The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
Reference now should be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.
A first embodiment of the present invention will be described in detail with reference to
An apparatus for reducing exhaust gases according to a first embodiment of the present invention includes an air pump 30 which is electrically controllable. Air is supplied to the air pump 30 through a first air channel 31, and the first air channel 31 is connected to the suction pipe 2, located at the inlet end of an air flowmeter 12. The air pump 30 is operated such that the supplied air is injected to the exhaust pipe 3 located upstream of the main catalyst unit 5 through a second air channel 32. The second air channel 32 is connected to the exhaust pipe 3 located upstream or downstream of a lambda sensor 8. The lambda sensor, disposed to detect oxygen included in exhaust gases, is connected to an electronic unit 9 for transmitting signals from the lambda sensor 8 to a compensation unit 10. The compensation unit 10 is provided to determine signals related to the mixture of air and fuel and to transmit the signals to an injection unit 11 in the engine 1. The injection unit 11 is generally used at the place where the air flowmeter 12 is connected to an apparatus. The air pump 30 may include a check valve (not shown) serving to protect the air pump 30 from high-temperature exhaust gases reversely flowing toward the air pump 30. The air pump 30 is connected to an output terminal of an electronic switch 7 and a battery 6.
According to the present invention, the air pump 30 is connected to the battery 6 functioning to start an automobile, and the electronic switch 7 is a semiconductor type switch for minimizing damage and supplying electric current to the air pump 30 without danger of the generation of electromagnetic pulses, which is a phenomenon frequently occurring in automobiles. The electronic switch 7 may also be a relay type switch.
Further, an apparatus for reducing exhaust gases according to the first embodiment of the present invention includes a computer type control unit 16 designed to be connected to the electronic switch 7 and the air pump 30 and to transmit control signals thereto.
The control unit 16 serves to monitor an operation of supplying electric current from the battery 6 or a generator (not shown) in automobiles to the air pump 30 based on stop signals transmitted from the engine 1, and serves to control the operation of the air pump 30.
Hereinafter, the functions of the apparatus for reducing exhaust gases in an initial cold start period according to the present invention will be described based on the above constitution.
Exhaust gases discharged from the engine 1 in operation are converted into harmless gases by a catalytic reaction while they pass through the main catalyst unit 5 along the exhaust pipe 3. As such, the air pump 30 and the units for controlling the same do not operate during the engine operation period, but the processes for removing pollutants remaining in the exhaust pipe 3 are started by the control unit 16 having received signals from the engine 1 the moment the engine is stopped. The electronic switch 7 starts to be operated by the control unit 16 and then operates the air pump 30, and the air pump 30 sucks air from the suction pipe 2 through the first air channel 31 and then injects air into the exhaust pipe 3 through the second air channel 32, thereby pushing exhaust gases remaining in the exhaust pipe 3, located at the inlet end of the main catalyst unit 5, into the main catalyst unit 5. It is preferred that air be injected for 5˜10 seconds. When the injection of a predetermined amount of air is completed by the air pump 30, the injection of air is stopped by the control unit 16.
Hereinafter, the efficiency of the purification of exhaust gases, which can be obtained by removing exhaust gases remaining in the exhaust pipe, will be described based on the first constitution, described above.
Meanwhile, another object of the present invention can be accomplished through a method of discharging residual exhaust gases by, immediately after the engine is stopped, stopping the supply of fuel to an engine while performing a cranking process, thereby injecting only external air into the inlet end of a main catalyst unit, according to a second embodiment of the present invention.
According to the second embodiment of the present invention, a method of reducing exhaust gases includes a first step of determining whether or not engine rotation is stopped; a second step of performing a cranking process by applying a power source to a cranking motor immediately after the engine rotation is stopped in the first step; a third step of turning off a fuel pump while performing the second step; a fourth step of monitoring output values transmitted from an oxygen sensor provided in the inlet end of a main catalyst unit; and a fifth step of stopping the second step in the case where the output values are not more than predetermined values. Accordingly, air is sucked from the exterior concomitantly with the stopping of engine operation, and is then injected into a main catalyst unit, thereby removing exhaust gases including hydrocarbons remaining in the inlet end of the main catalyst unit.
In the first step, various means can be considered in order to determine whether or not engine rotation has stopped. Preferably, the engine stop state can be determined by checking whether or not a start switch has been turned off, checking output signals transmitted from an engine speed sensor, or checking output signals transmitted from a water temperature sensor. In the second embodiment of the present invention, in a state in which, immediately after the engine is stopped, a process of cranking an engine is performed, and simultaneously an operation of a fuel pump is stopped, thereby preventing fuel from being supplied to a cylinder, residual exhaust gases in previous operations can be discharged by injecting air sucked from the exterior into the inlet end of the main catalyst unit.
The second embodiment of the present invention will be described in detail with reference to
Hereinafter, the operation in the method according to the present invention will be described in detail with reference to
If operation in the method according to the present invention is started during normal engine operation (S1), whether or not engine rotation is stopped is determined (S2). For example, if a start key is not turned off, subsequent steps are not performed until it is turned off.
In step 2 (S2), if it is determined that the start key is turned off, an electronic control unit generates signals for operating a cranking motor, and a cranking process is performed in response to the signals (S3), thereby injecting air sucked from the exterior into a main catalyst unit. The electronic control unit generates signals for stopping fuel injection simultaneously when the cranking process is performed (S4), thereby stopping fuel supplies to a cylinder through each injector.
When the cranking process is performed in a state in which the supply of fuel is interrupted in step 3 and 4 (S3 and S4), air can be sucked from the exterior, and the sucked air can be injected into an exhaust pipe provided with the main catalyst unit in a state in which it is not mixed with fuel. If output values in a predetermined range are obtained by monitoring the output values transmitted from an oxygen sensor provided at the inlet end of the main catalyst unit (S5), the electronic control unit generates signals for stopping a cranking motor. Then, the operation in the method according to the present invention ends.
Meanwhile, the method and apparatus for reducing exhaust gases in an initial cold start period according to the present invention is illustrative. The reduction of exhaust gases is accomplished by removing exhaust gases remaining upstream of a main catalyst unit and supplying oxygen to a catalyst immediately after the stop of engine operations. In the embodiments of the present invention, an air injection method using an air pump or a cranking operation is described, but is not limited thereto. Here, it goes without saying that exhaust gases can be removed by sucking exhaust gases remaining in an exhaust pipe and discharging them to the exterior, or can be discharged to the exterior by converting the exhaust gases into harmless gases via a catalytic reaction in the case where a catalyst exists in optimal state by employing some trapping means and reversely discharging the exhaust gases into the exhaust pipe after the temperature of the catalyst reaches a light-off temperature. Further, in the fuel injection using an air pump, which is not limited to the embodiments, it goes without saying that the air pump can be replaced with an air compressor connected to an engine by a belt or a timing gear, or a subsidiary tank for storing air supplied from the air compressor.
Number | Date | Country | Kind |
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2006/0036978 | Apr 2006 | KR | national |
2006/0081655 | Aug 2006 | KR | national |