JP4284976B2 - Engine exhaust purification device and exhaust purification method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a purification process of exhaust gas discharged from an engine mounted on a forklift or the like, and more particularly to a technique for regenerating a collection means that collects particulates in the exhaust gas.
[0002]
[Prior art]
For example, exhaust gas discharged from a diesel engine of a forklift contains a relatively large amount of particulates (particulate matter) mainly composed of carbon. Particulates contained in the exhaust gas cause deterioration of visibility and are also regulated as one of the air pollutants, and it has been desired to reduce them. In view of this, various technologies have been proposed in the past in which an exhaust purification device that collects and removes particulates is installed on the downstream side of the diesel engine, and this exhaust purification device is suitably controlled according to the operating conditions.
Conventionally, as a regeneration processing technology for this type of exhaust purification device, for example, a forced regeneration type technology that forcibly regenerates the exhaust purification device during operation is known. In this technique, when a certain amount or more of particulates accumulates in the filter, the load applied to the engine is increased, the engine output is increased, and the temperature of the exhaust gas is increased. Thereby, the bed temperature of the filter is raised to the combustion temperature of the particulates (for example, the combustion temperature of 600 ° C.) and the state is maintained for a predetermined time to burn the particulates accumulated in the filter, thereby completing the regeneration process ( For example, see Patent Document 1.)
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-54270 (paragraph numbers (0017) to (0018), FIGS. 1, 3, and 5)
[0004]
[Problems to be solved by the invention]
However, depending on the work mode, the operation may not continue until the filter regeneration process is completed. For example, after the bed temperature of the filter reaches 600 ° C., the regeneration process is completed by maintaining the state for a predetermined time. However, if the work time does not reach the predetermined time, the engine is stopped to regenerate. Processing is interrupted. In particular, industrial vehicles such as forklifts are often used in such a work mode, and in such a case, a state in which the regeneration process is interrupted before the regeneration is completed is repeated. Therefore, although regeneration is not completed at all, extra fuel is consumed to raise the exhaust gas temperature.
Accordingly, the present invention has been made in view of the above points, and an engine exhaust gas purification apparatus having a collecting means for collecting particulates suppresses deterioration of fuel consumption regardless of the working time of the vehicle. It is an object of the present invention to provide a technique effective for performing the regeneration process of the collecting means.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the engine exhaust gas purification apparatus of the present invention is configured as described in claims 1 to 3. The engine exhaust purification method of the present invention is as described in claims 4 and 5.
[0006]
The exhaust emission control device for an engine according to claim 1 is used for purifying exhaust gas discharged from the engine, and includes a collecting means, an exhaust gas temperature adjusting means, a first switching means, a second switching means, Switching means, control means, and the like.
The collecting means is installed in the exhaust gas path of the engine. This collection means is provided with a filter capable of collecting particulates (particulate matter), and when exhaust gas discharged from the engine passes through the filter, particulates in the exhaust gas are collected by this filter. Be collected. The particulates collected by the filter are burned by the exhaust gas whose temperature has been adjusted by the exhaust gas temperature adjusting means, whereby the collecting means is regenerated.
The exhaust gas temperature adjusting means has a configuration capable of adjusting the exhaust gas acting on the collecting means. As this exhaust gas temperature adjusting means, for example, an intake throttle adjusting means for adjusting the amount of intake air to the engine, a fuel injection timing adjusting means for adjusting the fuel injection timing of the engine, an engine load adjusting means for adjusting the engine load of the engine, etc. These can be used as appropriate. By adjusting these means, the exhaust gas temperature can be adjusted to a predetermined temperature condition corresponding to the combustion temperature of the particulates, and the bed temperature of the collecting means can be set to the combustion temperature of the particulates.
Each of the first and second switching means is configured to be switchable between an on state and an off state. When each of these switching means is set to the on state, a signal for enabling the predetermined control is output to the control means, and conversely, when the switching means is set to the off state, a signal for releasing the control is output. Yes. As these first and second switching means, various buttons and switches can be used. Note that the first and second switching means can be shared by a single button or switch.
When the first switching unit is set to the on state, the control unit controls the exhaust gas temperature adjusting unit to perform the regeneration process of the collection unit during the operation of the engine. Moreover, if the engine is stopped during the regeneration process, the regeneration process is interrupted. This regeneration process is started, for example, when the particulate collection amount in the collection means reaches a predetermined value. For example, a control signal is output to the exhaust gas temperature adjusting means when the differential pressure across the filter constituting the collecting means reaches a predetermined value (threshold value). As a result, the exhaust gas temperature is raised, and the bed temperature of the filter is raised to the combustion temperature of the particulates (for example, the combustion temperature of 600 ° C.), whereby the regeneration process of the collection means is started.
Further, this control means controls the exhaust gas temperature adjusting means as it is when the second switching means is set to the ON state. In this case, the regeneration process of the collection means is forcibly started. Moreover, this regeneration process is continued until the regeneration process is completed even if the engine is stopped. For example, even if the work is finished and the ignition key is turned off, the regeneration process is continued until completion without stopping the engine.
In such a configuration, for example, when the operator determines that the work by the forlift is longer than the time required for the regeneration process (for example, 15 to 20 minutes), the first switching unit is set to the on state (automatic regeneration mode). To do. As a result, the regeneration process is automatically performed during the operation until the work is completed, so that the operator can perform the work without worrying about the regeneration process. On the contrary, when it is determined that the work is shorter than the time required for the regeneration process (for example, 15 to 20 minutes), the worker sets the first switching means to the off state. Then, the regeneration process is forcibly performed by setting the second switching means to the ON state (forced regeneration mode) before the work is completed. Thereafter, even if the engine is stopped, the regeneration process is completed at once without stopping the engine. As a result, the regeneration process is not interrupted in the course of processing, and wasteful regeneration process can be eliminated to prevent fuel consumption from deteriorating.
As described above, according to the exhaust emission control device of the first aspect, the operator suitably operates the first and second switching means according to the work mode, so that the working time of the vehicle can be reduced. Therefore, it is possible to perform the regeneration process of the collecting means that suppresses the deterioration of fuel consumption. The engine in the present invention is typically a diesel engine equipped with an exhaust purification device.
[0007]
further The control means of the present invention switches the setting to the off state even if the first switching means is set to the on state when it is determined that the vehicle is a vehicle mainly having a work mode with a short work time. . For example, when the control means detects that a short work within 10 minutes has continued for five consecutive times, the automatic regeneration mode is forcibly released. This is because even if the worker sets the first switching means to the on state and selects the automatic regeneration mode, the work mode of the vehicle may not necessarily correspond to the mode. Is based. If only the automatic regeneration mode is applied when the state of one working time is short, not only the fuel consumption is deteriorated but also the amount of accumulation on the filter is increased by continuing such work. Such a work mode with a short work time is often seen especially in industrial vehicles such as forklifts. Therefore, in such a case, the automatic playback mode is canceled based on the judgment of the control means. U By using the composition, it is possible to prevent deterioration in fuel consumption in a work mode with a short work time, and to prevent an increase in the amount of accumulation on the filter.
[0008]
Claims 1 The described engine is claimed 2 It is preferable that it is an engine used for an industrial vehicle as described in. In particular, in an industrial vehicle such as a forklift, depending on the work mode, the operation may not be continued until the regeneration process of the collecting means is completed, and the state where the regeneration process is interrupted before the completion of the regeneration is repeated, resulting in a reduction in fuel consumption. Although concerned, according to this invention, it is especially effective in solving such a problem.
[0009]
Claim 3 In the engine exhaust gas purification method described in 1), there is a step of performing a regeneration process of the collecting means by adjusting the exhaust gas temperature acting on the collecting means for collecting the particulates in the exhaust gas. A filter capable of collecting particulates (particulate matter) is provided as a collecting means, and the exhaust gas discharged from the engine is passed through the filter to collect the particulates in the exhaust gas. The particulate matter collected by the filter is combusted by the exhaust gas whose temperature is adjusted, so that the collection means is regenerated. For example, the exhaust gas temperature is adjusted by an operation of reducing the amount of intake air to the engine, an operation of adjusting the fuel injection timing of the engine, an operation of adjusting the engine load of the engine, or the like. As a result, the exhaust gas temperature is adjusted to a predetermined temperature condition corresponding to the combustion temperature of the particulates, and the bed temperature of the collection means can be set to the particulate combustion temperature.
The present invention has at least a first control mode (automatic regeneration mode) and a second control mode (forced regeneration mode) regarding the regeneration process of the collection means.
In the first control mode, the exhaust gas temperature is controlled, and the regeneration process of the collecting means is performed during operation of the engine. Moreover, if the engine is stopped during the regeneration process, the regeneration process is interrupted. For example, when the differential pressure before and after the filter constituting the collecting means reaches a predetermined value (threshold), the exhaust gas temperature is raised, and the bed temperature of the filter is changed to the particulate combustion temperature (for example, combustion temperature 600 ° C.). The regeneration process of the collecting means is started.
On the other hand, in the second control mode, the exhaust gas temperature is adjusted and the collection means is regenerated. Moreover, the regeneration process continues until the regeneration process is completed even if the engine is stopped. For example, even if the work is finished and the ignition key is turned off, the reproduction process is continued without stopping the engine.
Such setting of each control mode is performed by an operator operating various buttons and switches. For example, the first control mode (automatic regeneration) is performed when the operator determines that the work by four lift is longer than the time required for the regeneration process (for example, 15 to 20 minutes) and sets the first switching means to the on state. Mode). Thereby, since the regeneration process is automatically performed during the operation until the work is completed, the worker can perform the work without worrying about the regeneration process. On the contrary, the operator determines that the work is shorter than the time required for the regeneration process (for example, 15 to 20 minutes), sets the first switching means to the OFF state, and further sets the second switch before the work is finished. When the switching means is set to the on state, the second control mode (forced regeneration mode) is controlled. Thereafter, even if the engine is stopped, the regeneration process is completed at once without stopping the engine. As a result, the regeneration process is not interrupted in the course of the process, and wasteful regeneration process can be eliminated to prevent deterioration of fuel consumption.
As described above, the claims 3 If the exhaust gas purification method described in the above is used, the operator appropriately operates the first and second switching means according to the work mode, so that the fuel consumption is prevented from deteriorating regardless of the working time of the vehicle. The collecting means can be regenerated.
[0010]
further In the first control mode, when it is determined that the vehicle is a vehicle mainly composed of a work mode with a short work time, the regeneration process of the collecting means is not performed. This is based on the fact that even in the first control mode (automatic regeneration mode), the work mode of the vehicle may not necessarily correspond to that mode. If only the automatic regeneration mode is applied when the state of one working time is short, not only the fuel consumption is deteriorated but also the amount of accumulation on the filter is increased by continuing such work. Such a work mode with a short work time is often seen especially in industrial vehicles such as forklifts. Therefore, in such a case, cancel the auto play mode. System By using the control, it is possible to prevent deterioration in fuel consumption in a work mode with a short work time, and to prevent an increase in the amount of accumulation on the filter.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the exhaust emission control device 100 of the present embodiment will be described using FIG. Here, FIG. 1 is a schematic diagram showing the configuration of the exhaust purification apparatus 100 of the present embodiment.
In this embodiment, a case where the present invention is applied to a technology for purifying exhaust gas discharged from a diesel engine mounted on a forklift, which is one of industrial vehicles, will be described.
[0012]
As shown in FIG. 1, an exhaust purification device 100 is mounted on a diesel engine 10 as an embodiment of the engine in the present invention. This exhaust purification device 100 is used to purify exhaust gas discharged from the diesel engine 10. As shown in FIG. 1, the exhaust purification device 100 includes a collection means 14, a fuel supply amount adjustment means 20, an engine load adjustment means 30, an intake throttle adjustment means 40, which are disposed in the exhaust path 12 downstream of the diesel engine 10. It is comprised by the control part 50 grade | etc.,. The diesel engine 10 is provided with a rotation speed sensor 11 that detects the engine rotation speed.
[0013]
The collection means 14 includes a collection filter 14a having the ability to collect particulates in the exhaust gas. The collecting means 14 is provided with a differential pressure sensor 16 for detecting the differential pressure across the collection filter 14a and an exhaust temperature sensor 18 for detecting the exhaust temperature before and after the collection filter 14a.
[0014]
The fuel supply amount adjusting means 20 is interposed between the mechanical fuel pump 22, the accelerator 24 connected to the fuel pump 22, the accelerator 24 and the fuel pump 22, and the accelerator opening regardless of the operation of the accelerator pedal. It is comprised by the accelerator opening degree adjusting mechanism 26 etc. which can adjust these. The accelerator opening adjusting mechanism 26 is configured to be driven by a step motor (not shown), thereby adjusting the amount of fuel supplied to the fuel injection nozzle. The fuel pump 22 is provided with a fuel injection timing adjustment mechanism 28 (timer) that can adjust the fuel injection timing.
[0015]
The engine load adjustment means 30 includes a hydraulic pump 32 driven by the diesel engine 10 and a hydraulic adjustment mechanism 34 that can adjust the hydraulic pressure of the hydraulic pump 32. The hydraulic pressure adjusting mechanism 34 is a throttle valve arranged on a hydraulic circuit, for example, like a tilt relief valve of a tilt cylinder in a forklift, and controls the hydraulic pressure on the discharge side of the hydraulic pump 32 by restricting the hydraulic circuit as necessary. Be able to.
[0016]
The intake throttle adjusting means 40 includes an intake throttle valve 44 in the intake passage 42. The intake throttle valve 44 can adjust the amount of intake air to the diesel engine 10 by adjusting the flow passage area of the intake passage 42.
[0017]
The control unit 50 is configured by an ECU (electronic control unit). The control unit 50 includes a rotation speed sensor 11, a differential pressure sensor 16, an exhaust temperature sensor 18, a fuel pump 22, an accelerator opening adjustment mechanism 26, a fuel injection timing adjustment mechanism 28, a hydraulic pressure adjustment mechanism 34, an intake throttle valve 44, and Is electrically connected to each of the ignition key 60, the forced regeneration button 62, the automatic regeneration button 64, and the accumulation indicator 66, and is configured to exchange detection signals and control signals. The control unit 50 corresponds to the control means in the present invention.
[0018]
The start operation of the diesel engine 10 is performed by setting the ignition key 60 to the on state, and the stop operation of the diesel engine 10 is performed by setting the ignition key 60 from the on state to the off state.
[0019]
The accumulation indicator 66 is configured to display the particulate collection amount in the collection means 14 in a stepwise manner. For example, as shown in FIG. 1, the particulate collection amount is displayed in five levels in a bar graph form (the collection amount is displayed in five levels of 20%, 40%, 60%, 80%, and 100%). Is used. In the present embodiment, the case where the particulate collection amount reaches the limit of the filter captureable amount in the collection means 14 is defined as 100%. Further, the particulate collection is performed by displaying the one with the larger particulate collection amount (for example, 80% or 100% collection amount) using a color that is easy for the operator to recognize, for example, a red color. It is easy for the operator to understand that the amount is increasing. By displaying the accumulation indicator 66, the operator can determine the operation timing of the forced regeneration button 62.
[0020]
The forced regeneration button 62 is for forcibly starting the regeneration process of the collection means 14, and can be switched between an on state and an off state. This forced regeneration button 62 corresponds to the second switching means in the present invention. The forced regeneration button 62 indicates, for example, that the lamp built in the main body is turned on by being pressed once and is set to an on state (forced regeneration mode). It is turned off and set to the off state.
In the present embodiment, when the forced regeneration button 62 is set to the on state, the regeneration process of the collecting means 14 is continued until the process is completed. That is, in the present embodiment in which the exhaust gas discharged from the diesel engine 10 is used for the regeneration process of the collection means 14, the diesel engine is operated even when the operation is completed during the regeneration process and the ignition key 60 is set from the on state to the off state. The regeneration process is continued by maintaining the operation of the engine 10.
[0021]
The automatic regeneration button 64 is for automatically starting the regeneration process based on the particulate collection amount of the collection means 14, and can be switched between an on state and an off state. This automatic reproduction button 64 corresponds to the first switching means in the present invention. The automatic playback button 64 indicates, for example, that the lamp built in the main body is turned on by being pressed once, and is set to an on state (automatic playback mode). It is turned off and set to the off state. When the automatic regeneration button 64 is set to the ON state and the particulate collection amount of the collection means 14 reaches a predetermined reference value, the regeneration process is automatically started, and the regeneration process of the collection means 14 is performed during work. Can be completed. Note that if the ignition key 60 is set to the off state during the reproduction process, the reproduction is interrupted. In such a case, it is preferable to set the forced reproduction button 62 to the on state before the work is finished.
[0022]
Further, in the present embodiment, when the vehicle is a vehicle whose main work is a short working time, the automatic regeneration button 64 is switched to the off state even if the automatic regeneration button 64 is in the on state. It has become. The control unit 50 is configured to be able to detect the work mode (work time, number of work, etc.) of the vehicle. For example, when it is detected that a short work within 10 minutes has continued five times in succession, the vehicle automatically It is determined that the playback mode is not a suitable method, and the automatic playback mode is forcibly released. If only the automatic regeneration mode is applied when a short working time of one operation is continued, not only the fuel consumption is deteriorated but also the amount of accumulation on the filter increases by continuing such an operation. According to the present embodiment, it is possible to prevent deterioration in fuel consumption in a work mode having a short work time, and to prevent an increase in the amount of accumulation on the filter.
[0023]
Next, an example of the control for purifying the exhaust gas discharged from the diesel engine 10 using the exhaust purification device 100 having the above configuration will be described with reference to FIGS. This control is performed using the control unit 50.
Here, FIG. 2 is a time chart of the reproduction process when the work time is long and short. FIG. 3 is a flowchart showing an exhaust purification process by the exhaust purification apparatus 100. FIG. 4 is a flowchart showing the reproduction process of the first embodiment, and FIG. 5 is a flowchart showing the reproduction process of the second embodiment. FIG. 6 is a graph showing the relationship between engine speed and torque in the first embodiment (intake throttle control) and the second embodiment (intake throttle control + fuel injection amount control). FIG. 7 is a flowchart showing the engine stop process.
[0024]
Particulates in the exhaust gas discharged from the diesel engine 10 during vehicle operation are collected by the filter of the collecting means 14. Therefore, it is necessary to regenerate the collecting means 14 that has collected the particulates. In the present embodiment, the regeneration process of the collection means 14 is performed in an automatic regeneration mode or a forced regeneration mode. Which playback mode is used is determined based on the setting state of the forced playback button 62 and the automatic playback button 64.
[0025]
As shown in FIG. 2, when the worker determines that the work time is equal to or longer than the time required for the regeneration process (for example, 15 to 20 minutes) after the work is started, the worker turns on the automatic regeneration button 64. Set. In this state, when the particulate collection amount of the collection means 14 reaches a predetermined reference value, the regeneration process is automatically started. Thereafter, the reproduction process is completed, the work is completed, and the engine is stopped by setting the ignition key 60 to the off state. This aspect corresponds to the first control mode in the present invention. The engine stop process will be described later with reference to FIG.
[0026]
On the other hand, when the worker determines that the work time is less than the time required for the regeneration process (for example, 15 to 20 minutes), the worker sets the forced regeneration button 62 to the ON state before the work is finished. In this state, the reproduction process is forcibly started, and the reproduction process is continued without stopping the engine even if the operation is completed during the reproduction process and the ignition key 60 is set to the off state. Thereafter, the engine is stopped when the reproduction process is completed. This aspect corresponds to the second control mode in the present invention.
[0027]
Here, the control related to the reproduction process shown in FIG. 2 will be described in detail with reference to the flowcharts shown in FIGS.
In the present embodiment, first, it is determined in step S10 in FIG. If it is determined that the collecting means 14 is being regenerated (YES in step S10), the process proceeds to step S12. If it is determined that the collecting means 14 is not being regenerated (NO in step S10), step S20 is performed. Go ahead.
[0028]
In step S12, it is detected whether or not the automatic playback button 64 is on. If it is determined that the automatic playback button 64 is in the on state (YES in step S12), the process ends. If it is determined that the automatic playback button 64 is in the off state (NO in step S12), Proceed to step S14.
In step S14, it is detected whether or not the forced regeneration button 62 is on. If it is determined that the forced regeneration button 62 is in the on state (YES in step S14), the exhaust purification process is terminated as it is. If it is determined that the forced regeneration button 62 is in the off state (NO in step S14), the regeneration process is interrupted in step S16 and the process is terminated.
[0029]
In step S20, the particulate collection amount A is calculated. This particulate collection amount A can be calculated by using the differential pressure across the collection means 14 detected by the differential pressure sensor 16 and other operation information of the diesel engine.
In step S22, the accumulation indicator 66 is lit to urge the operator to operate the forced regeneration button 62.
In step S24, the calculated value of the particulate collection amount A calculated in step S20 is used as a predetermined reference value (threshold value) A. ₀ Compare with Particulate collection amount A is reference value A ₀ If the threshold value has been reached (YES in step S24), the process proceeds to step S26, where the particulate collection amount A is the reference value A. ₀ If (threshold value) has not been reached (NO in step S24), the process is terminated as it is. For example, the reference value A ₀ The (threshold value) can be set to 80% of the collectable limit amount of the collection filter 14a.
In step S26, it is detected whether or not the automatic playback button 64 is on. When it is determined that the automatic playback button 64 is in the on state (YES in step S26), the playback process is started in step S30, and when it is determined that the automatic playback button 64 is in the off state (NO in step 26). Then, proceed to step S28.
In step S28, it is detected whether or not the forced regeneration button 62 is on. When it is determined that the forced regeneration button 62 is in the on state (YES in step S28), the regeneration process is started in step S30, and when it is determined that the forced regeneration button 62 is in the off state (NO in step S28). In this case, the process is terminated as it is.
[0030]
In step S30, the reproduction process is performed according to the flowcharts of FIGS. 4 and FIG. 5 is executed once in parallel with the flowchart of FIG. 3 by a routine different from the flowchart of FIG. 3 once started.
As the exhaust gas temperature adjusting means for adjusting the exhaust gas temperature in the regeneration process of the collecting means 14, the fuel supply amount adjusting means 20, the engine load adjusting means 30, the intake throttle adjusting means 40, the fuel injection timing adjusting mechanism 28, etc. are required. Can be used in combination. Here, the first embodiment using the fuel supply amount adjusting means 20, the engine load adjusting means 30, and the intake throttle adjusting means 40 as the exhaust gas temperature adjusting means, and the fuel injection timing adjusting mechanism 28 are additionally used. A second embodiment will be described.
[0031]
[First embodiment]
First, in the first embodiment, regeneration processing of the collecting means 14 is performed according to the flowchart shown in FIG. First, in step S110 in FIG. 4, the engine speed N of the diesel engine 10 is detected by the engine speed sensor 11, and the detected value N is compared with a reference value (for example, 1000 rpm). If it is determined that the engine speed N is greater than or equal to the reference value (YES in step S110), the process proceeds to step S112. On the other hand, if it is determined that the engine speed N is smaller than the reference value (NO in step S110), the accelerator opening adjustment mechanism 26 of the fuel supply amount adjusting means 20 proceeds to step S111 and the accelerator opening is increased to idle up. I do. And the process of step S110 and step S111 is repeated until the engine speed N becomes more than a reference value.
[0032]
In step S112, the accelerator opening M is detected, and the detected value is compared with a reference value (for example, 10%). When it is determined that the accelerator opening degree M is equal to or larger than the reference value (YES in step S112), the process proceeds to step S114. Conversely, when it is determined that the accelerator opening M is smaller than the reference value (NO in step S112), the process proceeds to step S113, and the hydraulic pressure is increased by the hydraulic pressure adjustment mechanism 34 of the engine load adjustment means 30. And the process of step S112 and step S113 is repeated until the accelerator opening M becomes more than a reference value. The exhaust gas temperature of the engine varies depending on various conditions. However, in order to raise the exhaust gas temperature to 600 ° C. or higher, there are a minimum engine speed N and an accelerator opening M, which can be obtained experimentally. In steps S110 to S113, the diesel engine 10 is controlled to clear this minimum condition.
[0033]
In step S114, throttle control of the intake throttle valve 44 of the intake throttle adjusting means 40 is performed. The series of controls described above is performed at the inlet temperature T of the collecting means 14. ₁ Is set to be equal to or higher than the combustion temperature of the particulates (for example, 600 ° C.), and the throttle opening of the intake throttle valve 44 is suitable according to the operating situation using a map prepared in advance. Set to
[0034]
In step S115, the inlet temperature T ₁ Is compared with the combustion temperature of the particulates, and the inlet temperature T ₁ Is determined to be lower than the combustion temperature (NO in step S115), the process proceeds to step S116. In step S116, the hydraulic pressure is increased by the hydraulic pressure adjusting mechanism 34 of the engine load adjusting means 30, and the inlet temperature T ₁ Steps S115 and S116 are repeated until is equal to or higher than the combustion temperature. In step S115, the inlet temperature T ₁ If it is determined that the temperature has become equal to or higher than the combustion temperature (YES in step S115), the process proceeds to step S117. In step S117, the inlet temperature T ₁ If the predetermined time has not elapsed (NO in step S117), the process proceeds to step S118. If the predetermined time has elapsed (YES in step S117), the regeneration process is performed. Complete. In step S118, it is determined whether or not the “reproduction processing interruption” step (step S16) in FIG. 3 has been passed. If the “reproduction process interruption” step is passed (reproduction process interruption flag is ON) (YES in step S118), the reproduction process is completed, and otherwise (NO in step S118), the process returns to step S110.
[0035]
As described above, in the first embodiment, first, the engine speed and the fuel injection amount are controlled to be equal to or more than a predetermined value set as the minimum condition. Next, the exhaust gas temperature is raised by controlling the intake throttle of the engine to reduce the intake amount of the engine. Finally, by controlling the engine load and the fuel injection amount so that the exhaust gas temperature becomes equal to or higher than a predetermined value, the temperature rise portion where the exhaust gas temperature is insufficient is compensated by the increase in the fuel injection amount.
By implementing such a first embodiment, for example, an effect as shown in FIG. 6 can be obtained. That is, when the control as in the present embodiment is not used (when temperature increase control is not performed), the region G (engine speed and torque (engine load)) on the broken line (line without intake throttle control) in FIG. If it is not set to a high region), the inlet temperature T ₁ Cannot be brought to 600 ° C. On the other hand, by implementing the first embodiment, if the engine speed and torque (engine load) are set lower than the broken line as long as it is above the thin line in FIG. ₁ Can be brought to 600 ° C. Therefore, the fuel efficiency when the regeneration process of the collection means 14 is performed can be improved as compared with the case without temperature increase control.
[0036]
[Second Embodiment]
Next, in the second embodiment, regeneration processing of the collecting means 14 is performed according to the flowchart shown in FIG. In the reproduction process shown in FIG. 5, first, steps S110 to S113 similar to those in the first embodiment are performed. If it is determined in step S112 that the accelerator opening degree M is greater than or equal to the reference value (YES in step S112), the process proceeds to step S120.
[0037]
In step S120, the differential pressure ΔP before and after the collecting means 14 is detected, and the detected value is compared with the reference value BkPa. When it is determined that the differential pressure ΔP is equal to or lower than the reference value, that is, when the particulate accumulation amount in the collection means 14 is smaller than the predetermined management value (YES in step S120), the process proceeds to step S122. On the other hand, when it is determined that the differential pressure ΔP is smaller than the reference value, that is, when the particulate accumulation amount in the collection means 14 is larger than the predetermined management value (NO in step S120), the process proceeds to step S121.
[0038]
In step S121, the outlet temperature T of the collection means 14 ₂ Is detected, and the detected value is compared with a reference value (for example, 620 ° C.). Outlet temperature T ₂ Is determined to be equal to or higher than the reference value (YES in step S121), the process proceeds to step S123, and the outlet temperature T ₂ Is determined to be lower than the reference value (NO in step S121), the process proceeds to step S122.
[0039]
On the other hand, in step S122, the outlet temperature T of the collection means 14 ₂ Is detected, and the detected value is compared with a reference value (for example, 670 ° C.). Outlet temperature T ₂ Is determined to be equal to or higher than the reference value (YES in step S122), the process proceeds to step S123, and the outlet temperature T ₂ Is determined to be lower than the reference value (NO in step S122), the process proceeds to step S125. That is, the outlet temperature T ₂ Proceeds to step S123 when the temperature is high, and the outlet temperature T ₂ If the value is low, the process proceeds to step S125.
In addition, it is preferable to set the reference value in step S121 to be lower than the reference value in step S122, considering that the temperature rises excessively when the amount of accumulated particulates in the collecting means 14 is too large.
[0040]
In step S123, the advance control is performed to advance the fuel injection timing (timing) using the fuel injection timing adjustment mechanism 28. In step S124, the intake throttle valve 44 is controlled to open, and the process proceeds to step S129. That is, the amount of air is increased by the opening control of the intake throttle valve 44, and the rise of the exhaust gas temperature is suppressed, and the unburned gas exhausted from the diesel engine 10 is reduced by the advance angle control, and the rise of the exhaust gas temperature is suppressed. Thereby, it can prevent that the exhaust gas temperature which rose too much rises further.
[0041]
In step S125, retard control is performed to delay the fuel injection timing (timing) using the fuel injection timing adjustment mechanism 28. In step S126, throttle control (intake throttle control) of the intake throttle valve 44 is performed. That is, the throttle control of the intake throttle valve 44 reduces the amount of air and promotes an increase in exhaust gas temperature, and the retard control increases the amount of unburned gas exhausted from the diesel engine 10 and promotes an increase in exhaust gas temperature. Thereby, the exhaust gas temperature that has not reached the target temperature can be raised.
[0042]
In step S127, the inlet temperature T ₁ Determines whether or not the combustion temperature of the particulates (for example, 600 ° C.) has been reached. Inlet temperature T ₁ If it is determined that the combustion temperature has become equal to or higher than the combustion temperature (YES in step S127), the process proceeds to step S129. Conversely, inlet temperature T ₁ Is determined to be lower than the combustion temperature (NO in step S127), the process proceeds to step S128. In step S128, the hydraulic pressure is increased by the hydraulic pressure adjusting mechanism 34 of the engine load adjusting means 30, and the inlet temperature T ₁ Steps S127 and S128 are repeated until becomes equal to or higher than the combustion temperature. In step S129, the inlet temperature T ₁ If the predetermined time has not elapsed (NO in step S129), the process proceeds to step S130. If the predetermined time has elapsed (YES in step S129), the regeneration process is performed. Complete. In step S130, it is determined whether or not the “reproduction processing interruption” step (step S16) in FIG. 3 has been passed. If the “reproduction process interruption” step is passed (reproduction process interruption flag is on) (YES in step S130), the reproduction process is completed, and otherwise (NO in step S130), the process returns to step S110.
[0043]
As described above, in the second embodiment, first, the engine speed and the fuel injection amount are controlled to be equal to or greater than a predetermined value set as the minimum condition. Next, the temperature of the exhaust gas is raised by controlling the intake throttle of the engine to reduce the intake amount of the engine, and by controlling the fuel injection timing to delay the fuel injection timing. Finally, by controlling the engine load and the fuel injection amount so that the exhaust gas temperature becomes equal to or higher than a predetermined value, the temperature rise portion where the exhaust gas temperature is insufficient is compensated by the increase in the fuel injection amount.
By implementing such 2nd Embodiment, the effect as shown, for example in FIG. 6 can be acquired. That is, by implementing the second embodiment, the engine speed and torque (on the thick line (intake throttle control + injection timing retarding control (TCV control) line)) in FIG. Even when the engine load is low, the inlet temperature T ₁ Can be brought to 600 ° C. Therefore, the fuel consumption at the time of performing the regeneration process of the collection means 14 can be further improved as compared with the first embodiment.
[0044]
According to the embodiment as described above, the operator appropriately operates the forced regeneration button 62 and the automatic regeneration button 64 according to the work mode, thereby suppressing deterioration in fuel consumption regardless of the working time of the vehicle. The regeneration process of the collecting means 14 can be performed. In particular, in industrial vehicles such as forklifts, depending on the work mode, there is a concern that the operation may not be continued until the filter regeneration process is completed, and the state in which the regeneration process is interrupted before the completion of regeneration is repeated, resulting in a decrease in fuel consumption. However, the present embodiment is particularly effective for solving such a problem.
Further, in the present embodiment, when the vehicle is a vehicle mainly having a work mode with a short work time, the automatic regeneration button 64 is switched to the off state even if the automatic regeneration button 64 is in the on state. As a result, it is possible to prevent deterioration of fuel consumption in a work mode with a short work time, and to prevent an increase in the amount of accumulation on the filter.
Further, according to the present embodiment, since the exhaust gas temperature adjusting means is configured using the intake throttle adjusting means 40, the fuel injection timing adjusting mechanism 28, and the engine load adjusting means 30, the temperature rise of the exhaust gas temperature is high. An effect can be obtained. Therefore, the fuel efficiency when the regeneration process of the collection means 14 is performed can be improved as compared with the case without temperature increase control.
[0045]
Finally, the engine stop process of the present embodiment will be described with reference to the flowchart shown in FIG.
In the engine stop process shown in FIG. 7, it is detected in step S140 whether or not the ignition key 60 has been turned off. If the ignition key 60 is turned off (YES in step S140), the process proceeds to step S142. If the ignition key 60 is not turned off (NO in step S140), the process is terminated as it is.
In step S142, it is determined whether the collection means 14 is reproducing | regenerating. If it is determined that the collecting means 14 is being regenerated (YES in step S142), the process proceeds to step S144. If it is determined that the collecting means 14 is not being regenerated (NO in step S142), the engine is turned on. Stop.
In step S144, it is detected whether or not the forced regeneration button 62 is on. If it is determined that the forced regeneration button 62 is in the on state (YES in step S144), the process ends. If it is determined that the forced regeneration button 62 is in the off state (NO in step 144), Stop the engine.
[0046]
In addition, this invention is not limited only to said embodiment, A various application and deformation | transformation can be considered. For example, each of the following embodiments to which the above embodiment is applied can be implemented.
[0047]
In the above embodiment, the case where the forced regeneration process of the collection means 14 is started during the operation of the engine has been described. However, the forced regeneration process is not limited to being started during the operation of the engine. It may be started after the stop operation is performed.
[0048]
Moreover, in the said embodiment, although the case where the forced reproduction | regeneration button 62 and the automatic reproduction | regeneration button 64 which switch an ON state and an OFF state by each pressing operation was used was described, an ON state and an OFF state are other than a pressing operation. Various switches that can be switched can also be used. Further, instead of the forced regeneration button 62 and the automatic regeneration button 64, one operation member (switching means) that can be switched to three modes of the forced regeneration mode, the automatic regeneration mode, and the regeneration interruption mode can be used.
[0049]
Moreover, although the case where this invention was applied to the diesel engine which has an exhaust purification apparatus was described in the said embodiment, this invention can also be applied to the other engine which has an exhaust purification apparatus.
[0050]
【The invention's effect】
As described above, according to the present invention, in the exhaust emission control device for an engine provided with a collecting means for collecting particulates, the collecting means that suppresses deterioration of fuel consumption regardless of the working time of the vehicle. It became possible to perform the reproduction processing.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of an exhaust emission control device 100 of the present embodiment.
FIG. 2 is a time chart of a reproduction process when the work time is long and short.
FIG. 3 is a flowchart showing an exhaust purification process performed by the exhaust purification apparatus 100.
FIG. 4 is a flowchart showing a reproduction process according to the first embodiment.
FIG. 5 is a flowchart illustrating a reproduction process according to the second embodiment.
FIG. 6 is a graph showing the relationship between engine speed and torque in the first embodiment (intake throttle control) and the second embodiment (intake throttle control + fuel injection amount control).
FIG. 7 is a flowchart showing an engine stop process.
[Explanation of symbols]
10 ... Diesel engine
12 ... Exhaust route
14 ... Collection means
14a ... Collection filter
16 ... Differential pressure sensor
18 ... Exhaust temperature sensor
20 ... Fuel supply amount adjusting means
22 ... Fuel pump
24 ... Accelerator
26 ... Accelerator opening adjustment mechanism
28 ... Fuel injection timing adjustment mechanism
30. Engine load adjusting means
32 ... Hydraulic pump
34 ... Hydraulic adjustment mechanism
40. Intake throttle adjustment means
42 ... Intake route
44 ... Intake throttle valve
50. Control unit
60 ... Ignition key
62 ... Forced regeneration button (second switching means)
64 ... Automatic playback button (first switching means)
66 ... Accumulation indicator
100. Exhaust purification device

Claims (3)

An engine exhaust gas purification device used for purifying exhaust gas exhausted from an engine,
Switching between a collecting means for collecting particulates in the exhaust gas discharged from the engine, an exhaust gas temperature adjusting means capable of adjusting an exhaust gas temperature acting on the collecting means, and an on state and an off state Possible first and second switching means, and control means,
When the first switching means is set to the on state, the control means determines that the particulate collection amount in the collection means has reached a predetermined value, and the exhaust gas temperature adjustment means the start performed regeneration process of during operation of the engine control to the collecting means, yet with the case where the engine is stopped operation to interrupt the regeneration process in the reproduction process, the second switching means Is set to the on state, the exhaust gas temperature adjusting means is controlled to regenerate the collection means, and this regeneration process is completed even if the engine is stopped. to be configured so as to continue,
Further, when the control unit determines that the vehicle is a vehicle mainly having a work mode with a short work time, the control unit switches the setting to the off state even if the first switching unit is set to the on state. An exhaust emission control device for an engine characterized by being configured as described above . An exhaust emission control device for an engine according to claim 1 ,
The engine exhaust purification apparatus according to claim 1, wherein the engine is an engine used in an industrial vehicle. For an engine that purifies exhaust gas discharged from the engine, the step of regenerating the collection means by adjusting the exhaust gas temperature acting on the collection means that collected particulates in the exhaust gas is performed. An exhaust purification method comprising:
When it is determined that the particulate collection amount in the collection means has reached a predetermined value, the exhaust gas temperature adjustment means is controlled to start the regeneration process of the collection means during operation of the engine. A first control mode for interrupting the regeneration process when the engine is stopped during the regeneration process;
The performed by controlling the exhaust gas temperature adjusting means regeneration process of the collecting means, the reproduction process have a second control mode to continue until the engine the reproduction process be stopped operation is completed ,
Further, in the first control mode, when it is determined that the vehicle is a vehicle mainly having a work mode with a short work time, the regeneration process of the collecting means is not started. Purification method.

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