Reciprocating piston type gas engine anti-backfire system

Abstract

The invention relates to the technical field of reciprocating piston type gas engines, in particular to an anti-backfire system of a reciprocating piston type gas engine. A flame arrester is connected between an air inlet manifold and an inlet of an air inlet channel of an air cylinder cover; the intake valve is controlled by an intake cam, the phase position of the intake valve is changed through design, so that the intake valve is opened after an air cylinder ventilation top dead center, and the opening delay angle alpha of the intake valve is a crank angle of 0-60 degrees. The exhaust valve is controlled by an exhaust cam, and the phase position of the exhaust valve is changed through design, so that the exhaust valve is closed at a cylinder ventilation top dead center. The system is suitable for different types of reciprocating piston type gas engines of 1-24 cylinders, self-suction or pressurization and the like, and is simple in structure, high in reformability and high in safety.

Description

Technical Field

[0001] This invention relates to the field of reciprocating piston gas engine technology, and particularly to a backfire prevention system for reciprocating piston gas engines. Background Technology

[0002] Existing reciprocating piston gas engines generally have the problem and risk of backfire explosion, especially when using LPG or hydrogen-containing combustible gases, the frequency of backfire explosion increases.

[0003] To reduce the problems and risks of backfire explosions in reciprocating piston gas engines, many preventative measures have been implemented. For example, flame arresters are installed on the intake manifold to prevent damage to the intercooler and turbocharger in the event of backfire; maintenance frequency is increased, and valve clearances are checked to prevent backfire explosions caused by valve leaks. For combustible gases prone to backfire, naturally aspirated reciprocating piston gas engines are used to minimize the damage from backfire explosions.

[0004] In order to completely suppress the problem and risk of backfire explosion in reciprocating piston gas engines, the applicant has designed a backfire prevention system for reciprocating piston gas engines to solve the above problems. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a backfire prevention system for a reciprocating piston gas engine, comprising a reciprocating piston gas engine body having an intake manifold, cylinder head, intake valves, intake camshaft, exhaust camshaft, and exhaust valve, characterized in that: A flame arrester is connected between the intake manifold and the intake port of the cylinder head; the intake valve is controlled by the intake cam, and its phase is modified by design so that the intake valve opens after the top dead center of the cylinder, and the angle α of the intake valve delay opening is 0 to 60° of crankshaft rotation. The exhaust valve is controlled by an exhaust cam, and its phase has been modified so that the exhaust valve closes at the top dead center of the cylinder during scavenging.

[0006] Furthermore, in order to better realize the present invention, the intake cam can achieve angle α by changing the mounting phase or profile, or the intake cam can be equipped with a variable valve timing mechanism to adjust the angle α under different operating conditions.

[0007] Furthermore, in order to better realize the present invention, the exhaust cam changes the installation phase or profile to make the exhaust valve close at the top dead center of the scavenging, thereby making the overlap angle of the intake and exhaust valves near the top dead center of the scavenging ≤0°CA.

[0008] Furthermore, in order to better realize the present invention, the flame arrester is located near the intake port of the cylinder head and is detachably connected to the intake manifold for maintenance and replacement.

[0009] Furthermore, in order to better realize the present invention, the reciprocating piston gas engine body is a 1-cylinder to 24-cylinder reciprocating piston gas engine.

[0010] Furthermore, in order to better realize the present invention, the backfire prevention system is applicable to both self-aspirated and turbocharged reciprocating piston gas engines.

[0011] The beneficial effects of this invention are: The backfire prevention system for reciprocating piston gas engines provided in this application prevents backfire flames from propagating to the intake manifold under low-load conditions, ensuring stable operation of the engine. Under medium-to-high-load conditions, the intake valves delay opening at top dead center during the scavenging process, allowing residual exhaust gases in the cylinders to expand adiabatically first, reducing their pressure and temperature. When the intake valves open, the pressure and temperature of the residual exhaust gases in the cylinders are lower than the intake manifold pressure and temperature, respectively, preventing them from entering the intake manifold and igniting the combustible mixture. Simultaneously, under medium-to-high load conditions, backfire caused by valve wear and subsequent valve sealing defects is prevented from propagating to the intake manifold by the intake manifold flame arrester, thus avoiding greater backfire explosions and damage. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the anti-backfire system for a reciprocating piston gas engine according to the present invention; Figure 2 This is a schematic diagram of the valve timing and valve lift curves of the present invention.

[0013] In the picture, 1. Intake manifold, 2. Flame arrester, 3. Cylinder head, 4. Intake valve, 5. Intake camshaft, 6. Exhaust camshaft, 7. Exhaust valve. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0016] Figures 1-2 As a specific embodiment of the present invention, such as Figure 1 As shown, this embodiment is a backfire prevention system for a reciprocating piston gas engine, applied to a single-cylinder engine. The combustible mixture is connected to a flame arrester through the intake manifold, and the flame arrester is connected to the intake port inlet of the cylinder head. The intake process is then controlled by the intake cam via the intake valve. By designing and modifying the intake cam, the intake valve opens after the top dead center of the cylinder stroke. The angle α of the intake valve opening delay is called the backfire delay angle, which ranges from 0 to 60°CA. This can prevent residual exhaust gas in the cylinder from flowing back into the intake port under medium and high loads, and the temperature of the residual exhaust gas in the cylinder is lower than the ignition point of the combustible mixture in the intake port. The exhaust gas after combustion is discharged through the exhaust valve controlled by the exhaust cam. By designing and modifying the exhaust cam, the exhaust valve closes at the top dead center of the cylinder stroke. This ensures that the residual exhaust gas in the cylinder is in an adiabatic expansion state during the intake stroke, reducing the pressure and temperature of the residual exhaust gas in the cylinder.

[0017] like Figure 2 As shown, the exhaust valve closes at top dead center of the intake manifold, and the intake valve opens after the top dead center of the intake manifold by an angle α (0~60°CA). This ensures that residual exhaust gas in the cylinder will not flow back into the cylinder.

[0018] The two diagrams combined form a backfire prevention system for reciprocating piston gas engines. By using an intake manifold flame arrester, backfire in reciprocating piston gas engines can be prevented under unexpected conditions (low load, valve wear). By closing the exhaust valve at top dead center and opening the intake valve after top dead center, residual exhaust gas in the cylinder will not flow back into the cylinder. Furthermore, the temperature of the residual exhaust gas in the cylinder is lower than the ignition point of the combustible mixture, thus preventing the ignition of the combustible mixture in the intake manifold and causing backfire.

[0019] Backfire prevention systems for reciprocating piston gas engines can be applied to both single-cylinder and multi-cylinder engines, including naturally aspirated and turbocharged reciprocating piston gas engines.

[0020] This embodiment achieves suppression of gas pressure fluctuations and stability of air-fuel ratio, as well as reduction of intake resistance, through two-stage pressure regulation and a Venturi mixer; and achieves higher thermal efficiency and higher power under the same knock tendency conditions through multiple sets of converging exhaust manifolds and high compression ratio pistons.

[0021] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A backfire prevention system for a reciprocating piston gas engine, comprising a reciprocating piston gas engine body having an intake manifold (1), a cylinder head (3), an intake valve (4), an intake cam (5), an exhaust cam (6), and an exhaust valve (7), characterized in that: A flame arrester (2) is connected between the intake manifold (1) and the intake port of the cylinder head (3); the intake valve (4) is controlled by the intake cam (5), and its phase is modified by design so that the intake valve (4) opens after the top dead center of the cylinder, and the angle α of the intake valve (4) being delayed is 0 to 60° of crankshaft rotation. The exhaust valve (7) is controlled by the exhaust cam (6), and its phase is modified by design so that the exhaust valve (7) closes at the top dead center of the cylinder.

2. The backfire prevention system for reciprocating piston gas engines according to claim 1, characterized in that: The intake cam (5) can achieve angle α by changing the mounting phase or profile, or the intake cam (5) can be equipped with a variable valve timing mechanism to adjust the angle α under different operating conditions.

3. The anti-backfire system for reciprocating piston gas engines according to claim 1, characterized in that: The exhaust cam (6) closes the exhaust valve (7) at the top dead center of the scavenging process by changing the installation phase or profile, so that the overlap angle of the intake and exhaust valves near the top dead center of the scavenging process is ≤0°CA.

4. The anti-backfire system for reciprocating piston gas engines according to claim 1, characterized in that: The flame arrester (2) is located near the intake port of the cylinder head (3) and is detachably connected to the intake manifold (1) for maintenance and replacement.

5. The anti-backfire system for reciprocating piston gas engines according to claim 1, characterized in that: The reciprocating piston gas engine body is a 1-cylinder to 24-cylinder reciprocating piston gas engine.

6. The anti-backfire system for reciprocating piston gas engines according to claim 1, characterized in that: The backfire prevention system is applicable to both self-aspirated and turbocharged reciprocating piston gas engines.

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