to claim 1 , wherein:
before switching the operation modes, a second fuel supply amount is controlled by the speed-governing control based on the engine rotation number, and
after the first fuel supply amount reaches the switching threshold value the second fuel supply amount is gradually decreased.

3. The engine device according to claim 2 , wherein, to switch between the operation modes, the second fuel supply amount is stopped when the second fuel supply amount reaches a minimum threshold value.

4. The engine device according to claim 1 , wherein the switching threshold value is set to a small value, when the engine rotation number or an engine load is low.

5. The engine device according to claim 1 , wherein:
the engine controlling device is configured to instantly switch between operation modes, and
when instantly switching from the gas mode to the diesel mode, a supply amount of a liquid fuel is started and set based on the engine rotation number or an engine load, a supply of the gaseous fuel is simultaneously stopped, and
the supply amount of the liquid fuel is controlled by the speed-governing control.

6. The engine device according to claim 5 , wherein the supply amount of the liquid fuel after an instant switching is set to a small amount, when the engine rotation number or the engine load is low.

7. An engine system comprising:
an engine controlling device configured to drive an engine in either:
a gas mode in which gaseous fuel is supplied into a cylinder of the engine; or
a diesel mode in which liquid fuel is supplied into the cylinder,

wherein:
prior to a time of switching an operation mode from one to another between the gas mode and the diesel mode:
a supply amount of a second fuel to be supplied in a pre-switching operation mode is controlled by a speed-governing control based on an engine rotation number;

at the time of switching an operation mode from one to another between the gas mode and the diesel mode:
a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, the switching threshold value is set based on an engine rotation number or an engine load; and

after the supply amount of the first fuel reaches the switching threshold value through the increase control:
the first fuel to be supplied in the post-switching operation mode is controlled by the speed-governing control based on the engine rotation number; and
the supply amount of the second fuel is decreased by a decrease control which monotonously decreases the supply amount.

8. The engine system according to claim 7 , further comprising:
an intake manifold configured to supply air into a cylinder of a plurality of cylinders;
an exhaust manifold configured to output an exhaust gas from the cylinder;
a gas injector configured to mix the gaseous fuel with the air supplied from the intake manifold; and
a main fuel injection valve configured to inject the liquid fuel into the cylinder for combustion, the gas injector and the main fuel injection valve being coupled to each of the plurality of the cylinders.

9. The engine system according to claim 8 , further comprising:
the engine comprising the plurality of cylinders and coupled to the intake manifold and to the exhaust manifold.

10. The engine system according to claim 7 , wherein switching the operation mode from one to another between the gas mode and the diesel mode comprises switching from the gas mode to the diesel mode such that the first fuel comprises the liquid fuel and the second fuel comprises the gaseous fuel.

11. The engine system according to claim 7 , wherein switching the operation mode from one to another between the gas mode and the diesel mode comprises switching from the diesel mode to the gas mode such that the first fuel comprises the gaseous fuel and the second fuel comprises the liquid fuel.

12. The engine system according to claim 7 , wherein supply of the second fuel is stopped when the supply amount of the second fuel reaches a lower limit value by the decrease control.

13. The engine system according to claim 7 , wherein, at a time of instantly switching from the gas mode to the diesel mode, a supply amount of a liquid fuel after the switch to the diesel mode is set based on the engine rotation number or the engine load, supply of the liquid fuel is started and supply of the gaseous fuel is stopped, and then the supply amount of the liquid fuel is controlled by the speed-governing control.

14. The engine system according to claim 7 , after the supply amount of the first fuel reaches the switching threshold value through the increase control, the supply amount of the second fuel is decreased by the decrease control independent of the supply amount of the first fuel.

15. An engine system comprising:
an engine controlling device configured to drive an engine in either of:
a gas mode in which gaseous fuel is supplied into a cylinder of the engine; or
a diesel mode in which liquid fuel is supplied into the cylinder,

wherein, to switch between operation modes, the engine controlling device is configured to:
calculate a switching threshold value based on an engine rotation number; and
based on determination that a first fuel supply amount of a first fuel is greater than or equal to the switching threshold value, perform a speed-governing control of the first fuel supply amount.

16. The engine system of claim 15 , wherein:
the engine controlling device is configured to:
prior to initiation of a switch operation to switch between the operation modes, perform speed-governing control of a second fuel; and
to switch between the operation modes:
identifying the engine rotation number;
increase the first fuel to the first fuel supply amount;
compare the first fuel supply amount to the switching threshold value; and
based on a determination that the first fuel supply amount is greater than or equal to the switching threshold value:
initiate a decrease of a second fuel; and
perform speed-governing control of the first fuel.

17. The engine system of claim 16 , wherein, to switch between the operation modes, the engine controlling device is further configured to:
compare a decreased amount of the second fuel to a minimum threshold value; and
when the decreased amount is less than or equal to the minimum threshold value, stop supply of the secon

Assignees

• Yanmar Co Ltd

Inventors

• Hagiwara Ryoichi
• Doi Masayoshi
• Murakami Taishi
• OHSARA Tatsuro
• Yamagishi Osamu

Classifications

• F02D19/105

  operating in a special mode, e.g. in a liquid fuel only mode for starting · CPC title

• F02D19/0618

  depending on the engine's or vehicle's position, e.g. on/off road or proximity to a harbor · CPC title

• F02D2041/389

  for injecting directly into the cylinder · CPC title

• F02D19/061

  by controlling fuel injectors · CPC title

• F02D19/0647

  the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME] · CPC title