Hydrogen Engine System

Abstract

To provide a hydrogen engine system having improved safety.SOLUTION: The problem can be solved by a hydrogen engine system comprising: a hydrogen engine equipped with a fuel injection system that injects hydrogen as fuel; a cover covering the fuel injection system; a hydrogen concentration sensor for detecting a hydrogen concentration in the inside of the cover; an injection device for injecting an inert gas into the inside of the cover; and a control device that controls the injection device in accordance with the detection result of the hydrogen concentration sensor to inject the inert gas into the inside of the cover so that the hydrogen in the inside of the cover is diluted.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrogen engine system. [Background technology]

[0002] BACKGROUND ART A hydrogen engine equipped with a fuel injection system that injects hydrogen as fuel is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-214937 Summary of the Invention [Problem to be solved by the invention]

[0004] For such hydrogen engines, it is desirable to improve safety against hydrogen leakage from the fuel injection system.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a hydrogen engine system with improved safety. [Means for solving the problem]

[0006] The above object can be achieved by a hydrogen engine system comprising: a hydrogen engine equipped with a fuel injection system that injects hydrogen as fuel; a cover that covers the fuel injection system; a hydrogen concentration sensor that detects the hydrogen concentration within the cover; an injection device that injects inert gas into the cover; and a control device that controls the injection device in accordance with the detection result of the hydrogen concentration sensor to inject the inert gas into the cover so as to dilute the hydrogen within the cover.

[0007] A plurality of the hydrogen concentration sensors may be provided at different positions.

[0008] When the hydrogen concentration detected by at least one of the plurality of hydrogen concentration sensors is equal to or greater than a first threshold value, the control device may control the injection device to inject the inert gas into the cover.

[0009] When the hydrogen concentration detected by each of the multiple hydrogen concentration sensors is less than a second threshold value that is less than the first threshold value, the control device may control the injection device to stop injecting the inert gas into the cover. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a hydrogen engine system with improved safety. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a hydrogen engine system. [Figure 2] Figure 2 shows a top view of a hydrogen engine. [Figure 3] FIG. 3 is a flowchart illustrating the hydrogen dilution control. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Overview of hydrogen engine system] Fig. 1 is a schematic diagram of a hydrogen engine system 1. This hydrogen engine system 1 comprises a hydrogen engine 10, a cover 30, and an ECU (Electronic Control Unit) 50. Fig. 2 is a diagram showing the hydrogen engine 10 as seen from above. The hydrogen engine system 1 is mounted on, for example, a vehicle. The vehicle may be, for example, an engine vehicle equipped with only the hydrogen engine 10 as a power source for running, or it may be a hybrid vehicle equipped with both the hydrogen engine 10 and a motor as a power source for running.

[0013] The crankshaft 11 of the hydrogen engine 10 rotates due to the combustion of hydrogen gas injected into the combustion chamber of the hydrogen engine 10 from a fuel injection system 12. The fuel injection system 12 is installed on the intake side at the top of the hydrogen engine 10. The fuel injection system 12 includes, for example, a delivery pipe connected to a fuel tank and a fuel injection valve connected to the delivery pipe. The fuel injection valve includes, for example, a port injection valve or an in-cylinder injection valve.

[0014] The cover 30 covers the upper part of the hydrogen engine 10. The cover 30 includes side walls 31 to 34 and an upper wall 35. The side walls 32 and 33 are located on the exhaust side and intake side, respectively, of the upper part of the hydrogen engine 10. The side walls 31 and 34 are located on one end side and the other end side of the crankshaft 11, respectively, of the upper part of the hydrogen engine 10. The lower edges of the side walls 31 to 34 are located below the fuel injection system 12. The cover 30 is preferably made of a material with low hydrogen permeability.

[0015] The upper wall portion 35 is provided with hydrogen concentration sensors 61 and 62 at different positions. The hydrogen concentration sensors 61 and 62 detect the hydrogen concentration inside the cover 30. The hydrogen concentration sensors 61 and 62 are electrically connected to the ECU 50. If hydrogen leaks from the fuel injection system 12, the specific gravity of hydrogen is lighter than that of air, and the hydrogen accumulates in the upper portion of the cover 30. In this manner, the cover 30 collects the hydrogen leaked from the fuel injection system 12. The hydrogen concentration sensors 61 and 62 detect the hydrogen concentration inside the cover 30, and therefore can detect hydrogen leakage from the fuel injection system 12 at an early stage. The positions at which the hydrogen concentration sensors 61 and 62 are provided are not limited to the upper wall portion 35. For example, the hydrogen concentration sensor 61 may be provided on one of the side wall portions 31 to 34 or the upper wall portion 35, and the hydrogen concentration sensor 62 may be provided on one of the other side wall portions 31 to 34 or the upper wall portion 35.

[0016] The ECU 50 is mainly composed of a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and other volatile and non-volatile memories. The ECU 50 executes various control processes related to the hydrogen engine 10 by running programs installed in the memory on the CPU. The ECU 50 is an example of a control device.

[0017] An injection nozzle 41 is provided to penetrate the side wall portion 33. The injection nozzle 41 is connected to a gas tank 43 via a hose 42. The gas tank 43 stores an inert gas. The inert gas is, for example, carbon dioxide, nitrogen, or argon. The ECU 50 controls the injection nozzle 41 to inject the inert gas from the injection nozzle 41 into the cover 30. The injection nozzle 41 is an example of an injection device. The position where the injection nozzle 41 is provided is not limited to the side wall portion 33, and the injection nozzle 41 may be provided on another wall portion.

[0018] [Hydrogen dilution control] 3 is a flowchart illustrating hydrogen dilution control. The ECU 50 determines whether at least one of the detected hydrogen concentrations H1 and H2 detected by the hydrogen concentration sensors 61 and 62, respectively, is equal to or greater than threshold value A (step S1). Threshold value A is set to a hydrogen concentration at which it is preferable to dilute the hydrogen from the perspective of ensuring safety. If both detected hydrogen concentrations H1 and H2 are less than threshold value A, the determination in step S1 is No, and this control ends. If the determination in step S1 is Yes, the ECU 50 controls the injection nozzle 41 to inject inert gas into the cover 30 (step S2). This dilutes the hydrogen in the cover 30.

[0019] Next, the ECU 50 determines whether both the detected hydrogen concentrations H1 and H2 are less than the threshold value B (step S3). The threshold value B is lower than the threshold value A. The threshold value B is set to a hydrogen concentration that ensures sufficient safety. If at least one of the detected hydrogen concentrations H1 and H2 is equal to or greater than the threshold value B, the determination in step S3 is No, and step S2 continues. As a result, the hydrogen inside the cover 30 is sufficiently diluted, and the gas with the reduced hydrogen concentration is discharged from the cover 30 to the outside.

[0020] If the answer to step S3 is Yes, the ECU 50 controls the injection nozzle 41 to stop the injection of the inert gas (step S4). In this way, even if hydrogen leaks from the fuel injection system 12, the hydrogen can be diluted, thereby improving safety.

[0021] In the above embodiment, an example in which two hydrogen concentration sensors 61 and 62 are provided has been described, but the present invention is not limited to this, and the number of hydrogen concentration sensors may be one, or three or more.

[0022] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0023] 1 Hydrogen engine system 10 Hydrogen engine 30 Cover 41 Injection nozzle (injection device) 50 ECU (control unit) 61, 62 Hydrogen concentration sensor

Claims

[Claim 1] A hydrogen engine system mounted on a vehicle, comprising: a hydrogen engine that is a power source for driving the vehicle and that includes a fuel injection system that injects hydrogen as fuel; a cover having four side walls and a top wall, which covers the top of the hydrogen engine, thereby covering the fuel injection system but not the crankshaft of the hydrogen engine; a hydrogen concentration sensor for detecting the hydrogen concentration inside the cover; an injector for injecting an inert gas into the cover; a control device that controls the injection device to inject the inert gas into the cover in accordance with a detection result of the hydrogen concentration sensor so as to dilute the hydrogen in the cover; a plurality of the hydrogen concentration sensors are provided at different positions on the upper wall portion; When the hydrogen concentration detected by at least one of the plurality of hydrogen concentration sensors is equal to or greater than a first threshold value, the control device controls the injection device to inject the inert gas into the cover, A hydrogen engine system, wherein when the hydrogen concentration detected by each of the plurality of hydrogen concentration sensors is less than a second threshold value which is equal to or less than the first threshold value, the control device controls the injection device to stop injection of the inert gas into the cover.

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