JPS6136743Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an exhaust gas temperature control device for exhaust turbine supercharging, and more specifically, to a device for controlling the temperature of exhaust gas after the turbine in an exhaust turbine supercharging diesel engine, etc. .

A conventional exhaust turbine supercharging diesel engine has a configuration as shown in FIG. 1, for example.
In the figure, 1 is a supercharger blower, 2 is a supercharger turbine, 3 is an air cooler, 4 is an air supply pipe, 5 is an exhaust pipe, 6 is an engine cylinder, and 7 is an exhaust gas economizer. The effect is that the exhaust gas coming out of the cylinder 6 passes through the exhaust pipe 5 and enters the turbine 2. At this time, the turbine 2 is driven by the energy of the exhaust gas, and the rotational force of the turbine 2 rotates the blower 1 provided coaxially with the turbine 2 to compress the air. The compressed air is cooled by an air cooler 3,
Air is supplied from the air supply pipe 4 to the cylinder 6.

In such a supercharged diesel engine, especially in the recent high supercharging system, the amount of air increases at high load, and the exhaust temperature becomes lower than at partial load. Also, the blower inlet intake air temperature (atmospheric temperature)
The exhaust temperature also decreases when the temperature is low. For example, the second
The relationship is shown in the figure. Curve a in the figure is for a high atmospheric temperature, curve b is for a medium atmospheric temperature, and curve c is for a low atmospheric temperature. Because of these fluctuations in exhaust gas temperature, the exhaust gas economizer 7 and exhaust gas turbo generator that recover exhaust gas energy must be large and expensive if they are designed to have sufficient capacity even at low exhaust gas temperatures. becomes. Furthermore, if designed for high exhaust gas temperatures, there is a drawback that desired performance cannot be obtained when the exhaust gas temperature is low. On the other hand, if the exhaust gas energy recovery device is the same and the amount of exhaust gas energy is the same, as shown in FIG. 3, the higher the exhaust gas temperature is, the less energy is wasted by the amount shown by the parallel hatched area. Therefore, more energy can be recovered by increasing the exhaust temperature as high as the engine design allows. However, with conventional systems, the exhaust temperature cannot be freely controlled, making it difficult to use energy when the exhaust temperature is low. Therefore, it is possible to adjust the air cooler 3 to control the exhaust temperature according to the supply air temperature at the engine inlet, but this method cannot be adjusted significantly and the supply air pressure will increase if the supply air temperature is increased. If it becomes high, the combustion pressure will increase, and if it becomes low, a large amount of condensate will be generated in the air supply, which will harm the engine.
This is not a desirable method. For this reason, in the past, it was necessary to allow a margin in the heat resistance limit of the exhaust gas energy recovery device in anticipation of the exhaust temperature becoming higher than the planned value due to dirt in the engine or changes in atmospheric temperature. .

This invention is an exhaust gas temperature control device that maintains the exhaust gas temperature constant, thereby making the design conditions for exhaust gas economizers and exhaust gas turbo generators more accurate, and making it difficult for under- or over-output conditions to occur. The purpose is to provide

For this reason, the configuration of the present invention is provided with a main bypass pipe having a flow control valve therein and connecting the outlet of the turbocharger blower and the inlet of the turbocharger turbine,
The system is characterized by comprising at least one of a supercharged air bypass pipe having a flow control valve thereon and connecting the outlet and inlet of the supercharger blower, and an exhaust gas bypass pipe having a flow control valve thereon and connecting the inlet and outlet of the supercharger turbine, and further comprising an exhaust temperature sensor provided at the outlet of the supercharger turbine, and a controller which inputs a temperature signal from this temperature sensor, calculates the deviation from a set temperature, and controls the flow control valve of each bypass pipe so as to eliminate the deviation.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 shows a first embodiment of the present invention, and FIG. 5 shows a second embodiment of the present invention.

In FIG. 4, 1 to 7 are the same as in FIG. 1. 8 is a main bypass pipe, which has a flow rate regulating valve 10 in the middle and connects the outlet of the supercharger blower 1 and the inlet of the supercharger turbine 2. Reference numeral 9 denotes a supercharged air bypass pipe that connects the outlet and inlet of the supercharger blower 1 with a flow rate regulating valve 11 in the middle. 12
is an exhaust gas temperature sensor, which is provided at the outlet of the supercharger turbine 2. A controller 13 inputs the temperature signal from the temperature sensor 12, calculates the deviation from the set temperature, and controls the opening degrees of the flow rate regulating valves 10 and 11 so that the deviation disappears.

In the exhaust gas temperature control device for exhaust turbine supercharging configured as shown in FIG. Send to. The controller 13 receives the temperature signal and calculates the deviation from the set temperature. Here, if there is no deviation, the controller 13 closes both the flow regulating valves 10 and 11, but if the exhaust temperature is high, it opens the flow regulating valve 10 of the main bypass pipe 8 and Part of the supercharging air is guided from the outlet of the charger blower 1 to the inlet of the supercharger turbine 2 through a main bypass pipe 8 . At this time, the flow rate is adjusted by the flow rate adjustment valve 10 according to the deviation, and the exhaust gas temperature is controlled to a predetermined (set) exhaust temperature. That is, by mixing the bypass air and exhaust gas, the exhaust gas temperature is lowered to a predetermined temperature. On the other hand, when the exhaust temperature is low, open the flow rate adjustment valve 11 of the supercharged air bypass pipe 9 and let a portion of the supercharged air pass through the supercharged air bypass pipe 9 from the outlet of the supercharger blower 1. Guide it to the inlet side of blower 1. At this time, the flow rate is adjusted by the flow rate adjustment valve 11 according to the deviation to control the exhaust gas temperature to a predetermined (set) value. In other words, the temperature of the air bypassed from the outlet of the blower 1 is increased due to compression, and when this is mixed with the intake air, the temperature of the inlet air of the blower 1 is increased. Since the amount of air supplied to the exhaust gas decreases, the exhaust temperature increases.

In FIG. 5, reference numeral 14 denotes an exhaust gas bypass pipe, which has a flow rate regulating valve 15 in the middle and connects the inlet and outlet of the supercharger turbine 2. That is,
The exhaust gas bypass pipe 1 of the turbine 2 is replaced with the supercharged air bypass pipe 9 of the blower 1 in the case of FIG.
I have 4. In the case of this Fig. 5, when the exhaust temperature is at the predetermined value, that is, when there is no deviation, the fourth
As in the case shown in the figure, both flow regulating valves 10 and 15 are closed, and when the exhaust gas temperature is high,
As in the case of FIG. 4, a part of the supercharging air is bypassed from the outlet of the blower 1 to the inlet of the turbine 2 by opening the flow rate regulating valve 10, but conversely, when the exhaust temperature is low, the flow rate is The regulating valve 15 is opened to guide a portion of the exhaust gas at the inlet of the turbine 2 to the outlet of the turbine 2 through the exhaust gas bypass pipe 14 . At this time, the flow rate is adjusted by the flow rate adjustment valve 15 according to the deviation to control the exhaust gas temperature to a predetermined (set) value. In other words, the exhaust temperature increases because the high-temperature gas bypassed from the inlet of the turbine 2 mixes with the low-temperature gas at the outlet of the turbine 2, and the bypass reduces turbine work and reduces the amount of air discharged from the blower. .

In this way, in both the case of FIG. 4 and the case of FIG. 5, the temperature is measured by the exhaust temperature sensor 12 provided at the outlet of the supercharger turbine 2,
The deviation from the set temperature is calculated, and the flow rate control valve 10 or 11, 15 is controlled by the controller 13 so that the deviation is eliminated, and the exhaust gas temperature at the outlet of the supercharger turbine 2 is From a macroscopic perspective, it is kept constant like the horizontal straight line d in FIG.

Therefore, since the present invention has the above-mentioned configuration, the exhaust gas temperature can be kept constant.
The design conditions for exhaust gas economizers and exhaust gas turbo generators have become more accurate, making it less likely that output will be under- or over-output.Furthermore, it will be possible to maintain a higher exhaust gas temperature during regular load than before, making it possible to utilize exhaust gas energy. Efficiency can be increased.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional exhaust turbine supercharged diesel engine, Figure 2 is an explanatory diagram showing the relationship between engine load and exhaust gas temperature, and Figure 3 is an explanatory diagram showing the relationship between gas amount and gas temperature. , FIG. 4 is an explanatory diagram showing the first embodiment of the present invention, and FIG. 5 is an explanatory diagram showing the second embodiment. 1...Supercharger blower, 2...Supercharger turbine,
3... Air cooler, 4... Air supply pipe, 5... Exhaust pipe, 6... Engine cylinder, 7... Exhaust gas economizer, 8... Main bypass pipe, 9... Supercharged air bypass pipe, 10, 11 ...Flow rate adjustment valve, 12...Exhaust temperature sensor, 13...Controller, 14...Exhaust gas bypass pipe, 15...Flow rate adjustment valve.

Claims (1)

[Scope of utility model registration request] A main bypass pipe having a flow rate regulating valve in the middle and connecting the outlet of the supercharger blower and the inlet of the supercharger turbine, and having a flow rate regulating valve in the middle and connecting the outlet of the supercharger blower. and an exhaust gas bypass pipe having a flow rate regulating valve in the middle and connecting the inlet and outlet of the supercharger turbine, and further comprising:
An exhaust temperature sensor provided at the outlet of the supercharger turbine, and a temperature signal from this temperature sensor inputted to calculate the deviation from the set temperature, and a flow rate regulating valve of each bypass pipe to eliminate the deviation. An exhaust gas temperature control device for exhaust turbine supercharging, characterized in that it is equipped with a controller for controlling.