JPS62118051A - Device of feeding fuel additive for reproduction for diesel exhaust gas disposing device - Google Patents

Abstract

PURPOSE:To enable weighing and feeding of a desired amount of an additive irrespective of a fluctuation in the number of revolutions of an engine, by a method wherein, through utilization of a fuel pressure outgoing through the overflow port of a fuel pump, the additive is pressurized. CONSTITUTION:In an ECU 62, a fuel liquid level in a fuel tank 34 is read by means of a signal from a sender gauge 64 each time fuel is supplied to the fuel tank 34. When the temperature of cooling water exceeds a set value, a demanded supply amount of an additive is calculated in proportion to a fuel supply amount calculated based on a rise in a fuel liquid level. A pulse driving signal responding to the demanded supply amount of the additive is outputted to a feed valve 60 to supply the additive to fuel in the fuel tank 34. The additive added to the fuel is fed to an engine togetherwith the fuel with the aid of an injection pump 30, and is accompanied with particulate generated along with combustion of the fuel.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diesel exhaust treatment device that collects particulates (solid particles whose main component is carbon) contained in diesel engine exhaust gas. The present invention relates to a technique for regenerating a filter of a particulate trap by incinerating particulates deposited on the filter.

More particularly, the present invention relates to an activating additive delivery system for promoting filter regeneration.

[Prior art]

Diesel engine exhaust gas contains particulates, which are known to cause black exhaust smoke. For this reason, in the prior art, a particulate trap containing a filter made of porous ceramic is provided in the engine exhaust system to collect particulates mainly based on the principle of collision collection. When particulates collected during diesel engine operation accumulate in the filter, the filter becomes clogged, increasing ventilation resistance and decreasing the tiiffi rate. must be played. For this reason, a method has been proposed in which an electric heater is provided upstream of the filter in the particulate trap, and the electric heater is energized during filter regeneration to forcibly ignite the particulates (for example, JP-A-59 -190418, Utility Model Application No. 59-160809, Utility Model Application No. 59-165516).

It is also known that when the exhaust gas temperature approaches about 600° C., particulates deposited on the filter are spontaneously ignited and incinerated, thereby regenerating the filter. In this particulate incineration method using spontaneous ignition, additives containing compounds such as cerium and manganese are added to the fuel in small amounts (
It is known that if the particulates are premixed by 10~LOOppm), the particulates will be activated and the filter will be regenerated by incinerating the particulates at a temperature lower than 600°C (SAE Papers 850016 and 8).
50017).

The particulate activating additive is stored in an additive tank, the additive is pressurized by some means, and the pressurized additive is delivered to the fuel system through a supply valve, such as an injection valve.

[Problems with conventional technology]

In the additive supply device disclosed in SAE Paper 850017, the supercharging pressure of the turbocharger is used as a means for pressurizing the additive. In Yuko's method, the supercharging pressure fluctuates depending on the engine speed. Therefore, when the additive is supplied through the injection valve, there is a problem that the amount of the additive supplied varies depending on the engine rotation speed, and the amount of supply cannot be accurately measured.

Furthermore, since the supercharging pressure decreases during idle operation or low speed rotation, there may be cases where no additive can be supplied at all. Furthermore, this pressurization method cannot be applied to diesel engines that are not equipped with a turbocharger.

[Means for solving problems]

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to accurately measure the amount of additive supplied, and it can be applied to diesel engines without a turbo supercharger. The purpose is to provide an additive supply device.

The present invention focuses on the fact that a diesel engine is inherently equipped with a fuel injection pump, and is characterized in that the additive in the additive tank is pressurized using the fuel pressure flowing out from the overflow port of the injection pump. It is something to do. The fuel pressure is regulated to a constant pressure by a constant pressure valve and applied to the additive tank.

In a preferred embodiment of the invention, the additive is added to the fuel in the fuel tank each time the fuel tank is refueled, and the amount of additive dispensed is metered according to the amount of fuel dispensed.

〔Example〕

Referring to FIG. 2, a diesel engine 10 has an intake manifold 12 and an exhaust manifold 14, and includes particulate matter constituting a diesel exhaust treatment device.
Trap 16 is located between exhaust manifold 14 and exhaust pipe 1.

An exhaust gas passage 22 shown by an arrow is formed in the housing 20 of the trap 16, and a filter 24 made of, for example, porous ceramic with a honeycomb structure is disposed therein to trap particulates in the exhaust gas. It is now possible to collect them. The filter is regenerated by incinerating the particulates collected on the filter 24.

A bypass control valve 28 provided in the bypass passage 26 is used to limit the flow rate of exhaust gas flowing into the filter 24 during particulate incineration to ensure smooth incineration.

FIG. 1 shows the additive supply device of the present invention incorporated into a conventional diesel engine fuel injection device. The fuel system includes a fuel injection pump 30, an injector 32, a fuel tank 34, a fuel supply pipe 36, a water separation ceramic 38,
It is equipped with a fuel filter 40 and an overflow pipe 42. As is well known, the overflow piping 42 carries excess fuel that has not been injected out of the fuel that has been pressurized to the feed pressure by a feed pump (not shown) built into the injection pump 30 from the overflow port 44 to the fuel tank. The fuel pressure in the overflow pipe is approximately 2.2 to 7.3 k depending on the engine speed and load.
g/cm".

A constant pressure valve 46 with a check valve function is provided in the middle of the overflow pipe 42, and the pressure is approximately 2.2 kg/cm2.
The fuel whose pressure has been regulated to the pressure can be introduced into the pressurizing chamber 52 of the additive storage tank 50 via the pressure guiding pipe 48. A slidable piston 56 is fitted in the tank 50 in order to pressurize the additive while preventing the particulate activation additive 54 stored in the additive tank 50 from mixing with fuel. The additive tank 50 can store the necessary additives during the entire life of the vehicle and typically has a capacity of, for example, about 500 C#13. The additive tank 50 is connected to an addition side supply valve 60 by an additive supply pipe 58. An electromagnetic fuel injection valve of a fuel injection device for a gasoline engine can be used as the supply valve 60, and an engine control computer (ECU)
A predetermined amount of additive is injected into the fuel tank 34 in response to a pulse signal output from the fuel tank 62 .

The fuel tank 34 is provided with a well-known sender gauge 64 for detecting the fuel level, and its output is EC
It is input to U62. Information regarding the cooling water temperature is also input to the ECU 62.

The ECU 62 is an existing one used for various engine controls, and can also measure additives. As shown in the block diagram of FIG. 3, an ECU 62, a central processing unit I-(CPU) 66, a read-only memory (ROM) 68 in which various control programs are stored,
Random access memory (RAM) 70, input/output capo
It is composed of a door 2 and a common path line 74.

FIG. 4 shows a flowchart of the additive supply control routine. This control routine can be executed as an interrupt routine of the main routine executed by the ECL 162 every time the fuel tank 34 is refilled with fuel. Step 10
1, an interrupt routine is started, and in step 102, the cooling water temperature is read, and the fuel level in the fuel tank is read based on the signal from the sender gauge 64. Next, the process proceeds to step 103, where it is determined whether the cooling water temperature is 40° C. or higher. If the temperature is 40° C. or lower, the additive has a high viscosity and is not suitable for injection, so the process proceeds to step 107, and the process returns to the main routine.

If the cooling water temperature is higher than 40°C, the process proceeds to step 104, where the amount of refueling is calculated based on the rise in the fuel level. Next, in step 105, the required additive supply amount is calculated in proportion to the refueling amount. The required feed rate can be calculated such that the additive concentration in the fuel is in the range of 10 to 100 pprR.

Next, in step 106, a drive signal with a pulse width corresponding to the required supply amount is output to the supply valve 60 to add the additive to the fuel in the fuel tank. The additive added to the fuel is supplied to the engine from an injection pump along with the fuel, and is entrained in particulates generated as the fuel is combusted. Therefore, the particulates collected in the filter 24 of the particulate trap 16 are activated by this additive and are easily ignited and incinerated.
The filter is regenerated.

〔Effect of the invention〕

As described above, the additive supply device of the present invention utilizes the feed pressure of the fuel injection pump to regulate the pressure to a constant pressure and then pressurizes the additive in the additive tank. The desired amount of additive can be metered in regardless of the number variations.

Furthermore, unlike a turbocharger, an injection pump is attached to all diesel engines, so the additive supply device of the present invention can be applied to any diesel engine.

Furthermore, if the additive is measured and supplied to the fuel tank in accordance with the amount of refueling, the fuel supplied to the engine will always contain a constant concentration of the additive.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the additive supply device of the present invention incorporated into a diesel engine fuel system, Fig. 2 is a partially cutaway plan view of a diesel engine equipped with a particulate trap, and Fig. 3 is a block diagram of the control computer, and FIG. 4 is a flowchart of the additive supply control routine. 16... Particulate trap (exhaust treatment device) 24... Filter, 30... Fuel injection pump, 34... Fuel tank, 44... Overflow port, 46... Constant pressure valve, 50... ...Additive tank, 60...Additive supply valve. 30-11 Fuel injection pump 34- Fuel tank 46- Constant pressure valve 50- Additive tank 60- Supply valve Fig. 4

Claims (1)

[Scope of Claims] 1. A device for supplying a particulate activating additive to fuel for regenerating the filter of an exhaust treatment device of a diesel engine having a fuel injection pump, the device comprising: Fuel pressure is introduced into the additive tank via a constant pressure valve to pressurize the additive stored in the additive tank, and the pressurized additive is supplied to the fuel system via the additive supply valve. An additive supply device characterized by: 2. The additive supply device according to claim 1, wherein the additive is supplied to a fuel tank. 3. The additive supply device according to claim 2, wherein the amount of the additive supplied to the fuel in the fuel tank is measured in accordance with the amount of refueling.