Work vehicle power system with dynamic auto-ignition assistance compression ratios

Patent metadata

Field	Value
Publication number	US-12553395-B2
Application number	US-202218145524-A
Country	US
Kind code	B2
Filing date	Dec 22, 2022
Priority date	Dec 22, 2022
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A power system for a work vehicle includes a compression ignition engine with piston-cylinder set that defines a compression ratio. The engine further includes a piston actuation arrangement coupled to the piston of the first piston-cylinder set and configured to be repositioned to dynamically modify the compression ratio of the first piston-cylinder set. The system includes a controller coupled to command the first piston actuation arrangement such that, in an auto-ignition assistance mode, the first piston actuation arrangement places the first piston into a first configuration resulting in a first compression ratio; and in a nominal mode, the first piston actuation arrangement places the first piston into a second configuration resulting a second compression ratio that is lower than the first compression ratio.

First claim

What is claimed is:

1 . A power system for a work vehicle, comprising:
an intake arrangement configured to intake charge air; a compression ignition engine including:
a plurality of piston-cylinder sets configured to receive, ignite, and combust intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas, wherein at least a first piston-cylinder set of the piston-cylinder sets includes:
a cylinder defining an intake port and an exhaust port;
a piston positioned at least partially within the cylinder to from a combustion chamber in between that defines a compression ratio, the combustion chamber being in fluid communication with the intake port and the exhaust port;
an intake valve configured to open and close the intake port;
an exhaust valve configured to open and close the exhaust port; and
a fuel injector configured to inject fuel into the combustion chamber; and

a plurality of piston actuation arrangements, including a first piston actuation arrangement coupled to the piston of the first piston-cylinder set and configured to be repositioned to dynamically modify the compression ratio of the first piston-cylinder set;
an exhaust sensor configured to sense a temperature of the exhaust gas; and a controller coupled to command the first piston actuation arrangement such that,
in an auto-ignition assistance mode, the first piston actuation arrangement places the first piston into a first configuration resulting in a first compression ratio; and
in a nominal mode, the first piston actuation arrangement places the first piston into a second configuration resulting a second compression ratio that is lower than the first compression ratio;
wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on signals from the exhaust sensor associated with the exhaust gas temperature.

2 . The power system of claim 1 , wherein the compression ignition engine is configured to operate with a low cetane fuel.

3 . The power system of claim 1 , wherein the compression ignition engine is configured to operate with a low cetane fuel having a cetane value of less than 40.

4 . The power system of claim 3 , wherein the first compression ratio of the first piston-cylinder set in the auto-ignition assistance mode is sufficient to auto-ignite the low cetane fuel.

5 . The power system of claim 3 , wherein the first compression ratio of the first piston-cylinder set in the auto-ignition assistance mode is sufficient to result in a temperature within the combustion chamber of at least 800° C. independent of operating conditions.

6 . The power system of claim 1 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on ambient temperature.

7 . The power system of claim 1 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on intake temperature.

8 . The power system of claim 1 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on engine load.

9 . The power system of claim 1 , wherein the controller is configured to command the first piston actuation arrangement to place or maintain the first piston-cylinder set at the first compression ratio during start-up in the auto-ignition assistance mode.

10 . A work vehicle, comprising:
a chassis; a drive assembly supported on the chassis; a power system supported on the chassis and configured to power the drive assembly, the power system comprising:
an intake arrangement configured to intake charge air; and
a compression ignition engine including:
a plurality of piston-cylinder sets configured to receive, ignite, and combust intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas, wherein at least a first piston-cylinder set of the piston-cylinder sets includes:
a cylinder defining an intake port and an exhaust port;
a piston positioned at least partially within the cylinder to from a combustion chamber in between that defines a compression ratio, the combustion chamber being in fluid communication with the intake port and the exhaust port;

an intake valve configured to open and close the intake port;
an exhaust valve configured to open and close the exhaust port; and
a fuel injector configured to inject fuel into the combustion chamber; and
a plurality of piston actuation arrangements, including a first piston actuation arrangement coupled to the piston of the first piston-cylinder set and configured to be repositioned to dynamically modify the compression ratio of the first piston-cylinder set;
an exhaust sensor configured to sense a temperature of the exhaust gas; and

a controller coupled to command the first piston actuation arrangement such that,
in an auto-ignition assistance mode, the first piston actuation arrangement places the first piston into a first configuration resulting in a first compression ratio; and
in a nominal mode, the first piston actuation arrangement places the first piston into a second configuration resulting a second compression ratio that is lower than the first compression ratio;
wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on signals from the exhaust sensor associated with the exhaust gas temperature.

11 . The work vehicle of claim 10 , wherein the compression ignition engine is configured to operate with a low cetane fuel.

12 . The work vehicle of claim 10 , wherein the compression ignition engine is configured to operate with fuel having a cetane value of less than 40.

13 . The work vehicle of claim 12 , wherein the first compression ratio of the first piston-cylinder set in the auto-ignition assistance mode is sufficient to auto-ignite the low cetane fuel.

14 . The work vehicle of claim 12 , wherein the first compression ratio of the first piston-cylinder set in the auto-ignition assistance mode is sufficient to result in a temperature within the combustion chamber of at least 800° C. independent of operating conditions.

15 . The work vehicle of claim 10 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on ambient temperature.

16 . The work vehicle of claim 10 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on intake temperature.

17 . The work vehicle of claim 10 , wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on engine load.

18 . The work vehicle of claim 10 , wherein the controller is configured to command the first piston actuation

Assignees

• Deere & Co

Inventors

• Devries Kevin B
• Lohmann Craig W
• Dou Danan

Classifications

• F02B75/18

  Multi-cylinder engines (scavenging aspects F02B25/00) · CPC title

• F02B75/045 Primary

  by means of a variable connecting rod length · CPC title

• F02B9/02

  with compression ignition (engines characterised by fuel-air mixture compression with compression ignition F02B1/12; engines characterised by air compression and subsequent fuel addition with compression ignition F02B3/06) · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title

• B62D49/06

  adapted for multi-purpose use · CPC title