JPS58183809A - Judging of regenerating time of collecting unit for particles in diesel engine - Google Patents

Abstract

PURPOSE:To prevent the decreased output of an engine and the increased volume of black smoke caused by the excessive recirculation of exhaust gas by a method wherein a time when the recirculation flow rate of exhaust gas caused by the exhaust gas pressure exceeds the desired allowable value is judged as the regenerating time for a particle collector. CONSTITUTION:Exhaust gas pressure allowing the recirculation of the exhaust gas corresponding to the engine load and the number of rotation of the engine which are measured by a sensor 36 for the degree of opening of a pump lever and the sensor 37 for the number of rotation of the engine is sensed. The exhaust gas pressure for allowing a recirculation of the exhaust gas and the exhaust gas pressure upstream of a collector 12 for particles sensed by an exhaust gas pressure sensor 60 are compared and it is judged that the regenerating time for the particle collector 12 corresponds to a time when the exhaust gas pressure sensed by the exhaust gas pressure sensor 60 exceeds the exhaust gas pressure allowing a recirculation of the exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining regeneration timing of a particle collector for a diesel engine used in vehicles such as automobiles.

In vehicle diesel engines, a particle collector is installed in the middle of the exhaust passage to collect particles such as carbon particles in the exhaust gas emitted from the engine and prevent them from being released into the atmosphere. That is what is being considered. This particle collector generally has a heat-resistant filter structure that collects particles in the exhaust gas.

Therefore, as the amount of trapped particles increases, the filter structure becomes clogged, and the exhaust gas pressure in the exhaust passage upstream from this structure increases accordingly.

Furthermore, in order to reduce NOx in the exhaust gas emitted from a diesel engine, it has been considered to perform so-called exhaust gas recirculation, in which a portion of the exhaust gas is returned to the intake system. Exhaust gas intake boats for exhaust gas recirculation provide the required exhaust gas flow for exhaust gas recirculation.
Generally, the particle collector is installed in the exhaust passage upstream of the particle collector to obtain the As the exhaust gas pressure in the exhaust gas intake boat increases and the particulate collector becomes more clogged, the exhaust gas recirculation tIL increases, until it exceeds the predetermined tolerance and the engine performance is affected. It can cause major damage.

In view of the above-mentioned problems, the present invention aims at regenerating the particle collector when the exhaust gas pressure increases due to clogging of the particle collector due to aging and the exhaust gas recirculation aist exceeds a predetermined allowable value. At this time, it is determined that there is a particle trap Wa
By regenerating S, it is possible to ensure that exhaust gas recirculation is performed at a flow rate exceeding a predetermined tolerance.
This paper aims to provide a method for determining the regeneration period of I.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

The attached figure is a schematic diagram showing a diesel engine equipped with a device for implementing the method for determining regeneration timing of a particle collector according to the present invention. In the figure, reference numeral 1 designates a diesel engine which slidably receives a piston 3 in a cylinder bore 2, the piston defining a combustion chamber 4 above it. The diesel engine 1 has a swirl chamber 5 communicating with a combustion chamber 4, and liquid fuel for the diesel engine is injected and supplied from a fuel injection nozzle 40 to the m flow chamber.

The diesel engine 1 inhales air into the combustion chamber 4 via the intake manifold 6 and the ventilation boat 7, and enters the fIA combustion chamber 4.
The exhaust gas is then discharged to an exhaust manifold 9 via an exhaust boat 8. The intake boat 7 and the exhaust boat 8 are each opened and closed by a poppet valve, and in the figure,
Only the poppet valve for evacuation is indicated by the reference numeral 10.

The exhaust manifold 9 includes an exhaust pipe 11, a particle collector 12,
exhaust! 13 are connected in sequence.

14 indicates an exhaust gas recirculation control valve. The exhaust gas recirculation control valve 14 directs its inlet boat 15! ! 16 is connected to an exhaust gas intake boat 17 formed in the exhaust manifold 9, and the outlet port 18 is connected by a conduit 19 to an exhaust gas injection boat 20 formed in the intake manifold 6. 1 gas re II & ring-1-valve 1
4 includes a valve element 21, which together with a valve seat 22 opens and closes the outlet boat 18 and controls its effective opening area. This valve W121 is connected to a diaphragm device i24 by a valve rod 23, and is driven by this diaphragm device. The diaphragm device 24 includes a diaphragm 25 which is driven upwards in the figure against the action of a helical compression spring 27 in response to an increase in the negative pressure introduced into its diaphragm chamber 26, and which is driven upwards in the figure against the action of a helical compression spring 27. 21 is moved upward to open the exit boat 18 and increase its effective opening cross-sectional area.

Negative pressure generated by a negative pressure pump (not shown) is supplied to the diaphragm chamber 26 through conduits 28 and 29, an on-off valve 30, and a conduit 31.
．． 32, and atmospheric pressure is selectively supplied via an on-off valve 33 and conduits 34 and 32.

The on-off valve 30 is configured as a normally closed solenoid valve, and the n-closed valve 33 is configured as a normally closed solenoid valve. A pulse signal generated by control 1@ff1135 is selectively applied to the on-off valves 30 and 33, so that the on-off valves 30 and 33 each close with a predetermined bias ratio according to the duty ratio of the pulse signal. , negative pressure is applied to the conduit 32 according to its duty ratio. In this case, the greater the duty ratio of the pulse signal, the greater the negative pressure generated in the conductor 1!32.

The control@W35 includes a microcomputer, known per se, including CPLI, ROM, RAM, etc., and a pulse generator, and presets the appropriate exhaust gas recirculation-]lll1l valve 14 according to the engine load and engine speed. The valve opening amount data (control 9th valve opening data) is stored in the ROM, and the pump lever opening sensor 36 of the fuel injection pump 38
The valve opening amount data corresponding to the engine load measured by the engine rotation speed sensor 37 and the engine rotation speed measured by the engine rotation speed sensor 37 are retrieved and read from the ROM, and the valve opening amount data and the exhaust gas recirculation control valve 14 are stored. A comparison is made with the data of the valve opening amount measured by the provided demand valve roar sensor 39, and based on the comparison result, a pulse signal with a predetermined duty ratio is generated and outputted to the on-off valve 30.33. It looks like this. In other words, the control WJ @ device 5 outputs the same signal as before when the control target opening amount data is equal to the actual valve opening amount data, and outputs the same signal as before when the control target opening amount data is smaller than the actual valve opening amount data. The duty ratio is made smaller than before, and on the other hand, when the control target opening valve data is larger than the actual valve opening amount data, the duty ratio of the pulse signal is made larger than before.

As a result, the opening amount of the exhaust gas recirculation control valve 14 is controlled according to the engine load and engine speed, and the exhaust gas recirculation control valve 14 performs exhaust gas recirculation at an appropriate flow rate.

An intake pipe 41 is connected to the intake manifold 6, and cough intake! 41 is provided with an intake throttle valve 42 for controlling the flow rate of air taken into the m-injection chamber 4. Intake throttle valve 42
is configured as a butterfly valve supported on a valve shaft 42a, connected to a rod 45 of a diaphragm @1144 via a lever 43, and driven by the diaphragm device. Diaphragm Ml! 44 has a diaphragm 46, which moves downward in the figure against the spring force of a compression coil spring 48 as the negative pressure introduced into the diaphragm chamber 47 increases, and the intake throttle valve 42 The valve is driven in the valve closing direction, that is, in the direction to throttle the intake air.

Negative pressure generated by a negative pressure pump (not shown) is transmitted to the diaphragm chamber 47 through the conduits 28, 49, the on-off valve 50, and the conduit! 5
1.52 is selectively supplied.

Further, atmospheric pressure is selectively supplied to the diaphragm chamber 47 from an on-off valve 53 via conduits 54 and 52. ! 1llll closing valves 50 and 53 are both configured as electromagnetically actuated on-off valves, and are opened when the electric device 11 is not energized, whereas they are opened when the electromagnetic device is energized. It is supposed to be done. When the on-off valve 50 is energized and the on-off valve 53 is not energized, negative pressure is introduced into the diaphragm 1!47, thereby increasing the intake throttling degree of the intake throttle valve 42. When the on-off valve 50 is not energized and the on-off valve 53 is energized, the negative pressure in the diaphragm chamber 47 decreases, causing the intake throttle valve 42 to reduce its degree of throttling. When no current is applied, fluid pressure is sealed in the diaphragm chamber 47, and the intake throttle valve 42 is held at the current position.

Power supply to the on-off valves 50 and 53 is controlled by the control device 35. The control device 35 stores in the ROM in advance an appropriate intake throttle valve opening flE (control target opening) according to the engine load and engine speed.
When it is determined by the method described above that it is time to regenerate the particle collector 12, the engine load measured by the pump lever opening sensor 36 and the engine rotation speed sensor 37 provided on the fuel injection pump 38 and The control target opening corresponding to the engine speed is retrieved from the ROM, and the control target opening is compared with the actual opening of the intake throttle valve 42 measured by the intake throttle valve opening sensor 56. Based on this, the energization of the on-off valves 50 and 53 is controlled.

That is, the control device determines that IpIt [the opening degree of the intake throttle valve measured by the sensor 56 is before &l! When the opening degree is larger than the control target opening degree, only the on-off valve 50 is energized;
When * is smaller than the control target opening degree, only the on-off valve 53 is energized, and the opening degree is the control target! ! The on-off valves 50 and 53 are equal when the control tolerance width is equal to
No electricity is applied to any of them.

As a result, when the particle collector 12 is regenerated, the intake throttle valve 42 is brought to an appropriate intake throttle position according to the operating state of the engine at that time, thereby increasing the concentration of exhaust gas and trapping it in the particle collector 12. The particles that have been removed are burned away. still,
When the intake pipe negative pressure detected by the negative pressure sensor 57 increases beyond a predetermined value, or when the exhaust gas temperature detected by the exhaust gas concentration sensor 58 increases beyond a predetermined value, the feedback control as described above is performed. This allows the intake throttle valve 42 to reduce the amount of intake throttle required.

□Kin5tt device 35 stores in ROM the allowable exhaust gas pressure for exhaust gas recirculation determined in advance through experiments etc. according to the engine load and engine speed, and stores the exhaust gas pressure in ROM according to the engine load and engine speed. The particle collector 12 reads out the exhaust gas recirculation allowable exhaust gas pressure corresponding to the engine load and engine rotation speed measured by the exhaust gas recirculation allowable exhaust gas pressure measured by the exhaust gas recirculation allowable exhaust gas pressure and the exhaust gas pressure sensor 60 . The exhaust gas pressure on the more upstream side, in this embodiment, the exhaust gas pressure in the conduit 16, is compared, and the exhaust gas pressure detected by the exhaust gas pressure sensor 60 is determined as the exhaust gas pressure allowed for exhaust gas recirculation. It is determined that it is time to regenerate the particle collector 12 when the exhaust gas pressure rises to a value that causes the exhaust gas recirculation flow rate to exceed a predetermined allowable value. This starts the intake throttling and regenerates the particle collector. Note that the particle collector may be regenerated by an electric heater instead of the intake throttle.

As described above, by determining the regeneration timing of the particle collector, exhaust gas recirculation is prevented from exceeding the permissible value, and excessive exhaust gas recirculation can reduce engine output, unburnt components, and black smoke. Smoke increase is prevented.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and it is understood that various other embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of the drawing]

The attached figure is a schematic configuration diagram showing one embodiment of a diesel engine equipped with a device for implementing the method for determining regeneration timing of a particle collector according to the present invention. 1...Diesel engine, 2...Cylinder bore. 3... Piston, 4... tIA baking chamber, 5... Vortex i
chamber, 6... intake manifold, 7... intake boat,
8...Exhaust boat, 9...Exhaust manifold, 10
...Poppet valve. 11... Exhaust pipe, 12... Particle collector, 13...
Exhaust pipe. 14...Exhaust gas recirculation control valve, 15...Inlet boat. 16... Conduit, 17... Exhaust gas intake boat, 18
...Exit port, 19...I! ! , 20... Exhaust gas injection boat, 21... Valve element, 22... Valve seat portion, 23... Valve rod, 24... Diaphragm device,
25...Diaphragm, 26...Diaphragm chamber,
27... Compression coil spring, 28.29... Conduit, 3
0... Open/close valve, 31° 32... Conduit, 33...!
pHllS valve, 34...111.35...Control W stomach filling,
36... Pump lever opening sensor, 37... Engine rotation speed sensor, 38... Fuel injection pump. 40... Fuel injection nozzle, 41... Intake pipe, 42...
...Intake throttle valve, 43...Lever, 44...Diaphragm device, 45...Rod, 46...Diaphragm, 47...Diaphragm chamber, 48...Compression coil spring, 49... Conduit, 50... Opening/closing valve, 51.52
...Specialty, 53...Opening/closing valve, 54...Conduit, 56
...Opening sensor, 57...Negative pressure sensor, 58...
Exhaust gas temperature sensor, 60...exhaust gas pressure sensor

Claims (1)

[Claims] In a method for determining the regeneration timing of a particle trap IIm installed in the exhaust system of a diesel engine in which exhaust gas recirculation is performed, the exhaust gas pressure generated in the exhaust passage upstream of the particle trap is measured, and the exhaust gas pressure generated in the exhaust passage upstream of the particle trap is measured. A particle collector for a diesel engine, characterized in that it is determined that it is time to regenerate the particle collector when the exhaust gas recirculation flow exceeds a predetermined tolerance value due to an increase in exhaust gas pressure due to a blockage in the collector. How to determine when it is time to regenerate a collector.