JPS6338544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine intake device that includes a fuel atomization device that atomizes fuel into particles of approximately several microns and then supplies the atomized fuel to the engine.

Traditionally, in diesel engines, apart from the main fuel that is injected directly into the combustion chamber from the fuel injection pump,
By supplying atomized fuel as an auxiliary fuel along with intake air, it is possible to improve the ignitability and combustibility of the fuel, increasing the utilization of intake air, improving thermal efficiency and output, and producing cleaner exhaust smoke. It is known that vibration and noise can also be reduced.

On the other hand, for diesel engines as well, an intake supercharging method has been proposed in which a supercharger is installed and intake air pressurized by the supercharger is supplied to the combustion chamber to increase charging efficiency and improve output. ing.

According to the present invention, when a supercharger is installed in an engine equipped with the fuel atomization device as described above, the characteristics of the supercharger are taken into account so that the atomization function of the fuel atomization device can be more effectively exhibited. The basic objective is to provide an arrangement structure between a fuel atomization device and a supercharger that allows the fuel atomization device and the supercharger to be connected to each other.

In order to achieve such an object, the present invention provides a fuel injection system for supplying atomized auxiliary fuel to an intake passage in a supercharged diesel engine that injects main fuel into a combustion chamber from a fuel injection nozzle arranged facing the combustion chamber. The fuel atomizer includes a casing and an ultrasonic vibrator that atomizes the auxiliary fuel in the casing, and an air inlet to the casing of the fuel atomizer is opened to the intake passage. At the same time, a supply port for supplying a mixture of atomized fuel generated in the casing of the fuel atomization device and air introduced from the air introduction port to the intake passage is opened downstream of the air introduction port,
An intake system for an engine is provided, characterized in that a blower of a supercharger is provided upstream of the air inlet to raise the temperature of intake air, and the intake air heated by the blower is introduced into a casing of a fuel atomization device. It is something to do.

Note that Japanese Patent Publication No. 44-6655 discloses a technology for atomizing fuel using a blower, but there are concerns about fuel adhesion to the blower, fuel leakage from the blower, etc. Difficulty in controlling atomized fuel and problems with stability of atomized fuel particle size may remain.

Hereinafter, the present invention will be specifically explained based on illustrated embodiments.

In Fig. 1, 1 is the diesel engine body with the fuel injection nozzle 2 facing into the combustion chamber 3, 4 is the intake passage of the engine with the air cleaner 5 installed upstream, 6 is the exhaust passage of the engine, and 7 is the intake passage. A turbo supercharger installed across the passage 4 and the exhaust passage 6, with a turbine 8 interposed in the exhaust passage 6.
The output shaft 8a of the air cleaner 5 is connected to the intake passage 4 downstream of the air cleaner 5.
The blower 9 is directly connected to the drive shaft of a blower 9 interposed therein, and the turbine 8 is driven by the power of the exhaust gas, thereby driving the blower 9 and increasing the pressure of intake air by the blower 9 before supplying it to the downstream of the intake passage 4.

On the other hand, 10 is a fuel atomization device installed horizontally along the horizontal portion of the intake passage 4 downstream of the blower 9 of the supercharger 7. This fuel atomization device 10 is a fuel supply system that pressurizes fuel from a main fuel supply system, that is, a fuel tank 11, using a fuel injection pump 12, and injects the fuel from a fuel injection nozzle 2 into a combustion chamber 3 at a predetermined timing. It constitutes an auxiliary fuel supply system for the system, and is equipped with a piezoelectric or magnetostrictive type ultrasonic vibrator 15 at the bottom of a rectangular parallelepiped-shaped casing 14 separated from the intake passage 4 by a partition wall 13. .

A fuel tank 1 is provided at the bottom of the casing 14.
A float chamber 1 provided on the side wall of the casing 14 receives fuel supplied from the fuel supply pump 16 from the float chamber 1.
The fuel is contained at a constant depth by the float 18 of No. 7, and the fuel is atomized into particles of about several microns by the vibration of the ultrasonic vibrator 15, and then dispersed into the upper mixing chamber 19 of the casing 14.

This mixing chamber 19 communicates with the intake passage 4 through an air inlet 20 provided on the upstream side of the partition wall 13.
A portion of the intake air that has passed through the air cleaner 5 and has been pressurized by the blower 9 is introduced into the interior, while a vent lily 21 formed downstream of the intake passage 4 is provided on the downstream side of the partition wall 13. The air-fuel mixture supply port 22 is opened to allow the air-fuel mixture in the mixing chamber 19 to be led out to the intake passage 4 by the negative pressure generated by the bench lily 21.

According to the above basic arrangement structure, when the intake air is pressurized by the blower 9, the temperature can be raised by the blower 9, and a part of the heated intake air is transferred to the air inlet 2.
Since the fuel can be introduced into the mixing chamber 19 of the fuel atomizer 10 from zero, atomization of the fuel can be promoted. Further, in the above structure, the fuel led out from the atomized fuel supply port 22 does not pass through the blower 9, and therefore is introduced into the combustion chamber 3 of the engine while maintaining its atomized state.

In FIG. 1, reference numerals 40 and 41 are intake and exhaust valves that respectively open and close the intake passage 4 and the exhaust passage 6 with respect to the combustion chamber 3 at predetermined timings.

The ultrasonic vibrator 15 of the atomization device 10 includes:
A high frequency voltage is applied by the control circuit 23, and the amount of atomized fuel generated is controlled by controlling the applied high frequency voltage. In this case, the amount of auxiliary fuel supplied by the atomizer 10 should be proportional to the injection amount Q _I per unit time injected by the fuel injection nozzle 2 at a constant ratio, as shown in FIG. is preferred. On the other hand, since the amount of atomized fuel generated by the ultrasonic vibrator 15 is approximately proportional to the electric power energy supplied to the ultrasonic vibrator 15, the control circuit 23 controls the high-frequency wave applied to the ultrasonic vibrator 15. The voltage is controlled to be proportional to the injection amount Q _I per unit time.

As shown in FIG. 3, for this reason, the control circuit 23
In this case, the position of the control sleeve 26, which determines the stroke amount of the plunger 25 of the fuel injection pump 12 and therefore the amount of fuel injection per injection, is set to the first position.
A fuel injection amount detection device 28 that detects the detection signal by a pickup 27 and outputs the detection signal as an output signal V _Q1 corresponding to the fuel injection amount, and a drive shaft 29 that rotates at a rotation speed of 1/2 of the engine rotation speed.
The rotation of the gear 30 for operating the governor fixed to the second
A rotation speed detection device 32 is provided which detects the engine rotation speed by a pickup 31 and outputs an output signal N corresponding to the engine rotation speed per unit time.
A multiplication circuit 33 multiplies V _Q1 and N to calculate a reference fuel injection amount signal V _Q per unit time.

The signal V _Q corresponding to the reference fuel injection amount per unit time is applied to the adder circuit 34, and the adder circuit 3
4 is the output signal from the multiplication circuit 33 by the output signal V _W output by the engine temperature detection device 35.
In addition to V _Q , this is input to the amplifier circuit 36 as the final control signal V _I , and the amplifier circuit 36 receives the control signal
_V As _a result, the amount of auxiliary fuel supplied to the intake passage 4 by the fuel atomizer 10 is proportional to the amount of main fuel.

The engine temperature detection device 35 is formed as a voltage dividing circuit in which a thermistor TH immersed in engine cooling water is connected to a fixed resistor R connected to a reference power source V _CC , and the resistance value of the thermistor TH is equal to the engine cooling water temperature. Utilizing the characteristic that the partial pressure V W decreases in inverse proportion to the rise in temperature, a partial pressure V _W that is inversely proportional to the rise in engine cooling water temperature is output to the adding circuit 34 . Therefore, when the engine temperature is cold, the second
As shown by the dotted line in the figure, the amount of auxiliary fuel is increased from the amount after the engine is warmed up, and can compensate for poor combustibility when the engine is cold.

In the above embodiment, light oil, which is the same as the main fuel, was used as the auxiliary fuel supplied to the intake passage, but alcohol, gasoline, etc. may also be used.

As is clear from the above description, the present invention provides a supercharged diesel engine that injects main fuel into a combustion chamber from a fuel injection nozzle arranged facing the combustion chamber, in which atomized auxiliary fuel is injected into the intake passage. The fuel atomizer includes a casing and an ultrasonic vibrator that atomizes the auxiliary fuel in the casing, and connects the air inlet to the casing of the fuel atomizer to an intake passage. and a supply port for supplying a mixture of atomized fuel generated within the casing of the fuel atomizer and air introduced from the air introduction port to the intake passage is opened downstream of the air introduction port, and To provide an intake device for an engine, characterized in that a blower of a supercharger for raising the temperature of intake air is provided upstream of an air inlet port, and the intake air heated by the blower is introduced into a casing of a fuel atomization device. It is something.

According to the present invention, since the fuel atomization device has the above structure, atomized auxiliary fuel can be stably generated, and a part of the intake air heated by the blower can be atomized into fuel atomization. Since the auxiliary fuel is introduced into the device, the atomized state of the auxiliary fuel can be effectively maintained, and the atomized state can be maintained and supplied to the combustion chamber of the engine, and the atomized fuel can pass through the blower. Because there are no fuel particles, the fuel particles do not become large due to adhesion to the blower or its casing, and it also has the advantage of effectively preventing leakage from the blower and wetting of the blower blades. It will be done.

Although the above embodiments have been described with reference to a diesel engine, the present invention can also be applied to a fuel injection type reciprocating engine.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic explanatory diagram showing an engine intake system according to an embodiment of the present invention, and FIG. 2 is a main fuel amount
A graph showing the ratio of the amount of auxiliary fuel to _QI , and FIG. 3 is a block circuit diagram showing the configuration of the control circuit shown in FIG. 1. 1...Engine body, 2...Fuel injection nozzle, 4...
Intake passage, 3...Air cleaner, 6...Exhaust passage, 7
...Turbocharger, 8...Turbine, 9...Blower, 1
0...Fuel atomization device, 15...Ultrasonic vibrator, 20...
Air introduction port, 22...supply port.

Claims (1)

[Scope of Claims] 1. A fuel atomizer that supplies atomized auxiliary fuel to an intake passage in a supercharged diesel engine that injects main fuel into a combustion chamber from a fuel injection nozzle arranged facing the combustion chamber. The fuel atomizer includes a casing and an ultrasonic vibrator that atomizes the auxiliary fuel in the casing, opens an air inlet to the casing of the fuel atomizer to the intake passage, and A supply port for supplying a mixture of atomized fuel generated in the casing of the fuel atomization device and air introduced from the air inlet to the intake passage is opened downstream of the air inlet and upstream of the air inlet. 1. An intake system for an engine, comprising a turbocharger blower that raises the temperature of intake air, and the intake air heated by the blower is introduced into a casing of a fuel atomization device.