JP5672198B2 - Hydrogen rotary piston engine - Google Patents

Description

  The present invention relates to a hydrogen rotary piston engine with an improved combustion process for improved thermal efficiency.

  As interest in the global environment increases, hydrogen engines with clean exhaust are attracting attention. A rotary piston engine has a structure in which a rotor is slidably contacted with a trochoidal inner peripheral surface of a rotor housing at a plurality of vertices to rotate while defining a plurality of working chambers. Since there is no heat source such as a spark plug in the room, abnormal combustion such as a backfire hardly occurs. Therefore, the rotary piston engine is more suitable for use as a hydrogen engine than the reciprocating engine. For example, Patent Literature 1 discloses a hydrogen rotary piston engine that employs hydrogen as a gaseous fuel.

JP 2006-250024 (paragraph 0024)

  Conventionally, the combustion system of a hydrogen rotary piston engine is usually a homogeneous combustion in which an air-fuel mixture premixed with air is ignited and burned. In that case, the following problems may occur. In general, since hydrogen combustion is faster than gasoline, a hydrogen engine has a larger cooling loss than a gasoline engine. In order to reduce the cooling loss, it is conceivable to perform lean combustion. However, when the air-fuel mixture is made lean, the combustion speed becomes slow, a combustion delay occurs, and the exhaust loss increases.

  In the rotary piston engine, due to the rotation of the rotor, a strong squish flow flows from the trailing side to the leading side in the rotation direction of the rotor in the combustion chamber during the combustion stroke. Due to this squish flow, the flame generated by ignition of the spark plug is more likely to propagate to the leading side than the spark plug, but difficult to propagate to the trailing side. This tendency becomes more conspicuous as the air-fuel mixture is leaned and the combustion speed is reduced. Therefore, combustion does not start until the air-fuel mixture present on the trailing side of the spark plug at the time of ignition of the spark plug moves to the leading side of the spark plug as the rotor rotates. This also causes a combustion delay of the air-fuel mixture and increases exhaust loss.

  In either case, when the air-fuel mixture is returned to the rich side, the exhaust loss is reduced, but the cooling loss is increased.

  The present invention is intended to address the above-described problems in a hydrogen rotary piston engine using hydrogen as a fuel, and reduces both a cooling loss and an exhaust loss that are in a trade-off relationship with each other. The purpose is to improve the thermal efficiency of.

  The inventors have found that a rich hydrogen rich mixture with an excess air ratio λ of less than 1 is a rich mixture of gasoline, light oil, CNG (compressed natural gas), LPG (liquefied petroleum gas) and other fuels. Focusing on the point that the combustion speed is higher than that of Qi, and utilizing the recess formed on the outer peripheral surface of the rotor and injecting hydrogen gas into this recess, the excess air ratio λ is 1 in the recess. The present invention has been completed by finding that less than a hydrogen-rich mixture is produced and that the resulting hydrogen-rich mixture can be present in the recess for a period of time, that is, the hydrogen-rich mixture can be stratified. .

  That is, in order to achieve the above object, a hydrogen rotary piston engine according to the present invention includes a rotor housing having a trochoid inner peripheral surface, a rotor that rotates with its apex in sliding contact with the inner peripheral surface, and an outer peripheral surface of the rotor. A hydrogen rotary piston engine comprising a recess formed on the inner peripheral surface and a spark plug disposed on a leading side of a short axis of the inner surface trochoidal curve, wherein the recess is located when the rotor is at a compression top And a means for stratifying a hydrogen-rich mixture having an excess air ratio λ of less than 1 in the recess, the spark plug being disposed in a combustion stroke. The stratified hydrogen-rich mixture is ignited and burned.

  According to such a configuration, the rich hydrogen-rich mixture having an excess air ratio λ of less than 1 stratified in the recess is burned by ignition of the spark plug. This hydrogen-rich mixture has a relatively high combustion rate and is stratified in the recess, and air is continuously supplied into the recess by a strong squish flow flowing from the trailing side to the leading side. For this reason, combustion is performed only in the recess and is completed in a short time only in the recess. Due to the localization of fuel, combustion is not performed using the entire combustion chamber as in homogeneous combustion, but combustion is performed using only a part of the combustion chamber. This reduces the area of the heat dissipation wall and reduces the cooling loss. In addition, since the combustion speed is fast and the combustion is completed in a short time, the exhaust loss does not increase. Therefore, both the cooling loss and the exhaust loss are reduced, and the thermal efficiency of the hydrogen rotary piston engine is improved.

  As a more specific configuration of the present invention, the means for stratifying the hydrogen-rich mixture is a hydrogen injector that injects hydrogen gas toward the recess of the rotor that contacts the working chamber in the intake stroke or the compression stroke Can be mentioned.

  According to such a configuration, a hydrogen-rich mixture having an excess air ratio λ of less than 1 in the recess by directly injecting hydrogen gas into the recess of the rotor using a conventionally used hydrogen injector. Can be stratified. And when injecting by an intake stroke, since the pressure of a working chamber is relatively low, there exists an advantage that it is not necessary to inject hydrogen by high pressure. On the other hand, in the case of injection in the compression stroke, since the time from injection to ignition is relatively short, there is an advantage that the degree of stratification of the hydrogen-rich mixture at the time of ignition is high.

  As a more specific configuration of the present invention, one having an excess air ratio λ of the hydrogen-rich mixture can be 0.5 to 0.8.

  According to such a configuration, when the excess air ratio λ is in the range of 0.5 to 0.8, the range in which the combustion speed of the hydrogen rich mixture is particularly higher than the combustion speed of the rich mixture of other fuels. Therefore, by burning such a hydrogen-rich mixture having an excess air ratio, the degree of reduction in cooling loss and exhaust loss is further increased, and the thermal efficiency of the hydrogen rotary piston engine is further improved.

  As a more specific configuration of the present invention, a heat insulation degree of a wall surface constituting the recess is higher than a heat insulation degree of an outer peripheral surface of a rotor outside the recess.

  According to such a configuration, the heat transfer coefficient (heat transfer coefficient) α of the portion that becomes a high temperature due to combustion of the hydrogen-rich mixture is reduced, so that the cooling loss can be further reduced.

  As a more specific configuration of the present invention, the spark plug may be disposed at a position overlapping with the recess when the rotor is on the compression top.

  According to such a configuration, the hydrogen rich mixture in the recess is reliably burned by the ignition of the spark plug ignited in the vicinity of the compression top.

  As a more specific configuration of the present invention, the ignition timing of the spark plug may be after the compression top.

  According to such a configuration, high torque can be obtained while preventing knocking, and fuel efficiency can be improved.

  According to the present invention, by adopting a new combustion process different from the homogeneous combustion in which a hydrogen rich mixture that has been rarely used is stratified and burned, it is possible to trade with each other in the case of homogeneous combustion. It is possible to reduce both the cooling loss and the exhaust loss that are in the off relationship, and the thermal efficiency of the hydrogen rotary piston engine can be greatly improved.

It is a perspective view showing an outline of a rotary piston engine concerning an embodiment of the present invention. It is a front view of a rotor housing and a rotor of the rotary piston engine. It is a fragmentary sectional view of a combustion chamber and its periphery when a rotor exists in the compression top vicinity. (A) is a plan view of the outer peripheral surface of the rotor in contact with the combustion chamber, and (b) is the combustion chamber and its air-fuel mixture, which is stratified in the recess, showing that air is supplied from the trailing side. FIG. It is a graph which shows the difference in the combustion rate of hydrogen and another fuel. It is a graph which shows the difference in the combustion rate of the hydrogen rich mixture and the hydrogen lean mixture. The difference between homogeneous combustion and stratified combustion is shown, (a) is the temperature distribution diagram of the combustion chamber in the case of homogeneous combustion, (b) is the temperature distribution diagram of the combustion chamber in the case of stratified combustion, (c) is the combustion chamber temperature distribution diagram It is a graph which shows the relationship between a surface coordinate and a cooling loss. It is a graph which shows the difference of the cooling loss of homogeneous combustion and stratified combustion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this embodiment is only an illustration and this invention is not limited to this embodiment at all.

  In the present embodiment, the present invention is applied to the hydrogen rotary piston engine 1 shown in FIGS. 1 and 2. The engine 1 is a two-rotor type engine having two rotors 2. Two rotor housings 3 on the front side (right side in FIG. 1) and the rear side (left side in FIG. 1) are provided on both sides of the intermediate housing 4. The two side housings 5 are stacked in this order and integrated.

  In FIG. 1, the rotor housing 3 and the side housing 5 on the front side are partially cut away to show the inside. The rear side housing 5 is separated from the rotor housing 3 to show the interior. Moreover, the code | symbol X in a figure shows the rotating shaft center of the eccentric shaft 6 (refer FIG. 2) as an output shaft.

  A rotor accommodating chamber 7 is formed by the trochoidal inner peripheral surface 3 a drawn by the parallel trochoidal curve of the rotor housing 3, the inner side surface 5 a of the side housing 5, and the side surface 4 a of the intermediate housing 4. As shown in FIG. 2, the rotor storage chamber 7 has a substantially elliptical shape like a bowl when viewed from the direction of the rotation axis X. In addition, the code | symbol Y in a figure shows the long axis of the trochoid curve of the trochoidal inner peripheral surface 3a, and the code | symbol Z shows a short axis.

  The rotor 2 is rotatably accommodated in the rotor accommodating chamber 7. The rotor 2 is composed of a substantially triangular block body in which the central part of each side bulges outward as viewed from the direction of the rotation axis X. Reference numeral 2a in the drawing indicates an outer peripheral surface (flank surface) of the rotor 2 that is in contact with a working chamber 8 described later. Each flank surface 2 a is formed with a recess 2 b that is a recess for adjusting the compression ratio of the engine 1. The recess 2b is arranged so as to be biased toward the leading side in the rotational direction of the rotor 2 with respect to the longitudinal center portion of the flank surface 2a.

  Apex seals (not shown) are provided at the three vertices of the rotor 2, and these apex seals abut against the trochoidal inner peripheral surface 3 a of the rotor housing 3, so that the trochoidal inner peripheral surface 3 a of the rotor housing 3. Three working chambers 8 are defined in the rotor accommodating chamber 7 by the flank surface 2a of the rotor 2, the inner side surface 5a of the side housing 5, and the side surface 4a of the intermediate housing 4. .

  Although not shown, the rotor 2 includes an intermediate housing 4 and an internal gear (rotor gear) provided in the center of the rotor 2 and an external gear (fixed gear) provided in the side housing 5 while meshing with each other. The eccentric shaft 6 penetrating the side housing 5 is supported so as to make a planetary rotational movement.

  The rotor 2 rotates around the eccentric ring 6a of the eccentric shaft 6 while the three apex seals are in sliding contact with the trochoid inner peripheral surface 3a of the rotor housing 3, and the same direction as the rotation around the rotation axis X (When the rotation of the rotor 2 is simply referred to, it means the planetary rotation of the rotor 2 including this rotation and revolution). As the rotor 2 rotates, the three working chambers 8 move in the circumferential direction along the trochoidal inner peripheral surface 3a, and the intake, compression, combustion, and exhaust strokes are performed in the working chambers 8 and generated. Torque is output from the eccentric shaft 6 through the rotor 2.

  In FIG. 2, the rotor 2 rotates clockwise as indicated by an arrow. In the rotor storage chamber 7, a portion on the left side of the long axis Y (referred to in FIG. 2, the same applies hereinafter) is a region for the intake stroke and the exhaust stroke, and a portion on the right side is a region for the compression stroke and the combustion stroke.

  Air intake ports 11, 12, 13 are opened on the side surface 4 a of the intermediate housing 4 and the inner side surface 5 a of the side housing 5 on the left side of the long axis Y of the rotor housing chamber 7 and above the short axis Z. In the low rotation region of the engine 1, intake is performed only from the first intake port 11, intake is also performed from the second intake port 12 in the intermediate rotation region, and intake is also performed from the third intake port 13 in the high rotation region. Thus, intake is efficiently performed over the entire operation region of the engine 1.

  Exhaust ports 10... 10 are opened on the side surface 4 a of the intermediate housing 4 and the inner side surface 5 a of the side housing 5 on the left side of the long axis Y of the rotor housing chamber 7 and below the short axis Z. As described above, the engine 1 employs the side exhaust system, and is set so that the intake opening timing of the intake ports 11 to 13 and the exhaust opening timing of the exhaust ports 10... 10 do not overlap. Thereby, residual exhaust gas brought into the intake stroke is reduced, and combustion stability is improved even when the air-fuel mixture is lean.

  A high-pressure hydrogen injector 15 that directly injects hydrogen as fuel into the working chamber 8 (combustion chamber) is provided on the short axis Z in a portion on the right side of the long axis Y of the rotor housing 3. The injector 15 is connected to a high-pressure hydrogen tank (not shown), and is configured such that the injection pressure and the injection time can be controlled. Similarly, a leading side spark plug 21 is disposed on the leading side of the short axis Z in a portion on the right side of the long axis Y of the rotor housing 3. The leading spark plug 21 is ignited when the rotor 2 is in the vicinity of the compression top (compression top dead center: TDC).

  In FIG. 2, the upper left working chamber 8 is in the intake stroke. In the intake process, air is sucked into the working chamber 8 from the intake ports 11 to 13. Next, when the compressor 2 shifts to the compression stroke as the rotor 2 rotates, the volume of the working chamber 8 is reduced and the air is compressed. Next, as in the right working chamber 8 (combustion chamber), when the rotor 2 is in the vicinity of the compression top, high-pressure hydrogen gas is injected from the high-pressure hydrogen injector 15, and then the leading spark plug 21 is ignited. . Thereby, hydrogen burns and shifts to the combustion stroke. Next, when the exhaust stroke is started as the rotor 2 rotates, exhaust gas is discharged from the exhaust ports 10... 10 as in the lower left working chamber 8.

  Based on the above configuration, the engine 1 according to the present embodiment has the following characteristics.

  As described above, the recess 2b is arranged to be biased toward the leading side with respect to the central portion in the longitudinal direction of the flank surface 2a. Therefore, as shown in FIG. 3, the rotor 2 is in the compression top or in the vicinity of the compression top. In some cases, the recess 2b is arranged to be deviated from the short axis Z toward the leading side. Thereby, when the hydrogen gas is injected from the high-pressure hydrogen injector 15 when the rotor 2 is in the vicinity of the compression top, the injected hydrogen gas enters the recess 2b and moves to the leading side from the short axis Z.

  Note that the recess 2b is biased to the leading side with respect to the short axis Z not only when the recess 2b is entirely on the leading side with respect to the short axis Z but also with the center in the longitudinal direction of the recess 2b being short. This includes the case where it is arranged at a position shifted to the leading side by a predetermined distance from the axis Z.

  Since the high-pressure hydrogen injector 15 injects hydrogen gas toward the recess 2b of the rotor 2 in contact with the working chamber 8 in the compression stroke, the injector 15 has a hydrogen excess with an excess air ratio λ of less than 1 in the recess 2b. It functions as a means for stratifying the rich mixture. That is, the hydrogen gas injected from the high-pressure hydrogen injector 15 and entering the recess 2b becomes a lump of a rich hydrogen rich mixture R having an excess air ratio λ of less than 1, and is stratified in the recess 2b for a certain period of time. . Then, the stratified hydrogen-rich mixture R moves to the leading side from the short axis Z and approaches the leading side spark plug 21.

  A hydrogen-rich mixture R having an excess air ratio λ of less than 1 is stratified in the recess 2b by directly injecting hydrogen gas into the recess 2b of the rotor 2 using a hydrogen injector 15 that is conventionally used. be able to.

  The leading spark plug 21 is ignited after the hydrogen gas is injected from the high-pressure hydrogen injector 15, so that the spark plug 21 forms a hydrogen rich mixture R stratified in the recess 2 b during the combustion stroke. It will ignite and burn.

  The rich hydrogen mixture R has a higher combustion speed than the rich fuel mixture of other fuels such as gasoline, light oil, CNG, and LPG. Moreover, the hydrogen-rich mixture R is stratified in the recess 2b. Further, as shown in FIG. 4, air is constantly supplied into the recess 2b by a strong squish flow flowing from the trailing side to the leading side. Therefore, the combustion caused by the ignition of the leading spark plug 21 is mainly performed only in the recess 2b and is completed in a short time only in the recess 2b. Due to the localization of fuel, combustion is not performed using the entire combustion chamber as in homogeneous combustion, but combustion is performed using only a part of the combustion chamber. This reduces the area of the heat dissipation wall and reduces the cooling loss. Moreover, since the combustion speed is high and the combustion is completed within a short time, the exhaust loss does not increase. Therefore, both the cooling loss and the exhaust loss are reduced, and the thermal efficiency of the hydrogen rotary piston engine 1 is improved.

  FIG. 5 shows the relationship between the equivalence ratio and the laminar combustion rate for four types of gases, namely hydrogen, ethylene, propane, and methane. In substantially the entire range of the equivalence ratio shown in the figure, the burning rate of hydrogen is faster than that of other gases. Moreover, ethylene, propane, and methane have a maximum combustion rate near an equivalent ratio of 1 to 1.1 (λ = 0.9 to 1), whereas hydrogen has an equivalent ratio of 1.6 (λ = The combustion speed becomes maximum in the vicinity of 0.63). Therefore, the difference between the burning rate of hydrogen and the burning rate of other gases is only opening when the equivalence ratio is in the range of 1.2 to 2 (λ = 0.5 to 0.8).

  For this reason, the excess air ratio λ of the hydrogen-rich mixture R is preferably 0.5 to 0.8, even if it is less than 1. That is, the range where the excess air ratio λ is 0.5 to 0.8 is a range in which the combustion rate of the hydrogen rich mixture R is particularly faster than the combustion rate of the rich mixture of other fuels. This is because by burning the hydrogen-rich mixture R having an excess air ratio, the degree of reduction of the cooling loss and the exhaust loss is further increased, and the thermal efficiency of the hydrogen rotary piston engine 1 is further improved.

  Adjusting the excess air ratio λ of the hydrogen-rich mixture R to less than 1 or adjusting it to a range of 0.5 to 0.8, for example, controls the injection pressure and the injection time of the high-pressure hydrogen injector 15. Is achieved. In that case, good results can be obtained if the injection pressure of the high-pressure hydrogen injector 15 is set to 10 MPa, for example.

  FIG. 6 shows combustion of a hydrogen rich mixture having an excess air ratio λ of 0.9 (equivalence ratio 1.1) and a hydrogen lean mixture having an excess air ratio λ of 2.05 (equivalence ratio 0.49). Show the difference in speed. As is clear from this, since the hydrogen lean mixture has a slow combustion rate, a combustion delay occurs and exhaust loss increases. On the other hand, the hydrogen rich mixture has a high combustion rate, so there is no combustion delay. Increase in exhaust loss is suppressed. Note that the ignition timing differs between the hydrogen rich mixture and the hydrogen lean mixture shown in the figure, and the ignition timing of the hydrogen rich mixture is retarded after the compression top to prevent knocking.

  The cooling loss can be reduced by reducing the S / N ratio. The cooling loss can be calculated according to the equation “Qw = Aα (T−Tw)”. Here, Qw is the cooling loss, A is the area of the wall of the combustion chamber, α is the heat transfer coefficient (heat transfer coefficient), T is the combustion temperature, and Tw is the temperature of the wall of the combustion chamber.

  In the present embodiment, as described above, the combustion is performed using only a part of the combustion chamber due to the localization of the fuel. Therefore, the range of the combustion chamber that becomes a high temperature by the combustion is narrowed, and the heat radiation wall is reduced. The area is reduced. Specifically, for example, if the combustion temperature T of the hydrogen rich mixture R is 1500 K and the temperature Tw of the wall of the combustion chamber in contact therewith is 200 ° C., (T−Tw) is a relatively large value. The area of the heat radiation wall to which this value is applied is not the entire area of the wall of the combustion chamber, but only the area of a part of the wall of the combustion chamber. On the other hand, for example, if the temperature T of the other part of the combustion chamber that is heated only by air compression is 800 K, and the temperature Tw of the wall of the combustion chamber in contact with this is 80 ° C., (T−Tw) is a relatively small value. And this value applies to the remaining area of the combustion chamber wall. Therefore, when combined, the total cooling loss is reduced.

  FIG. 7A shows the temperature distribution of the combustion chamber when hydrogen is homogeneously burned, and FIG. 7B shows the temperature distribution of the combustion chamber when hydrogen is stratified. As is clear from this, in homogeneous combustion, combustion is performed using the entire combustion chamber, so that the temperature rise spreads over almost the entire range of the combustion chamber, and the temperature is relatively high (hatching in the figure). On the other hand, in the stratified combustion, combustion is performed using only a part of the combustion chamber, so that the temperature rise is limited to a narrower range on the leading side than the leading side spark plug 21. The range where the temperature is relatively high (the hatched portion in the figure) is relatively narrow. Thereby, as shown in FIG.7 (c), in the stratified combustion, compared with homogeneous combustion, the cooling loss is reducing in the most part range of a combustion chamber. Therefore, when combined, stratified combustion reduces the total cooling loss.

  As shown in FIG. 8, when stratified combustion of hydrogen was performed, the cooling loss was improved by 16% compared to the case of homogeneous combustion.

  In this embodiment, it is preferable that the heat insulation degree of the wall surface which comprises the recess 2b is made higher than the heat insulation degree of the flank surface 2a of the rotor 2 outside the recess 2b. That is, this is because the heat transfer coefficient α in the portion where the temperature is high due to the combustion of the hydrogen rich mixture R is reduced, and the cooling loss can be further reduced.

  The method for increasing the heat insulation degree of the wall surface constituting the recess 2b is not particularly limited. For example, as shown by reference numeral 2c in FIG. 3, a heat insulating material is laid on the wall surface constituting the recess 2b. Although the heat insulating material 2c is not specifically limited, For example, ceramic etc. are preferable from a heat resistant viewpoint.

  In the present embodiment, it is preferable that the leading spark plug 21 is disposed at a position overlapping the recess 2b when the rotor 2 is at the compression top. This is because the hydrogen rich mixture R in the recess 2b is reliably burned by the ignition of the leading spark plug 21 ignited in the vicinity of the compression top.

  In the present embodiment, the ignition timing of the leading spark plug 21 is preferably after the compression top. Thereby, high torque can be obtained while knocking is prevented, and fuel efficiency is improved.

  For example, when the ignition timing is ATDC (after compression top) 5 °, combustion is completed between 5 and 30 ° ATDC, and good results are obtained.

  In this embodiment, the excess air ratio λ of the hydrogen-rich mixture R is less than 1, preferably 0.5 to 0.8. However, the excess air ratio λ of the entire combustion chamber depends on the operating state of the engine 1. Accordingly, it is adjusted to a lean state of 2 to 3, preferably 2.2 to 2.6. In this case, for example, the throttle valve is always fully opened (WOT), the intake air amount is constant, and the amount of hydrogen-rich mixture R, that is, the amount of hydrogen gas injected from the high-pressure hydrogen injector 15 is relatively small at low load. When the load is high, the amount of the hydrogen rich mixture R, that is, the amount of hydrogen gas injected from the high pressure hydrogen injector 15 is relatively increased.

  The increase / decrease adjustment of the amount of the hydrogen rich mixture gas R is achieved, for example, by controlling the injection pressure and the injection time of the high-pressure hydrogen injector 15. In that case, good results can be obtained if the injection pressure of the high-pressure hydrogen injector 15 is set to 10 MPa, for example.

  The features of this embodiment are summarized below.

  The hydrogen rotary piston engine 1 according to the present embodiment is based on a new combustion concept of stratified combustion of a hydrogen rich mixture that has been rarely used, and the new concept is that the excess air ratio λ is Hydrogen rich mixture using the recess 2b formed on the flank surface 2a of the rotor 2 in order to adjust the compression ratio in order to adjust the compression ratio. It was conceived and completed by confining the gas R in the recess 2b and realizing the stratification of the hydrogen-rich hydrogen mixture R for a certain period of time. Thereby, the thermal efficiency not inferior to a reciprocating engine is achieved, and according to examination by the present inventors, the thermal efficiency of the hydrogen rotary piston engine 1 according to the present embodiment is improved to 45% or more. This new combustion concept can be a future engine core technology that is inferior in terms of robustness and price compared to, for example, fuel cells.

  A modification of the embodiment will be described below.

  In the embodiment, as a means for stratifying a hydrogen-rich mixture having an excess air ratio λ of less than 1 in the recess, a high-pressure hydrogen injector that injects hydrogen gas toward the recess of the rotor that contacts the working chamber in the compression stroke However, instead of this, a hydrogen injector that injects hydrogen gas toward the recess of the rotor in contact with the working chamber in the intake stroke may be used. Injecting in the intake stroke has an advantage that hydrogen does not need to be injected at a high pressure because the pressure in the working chamber is relatively low. On the other hand, in the case of injection in the compression stroke, since the time from injection to ignition is relatively short, there is an advantage that the degree of stratification of the hydrogen-rich mixture at the time of ignition is high.

  The present invention is expected to have wide industrial applicability in the technical field of hydrogen rotary piston engines.

1 Hydrogen rotary piston engine 2 Rotor 2a Rotor outer peripheral surface (flank surface)
2b Recess 2c Heat insulating material 3 Rotor housing 3a Trochoidal inner peripheral surface 4 Intermediate housing 4a Intermediate housing side surface 5 Side housing 5a Side housing inner surface 6 Eccentric shaft 7 Rotor housing chamber 8 Working chamber 10 Exhaust port 11-13 Intake port 15 High pressure hydrogen injector 21 Leading side spark plug 22 Trailing side spark plug R Hydrogen-rich mixture X Rotational axis Y Long axis Z Short axis

Claims (6)

A rotor housing having a trochoidal inner peripheral surface;
A rotor that rotates while the vertex is in sliding contact with the inner peripheral surface;
A recess formed on the outer peripheral surface of the rotor;
A hydrogen rotary piston engine comprising a spark plug disposed on the leading side of the short axis of the inner surface trochoidal curve,
The recess is arranged biased to the leading side with respect to the short axis when the rotor is at the compression top,
Means for stratifying a hydrogen-rich mixture having an excess air ratio λ of less than 1 in the recess;
In the combustion stroke, the ignition plug ignites and burns the stratified hydrogen-rich mixture.   The means for stratifying the hydrogen-rich mixture is a hydrogen injector that injects hydrogen gas toward a recess in a rotor in contact with a working chamber in an intake stroke or a compression stroke. Hydrogen rotary piston engine.   The hydrogen rotary piston engine according to claim 1 or 2, wherein an excess air ratio λ of the hydrogen-rich mixture is 0.5 to 0.8.   4. The hydrogen rotary piston engine according to claim 1, wherein a heat insulation degree of a wall surface constituting the recess is higher than a heat insulation degree of an outer peripheral surface of a rotor outside the recess.   5. The hydrogen rotary piston engine according to claim 1, wherein the spark plug is disposed at a position overlapping the recess when the rotor is at a compression top. 6.   The hydrogen rotary piston engine according to any one of claims 1 to 5, wherein the ignition timing of the spark plug is after the compression top.

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