A multifunctional HCCI combustion process controllable combustion chamber

Abstract

The present invention provides a multifunctional HCCI combustion process controllable combustion chamber, including a cylinder head, an energy storage chamber, an intake valve, an exhaust valve, a spark plug, a high-speed solenoid valve, a main combustion chamber, a piston, a cylinder barrel, an air flow channel and a pressure sensor; wherein the bottom of the cylinder head is provided with an intake valve and an exhaust valve, the top of the energy storage chamber is provided with a spark plug, the energy storage chamber and the combustion chamber are connected through an air flow channel of a certain diameter; a high-speed solenoid valve is provided in the air flow channel, a pressure sensor is provided on the high-speed solenoid valve, and the piston is provided in the cylinder barrel; when the piston is at the top dead center, the top surface of the piston and the cylinder barrel constitute the space of the main combustion chamber. The present invention realizes the heating of the rarefied gas or enriched gas in the main combustion chamber by the high-temperature gas in the energy storage chamber, prompting the gas in the main combustion chamber to reach the ignition condition, realizing multi-point ignition combustion, stabilizing the engine combustion process, and greatly improving the engine combustion and emission quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine combustion research, and in particular relates to a combustion chamber for realizing a controllable HCCI (Homogeneous Charge Compression Ignition) combustion process. Background Art

[0002] Faced with increasingly stringent emission regulations, traditional internal combustion engine combustion methods have gradually reached bottlenecks in terms of emission restrictions and fuel utilization restrictions. Combustion methods characterized by homogeneous compression ignition and low-temperature combustion have shown great potential in energy saving and emission reduction.

[0003] Homogeneous charge compression ignition (HCCI combustion method) forms a homogeneous mixture during the compression process. When it reaches the top dead center of compression, the mixture spontaneously ignites. Not only can an ultra-high air-fuel ratio be achieved to realize lean combustion, but the mixture also burns and releases energy almost simultaneously during the compression ignition process, avoiding the energy loss of flame diffusion combustion when the spark plug is ignited, and the combustion thermal efficiency is high. Lean combustion can reduce NOx and PM emissions, and is a clean combustion method.

[0004] Since the ignition and combustion process of HCCI is controlled by the chemical reaction kinetics of the fuel, it faces the problems of difficult to control the ignition time and narrow working range. At present, the control of HCCI is mainly based on the control model, which calculates the required output according to the sensor input signal to control the operation of the actuator. The control model predicts the combustion process based on the key signals collected by the sensor, and determines the amount of fresh air and injected fuel required for the next cycle of combustion in advance according to the combustion state of the previous cycle, so as to realize the HCCI cycle control. This control method is relatively complicated and has poor adaptability to fuel combustion in a wide air-fuel ratio range. Therefore, it is necessary to design a combustion chamber to realize the control of HCCI combustion mode. Summary of the invention

[0005] In view of the above situation, the purpose of the present invention is to provide a combustion system that can control the ignition timing of the HCCI combustion mode, utilize the energy in the energy storage chamber to realize multi-point ignition combustion of the premixed fuel in the main combustion chamber, and at the same time widen the combustion air-fuel ratio range to achieve combustion stability of the engine under low load and high load conditions.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a multifunctional HCCI combustion process controllable combustion chamber, whose structure includes a cylinder head, an energy storage chamber, an intake valve, an exhaust valve, a spark plug, a high-speed solenoid valve, a main combustion chamber, a piston, a cylinder barrel, an air flow channel and a pressure sensor; wherein, an energy storage chamber and an air flow channel are arranged at the bottom of the cylinder head, and an intake valve and an exhaust valve are arranged at the bottom of the cylinder head; a spark plug is arranged at the top of the energy storage chamber; a high-speed solenoid valve is arranged in the air flow channel, and a pressure sensor is arranged in the high-speed solenoid valve; the piston is arranged in the cylinder barrel; when the piston is at the top dead center, the top surface of the piston and the cylinder barrel constitute the space of the combustion chamber; the energy storage chamber is connected to the main combustion chamber through an air flow channel of a certain diameter.

[0007] The energy storage chamber is arranged at the center of the combustion chamber on the bottom surface of the cylinder head, and the intake valve and the exhaust valve are arranged on both sides of the energy storage chamber; a spark plug is arranged in the center of the energy storage chamber.

[0008] The beneficial effects of the present invention are: through the energy storage chamber and the high-speed solenoid valve, the high-temperature gas in the energy storage chamber heats the rarefied gas or the enriched gas in the main combustion chamber, prompting the gas in the main combustion chamber to reach the ignition condition, realizing multi-point ignition and combustion, stabilizing the engine combustion process, and greatly improving the engine combustion and emission quality. In addition, the mixed gas in the main combustion chamber can be coalbed methane with low-concentration component changes or low-concentration petroleum-based fuel, realizing flexible replacement of the combustion medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the combustion system of the present invention.

[0010] In the figure, 1, cylinder head; 2, energy storage chamber; 3, intake valve; 4, exhaust valve; 5, spark plug; 6, high-speed solenoid valve; 7, main combustion chamber; 8, piston; 9, cylinder block; 10, air flow channel; 11, pressure sensor. DETAILED DESCRIPTION

[0011] like Figure 1 As shown, a multifunctional HCCI combustion process controllable combustion chamber includes a cylinder head 1; an energy storage chamber 2; an intake valve 3; an exhaust valve 4; a spark plug 5; a high-speed solenoid valve 6; a main combustion chamber 7; a piston 8; a cylinder barrel 9; an air flow channel 10; and a pressure sensor 11; wherein the intake valve 3 and the exhaust valve 4 are arranged at the bottom of the cylinder head 1; the spark plug 5 is arranged at the top of the energy storage chamber 2; the energy storage chamber 2 is connected to the combustion chamber 7 through an air flow channel 10 of a certain diameter; a high-speed solenoid valve 6 is arranged in the air flow channel 10; a pressure sensor 11 is arranged on the high-speed solenoid valve 6; the piston 8 is arranged in the cylinder barrel 9; when the piston 8 is at the top dead center, the top surface of the piston 8 and the cylinder barrel 9 constitute the space of the main combustion chamber 7.

[0012] 1) Through the design and calculation of the intake temperature and compression ratio, the mixture in the main combustion chamber 7 is controlled so that the premixed gas does not spontaneously ignite when the piston 8 is compressed to the top dead center under any circumstances.

[0013] 2) Engine starting process: The high-speed solenoid valve 6 remains open, the energy storage chamber 2 is connected to the main combustion chamber 7, the spark plug 5 sparks, ignites the mixed gas in the energy storage chamber 2, and the premixed gas in the energy storage chamber 2 and the main combustion chamber 7 ignites and burns, and the mixed gas pressure increases. According to the built-in pressure sensor 11 of the high-speed solenoid valve 6, when the gas pressure in the energy storage chamber 2 increases to a given value, the high-speed solenoid valve 2 is closed, and part of the high-pressure and high-temperature gas exists in the energy storage chamber 2. Entering the next working cycle, the piston 8 moves upward along the wall of the cylinder barrel 9, compressing the premixed gas in the main combustion chamber 7, and the temperature of the premixed gas continues to increase. When the piston 8 reaches the top dead center, the spark plug 5 no longer sparks, the high-speed solenoid valve 6 opens, and the high-energy gas in the energy storage chamber 2 enters the main combustion chamber 7 through the air flow channel 10, compressing and adiabatically heating the unburned premixed gas in the main combustion chamber 7. When the temperature of the premixed gas in the main combustion chamber 7 reaches the gas auto-ignition temperature at this time, multiple fire cores are formed in the main combustion chamber 7, and the premixed gas begins to burn. When the mixed gas pressure in the main combustion chamber 7 reaches a preset value, the high-speed solenoid valve 6 is closed, the energy storage chamber 2 and the main combustion chamber 7 are separated by the high-speed solenoid valve, and the high-temperature combustion gas in the main combustion chamber 7 continues to work on the piston 8. The high-temperature and high-pressure gas in the energy storage chamber 2 stores energy to prepare for igniting the premixed gas in the main combustion chamber 7 of the next cycle.

[0014] 3) Normal working condition: After the engine reaches normal operating condition, the mixed gas stored in the energy storage chamber 2 has a certain amount of energy, which is enough to heat the unburned premixed gas in the main combustion chamber 7 near the top dead center after being released, so that it reaches the auto-ignition temperature. During the combustion and working process of the engine, the pressure of the mixed gas in the main combustion chamber 7 gradually decreases. When the pressure drops to a preset value, the high-speed solenoid valve 6 closes, and the high-temperature and high-pressure gas is stored in the energy storage chamber 2 to prepare for the ignition of the premixed gas in the next working cycle.

[0015] 4) Acceleration and high-load conditions: By adjusting the throttle opening or the intake valve (low-concentration coalbed methane), the quality of the premixed gas is increased, thereby increasing the average effective pressure of the mixed gas during the work process and increasing the work capacity. This control method increases the thermal load and mechanical load of the engine due to the increase in temperature and average effective pressure; therefore, it cannot be used for a long time. It can only be used for a moment during the acceleration process.

[0016] 5) Low load condition: By adjusting the set value of the built-in pressure sensor 11 of the high-speed solenoid valve 6, the high-temperature fuel gas pressure (mass) in the energy storage chamber 2 is increased. When the engine runs to the next working cycle and the piston 8 moves to the vicinity of the top dead center, the high-temperature fuel gas with more energy in the energy storage chamber 2 enters the main combustion chamber 7 through the air flow channel 10, thereby increasing the compression terminal temperature and pressure of the low-concentration mixture in the main combustion chamber 7, so that it can stably ignite, thereby improving the working stability of the variable-concentration mixture of the engine.

Claims

1. A multifunctional HCCI combustion process controllable combustion chamber, characterized in that: The structure includes a cylinder head, an energy storage chamber, an intake valve, an exhaust valve, a spark plug, a high-speed solenoid valve, a main combustion chamber, a piston, a cylinder barrel, an air flow channel and a pressure sensor; wherein, an energy storage chamber and an air flow channel are arranged at the bottom of the cylinder head, and an intake valve and an exhaust valve are arranged at the bottom of the cylinder head; a spark plug is arranged at the top of the energy storage chamber; a high-speed solenoid valve is arranged in the air flow channel; a pressure sensor is arranged on the high-speed solenoid valve; a piston is arranged in the cylinder barrel; when the piston is at the top dead center, the top surface of the piston and the cylinder barrel form the space of the combustion chamber; the energy storage chamber is connected to the main combustion chamber through an air flow channel with a certain diameter; The energy storage chamber is arranged at the center of the combustion chamber on the bottom surface of the cylinder head, and the intake valve and the exhaust valve are arranged on both sides of the energy storage chamber.

Images