JPH0337367A - Fuel feeding device for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce NOx by permitting the lean combustion by installing a limiter for varying the max. flow rate of hydrogen in a direct injection passage, in the constitution in which the direct injection passage for directly jetting hydrogen into a combustion chamber and a premixing passage for feeding hydrogen into an intake passage are provided. CONSTITUTION:The opened port part of an intake passage 14, opened port part of an exhaust passage 15, and the opened port part of a hydrogen feeding passage 16 are formed on a cylinder head 3, and a suction valve 17b, exhaust valve, and a hydrogen valve 19 are installed at the respective opened port parts. A fuel feeding device C is constituted of a premixing passage D for feeding hydrogen into a suction passage B and a direct injection passage E for directly jetting hydrogen into a combustion chamber 6, and the hydrogen supplied from a hydrogen cylinder 61 is branching-supplied into the passages D and E through an emergency stop valve 63 and a decompression valve 64, and an acceleration valve 70 and a limiter 69 which also acts as a flow rate control means which increases the max. flow rate of hydrogen according to the engine revolution speed and increases the hydrogen feed quantity over the hydrogen feed quantity passing through the premixing passage D are installed into the direct injection passage E.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a fuel supply device for an internal combustion engine that supplies hydrogen fuel according to operating conditions.

[Conventional technology]

BACKGROUND ART Internal combustion engines that use hydrogen as fuel are known. As a fuel supply device for this internal combustion engine, for example, Japanese Patent Laid-Open No. 63
As shown in Japanese Patent No. 246460, there are some types that have a direct injection path for directly injecting hydrogen into the combustion chamber and a premixing path for sucking hydrogen together with intake air through an intake valve.

[Problem to be solved by the invention]

In such an internal combustion engine, it is necessary to supply a large amount of hydrogen to obtain high output at high loads, but at high loads the hydrogen occupies a large volume, making it impossible to increase the amount of air intake. As the temperature rises and NOx increases, the volume occupied by hydrogen increases, making it impossible to increase the amount of air, making it impossible to thin the air-fuel mixture by taking advantage of hydrogen's good ignitability, and leaving room for improvement in improving fuel efficiency. there were. For this reason, it is possible to supply more air by installing a compressor in the intake passage to supercharge the intake air, but in models equipped with a premixing path, hydrogen may also be compressed by the compressor instead of air. As a result, a large compressor is required, and the intake air becomes hot due to compression, causing problems such as backfire. This invention was made in view of these circumstances, and
The object of the present invention is to provide a fuel supply device for an internal combustion engine that can reduce Ox, improve fuel efficiency, downsize the compressor, and prevent backfire. [Means for Solving the Problems] In order to solve the above problems, the present invention provides an internal combustion engine equipped with a direct injection path for directly injecting hydrogen into a combustion chamber and a premixing path for supplying hydrogen to an intake passage. In the fuel supply device, a compressor for compressing intake air is provided in the intake passage, and a limiter is provided in the direct injection path to change the maximum flow rate of hydrogen according to the engine speed, and the fuel supply device is provided with a The present invention is characterized by comprising a flow rate control means for making the amount of hydrogen supplied through the direct injection path larger than the amount of hydrogen supplied through the premixing path. [Operation] In the present invention, a compressor provided in the intake passage compresses intake air, and a limiter provided in the direct injection path changes the maximum flow rate of hydrogen according to the engine speed. Therefore, the compressor can supply a large amount of air commensurate with the controlled amount of hydrogen in all rotation ranges, making lean combustion possible. Further, in the operating range other than idling, the amount of hydrogen supplied by the direct injection path is larger than the amount of hydrogen supplied by the premixing path using the flow rate control means, so that the intake air can be compressed with a small compressor. Furthermore, the intake passage tends to become hot under high loads, but the hydrogen supplied to the intake passage can be kept at a low 4 degrees Celsius, preventing flashback. [Embodiment J] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. FIG. 1 is an overall configuration diagram of a fuel supply system for an internal combustion engine according to the present invention, and FIG. 2 is a sectional view of an intake system and an exhaust system of the fuel supply system.
Figure 3 is a bottom view of the cylinder head, Figure 4 is a diagram showing valve opening/closing timing, Figures 5 and 6 are cam diagrams, and Figure 7 is a diagram showing the valve opening/closing timing.
The figure is a diagram showing the relationship between hydrogen flow rate and engine speed. In the figure, reference numeral 1 denotes a water-cooled internal combustion engine, and a cylinder head 3 is attached to a cylinder block 2 mounted on a crankcase (not shown), and a head cover 4 is provided on the cylinder head 3. cylinder block 2
A combustion chamber 6 is defined by the cylinder head 3 and the piston 5, and a spark plug 7 is provided in the cylinder head 3. This spark plug 7 is configured to spark at a predetermined timing by a computer 8.
The air-fuel mixture compressed in the combustion chamber 6 is ignited. The piston 5 is connected to a crankshaft 10 via a connecting rod 9, and the reciprocating motion of the piston 5 rotates the crankshaft 10. The rotation of the crankshaft 10 is detected by an engine rotation speed detection sensor 11. Engine rotation speed information is sent to the computer 8. A spark plug 7 is attached to the center of the cylinder head 3, and an intake system 12 and a tJi air system 13 are provided. As shown in FIGS. 1 and 2, the cylinder head 3 has
Openings 14a, 1 of the intake passage 14 face the combustion chamber 6.
4b is formed by branching into two, one opening 15a of the exhaust passage 15 is formed, and one opening 16a of the hydrogen supply passage 16 is formed on the other side, and these openings 14a, 14b, 15a and 16a have intake valves 17a. A 17b1 exhaust valve 18 and a hydrogen valve 19 are provided. The intake valves 17a, 17b, the % exhaust valve 18, and the hydrogen valve 19 operate at the valve opening/closing timing as shown in FIG. 4, and the intake cam 2G operates as shown in the cam diagram of FIG. 5 or 6. 21, exhaust cam 22 and hydrogen cam 23. In the cam diagram of FIG. 5, the opening/closing intake cam 20 of the intake valve 17a has a slightly longer opening/closing movement stroke (lift amount) than the opening/closing intake cam 21 of the intake valve 17b.
Moreover, it opens early and closes late. Also,
The cam diagram in FIG. 6 shows that the opening/closing intake cam 20 of the intake valve 17a is closer to the opening/closing intake cam 21 of the intake valve 17b.
It is the same as the one shown in FIG. 5 in that the movement stroke for opening and closing is slightly longer, but the closing timing of the intake cam 20 is delayed. Therefore, regardless of whether the on-off valve 29 (described later) is opened or closed, more air is supplied into the combustion chamber 6 from the opening 14a over a long period of time than from the opening 14b. Therefore, since a swirl is generated in the combustion chamber 6 as shown by the arrow in FIG. 3, collision between the hydrogen supplied from the opening 16a and the air supplied from the opening 14b is prevented. Promote mixing with air. An intake pipe 24 of the intake system 12 is connected to the cylinder rad 3, and a surge tank 25 is formed in the intake pipe 24.
On the upstream side, there are a known intercooler 26, an air flow meter 27, and an air cleaner 28 for cooling intake air.
is provided. The intake pipe 24 branches into a pair of intake passages 24a and 24b on the downstream side of the surge tank 25, and an on-off valve 2 is connected to one of the intake passages 24a and 24b.
9, and on the downstream side of this on-off valve 29, an intake passage 24a,
24b is merging. As shown in FIG. 1, the on-off valve 29 is connected to a diaphragm 32 of an actuator 31 via a link mechanism 30, and is always urged in the closing direction by a spring 33 disposed within the actuator 31. A pressure g34 is defined within the actuator 31 by a diaphragm 32, and this pressure chamber 34 is connected to the intake pipe 24 via a pipe 35, and the valve body 36a of the electromagnetic valve 36 is connected to the spring 36b.
When the pressure chamber 34 opens against the pressure, the pressure inside the pressure chamber 34 becomes positive. This allows the diaphragm 32 of the actuator 31 to actuate the on-off valve 29 against the screw 33 via the push bar and the link mechanism 30. The on-off valve 29 is closed in the low rotation range and supplies air only from the other intake passage 24a, and when the engine rotation speed exceeds a predetermined value, it drives the solenoid valve 36 to close the actuator 31.
is operated, the on-off valve 29 is opened in the high rotation range, and air is supplied from the pair of intake passages 24a and 24b. A temperature sensor 37 is provided in the surge tank 25 of the intake pipe 24 to send temperature information of the intake air to the computer 8, and the air flow meter 27 is provided with an intake amount detection sensor 38 for detecting the amount of air intake. , the air intake amount information is input into the computer 8. An exhaust pipe 39 is connected to the exhaust passage 15 of the cylinder head 2, and an exhaust temperature sensor 40 is provided at the tip of the exhaust pipe 39. Exhaust temperature information from the exhaust temperature sensor 40 is sent to the combiator 8. A turbo supercharger 41 is arranged between the intake system 12 and the exhaust system 13, a compressor 42 with four turbo superchargers is arranged in a compressor chamber 43 of the intake pipe 24, and an exhaust turbine 44 is arranged in the exhaust pipe 39. It is arranged in the turbine chamber 45 of. The compressor 42 and the exhaust turbine 44 of the turbocharger 41 are connected to rotate together by a rotating shaft 47 supported in a bearing holder 46, and when exhaust gas passes through the exhaust turbine 44, the exhaust energy causes the rotating shaft 47 to rotate. rotates to drive the compressor 42 and pressurize the intake air. A turbine chamber 45 is provided in the exhaust passage A formed by the exhaust pipe 39.
A bypass passage 4B is formed that connects the inlet side 45m and the outlet side 45b, and this bypass passage 48 has an on-off valve 4.
9 is provided. This on-off valve 49 is connected to a diaphragm 52 of an actuator 51 via a linkage mechanism 50, and is always urged in the closing direction by a spring 53 disposed within the actuator 51. A pressure chamber 54 is defined within the actuator 51 by a diaphragm 52, and this pressure chamber 54 is connected to the compressor chamber 43 by a supercharging pressure extraction pipe 55.
The pressure chamber 54 is connected to the discharge side 43a of the pressure chamber 54, so that supercharging pressure acts within the pressure chamber 54. Therefore, the on-off valve 49 of the bypass passage 4B is controlled by its pressure chamber 5.
4 is higher than the predetermined pressure, that is, the spring 53
When the elastic force of the diaphragm 52 becomes larger than the elastic force of The drive of the supercharger 41 is suppressed, and further increase in supercharging pressure is regulated. Further, the pressure chamber 54 of the actuator 51 is connected to the suction side 43b of the compressor 42 via a pipe 56, a solenoid valve 57, and a pipe 58, and the valve body 57a of the solenoid valve 57 is
is opened against the spring 57b, thereby communicating the pressure chamber 52 with the suction side 43b of the compressor 42 of the intake passage B. Therefore, the diaphragm 52 is restricted from moving against the spring 53, and the supercharging pressure of the compressor 42 is restricted from being immediately applied to the pressure chamber 54.
Maintains high boost pressure during acceleration transient conditions, improving acceleration performance. A water temperature sensor 59 is provided in the cylinder block 2 and sends cooling water temperature information to the computer 8. Further, a knock sensor 60 is provided in the cylinder block 2, and as soon as knocking occurs, the knock sensor 60 senses vibration and delays the ignition timing to prevent the occurrence of knocking. ``The internal combustion engine 1 is equipped with a fuel supply bag [C, and this fuel supply device C has a premixing path for supplying hydrogen to the intake passage B and a direct injection path E for directly injecting hydrogen into the combustion chamber 6. We are prepared. Hydrogen is compressed and stored in the hydrogen cylinder 61, and this hydrogen may be contained in, for example, a hydrogen storage alloy. The pressure is reduced to a predetermined pressure by a pressure reducing valve 64. This reduced pressure hydrogen is branched into two directions by a branch vibro 5.68, and the hydrogen from one branch vibro 5 is passed through a stop valve 67 and a low pressure regulating valve 68 to a bench area 80 provided upstream of the compressor 42. supplied to The path from the hydrogen cylinder 61 to the venturi 80 constitutes a premixing path that supplies hydrogen to the intake passage B, and the venturi 80 is a mixture of hydrogen and air that is supplied from the premixing path. Since hydrogen is supplied according to the amount of air passing through the premixing path, hydrogen is not supplied excessively into the intake passage 14. Hydrogen from the other branch vibe 66 passes through a limiter 69, an accelerator valve 70, and a stop valve 71 to the cylinder rad 3.
Hydrogen is supplied to the combustion chamber 6 from the opening 16a of the hydrogen supply passage 16 formed in the above, and the path from the hydrogen cylinder 61 to the combustion chamber 6 constitutes a direct injection path E that directly injects hydrogen into the combustion M6. The direct injection path E and the premixing path share a portion from the hydrogen cylinder 61 to a branching point of the same path. Note that the abutment 69 can be provided directly in the injection path E so as to be located upstream of the branching portion. The limiter 69 is composed of an electronic governor, and a valve body 69a operates at the engine speed to increase the maximum flow rate of hydrogen according to the engine speed, and an accelerator valve 70 (described later)
When the valve is fully open, the maximum flow rate at that engine speed can be flowed, and constitutes a flow rate control means. That is,! In Figure @7, the curve Ql shows the maximum flow rate of hydrogen supplied from the premixing route, and the curve Q2 shows the sum of the maximum flow rate of hydrogen supplied from the direct injection route E and the premixing route, The limiter 69 controls the maximum flow rate of hydrogen flowing through the direct injection path E so that the amount of hydrogen supplied through the direct injection path E is greater than the amount of hydrogen supplied through the premixing path, and the difference between the curve MQ2 and the curve Ql is is the direct injection path E
is the maximum flow rate of hydrogen due to Note that the flow rate control means is not limited to the stem 69, but may include a stop valve 67, a low pressure regulating valve 68, and a branch vibro 5.
．． 66 can also be configured. That is, by controlling the stop valve 67 and the low pressure regulating valve 68 and by making the diameter of the branch vibro 5 smaller than the diameter of the branch pipe 66, the amount of hydrogen flowing through the premixing path is restricted, and the amount of hydrogen flowing through the direct injection path E is reduced. The amount of hydrogen supplied can also be greater than the amount of hydrogen supplied through the premixing route. Furthermore, as shown in FIG. 7, for example, the hydrogen flow rate q can be increased according to the engine speed, and as shown in FIG. When the hydrogen supply amount is controlled to reduce and stop the hydrogen supply with af2, only air flows through the intake pipe 24, so the air reaches the maximum flow rate according to the engine speed, as shown in Figure 8. In addition, the maximum horsepower can be obtained at the engine speed f1. Further, the accelerator valve 70 is opened by the valve body 70 by the accelerator operation.
a is activated, and the valve opening degree is adjusted. This accelerator valve 70 changes the flow rate of hydrogen according to the engine load within the range of the maximum flow rate of hydrogen flowing through the direct injection path E at the engine speed. For example, in a full load state where the accelerator valve 70 is fully open. The maximum flow rate is flowing at 1/2 load, and the maximum flow rate of 172 is flowing at 1/2 load. Although the flow rate and the engine load may be made proportional in this way, it is not necessary. In this way, the compressor 42 that compresses intake air is provided in the intake passage B of the premixing path, and the limiter 69 that changes the maximum flow rate of hydrogen according to the engine speed is provided in the direct injection path E. A compressor supplies a large amount of air commensurate with the controlled amount of hydrogen in the rotation range. This enables lean combustion, which reduces NOx and improves fuel efficiency. Furthermore, in the operating range excluding idling, the fuel supply device C is set so that the amount of hydrogen supplied through the direct injection path E is larger than that through the premixing path. It is designed to supply hydrogen to Therefore, since the amount of hydrogen to be compressed by the compressor 42 can be reduced, the size of the compressor 42 can be reduced. Furthermore, the concentration of hydrogen supplied to the intake passage B can be kept low at high engine speeds when the intake passage B tends to be at a high temperature, making it possible to prevent flashback. In addition, since the premixing path is connected upstream of the intercooler 26, hydrogen, which has better heat transfer than air, flows through the intercooler 26, which improves the cooling performance of the pressurized intake air. will improve. Therefore, the intercooler 26 can be made smaller. [Effects of the Invention] As described above, the present invention provides a compressor for compressing intake air in the intake passage, and also uses a limiter to change the maximum flow rate of hydrogen in the direct injection path according to the engine speed, so that all Since the compressor supplies a large amount of air commensurate with the controlled amount of hydrogen in the rotation range, lean combustion becomes possible, reducing NOx and improving fuel efficiency. In addition, the flow rate control means allows the amount of hydrogen supplied through the direct injection path to be greater than the amount of hydrogen supplied through the premixing path in operating regions other than idling, so the amount of hydrogen gas to be compressed by the compressor can be reduced. Miniaturization becomes possible. Furthermore, the concentration of hydrogen supplied to the intake passage at high engine speeds, when the intake passage tends to reach high temperatures, is kept low, thereby preventing flashback.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is an overall configuration diagram of a fuel supply system for an internal combustion engine according to the present invention, and Fig. 2 is a sectional view of an intake system and an exhaust system of the fuel supply system.
Figure 3 is a bottom view of the cylinder head, Figure 4 is a diagram showing valve opening and closing timing, Figures 5 and 6 are cam diagrams, ]!
FIG. 7 is a diagram showing the relationship between hydrogen flow rate and engine speed, and FIG. 8 is a diagram showing the relationship between horsepower and engine speed. In the drawings, 1 is an internal combustion engine, 6 is a combustion chamber, 8 is a computer, 12 is an intake system, 13 is an exhaust system, 24 is an intake pipe, 39 is an exhaust pipe, 41 is a turbo supercharger, 42 is a compressor, 44 69 is an exhaust turbine, 69 is a limiter (flow control means), A is an exhaust passage, B is an intake passage, C is a fuel supply device, D is a premixing path, and E is a direct injection path. Patent applicant: Yamaha Motor Co., Ltd.

Claims (1)

[Claims] In a fuel supply device for an internal combustion engine, which includes a direct injection path for directly injecting hydrogen into a combustion chamber and a premixing path for supplying hydrogen to an intake passage, a compressor for compressing intake air is provided in the intake passage, and a compressor for compressing intake air is provided in the intake passage; A limiter is installed in the injection path to change the maximum flow rate of hydrogen according to the engine speed, and the flow rate control is such that the amount of hydrogen supplied by the direct injection path is greater than the amount of hydrogen supplied by the premixing path in operating regions other than idling. A fuel supply device for an internal combustion engine, comprising: means.