RU2377423C1 - Method of internal combustion engine operation - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to machine building, particularly to engine production. Invention consists in that, to reduce content of toxic components in exhaust gases, i.e. nitrogen oxides, carbon oxide, hydrocarbons and smoke in two-phase fuel feed, maximum combustion rate in central combustion phase is decreased and combustion rate in final combustion phase is relatively increased. Both effects are attained by injecting the main portion of phase feed (90-92%) during first stage of injection. Injection is made in such a phase of crankshaft turn which, along with amount of injected fuel, ensures maximum combustion rate in the phase corresponding to 15° to 18° of crankshaft turn over TDC. Second portion, i.e. 8 to 10% of phase feed, is injected in preset phase of final combustion stage.

EFFECT: reduced toxicity of combustion products.

Description

The invention relates to mechanical engineering, in particular to engine building.

The method of operation of an internal combustion engine with volumetric mixture formation and compression ignition, including two-phase fuel supply and its ignition, is characterized in that the reduction in the content of harmful emissions with exhaust gases is ensured by such a two-phase fuel injection arrangement in which the first phase makes up the main part of the cyclic supply, and a second smaller portion of the cyclic feed is injected in a predetermined phase of the combustion process.

A known method of operation of an internal combustion engine (patent RU 2164300 C2, class F02B 3/12) with volumetric mixture formation and compression ignition, comprising a two-phase fuel supply with the amount of fuel in the first pilot phase, sufficient to ignite the fuel of the second main phase, with the input the second portion of fuel provides the maximum burning rate from the moment corresponding to 10 ÷ 15 ° crankshaft rotation for top dead center, and the combustion process ends no later than 40 ÷ 60 ° crankshaft rotation for top dead center a bite.

The main purpose of this method of engine operation is to reduce nitrogen oxide emissions by reducing the maximum temperature of the combustion process.

Proposed according to the present invention, the method of operation of an internal combustion engine allows to reduce emissions of both nitrogen oxides and carbon monoxide, hydrocarbons and smoke, at least in a limited range of engine operating modes due to the organization of the combustion process, characterized by a decrease in the maximum heat release rate in the central phase of the process combustion and its relative increase in a later phase, with the beginning of a relative increase in the burning rate, shifted relative to the maximum phase with burning speed at 8 ÷ 10 ° of rotation of the crankshaft in the direction of its rotation, which is achieved by fuel injection in two phases, while the injection of the first main portion of fuel, comprising 90 ÷ 92 percent of the cyclic feed, is carried out in a phase that ensures maximum burning speed at the moment corresponding to 15–18 ° of crankshaft rotation beyond the top dead center, and the phase of the injection of the second portion of fuel, which is 8–10 percent of the cycle feed, respectively, is shifted relative to the phase of the maximum speed 6 to 8 ° rotation of the crankshaft in the direction of its rotation.

The drawing shows the diagrams of injection and heat release characteristics, namely, the amount of heat released (X) and heat release rate (dX / dφ), characteristic, for example, for the full power mode of a medium-speed internal combustion engine with a cylinder power of 200 kW, when organizing its operation three options, namely:

a) with injection in one phase;

b) with injection in two phases with the first pilot phase, comprising 15 percent of the cycle feed;

c) according to the present invention, with an injection in two phases, with an amount of fuel in the first main phase of 91 percent of the cyclic supply.

From a comparison of the diagrams shown in the drawing, it can be seen that when the engine operates with both two-phase injection variants (variants b and c), at least in connection with the injection in the main phase only part of the cyclic feed, the maximum injection pressure is lower by δ ₁ and δ ₂ , respectively, and the maximum combustion rate is lower by δ ₃ and δ ₄ , respectively, than with the method with injection in one phase (option “a”). This circumstance leads to certain possibilities of both methods with two-phase injection in terms of reducing the formation and emission of exhaust gases from the engine of nitrogen oxides by reducing the maximum temperature of the combustion cycle.

With the method of operation of the engine according to the present invention (option “c”), by means of a corresponding advance of injection (φ _op ) and the corresponding amount of fuel injected in the first phase, namely 90 ÷ 92 percent of the cyclic supply, such a dynamics of the combustion process is ensured that the maximum speed combustion is achieved in phase (E), displaced relative to TDC in the direction of rotation of the crankshaft by an angle (G) of 15 ÷ 18 °, and after the start of an intensive reduction in the burning rate, after the crankshaft rotates per phase (E) at an angle (D) of 6–8 °, the second portion of fuel is injected, comprising 8–10 percent of the cyclic feed.

The introduction of this portion of fuel into the combustion process, as well as its certain homogenizing effect exerted by the physical effect of the fuel jets and flames on the combustion products, leads to a relative activation of the oxidation processes in the final phase of combustion, with a relative increase in the rate of heat release in section (G), with a relative increase in the combustion rate, shifted relative to the phase (E) in the direction of rotation of the crankshaft by an angle (I), equal to 8 ÷ 10 °. As a result of more complete oxidation of the combustion products, the content of carbon monoxide, carbohydrates and smoke in the exhaust gases is reduced.

The table shows the specific fuel consumption and the content of emissions of nitrogen oxides, carbon monoxide, hydrocarbons and smoke, typical for the full power mode of a medium-speed internal combustion engine with a cylinder power of 200 kW, with the three engine operation methods illustrated in the drawing.

Name, designation and dimension of the parameters of the combustion process Ways of working ICE. (Full power mode) With injection in one phase (option "a") With two-phase injection with the first pilot phase (option "b") According to the present invention (option "C") Specific fuel consumption (g _e ), g / kW · h 202.50 212.80 202.40 Emissions of nitrogen oxides (NO _x ), g / kW · h 9.71 8.46 8.51 Emissions of carbon monoxide (СО), g / kW · h 5.12 4.89 1.36 Hydrocarbon emissions (CH), g / kW · h 0.85 0.71 0.62 Smoke content, units BOSCH 0.20 0.6 0.16

As can be seen from the data in the table, with the method of operation of the engine according to the present invention (option "c"), the emissions of carbon monoxide, hydrocarbons and smoke are lower than with the method with two-phase supply and pilot injection (option "b"), and relative to the method with injection in one phase (option "a"), in addition, lower emissions of nitrogen oxides. In this case, in contrast to the method with two-phase supply and pilot injection, with the method of operation of the engine according to the present invention, the reduction of harmful substances is ensured without deterioration of fuel consumption relative to, for example, the method of operation of the engine with injection in one phase.

Claims (1)

The method of operation of an internal combustion engine with volumetric mixture formation and compression ignition, including two-phase fuel supply and ignition, characterized in that the reduction of the content of nitrogen oxides, carbon monoxide, hydrocarbons and smoke in the exhaust gases of the engine, at least in a limited range of its modes work is ensured by such an organization of two-phase fuel injection, in which the first portion of the fuel is 90-92% of the cyclic feed and is injected in such a phase of crankshaft rotation, which Combined with the amount of fuel injected, it achieves the maximum burning speed in the phase corresponding to 15-18 ° crankshaft rotation beyond the top dead center, and the second injection phase, comprising 8-10% of the cycle feed, with the start of the injection shifted relative to the phase corresponding to the maximum speed of combustion, by 6-8 ° of rotation of the crankshaft in the direction of its rotation, provides a relative increase in the rate of combustion in the phase of the combustion process, shifted relative to the phase with a maximum speed in the direction ii crankshaft rotation at 8-10 ° of its rotation.

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