초록 ▼

During starting of an engine that has a circulation path through which argon, used as working gas, is circulated back to a combustion chamber and that uses hydrogen as fuel during operation, oxygen is supplied in such a manner that the oxygen supply ratio is higher than that used during normal opera

During starting of an engine that has a circulation path through which argon, used as working gas, is circulated back to a combustion chamber and that uses hydrogen as fuel during operation, oxygen is supplied in such a manner that the oxygen supply ratio is higher than that used during normal operation. Thus, the entirety of hydrogen supplied into the combustion chamber reacts with oxygen and is burned. When the engine is being started, because gas is not turbulent enough, hydrogen and oxygen are likely to be mixed poorly. Therefore, when oxygen is supplied in such a manner that the ratio of oxygen supply amount to the hydrogen supply amount is higher than the theoretical ratio, even if oxygen and hydrogen are not mixed so well, the chance that hydrogen contacts oxygen is increased. As a result, combustion takes place in a more appropriate manner, which improves the engine startability.

대표청구항 ▼

1. An internal combustion engine, comprising: an oxidant supply device that supplies an oxidant into a combustion chamber;a reductant supply device that supplies a reductant, which is burned by reaction with the oxidant, into the combustion chamber;a circulation path which is communicated at both en

1. An internal combustion engine, comprising: an oxidant supply device that supplies an oxidant into a combustion chamber;a reductant supply device that supplies a reductant, which is burned by reaction with the oxidant, into the combustion chamber;a circulation path which is communicated at both ends with the combustion chamber, into which exhaust gas generated after the reductant is burned in the combustion chamber flows through one of the both ends, from which gas that is taken in the combustion chamber flows into the combustion chamber through the other end, and through which working gas which is gas that has a specific heat ratio higher than a specific heat ratio of air and that is circulated back to the combustion chamber flows; anda supply amount setting unit that sets a supply amount of the reductant and a supply amount of the oxidant, wherein when the internal combustion engine is in a predetermined operating state, the supply amount setting unit sets the supply amount of the reductant and the supply amount of the oxidant in such a manner that one of a ratio of the supply amount of the reductant to the supply amount of the oxidant and a ratio of the supply amount of the oxidant to the supply amount of the reductant is higher than the one of the ratios used during normal operation. 2. The internal combustion engine according to claim 1, wherein the supply amount setting unit sets the supply amount of the reductant and the supply amount of the oxidant in such a manner that a concentration of the reductant in the exhaust gas and a concentration of the oxidant in the exhaust gas are both equal to or lower than a predetermined concentration. 3. The internal combustion engine according to claim 1, wherein the predetermined operating state includes a state where the internal combustion engine is being started. 4. The internal combustion engine according to claim 3, wherein the predetermined operating state includes a state where the internal combustion engine is being warmed up. 5. The internal combustion engine according to claim 1, wherein the supply amount setting unit sets the supply amount of the reductant and the supply amount of the oxidant in such a manner that one of the reductant and the oxidant is constantly contained in the exhaust gas but the other of the reductant and the oxidant is not contained in the exhaust gas during normal operation of the internal combustion engine. 6. The internal combustion engine according to claim 1, wherein: a concentration detection unit that detects at least one of concentrations of the reductant and the oxidant in the exhaust gas that flows through the circulation path is provided in the circulation path; andthe supply amount setting unit sets the supply amount of the reductant and the supply amount of the oxidant based on a detection result obtained by the concentration detection unit. 7. The internal combustion engine according to claim 1, wherein one of the supply amount of the reductant and the supply amount of the oxidant is set first, and then the other of the supply amount of the reductant and the supply amount of the oxidant is set based on the supply amount that is set first. 8. The internal combustion engine according to claim 1, wherein: the oxidant is oxygen;the reductant is hydrogen; andthe working gas is argon. 9. The internal combustion engine according to claim 1, wherein the oxidant supply device is arranged in such a manner that the oxidant supply device supplies the oxidant to the combustion chamber by injecting the oxidant into the circulation path. 10. A method for controlling an internal combustion engine that includes an oxidant supply device that supplies an oxidant into a combustion chamber, a reductant supply device that supplies a reductant, which is burned by reaction with the oxidant, into the combustion chamber, and a circulation path which is communicated at both ends with the combustion chamber, into which exhaust gas generated after the reductant is burned in the combustion chamber flows through one of the both ends, from which gas that is taken in the combustion chamber flows into the combustion chamber through the other end, and through which working gas which is gas that has a specific heat ratio higher than a specific heat ratio of air and that is circulated back to the combustion chamber flows, the method comprising:setting a supply amount of the reductant and a supply amount of the oxidant, wherein when the internal combustion engine is in a predetermined operating state, the supply amount of the reductant and the supply amount of the oxidant are set in such a manner that one of a ratio of the supply amount of the reductant to the supply amount of the oxidant and a ratio of the supply amount of the oxidant to the supply amount of the reductant is higher than the one of the ratios used during normal operation. 11. The method according to claim 10, wherein the supply amount of the reductant and the supply amount of the oxidant are set in such a manner that a concentration of the reductant in the exhaust gas and a concentration of the oxidant in the exhaust gas are both equal to or lower than a predetermined concentration. 12. The method according to claim 10, wherein the predetermined operating state includes a state where the internal combustion engine is being started. 13. The method according to claim 12, wherein the predetermined operating state includes a state where the internal combustion engine is being warmed up. 14. The method according to claim 10, wherein the supply amount of the reductant and the supply amount of the oxidant are set in such a manner that one of the reductant and the oxidant is constantly contained in the exhaust gas but the other of the reductant and the oxidant is not contained in the exhaust gas during normal operation of the internal combustion engine. 15. The method according to claim 10, wherein the supply amount of the reductant and the supply amount of the oxidant are set based on a detection result obtained by a concentration detection unit that is provided in the circulation path and that detects at least one of concentrations of the reductant and the oxidant in the exhaust gas that flows through the circulation path. 16. The method according to claim 10, wherein one of the supply amount of the reductant and the supply amount of the oxidant is set first, and then the other of the supply amount of the reductant and the supply amount of the oxidant is set based on the supply amount that is set first. 17. The method according to claim 10, wherein: the oxidant is oxygen;the reductant is hydrogen; andthe working gas is argon. 18. The method according to claim 10, wherein the oxidant supply device supplies the oxidant to the combustion chamber by injecting the oxidant into the circulation path.