RU2226618C1 - Starting preheater of internal combustion engine - Google Patents

Abstract

FIELD: transport engineering; internal combustion engines. SUBSTANCE: invention is aimed at provided required prestarting temperature conditions of engine and heating of automobile cab at low ambient air temperatures. Proposed starting preheater of internal combustion engine contains combustion chamber divided by diaphragm into two spaces with igniter chamber arranged in mixing chamber in one of two spaces, igniter chamber being connected with mixing chamber by means of holes made in igniter chamber housing, heat exchanger enclosing combustion chamber and made in form of cup with external helical ribs connected with cooling liquid supply system, flame pickup installed in mixing chamber, stabilizer arranged at outlet of igniter chamber before diaphragm, glow plug arranged in igniter chamber, and nozzle connecting combustion chamber with fuel feed system, mixing chamber being connected with air supply system. Proposed starting preheater, as distinct from known, ones, is furnished with swirler installed on walls of combustion chamber and enclosing igniter chamber, and condenser-fuel evaporator located over perimeter of igniter chamber. Flame pickup is made in from of hollow tube with photocell built into end face wall of housing, and radial holes are made in tube between photocell and outlet into combustion chamber coupled with air supply system. External helical ribs of heat exchanger pass from cylindrical surface of cup onto bottom in form of part of spiral with gradually decreasing height of rib to central part of bottom, and internal ribs are arranged along axis of heat exchanger cup with thickness of rib in section increasing towards base and variable thickness over length of rib. Invention provides decrease of power consumption at starting under below zero temperatures, improved economy of starting preheater owing to provision of reliable ignition and higher efficiency. EFFECT: reduced cost of starting preheater. 3 cl, 7 dwg

Description

The invention relates to the field of engine construction and operation of vehicles, more precisely, providing the necessary pre-start thermal regime of the engine and heating the car cabin at low air temperatures.

Known preheater of an internal combustion engine (see patent RU No. 2112138, F02N17 / 06, 20.11.98), comprising a combustion chamber with nozzles, a heat exchanger, a pre-chamber, a heat exchanger with a two-way system of movement of combustion products, a fuel electric heater with an electric air heater around the pre-chamber.

The disadvantage of this pre-heater internal combustion engine is a sufficiently high voltage and power consumption when starting the heater.

The closest in technical essence to the invention adopted as a prototype is a pre-heater for an internal combustion engine (see prospectus "The New Add-Heater from Eberspacher". By Dipl.-Ing. Michael Hamburg. Published in ATZ Automobiltechniche Zeitschrift 97 (1995) 12) comprising a combustion chamber divided by a diaphragm into two cavities, in one of which a firing chamber is located in the mixing chamber, the volume of which is connected to the volume of the mixing chamber through openings made in the casing of the ignition chamber, enclosing the combustion chamber in the form of stacks on with external screw ribs connected to the coolant supply system, a flame sensor installed in the mixing chamber, a stabilizer located at the outlet of the ignition chamber in front of the diaphragm, an glow plug placed in the ignition chamber, and a nozzle connecting the combustion chamber to the fuel supply system, wherein the mixing chamber is connected to the air supply system.

The disadvantages of this pre-heater for an internal combustion engine are a rather high power consumption, and, consequently, low cost-effectiveness, as well as the high cost of the design as a whole.

The problem solved by the invention is to reduce the power consumption of the heater when starting at low, negative temperatures, increasing the efficiency of the heater, by increasing the efficiency of the fuse and improve efficiency, as well as cheaper heater.

The problem is solved in that in the pre-heater of the internal combustion engine containing a combustion chamber divided by a diaphragm into two cavities, in one of which a firing chamber is located in the mixing chamber, the volume of which is connected to the volume of the mixing chamber through openings made in the casing of the ignition chamber, covering combustion chamber a heat exchanger in the form of a cup with external screw ribs connected to the coolant supply system, a flame sensor installed in the mixing chamber, a stabilizer located at the exit of the ignition chamber in front of the diaphragm, an glow plug placed in the ignition chamber, and a nozzle connecting the combustion chamber to the fuel supply system, while the mixing chamber is connected to the air supply system, unlike the known ones, a swirl is introduced into it mounted on the walls of the combustion chamber and covering the ignition chamber, as well as a condenser-fuel evaporator located along the perimeter of the ignition chamber.

In the pre-heater of the internal combustion engine, the flame sensor is proposed to be made in the form of a hollow tube with a photocell mounted in the end wall of its housing, while radial holes are made in the tube between the photocell and the outlet to the combustion chamber associated with the air supply system.

In the heat exchanger, it is proposed to perform external screw ribs passing from the cylindrical surface of the glass to the bottom in the form of a part of a spiral and converging to the center of the bottom, and also to perform internal ribs located along the axis of the glass of the heat exchanger.

Improving the processes of mixing and uniform evaporation of the fuel deposited on the condenser-evaporator leads to an improvement in the process of afterburning of fuel; increase the efficiency, and, therefore, allows to reduce the size and weight, as well as the reliability of the pre-heater. Due to the increase in the area of contact of the coolant with the surfaces of the heat exchanger, it becomes possible to quickly and reliably start both the heater itself and the internal combustion engine and heating the car cabin at low air temperatures.

The essence of the invention is illustrated in figures 1-6, which show

figure 1 is a longitudinal section of a prestarting heater of an internal combustion engine;

AA (by flame detector and swirl);

figure 3 is a section along BB (ignition chamber with condensate-evaporator);

figure 4 and figure 5 - the shape and placement of the outer ribs on the bottom of the heat exchanger;

figure 6 is a cross-section along G-G (along the inner ribs of the heat exchanger);

7 is a scan of the outer ribs.

The pre-heater of the internal combustion engine contains a combustion chamber 2 located in the housing 1, divided by a diaphragm 3 into two cavities, in one of the cavities, the cavity being the cavity of the mixing chamber 4, there is an ignition chamber 5. In the casing 6 of the ignition chamber 5 there are openings 7 communicating volumes of the ignition 5 and mixing chamber 4.

The combustion chamber 2 is covered by a heat exchanger 8. The heat exchanger is connected to a coolant supply system (not shown) through a pipe 9. A flame sensor 10 is installed in the combustion chamber 2 in the mixing chamber 4, a stabilizer 11 is installed at the outlet of the ignition chamber 5 in front of the diaphragm 3, in the ignition chamber 5 also houses a glow plug 12.

The combustion chamber 2 is connected by a nozzle 13 to a fuel supply system (not shown), and the mixing chamber 4 is connected by a channel 14 to an air supply system containing an electric motor 15, on the axis of which a supercharger 16 is mounted.

A swirler 17 is installed on the walls of the combustion chamber 2, covering the ignition chamber 5, and a condenser-evaporator 18 is arranged along the perimeter of the ignition chamber 5, made in the form of a grid fixed to the wall of the ignition chamber 5 from the outside.

The heat exchanger is made in the form of a glass with external screw ribs 19 on the cylindrical surface and on the bottom of the glass and internal ribs 20, while the internal ribs 20 are connected by the outlet pipe 21 to a flexible metal corrugated sleeve (not shown), and the external screw ribs 19 are connected through a collector 22 into the engine heating system.

The outer screw ribs 19, passing from the cylindrical surface of the glass to the bottom, are made in the form of a part of a spiral with a gradually decreasing height of the ribs to the central part of the bottom, and the internal ribs 20 are located along the axis of the glass of the heat exchanger with the thickness of the ribs to the base increasing in cross section and of variable thickness along the length ribs.

The flame sensor 10, mounted in the end wall 23 of the combustion chamber 2, is made in the form of a hollow tube 24, with a photocell 25 placed therein; the flame sensor tube 24 is mounted in the end wall 23 from the outside of the combustion chamber 2. In this case, radial holes 26 are made in the tube 24 between the photocell 25 and the outlet to the combustion chamber 26, connected to an air supply system (not shown).

The fuel supply system includes a fuel supply pump with pipelines (not shown).

The coolant supply system includes a coolant pump (not shown).

The fuel supply pump, supercharger and coolant pump are driven by electric motors.

The work is controlled by a processor, into the control unit of which a work algorithm is introduced that controls all the necessary parameters and ensures safe operation.

Before starting the heater, the power supply is controlled and the system is purged for a certain time. Air, both during purging and at start-up, in operating modes, is supplied by a supercharger 16 driven by an electric motor 15. First, cooled air passes through the channel 9 and partially through the tube 22 of the flame sensor 10 into the mixing chamber 4 with a low pressure. Coolant pumping starts. A voltage is applied to the glow plug 12, as a result of which it is warmed up and all the elements of the ignition chamber 5 are heated (most intensively). Fuel is supplied through the nozzle 13 to the heated ignition chamber 5, and in order to provide fuel in small portions, it is injected through the needle, which ends with the nozzle 13. The glow plug is started.

Part of the fuel in the process evaporates, part settles on the condenser-evaporator 18, from which, also evaporating, is mixed with air in the mixing chamber 4, and partially with air in the ignition chamber 5 already in operating conditions.

The swirler 17 swirls the air flow when moving from the zone located between the swirl 17 and the inlet of the mixing chamber to the zone between the swirl 17 and the diaphragm 3. In this case, part of the air through the openings 7 enters the ignition chamber 5. Burning gases pass through the opening of the diaphragm 3 from one cavity of the mixing chamber into another cavity, striking at the bottom, passes along the inner ribs 20, transferring heat and then exiting through the outlet pipe 21 into a flexible metal corrugated sleeve, ending with a damper burning particles (not shown).

The heat exchanger is made of stainless steel to increase its service life.

To increase the heat transfer of the coolant, external screw ribs 19 are made on the cup of the heat exchanger 8, flowing through which the coolant removes heat, and the heated one exits through the annular collector 22 of the heat exchanger 8. In addition, to increase the heat exchange, the heat exchanger has internal ribs located along the axis of the heat exchanger cup. , for taking heat from hot gases and transferring heat to the coolant passing through the 4-way screw auger.

The heat transfer coefficient from the coolant heat exchanger increases with an increase in the contact area with the coolant and an increase in its pumping speed through the heat exchanger. When the external fins of the heat exchanger are made in one-way mode (at equal pumping speeds), the coolant will be more in contact with the surfaces of the heat exchanger and, therefore, the coolant and exhaust gases will be warmer, not giving off all the heat. To eliminate these disadvantages is possible due to the proposed refinement of the heat exchanger.

The most optimal is the design of the heat exchanger with external fins, helical in shape, made 4 inlets, and to increase contact areas passing from the cylindrical surface of the glass to the bottom in the form of a part of a spiral with gradually decreasing rib height to the central part of the bottom, with the total passage area the channel cross section for coolant S _SUMM = (1.2 ÷ 1.4) S _TP is the internal section of the pipeline, where S _tr is the internal section of the pipeline of the coolant supply system. It is advisable to perform internal ribs located along the axis of the heat exchanger cup with increasing thickness of the rib towards the base and a variable thickness along the length of the rib from S ₁ - the smallest thickening to S ₂ - the largest thickening in the plane intersecting with the outer screw ribs, with the ratio S ₂ = (l, 4 ÷ 2.0) · (S ₁ (see Fig.6).

The parameters of the heat exchanger are selected from the following ratios :.

The cross-sectional area along the bottom of the heat exchanger cup

S _{end face} = Z · π · D _i

where Z is the gap between the bottom of the glass of the heat exchanger and the housing of the heater is determined by the diameter of the section along the bottom of the glass D _i :

S is the flow area of the pipeline cooling system;

S _REB.DN - the cross-sectional area along the normal rib on the bottom;

n is the number of visits of the outer helical ribs (accepted = 4).

Consequently,

S _{TORTI i} = Z · π · D _i = (l, 2 ÷ l, 4) S _ТР + S _REB.DN · n.

The pitch of the outer helical ribs on a cylindrical surface is determined by the ratio:

S _REB.CYL - cross-sectional area of the outer helical rib along the normal (structural parameter of the heater);

D is the diameter of the heat exchanger along the height of the outer helical ribs (equal to the inner diameter of the heater body);

d is the outer diameter of the heat exchanger cup;

γ is the angle of elevation of the helix of the outer helical rib along the cylindrical surface of the heat exchanger cup;

L is the stroke of the outer helical ribs along the cylindrical surface of the heat exchanger cup;

L = nl (n = 4).

The cross-sectional area of the outer helical ribs S _pass.cycle is determined by the ratio

l _n - the distance between adjacent external screw ribs along the normal:

l _n = l _cosγ

Substituting the value of l _n in (2), respectively:

Cross section for coolant S _sum = (1.2 ÷ 1.4) S _TP

Consequently,

From this we obtain the expression (1).

The proposed design improves mixing and uniform evaporation of the fuel deposited on the condenser-evaporator, which leads to an improvement in the process of afterburning of fuel; increase the efficiency and reliability of the pre-heater, and, therefore, allows to reduce the size and weight, as well as the reliability of the pre-heater. By increasing the area of contact of the coolant with the surfaces of the heat exchanger, both the heater itself and the internal combustion engine and the heating of the car’s cabin are quickly and reliably launched at low air temperatures.

Claims (3)

1. Prestarting heater of an internal combustion engine containing a combustion chamber divided by a diaphragm into two cavities, in one of which a firing chamber is located in the mixing chamber, the volume of which is connected to the volume of the mixing chamber through openings made in the casing of the ignition chamber, covering the combustion chamber in the form cups with external screw ribs connected to the coolant supply system, a flame sensor installed in the mixing chamber, a stabilizer located on leaving the ignition chamber in front of the diaphragm, the glow plug and the nozzle connecting the combustion chamber to the fuel supply system located in the ignition chamber, while the mixing chamber is connected to the air supply system, characterized in that a swirler installed on the walls of the combustion chamber and enclosing the ignition chamber, as well as a condenser-fuel evaporator located along the perimeter of the ignition chamber. 2. The pre-heater of the internal combustion engine according to claim 1, characterized in that the flame sensor is made in the form of a hollow tube with a photocell mounted in the end wall of its housing, while radial holes are made in the tube between the photocell and the exit to the combustion chamber air supply system. 3. The pre-heater of the internal combustion engine according to claim 1, characterized in that in the heat exchanger the external helical ribs are made passing from the cylindrical surface of the glass to the bottom in the form of a part of a spiral and converging to the center of the bottom, and also made internal ribs located along the axis of the glass of the heat exchanger .

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