SUPPLY SYSTEM

A supply system for supplying ozone to an engine includes an electrolysis part that electrolyzes water to generate hydrogen and oxygen, a first supply part that supplies hydrogen generated by the electrolysis part to an intake pipe of the engine, an ozone generation part that generates ozone from oxygen generated by the electrolysis part, and a second supply part that supplies ozone generated by the ozone generation part to the intake pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Applications number 2023-42030, filed on Mar. 16, 2023, contents of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present disclosure relates to a supply system for supplying ozone to an engine. A technology for supplying ozone to an engine is known. Japanese Unexamined Patent Application Publication No. 2019-52607 discloses a technology for generating ozone from intake air (air) by generating an electrical discharge in an intake pipe of an engine and supplying said ozone to the engine.

However, when ozone is generated from air, nitrogen oxides are generated from nitrogen contained in the air. Nitrogen oxides remain after a combustion process of an engine, which can increase the amount of nitrogen oxides emitted from the engine after combustion.

BRIEF SUMMARY OF THE INVENTION

The present disclosure focuses on this point, and an object thereof is to suppress an increase in nitrogen oxides emitted from an engine.

Means for Solving the Problems

An aspect of the present disclosure provides a supply system for supplying ozone to an engine that includes an electrolysis part1that electrolyzes water to generate hydrogen and oxygen, a first supply part that supplies hydrogen generated by the electrolysis part to an intake pipe of the engine, an ozone generation part that generates ozone from oxygen generated by the electrolysis part, and a second supply part that supplies ozone generated by the ozone generation part to the intake pipe.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present disclosure will be described through exemplary embodiments of the present disclosure, but the following exemplary embodiments do not limit the disclosure according to the claims, and not all of the combinations of features described in the exemplary embodiments are necessarily essential to the solution means of the disclosure.

[Configuration of Supply System S]

FIG.1illustrates a configuration of a supply system S. The supply system S includes an electrolysis part1, a first supply part21, a second supply part22, a supply control device4, an engine71, a temperature sensor72, a purification device73, an intake pipe80, and an exhaust pipe84. The supply system S supplies ozone to the engine71. The supply system S is provided in, for example, a vehicle, a ship, a power plant, or the like.

The electrolysis part1includes a power supply11, a U-shaped pipe14, and a water tank15. Each of a cathode12and an anode13of the power supply11is inserted into the U-shaped pipe14. The U-shaped pipe14is supplied with water from the water tank15. The water tank15stores water to which an electrolyte has been added. The electrolyte is sodium hydroxide, sodium carbonate, sodium sulfate or sodium bicarbonate, for example, but is not limited to thereto. The water before the electrolyte is added is industrial pure water, for example, but may be tap water or cooling water of the engine71.

The power supply11applies a voltage between the cathode12and the anode13. The electrolysis part1generates hydrogen and oxygen by electrolyzing water by controlling the power supply11to apply a voltage between the cathode12and the anode13. Specifically, when the power supply11applies a voltage between the cathode12and the anode13, hydrogen is generated from the cathode12of the electrolysis part1, and oxygen is generated from the anode13of the electrolysis part1. The electric power of the power supply11is supplied from a battery, for example. Further, the electric power of the power supply11may be supplied from a photovoltaic power generation system or a regenerative energy system installed in the vehicle, when the supply system S is installed in a vehicle.

The hydrogen generated in the electrolysis part1is supplied from the first supply part21to the intake pipe80. The first supply part21includes a first pipe line81, a hydrogen tank3, a control valve61, and a check valve621. The first pipe line81connects a cathode portion141of the U-shaped pipe14and the intake pipe80. The hydrogen tank3is provided between the electrolysis part1and the control valve61. The hydrogen generated by the cathode12of the electrolysis part1is stored in the hydrogen tank3. The control valve61is provided between the intake pipe80and the hydrogen tank3, and opens and closes under the control of the supply control device4.

The check valve621is provided between the control valve61and the intake pipe80. The check valve621passes the gas from the hydrogen tank3toward the intake pipe80, and blocks the gas travelling from the intake pipe80toward the hydrogen tank3. Specifically, the check valve621passes the hydrogen from the hydrogen tank3to the intake pipe80and blocks the hydrogen travelling from the intake pipe80toward the hydrogen tank3. The check valve621is a disk check valve, for example, but is not limited thereto, and may be a poppet check valve, a swing check valve, or another type of check valve.

A second pipe line82connects an anode portion142of the U-shaped pipe14and an ozone generation part5. The oxygen generated in the electrolysis part1is supplied from the second pipe line82to the ozone generation part5.

The ozone generation part5generates ozone from the oxygen generated by the electrolysis part1. The ozone generation part5converts the oxygen into ozone by irradiating oxygen with ultraviolet light, for example. Specifically, the ozone generation part5includes an ultraviolet lamp, generates ultraviolet light by turning on the ultraviolet lamp, and converts the oxygen passing through the ozone generation part5into ozone. Further, the ozone generation part5includes discharge electrodes, generates ultraviolet light by discharging between the discharge electrodes, and converts the oxygen passing through the ozone generation part5into ozone. The discharge is corona discharge or spark discharge, for example, but is not limited thereto. The electric power used by the ozone generation part5to generate ozone is supplied by the battery, the photovoltaic power generation system, or the regenerative energy system, as in the electrolysis part1.

The ozone generation part5is supplied with the oxygen generated by electrolysis of water, and therefore the oxygen gas supplied to the ozone generation part5through the second pipe line82has a nitrogen content smaller than that of air. The ozone generation part5generates ozone from the oxygen gas which has a nitrogen content smaller than that of air, thereby reducing the amount of nitrogen oxide generated compared to the case where ozone is generated from air.

The second supply part22supplies the ozone generated by the ozone generation part5to the intake pipe80. The second supply part22includes a third pipe line83and a check valve622. The third pipe line83connects the ozone generation part5and the intake pipe80. The check valve622is provided between the ozone generation part5and the intake pipe80. The check valve621passes the gas from the ozone generation part5to the intake pipe80and blocks the gas from the intake pipe80to the ozone generation part5. Specifically, the check valve622passes the ozone from the ozone generation part5to the intake pipe80and blocks the ozone from the intake pipe80to the ozone generation part5. The check valve622may be a check valve of the same type as the check valve621or a check valve of a different type.

The engine71is an internal combustion engine that burns and expands a mixture of fuel and intake air (air) to generate power. The fuel is, for example, gasoline, light oil, or natural gas. The engine71takes in the ozone and the hydrogen supplied to the intake pipe80when taking in the intake air (air) from the intake pipe80. The taking in of the ozone into the cylinder promotes combustion activity, thereby improving the efficiency of fuel combustion. In addition, hydrogen increases combustibility of fuel or acts as fuel. Specifically, the engine71can increase the power output by taking in the intake air including the hydrogen, as compared with the case where no hydrogen is taken in, when injecting the same amount of fuel.

The engine71dispels exhaust through the exhaust pipe84. The amount of nitrogen oxide in the exhaust gas flowing through the exhaust pipe84is lower in the case where the ozone generated from oxygen gas is supplied to the intake pipe80than in the case where the ozone generated from air is supplied to the intake pipe80. The exhaust pipe84is provided with the temperature sensor72and the purification device73.

The temperature sensor72detects an exhaust gas temperature. The temperature sensor72is a thermocouple or thermistor, for example, but is not limited thereto. The interval at which the temperature sensor72detects the exhaust gas temperature may be appropriately set, and a specific value of this interval is 100 milliseconds, for example.

The purification device73purifies the exhaust gas from the engine71. The purification device73is, for example, a Selective Catalytic Reduction (so-called Urea SCR). The SCR includes a catalyst that promotes reaction of nitrogen oxides and ammonia, and reduces nitrogen oxides to nitrogen and water by injecting urea water, a precursor of ammonia, into the exhaust gas flowing through the exhaust pipe84to cause the nitrogen oxides and ammonia to react on the catalyst. Further, the purification device73may include a catalyst that promotes reaction of nitrogen oxides and unburned fuel, and may cause the nitrogen oxides and the unburned fuel to react on the catalyst to achieve decomposition.

The supply control device4controls supply of the hydrogen and the ozone to the intake pipe80.FIG.2illustrates a configuration of the supply control device4. The supply control device4includes a storage41and a controller42. The storage41is a storage medium including a Read Only Memory (ROM), a Random Access Memory (RAM), a hard disk, and the like. The storage41stores a program executed by the controller42.

The controller42is a calculation resource including a processor such as a Central Processing Unit (CPU). The controller42implements functions as an acquisition part421and a supply control part422by executing the program stored in the storage41.

The acquisition part421acquires a requested torque of the engine71from the engine71. Specifically, the acquisition part421acquires the requested torque indicating a magnitude of a torque requested by the engine71from a control device that controls the engine71. Further, the acquisition part421acquires the exhaust gas temperature detected by the temperature sensor72.

The supply control part422causes the electrolysis part1to generate hydrogen and oxygen. Specifically, the supply control part422causes the electrolysis part1to electrolyze water by causing the power supply11of the electrolysis part1to apply a voltage to the cathode12and the anode13, thereby generating hydrogen and oxygen.

The supply control part422supplies the hydrogen, generated by the electrolysis part1, from the first supply part21to the intake pipe80. Specifically, the supply control part422opens the control valve61to supply the hydrogen stored in the hydrogen tank3to the intake pipe80. More specifically, the supply control part422adjusts an opening degree of the control valve61to supply the hydrogen in an amount corresponding to the requested torque from the hydrogen tank3to the intake pipe80. The supply control part422supplies the hydrogen in an amount proportional to the requested torque to the intake pipe80. This allows the engine71to take the hydrogen into a combustion chamber of the engine71, thereby reducing the amount of fuel injected into the cylinder when outputting the requested torque. As a result, the supply control part422can reduce nitrogen oxides generated in the combustion process and unburned fuel, thereby reducing the amount of nitrogen oxides supplied to the purification device73. Therefore, the supply control part422can improve an exhaust gas purification rate of the purification device73as compared with the case where ozone is generated from air and supplied to the intake pipe80.

The supply control part422supplies hydrogen to the intake pipe80when the exhaust gas temperature is lower than a predetermined value. The predetermined value is a reaction temperature at which at least any of i) nitrogen oxides and unburned fuel and ii) nitrogen oxides and ammonia start to react on the catalyst of the purification device73. The reaction temperature is 200 to 300 degrees Celsius, for example, but is not limited thereto. The supply control part422supplies hydrogen to the intake pipe80when the exhaust gas temperature is lower than the reaction temperature of the catalyst, thereby reducing the amount of fuel injected into the cylinder. As a result, the supply control part422can reduce the amount of unburned fuel and nitrogen oxides supplied to the purification device73, thereby improving the exhaust gas purification rate of the purification device73.

When the exhaust gas temperature is equal to or higher than the predetermined value, the supply control part422does not supply hydrogen to the intake pipe. Specifically, the supply control part422closes the control valve61to stop the supply of hydrogen from the hydrogen tank3of the first supply part21to the intake pipe80. Thus, hydrogen generated by the electrolysis part1is stored in the hydrogen tank3. In this manner, when the exhaust gas temperature is higher than the reaction temperature, the supply control part422can store the generated hydrogen in the hydrogen tank3.

The supply control part422supplies the ozone generated by the ozone generation part5to the intake pipe80. For example, the supply control part422causes the ozone generation part5to radiate ultraviolet light. This converts the oxygen passing through the ozone generation part5into ozone, thereby generating ozone. The supply control part422supplies the generated ozone from the second supply part22to the intake pipe80. As a result, the supply control part422can supply ozone having a lower nitrogen oxide content to the intake pipe80than in the case where ozone is generated from air, thereby suppressing an increase in nitrogen oxides emitted from the engine after combustion. Therefore, the supply control part422can suppress a decrease in the exhaust gas purification rate of the purification device73as compared with the case where ozone is generated from air.

The supply control part422supplies ozone to the intake pipe80when the exhaust gas temperature is lower than the predetermined value. The supply control part422can enhance the fuel combustion efficiency by supplying ozone to the intake pipe80, thereby reducing the amount of nitrogen oxides generated in the engine71. Accordingly, the supply control part422can suppress the nitrogen oxides emitted from the engine71. Further, the supply control part422can improve the exhaust gas purification rate of the purification device73.

When the exhaust gas temperature is equal to or higher than the predetermined value, the supply control part422does not supply ozone to the intake pipe80. Specifically, the supply control part422stops the application of the voltage to the cathode12and the anode13by the power supply11of the electrolysis part1, and stops an operation of the ozone generation part5. Thus, when the exhaust gas temperature is higher than the reaction temperature, the supply control part422can suppress the electric power for electrolysis of water and generation of ozone, thereby reducing power consumption.

[Process of Supplying Hydrogen and Ozone]

FIG.3is a flowchart showing an example of a process of supplying hydrogen and ozone, executed by the supply control device4. The flowchart inFIG.3is repeatedly executed while the apparatus in which the supply system S is installed is operating.

The acquisition part421acquires the exhaust gas temperature (step S1). Specifically, the acquisition part421acquires the exhaust gas temperature detected by the temperature sensor72.

The acquisition part421determines whether or not the exhaust gas temperature is lower than the predetermined value (step S2). When the exhaust gas temperature is equal to or higher than the predetermined value (No in step S2), the acquisition part421waits until the exhaust gas temperature becomes lower than the predetermined value. When the exhaust gas temperature is lower than the predetermined value (Yes in step S2), the acquisition part421acquires the requested torque (step S3).

When the requested torque has been acquired, the supply control part422supplies hydrogen in an amount corresponding to the requested torque from the first supply part21to the intake pipe80(step S4). Specifically, the supply control part422adjusts the opening degree of the control valve61to supply the hydrogen in an amount proportional to the requested torque from the hydrogen tank3of the first supply part21to the intake pipe80.

The supply control part422supplies ozone from the second supply part22to the intake pipe80(step S5). Specifically, when the exhaust gas temperature is lower than the predetermined value, the supply control part422first causes the electrolysis part1to electrolyze water to generate oxygen and hydrogen. Subsequently, the supply control part422operates the ozone generation part5to irradiate the oxygen passing through the ozone generation part5with ultraviolet light to convert the oxygen into ozone. It should be noted that the process of step S5may be executed before step S4or may be executed in parallel with step S4.

[Effect of the Supply System S]

As described above, the supply system S first electrolyzes water to generate hydrogen and oxygen. Subsequently, the supply system S generates ozone from the oxygen generated by the electrolysis. Therefore, the supply system S can generate ozone from the oxygen gas having a nitrogen content lower than air, thereby suppressing the generation of nitrogen oxides. The supply system S then supplies the generated hydrogen and ozone to the intake pipe80. As a result, the supply system S can suppress an increase in nitrogen oxides emitted from the engine71after combustion.

The supply system S can improve combustion efficiency of fuel by supplying ozone to the intake pipe80. As a result, the supply system S can reduce unburned fuel and nitrogen oxides, thereby improving the exhaust gas purification rate of the purification device73. Further, the supply system S can reduce the injection amount of fuel by supplying hydrogen to the intake pipe80instead of fuel. Therefore, the supply system S can reduce unburned fuel and nitrogen oxides, thereby improving the exhaust gas purification rate.

The present disclosure is explained on the basis of the exemplary embodiments. The technical scope of the present disclosure is not limited to the scope explained in the above embodiments and it is possible to make various changes and modifications within the scope of the disclosure. For example, all or part of the apparatus can be configured with any unit which is functionally or physically dispersed or integrated. Further, new exemplary embodiments generated by arbitrary combinations of them are included in the exemplary embodiments of the present disclosure. Further, effects of the new exemplary embodiments brought by the combinations also have the effects of the original exemplary embodiments.