Internal combustion engine

Abstract

An internal combustion engine with at least one combustion chamber, at least one fuel delivery line for the delivery of fuel to at least one combustion chamber, and at least one differential pressure control valve for controlling the pressure in the at least one fuel delivery line. The at least one differential pressure control valve is configured to perform a valve opening or valve closing movement based on a pressure difference between the at least one fuel delivery line and a reference volume having a reference pressure. The internal combustion engine further includes at least one pressure relief valve, separate from the at least one differential pressure control valve, and configured to open to cause a pressure relief in the reference volume and a decrease in the reference pressure if a drop occurs in the power to be performed by the internal combustion engine.

Claims

1. A system, comprising: a pressure control valve configured to couple to a fuel delivery line that delivers a fuel flow to at least one combustion chamber of an internal combustion engine, wherein the pressure control valve is adjustable to control a fuel pressure of the fuel flow; and a controller configured to control the pressure control valve to control a ratio between the fuel pressure and an air charge pressure of an air flow delivered to the at least one combustion chamber, wherein the controller is configured to control the ratio based on at least one threshold value, and the controller is configured to control a pressure relief valve to adjust the pressure control valve in response to a change in the air charge pressure while a compressor operates to generate the air charge pressure.

2. The system of claim 1, wherein the at least one threshold value comprises a high threshold.

3. The system of claim 2, wherein the at least one threshold value comprises a low threshold.

4. The system of claim 1, wherein the controller is configured to control the ratio based on the at least one threshold value in response to a load shedding on the internal combustion engine resulting in a power reduction of at least 50 percent or more.

5. The system of claim 4, wherein the controller is configured to control the ratio based on the at least one threshold value in response to a decrease in the air charge pressure associated with the load shedding by providing a corresponding decrease in the fuel pressure to ensure that the ratio is between a high threshold and a low threshold.

6. The system of claim 1, wherein the controller is configured to control the ratio at least by adjusting the pressure control valve based on an input indicating the change in the air charge pressure.

7. The system of claim 6, wherein the input comprises a target or actual value for the air charge pressure.

8. The system of claim 1, wherein the pressure control valve comprises a differential pressure control valve configured to move in response to a difference between a reference pressure and the fuel pressure, and the controller is configured to adjust the reference pressure to control the ratio.

9. The system of claim 8, wherein the controller is configured to control a pilot control valve and the pressure relief valve to adjust the reference pressure, the pilot control valve and the pressure relief valve are coupled to a bypass line, and the bypass line is coupled to the fuel delivery line upstream and downstream of the differential pressure control valve.

10. The system of claim 1, comprising the pressure relief valve configured to couple to a bypass line that couples to the fuel delivery line upstream and downstream of the pressure control valve.

11. The system of claim 1, comprising the internal combustion engine coupled to the fuel delivery line having the pressure control valve.

12. The system of claim 11, comprising a turbocharger coupled to the internal combustion engine, wherein the turbocharger comprises the compressor configured to deliver the air flow at the air charge pressure to the at least one combustion chamber.

13. A system, comprising: a controller configured to control a pressure control valve along a fuel delivery line that delivers a fuel flow to at least one combustion chamber of an internal combustion engine, wherein the pressure control valve is adjustable to control a fuel pressure of the fuel flow, wherein the controller is configured to control a ratio between the fuel pressure and an air charge pressure of an air flow delivered to the at least one combustion chamber, wherein the controller is configured to control the ratio based on at least one threshold value, and the controller is configured to control a pressure relief valve to adjust the pressure control valve in response to a change in the air charge pressure while a compressor operates to generate the air charge pressure.

14. The system of claim 13, wherein the at least one threshold value comprises a high threshold and a low threshold.

15. The system of claim 14, wherein the controller is configured to control the ratio based on the at least one threshold value in response to a load shedding on the internal combustion engine resulting in a power reduction of at least 50 percent or more, wherein the controller is configured to control the ratio based on the at least one threshold value in response to a decrease in the air charge pressure associated with the load shedding by providing a corresponding decrease in the fuel pressure to ensure that the ratio is between the high threshold and the low threshold.

16. The system of claim 13, wherein the controller is configured to control the ratio at least by adjusting the pressure control valve based on an input indicating the change in the air charge pressure.

17. The system of claim 13, wherein pressure control valve comprises a differential pressure control valve configured to move in response to a difference between a reference pressure and the fuel pressure, wherein the controller is configured to adjust the reference pressure to control the ratio.

18. A method, comprising: adjusting a fuel pressure via a pressure control valve coupled to a fuel delivery line that delivers a fuel flow to at least one combustion chamber of an internal combustion engine; and controlling the pressure control valve to control a ratio between the fuel pressure and an air charge pressure of an air flow delivered to the at least one combustion chamber, wherein the control of the ratio is based on at least one threshold value, wherein controlling the pressure control valve comprises controlling a pressure relief valve to adjust the pressure control valve in response to a change in the air charge pressure while a compressor operates to generate the air charge pressure.

19. The method of claim 18, wherein controlling the pressure control valve to control the ratio based on the at least one threshold value is in response to a load shedding on the internal combustion engine resulting in a power reduction of at least 50 percent or more, wherein controlling the pressure control valve to control the ratio based on the at least one threshold value is in response to a decrease in the air charge pressure associated with the load shedding by providing a corresponding decrease in the fuel pressure to ensure that the ratio is between a high threshold and a low threshold.

20. The method of claim 18, wherein controlling the pressure control valve to control the ratio based on the at least one threshold value comprises adjusting the pressure control valve based on an input indicating the change in the air charge pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and details of this invention can be found in the Figures and in the related description of those Figures. In that respect,

(2) FIG. 1 shows a first shows a schematic view of an embodiment according to the invention; and

(3) FIG. 2 shows a schematic overview of an internal combustion engine according to the invention.

DETAILED DESCRIPTION

(4) FIG. 1 shows the at least one fuel delivery line 3 with a through-flow into the direction that is indicated by the arrow with the reference X. The pressure in the at least one fuel delivery line 3 is controlled by a differential pressure control valve 4. For this purpose, a pressure chamber 11 is provided that is divided into a first partial volume 12 and a second partial volume 13. A spring-loaded movable diaphragm 14 takes care of the partition.

(5) The first partial volume 12 is fluidly connected to the at least one fuel delivery line 3, i.e., in the first partial volume 12, there is substantially the same pressure as in the at least one fuel delivery line 3. The fluid connection between the at least one fuel delivery line 3 and the first partial volume 12 of the pressure chamber 11 is resolved by a control line 17 that is connected downstream of a valve body 15 and a valve seat 16 with the at least one fuel delivery line 3.

(6) The second partial volume 13 is part of a reference volume 5 in which a reference pressure is present. Control of the reference pressure is described in further detail below.

(7) The plate-shaped valve body 15 in this embodiment is movably connected to the diaphragm 14 by a rod. Differences in pressure between the first partial volume 12 and the second partial volume 13 cause movements in the spring-loaded movable diaphragm 14 that further leads to relative movements of the valve body 15 to the valve seat 16 arranged in the at least one fuel delivery line 3.

(8) If the reference pressure in the second partial volume 13 is higher than the pressure in the at least one fuel delivery line 3, the diaphragm 14 moves downwards causing the valve body 15 to perform an opening movement, which then leads to an adjustment of the pressure in the at least one fuel delivery line 3 to the reference pressure. In turn, of course, pressure in the at least one fuel delivery line 3, which is higher than the reference pressure, leads to a closing movement of valve body 15 and, in this case, also leads to an adjustment of the pressure in the at least one fuel delivery line 3 to the reference pressure in the second partial volume 13.

(9) For supplying the reference volume 5, a bypass line 9 of the at least one fuel delivery line 3 is provided around the differential pressure control valve 4. Initially, a pilot control valve 8 is present in this bypass line 9. The pilot control valve 8 controls the reference pressure that exists downstream of the pilot control valve 8 and, therefore, also in the second partial volume 13 that has a fluid connection with bypass line 9. Consequently, the parts of the line downstream of the pilot control valve 8 of the bypass line 9 and the second volume part 13 of the pressure chamber 11 form the reference volume 5.

(10) An electronic open-loop or closed-loop control device 7 is provided that is connected to the pilot control valve 8. This connection specifies a target value for the reference pressure, which is defined, by way of example, on the basis of target or actual values for the charge pressure or power of the internal combustion engine.

(11) The pilot control valve 8 is divided into two parts, in the illustration shown with a left-hand input-output part for converting the electronically specified target value into a mechanical actuator movement and a second mechanical section on the right.

(12) According to the invention, a pressure relief valve 6 is provided which in this embodiment is also actuated by the open-loop or closed-loop control device 7. In the event of a drop in power, the open-loop or closed-loop control device 7 not only adapts the target value for the pilot control in the reference volume 5, it also opens the pressure relief valve 6. By this the reference volume 5 is opened relative to the environment, which can cause the reference pressure in reference volume 5 to drop rapidly, in particular with a similar speed as to the drop in charge pressure in response to a load shedding.

(13) Consequently, the differential pressure control valve 4 performs a closing movement of the valve body 15 with only a slight delay, by which the pressure in the at least one fuel delivery line 3 drops as rapidly as the charge pressure.

(14) A valve 19 in the bypass line 9 and downstream of the pilot control valve 8 substantially assumes the function of a restrictor (restrictor valve) with which a variable flow resistance can be induced and consequently a variable reference pressure can be built up. In the event of increased flow resistance, the pressure in the second partial volume 13 rises, causing an opposing movement of the diaphragm 14 to the spring force and resulting in an opening movement of valve body 15. In turn, an opening of the restrictor 19 leads to a decrease of the reference pressure in the second partial volume 13, causing the valve body 15 to perform a closing movement, which in turn results in a pressure reduction in the fuel delivery line 3.

(15) FIG. 2 shows the embodiment according to FIG. 1 in a schematic diagram of the internal combustion engine 1. In addition to the turbocharger 10 that provides a charge pressure for supplying the combustion chambers 2 in the form of piston-cylinder units, the differential pressure control valve 4 in the at least one fuel delivery line 3 as well as the pilot control valve 8 and the pressure relief valve 6 according to the invention are shown in the form of symbols. In most internal combustion engines 1 of this kind, the pressure in the at least one fuel delivery line 3 is always higher than the charge pressure.

(16) Reference symbol F indicates a fuel reservoir that takes the form of a gas pressure vessel in this embodiment.

(17) The delivery of the charge air generated by the turbocharger 10 to the piston-cylinder units is realized via a distributor space illustrated by a triangular symbol.

(18) Separately, each piston-cylinder unit is equipped with one direct injection or port injection valve 18.

(19) It is to be noted that the fuel, preferably gaseous fuel, is injected into the area of what is known as the intake port by port injection valve 18.

(20) The correct functional method for the direct injection valve or port injection valve 18 requires that the ratio between the pressure in the at least one fuel delivery line 3 and the charge pressure does not exceed a specific value.

(21) Without the pressure relief valve 6 according to the invention, it can happen that the charge pressure drops so fast (e.g., due to a major load shedding) that the control line for the pressure in the at least one fuel delivery line 3 is too slow. The ratio referred to then becomes too great, meaning that the port injection valves 18 are then no longer able to open, which, of course, causes disruptions to the correct operation of the internal combustion engine 1.

(22) The pressure relief valve 6 according to the invention delivers a fast adjustment of the reference pressure and, therefore, of the pressure in the at least one fuel delivery line 3, preventing the afore-mentioned disruptions. Subsequently, the internal combustion engine 1 consumes excess fuel from the at least one fuel delivery line 3 until the balance in the at least one fuel delivery line 3 is restored.