JPS6020582B2 - Air heating device for compression ignition engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air heating device for a compression ignition engine.

In order to improve the starting performance of a compression ignition engine, the engine is heated.

The simplest heating method would be to burn the fuel in a combustion chamber located at the air intake to the engine. In order to provide a precise amount of heat, it is necessary to carefully control the supply of fuel to the combustion chamber. Furthermore, in the case of supercharged compression ignition engines, it is necessary to maintain a heated state while the engine is running to ensure that the fuel injected into the combustion chamber of the engine is properly combusted. The amount of heat added to the engine while driving must be carefully controlled. One of the problems that arises in controlling the supply of fuel to the combustion chamber is that the pressure of the fuel from the fuel source varies. For example, if the fuel supply source is a battery-powered electric pump, variations in battery voltage will affect the fuel pressure supplied to the pump. For example, voltage fluctuations are significant during operation of a battery-powered engine starter. An object of the present invention is to provide a simple air heating device for a compression ignition engine.

The air heating device for a compression ignition engine according to the present invention includes a combustor, a combustion chamber through which fuel is supplied, and a second stage fuel pump for supplying fuel to the combustor. The output of the stage is connected to the nozzle,
The input of the second stage is connected to the output of the first stage, and the input of the second stage is connected to the output of the first stage.
a two-stage fuel pump, the input of the stage being connected in use to a source of pressurized fuel, the rate of fuel delivery being dependent on the speed at which the pump is driven; and a first motor for driving the pump. an apparatus, a valve arrangement operable to prevent a substantial pressure drop across the second stage of the pump in use, and a control arrangement for controlling the operating speed of the pump. There is.

Embodiments of the air heating device according to the present invention will be described with reference to the accompanying drawings. First of all, referring to FIG. 1 of the attached drawings, a V-type compression ignition engine 1 having intake manifolds 11 and 12 will be explained.
0 is shown.

The intake end of the air intake manifold communicates with the outlet of the combustion chamber 14 via a connecting member 13, and the intake end of the combustion chamber 14 communicates with the compressor of the turbo weekly feeder (not shown) through a pipe 15. Suitable for partial extraction and folding. The turbine of a turbo weekly payer is driven by engine exhaust gas. The combustion chamber 14 has a built-in combustor, and liquid fuel is supplied to the combustion gun through an intake port 16 and an intake port 17.
Pressurized air is supplied through the

Pressurized air is supplied via an air pump, designated 18, which draws air from pipe 15 upstream of the combustion chamber. Combustion chamber 1
4 incorporates an ignition device such as a spark plug, and electrical energy is supplied to the ignition device from a unit 19.
An intake port 16 is connected to an outlet of the fuel pump indicated by the reference numeral 20, and an electrically operated valve 21 is provided between the pump outlet and the intake port 16.

When the fuel pump 20 is not operating, this valve 21 prevents air pressure in the combustion chamber 14 due to operation of the supercharger from causing fuel to flow back into the pump. The fuel pump intake is connected to a source of pressurized fuel, shown as a pump 22, suitably located within the vehicle's fuel tank. Pump 22 is electrically driven, ie, powered by the vehicle's battery. As shown in FIG. 1, the pump 20' is a two stage pump, the first stage being designated by the numeral 23 and the second stage being designated by the numeral 24.

These two-stage structures are positive displacement pumps driven by an electric motor (not shown). It is convenient if the discharge amount of the first stage is twice the discharge amount of the second stage. Additionally, a valve, designated 25, is provided to ensure that no pressure drop occurs between the inlet and the outlet of the second stage 24 of the pump 20.
The output of pump 20 is therefore proportional to the speed at which it is driven, and the amount of fuel delivered to the combustion chamber can be easily controlled by varying the speed of the drive motor. The structures of the pump 20 and the valve 25 will be explained in detail later. However, it is worth mentioning at this point that it is necessary to supply fuel to the combustion chamber with widely varying fuel flow rates. That is, according to one example, a fuel flow rate change of 1.35 to 18.0 liters per hour is required. Varying the speed of the motor provides a change in flow rate. According to the experimental results, when the motor is operated at a relatively low speed, the fuel flow rate to the combustor decreases by 4.5 mm, but even in this case, even if the output pressure of the pump 22 changes significantly, the flow rate change does not change. It turns out that this does not occur. In a particular example, the engine 10' includes twelve cylinders, and fuel is supplied to the combustion zone of the engine through fuel injection nozzles.

One of these injection nozzles is designated by the reference numeral 26. In reality, it should be understood that twelve such injection nozzles are provided. Fuel is supplied to the nozzle at the appropriate time via a pump device 27. The pumping device 27 here comprises a camshaft on which twelve cams are mounted, by means of which each individual injection pump associated with the nozzle 26 is actuated. The camshaft of the pump device 27 is driven by the engine 10 via a coupling 28. The amount of fuel supplied to the engine by the pump device is controlled in a known manner via an adjustable control rod. The setting of the control rod takes place, according to a particular example, via an electromagnetic actuator arranged in a housing 29 attached to the body of the device 27. Also provided within the aforementioned housing is a transducer which generates an electrical signal of the actual position of the control rod. The supply of current to the electromagnetic actuators which determine the setting of the control rods is controlled by a control circuit generally designated 30. The control circuit not only receives request signals from the transducer 31 connected to the throttle pedal 32, but also receives various signals indicative of engine operating conditions. One of these signals is provided by transducer 33 which indicates the air pressure being supplied to the engine. A further signal is provided by a temperature sensor 34, which is indicative of the temperature of the metal parts of the engine structure. A further detector 35 is provided, which indicates the temperature of the engine exhaust gas. Also provided within the housing 29 is a transducer which provides a signal indicative of the speed of the pumping equipment and therefore the speed of the engine. The various signals provided by the various components are processed within the control circuit 30, and the signals are sent to the electromagnetic actuator so that it sets the control rod so that the engine operates as desired by the driver. Sent.
If this demand is such as to cause the engine to overspeed, for example, the control circuit will regulate the amount of fuel supplied to maintain the engine speed at a safe value. The signals provided by detectors 34 and 35 are also used to control the amount of fuel supplied to the engine under certain circumstances. Since the engine 10 is supercharged, the compression ratio of the engine will be lower than if the engine were not fed weekly.

Therefore, when starting an engine, the air supplied to the engine must be heated. This is because the supercharger
This is because pressurized air cannot be supplied under light load conditions, such as when the engine is at starting speed.
Combustion chamber 14 heats the air entering the engine when it is supplied with fuel and air to facilitate rapid start of the engine, and is supplied to the engine by pump equipment 27 during periods of light engine load. improves the combustion of fuel. FIG. 2 will be explained. This figure shows in block diagram form various components associated with the combustion chamber 14, including electronic components for controlling the generation of heat therethrough. On the downstream side of the combustion chamber,
That is, a temperature sensor 36 is installed inside the intake port of the air intake manifolds 11 and 12. This sensor senses the temperature of the supply air to the intake manifold, which varies depending on the amount of fuel coupled to the combustion chamber. Also shown in FIG. 2 is a drive motor 37 for fuel pump 20', along with a transducer 38. Here, the transducer 38 generates a signal indicating the rotational speed of the motor 37. When starting the engine, a constant supply of fuel to the combustion chamber is required.

The temperature of the air flowing through the absorption manifold will thus depend on the engine crank speed. Once the engine reaches its idle speed, during light load operation of the engine, control of fuel to the combustion chamber is by the temperature of the air sensed by detector 36.
Closed-loop control of temperature occurs during this period. If the engine stops for any reason, fuel supply to the combustion chamber must be prevented, and if the engine speed exceeds a predetermined speed value, fuel supply to the combustion chamber must also be prevented. would be obvious. Furthermore, when the pressure of the air fed by the weekly feeder reaches a predetermined value, the combustion of fuel by the engine should proceed satisfactorily without preheating the air supplied to the engine. be. The control system for the various components mentioned above includes a logic unit 39.
The unit receives a first input at terminal 40';
The input indicates the pressure of the air delivered by the supercharger and is conveniently derived from the transducer 33. The logic unit also receives at input 41 a signal indicating that the engine speed is below a predetermined value, and at input 42 another signal indicating the actual engine speed. The speed of the motor 37 is determined by a control member 43, which receives an input signal from the temperature sensor 36 and also receives a reference signal corresponding to the required temperature of the air supplied to the engine from an engine start input section 44. Receive. However, as previously mentioned, during engine starting, fuel is combined into the combustion chamber at a constant flow rate, and the fuel and air supplies are controlled at a predetermined minimum, such as 6 rpm, during cranking. It is only started when the value is exceeded. When the engine speed reaches this value, the air pump 18, igniter supply member 19 and motor 37 are energized and a flame is generated within the combustion chamber. If for some reason a flame (detected by detector 36) does not occur within a predetermined time, the entire system is shut off;
The system cannot be restarted until the engine speed drops below the aforementioned minimum value. The engine starts and its speed is set to a second value (e.g. 40 pm)
Once reached, unit 19 is de-energized and the logic circuit operates control member 43 to provide closed loop control of the fuel. A reference signal applied to terminal 44 sets a temperature value for the air flowing in the manifold, and control member 43 adjusts the speed of the motor to obtain this temperature value. The fuel supply operation continues until the engine speed exceeds a predetermined value or the pressure of the air supplied by the supercharger exceeds a predetermined value. That is, when either of these values is achieved, the system is shut down and the engine is allowed to operate without fuel supply to the combustion chamber. If the engine is allowed to run without load after a period of time under load, the supply of fuel to the combustion chamber will be reduced when the engine speed and the air pressure supplied to the engine fall below the aforementioned values. It will be restarted. Conveniently, the unit 19 is adapted to supply energy to the spark plugs whenever the temperature of the air flowing in the manifold is below a predetermined value. In this way, the fuel supplied to the combustion chamber can be ignited quickly. However, the detector 36
Supply of energy by the unit 19 is prevented when the temperature detected by the unit 19 indicates a flame and when the engine is operating within a predetermined engine speed above idling speed. From the foregoing description, it will be appreciated that the combustion chamber 14 has similar characteristics to the combustion chamber of a gas turbine engine.

It will also be appreciated, therefore, that the fuel supply to the combustion chamber must be controlled carefully to avoid extinguishing the flame by supplying too much or too little fuel. However, it is clear that as the engine speed increases, more fuel must be supplied to the combustion chamber in order to maintain the temperature of the air supplied by the engine at the desired value. Whenever fuel needs to be delivered to the combustion chamber, the
The valve 21 shown in the figure must be open. However, in order to prevent the air from forcing fuel back into the fuel pump, and thus to prevent a rapid induction of flame within the combustion chamber on its next operation, valve 21 is closed when fuel is no longer required. Must be closed immediately. Next, FIGS. 3 and 4 of the accompanying drawings showing the actual structure of the pump unit 20 will be explained.

Referring to FIGS. 3 and 4, the pump unit 20 has three
The housing 45 is formed of three parts 46, 47, 48. Parts 46 and 47 define a cylindrical bore 49 and part 48 forms an end closure for this bore. The pond end of hole 49 is partially closed by an end wall 50 defined by part 46;
A gate 51 is formed within this end wall. The connecting member between the housing parts 46 and 47 extends transversely to the axis of the bore 49; in addition, the parts 46 and 47 are provided with a lateral extension which accommodates the valve 25. Inside the hole 49,
A pump is provided which can be inserted into the hole after parts 46 and 47 are connected together by bolts 52. Once the pump is placed in the bore 49, the parts 47 are attached to the housing by bolts 53, thus completing the assembly of the pump. Next, the structure of the pump will be explained. The pump has a pair of outer stator parts 54, 55 and an intermediate stator part 5.
6.

These stator parts are angularly positioned relative to each other via dowel pins 57. The aforementioned stator sections are provided with centrally disposed holes through which extend drive shafts 58, which shafts 58 are carried by stator sections 54 and 55, respectively. It is supported within an annular carbon bearing 59.

The shaft 58 has a flange 60 at its end adjacent the end wall 501 and a thrust member 61 held on the shaft by a circlip at the L-shaped end.
is installed. Furthermore, the stator portion 54 is equipped with an oil seal 62, which is attached to the flange 60.
and the end wall 50 at a position intermediate the shaft. The shaft extends through bore 51 and abuts a coupling connecting the shaft to the dew motor. Between stator sections 55 and 56 the parts of the first stage 23 of the pump are arranged, and between the stator sections 54 and 56 the parts of the second stage 24 of the pump are arranged.

Each stage is a gyro pump. These two pumps have the same construction, except that the dimensions of the first stage 23 are chosen to deliver twice the amount of fuel that can be pumped by the second stage 24. The only point is that there is. A brief explanation of the structure of these step members will be given only for step 23.

The step 23 has an outer annular member 63 having a hole therein through which the dowel pin 57 passes.

The member 63 is thus prevented from moving angularly. The cylindrical hole defined in member 63 is eccentrically disposed with respect to the axis of rotation of shaft 58. Disposed within the bore is an inner annular member 64 having outer and inner cylindrical surfaces having gears formed thereon. Nao Dan 23
includes a gear 65 that is mounted around shaft 58 and keyed to the rotatable shaft. As the shaft rotates, the material 64
It also rotates, but such rotational action takes the form of gyroscopic motion. An arcuate fuel inlet port 66 (FIG. 4) is provided within the stator portion 55, and an arcuate fuel outlet port 67 is provided within the stator portion 56.

The outlet 67 is in communication with a hand inlet 68 to the stage 24 , and the outlet 67 and the inlet 68 formed in the stator section 54 are interconnected by a passageway formed in the stator section 56 . There is. This passage extends through the stator section 56 in a direction substantially parallel to the axis of rotation of the shaft, and to make this possible the two pump stages are arranged 1800 degrees from each other around the shaft.
Negotiations have been made with the following. The intake port 66 is located in the stator portion 5
The outlet 69 communicates with a circumferential groove 70 formed in the periphery of the stator portion 54 , while the outlet 69 communicates with a groove 71 formed in the stator portion 54 . On each side of the foundations 70, 71, each stator section has a groove for receiving a sealing ring, the arrangement of which is such that when the pump is installed, it is pushed axially into the hole 49. The end surface of the stator section 54 is positionable in the position shown in the accompanying figures in which it engages the end wall 50 of the housing section 46. The pump is held in position via a pair of disc springs 72 disposed within internal recesses formed within stator portion 55. Belleville spring 72 engages a projection formed on housing part 48. A small gap is provided between the end of the stator section 55 and the housing part 48, so that in certain instances the housing and the pump may be formed from different metals (for example the housing may be formed from an aluminum alloy). , the pump is usually made of steel) to accommodate differential expansion. Note that various portions of the bore 49 are tapered to avoid damaging the seal member when pushing the pump into the bore. Turning to Figure 3, valve 2
5 includes a valve chamber 73 defined between two housing parts 46 and 47.

A diaphragm 74 extends through the chamber 73 and divides it into two parts 75,76. The chamber portion 75 communicates with the circumferential groove 71 via a passage 77, which extends via a passage 78 to a vent on the housing portion 46, not shown. However, this outlet (not shown) is connected vertically to the combustor via the valve 21 when in use. The hole 49 is provided with a groove that coincides with the base 71, and the hole is also beveled toward this groove to prevent damage to the seal when the pump is inserted into the hole 49. Please note that Chamber part 7
6 is connected to a further groove 78 formed in the peripheral surface of stator portion 56 . This groove 78 is the port 67
And 68 and lotus are suitable. Also located within the chamber portion 76 is an outlet defined in a member 79 threaded into the housing portion 47 .

This outlet is in communication with an outlet 80 which can communicate with the outlet when in use. The outlet 8 is suitable for communication with the space defined between the river mamata pump and the portion 48 of the housing. A groove 70 formed on the pump fits in with an inlet (not shown) connected to the pump 22 in use. The diaphragm 74 has one side of the pump
The other side is exposed to the pressure at the outlet of the second stage.

As previously mentioned, the first stage of the pump can pump substantially twice as much fuel as the second stage, so that in most conditions of use the diaphragm 74 does not allow excess fuel to be removed. It will be displaced as if flowing to 18. The effect of this diaphragm is to prevent a substantial pressure drop across the second stage of the pump, thus causing the pump output to be directly proportional to the speed at which shaft 58 rotates. As shown in Figure 3,
Said diaphragm is inserted around its periphery between two parts 46, 47 of the housing, and annular sealing rings are arranged on opposite sides of the diaphragm.

These seal rings are arranged in an annular structure.
The diaphragm is constructed of beryllium steel alloy, preferably as a stamped part, and in the particular example is provided with a central disk 81 which cooperates with member 79 to direct the flow of fuel through the outlet. It is meant to be controlled.
However, the diaphragm can be of any suitable shape that does not require a disc, and can also be made of other materials, such as synthetic rubber. Experiments have shown that there is no practical need to be able to adjust the position of member 79 in the ratchet direction. However, in some cases it may be desirable to make this adjustment. In such a case, the cover material 79 is extended to the periphery of the housing, and is also a device for performing an adjustment action in the angular direction (due to the effect of the screw, this adjustment action also serves as an adjustment action in the wisteria direction). With the configuration described above, the present invention allows the first stage of the fuel pump to deliver an excess amount of fuel and spill the fuel so that the pressure drop between the second stage is zero. The amount of fuel flowing to the combustor can be controlled in exact proportion to the rotational speed of the pump, and the control of precisely made orifices and valves and the complex structure that controls them, as in the subordinate equipment. It does not require any mechanism, and can be simply and easily manufactured using a regular pump and a diaphragm valve with a relatively simple structure.Furthermore, even when this device is incorporated into a reciprocating piston engine, it can withstand engine vibrations sufficiently. It has effects such as obtaining.

[Brief explanation of the drawing]

Fig. 1 is a schematic layout diagram of this device applied to a compression ignition engine, Fig. 2 is a block diagram of a part of the device shown in Fig. 1, and Fig. 3 is a practical diagram of the pump shown in Fig. 1. FIG. 4 is a cross-sectional elevational view of the structure, and FIG. 4 is a view taken from FIG. 3 in a perpendicular direction. 10: Compression ignition engine, 11, 12: Intake manifold, 14: Combustion chamber, 20: Fuel pump, 22: Pressurized fuel source, 23: First stage of pump, 24: Second stage of pump, 25: Valve device, 26: Nozzle, 30: Control device, 34, 35, 36: Temperature detection device, 17: First motor device, 39: Logic unit, 74: Diaphragm, 1
8: Air pump. FIG.l, FIG. 3. N 9 Mountain size g U

Claims (1)

[Scope of Claims] 1. A combustion chamber including a combustor and to which fuel is supplied via the combustor, and a first combustion chamber that supplies fuel to the combustion chamber.
Fixed capacity type 2 with each stage and second stage having an inlet and an outlet.
a stage fuel pump; a first flow path device that communicates an outlet of the second stage with the combustor; a second flow path device that communicates an inlet of the second stage with an outlet of the first stage; a first motor device to drive and a valve including a valve element responsive to pressure at the inlet and outlet of the second stage of the pump to control the opening of a spill port connected to the second flow path device; an air heating system for a compression ignition engine, the inlet of the first stage being connected to a fuel source during operation, and a control device for controlling the speed of the pump; , depending on the speed at which the pump is driven, the valve arrangement operates to spill fuel through the spill port when activated;
An air heating system for a compression ignition engine, wherein the pressure drop across the second stage of the pump is zero, and the first stage of the pump is adapted to deliver more fuel than the second stage. . 2. The air heating device according to claim 1, including an air pump for supplying pressurized air to the combustor to assist in atomization of fuel, and a second air pump for driving the air pump. An air heating device for a compression ignition engine comprising a motor device and a motor device. 3. The air heating device of claim 2, wherein the control device maintains the speed of the first motor device substantially constant during engine starting mode to control combustion to the fuel device. An air heating system for a compression ignition engine configured to operate to provide a substantially constant feed rate. 4. The air heating device according to claim 3, wherein a signal detects the temperature of the air at a point downstream of the combustion chamber and enables the control device to adjust the speed of the first motor device. 1. An air heating system for a compression ignition engine, characterized in that it includes a temperature sensing device for providing a temperature of air supplied to the engine and thus maintaining a substantially constant temperature of air supplied to the engine during a running mode of the engine.