JPS62294758A - Suction device of internal combustion engine - Google Patents

Abstract

PURPOSE:To supply air in optimum oxygen content as well as rate of flow according to the engine operating condition, by controlling a suction throttle valve so that the suction oxygen amount determined from sensor information becomes optimum value according to the engine operating condition. CONSTITUTION:Engine revolving speed, load, suction neg. pres. and temperature are sensed by means of a rotation sensor 11, a load sensor 10, a pressure sensor 12 and a thermo-sensor 14. Thereupon the operating condition of engine is determined, and the suction amount of oxygen is calculated which is optimum according to said determined operating condition. If the suction amount of oxygen is less than the optimum value, a suction throttle valve 6 is throttled to enlarge the suction neg. pres. to be applied to an oxygen enriching device 4, and the amount of oxygen generated thereby is increased so that the optimum value is obtained. If the suction amount of oxygen is larger than the optimum value, said suction throttle valve 6 is opened to lessen the suction neg. pres., and the amount of oxygen generated is decreased so that the optimum value is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intake system for an internal combustion engine in which an oxygen enrichment device is interposed in the intake system of an internal combustion engine, and in particular improves the supply of oxygen-enriched air. related to what was done.

[Prior Art] One of the parameters that determines the oxygen concentration and air flow rate of oxygen-enriched air in a J3 engine equipped with an oxygen enrichment device is the repulsive force applied to the oxygen enrichment device, and normally this pressure uses the engine's intake negative pressure.

Therefore, when the intake negative pressure changes by operating the intake throttle valve attached to the intake system, the M element concentration of the oxygen-enriched air and the air flow rate also change at the same time. Therefore, the necessary oxygen-enriched air cannot be supplied to the engine unless the negative pressure is set according to the engine operating state.

However, with conventional engines equipped with oxygen enrichment devices,
Since negative pressure control 1211 was not carried out from such a point of view, there may be excess or deficiency l1. (there were.

In addition, as a prior art, the oxygen concentration of oxygen-enriched air is reduced according to the increase in load so that the combustion temperature does not become abnormally high (Japanese Patent Application Laid-Open No. 1983-455242), and the engine load range When switching between oxygen-enriched air and normal air according to
Publication No. 9).

[Problems to be solved by the invention] As mentioned above, in the conventional system, the negative pressure is not set according to the engine operating state, even though the amount of oxygen required varies depending on the engine operating state. Therefore, it was not possible to supply air with optimal oxygen concentration and flow rate.

Therefore, an object of the present invention is to provide an intake system for an internal combustion engine that can supply optimal oxygen-enriched air to the internal combustion engine depending on the operating state of the engine.

[Means for Solving the Problems] The present invention, which achieves the above object, detects intake information, such as intake negative pressure and oxygen concentration, on the downstream side of an oxygen enrichment device installed in the middle of the intake system. A control means is provided for determining the amount of intake oxygen based on the sensor information and controlling the intake throttle valve so that the amount of intake oxygen is the optimum value depending on the engine operating state.

[Operation] When the operating state of the engine is input to the control means, the optimum intake oxygen ω is calculated accordingly. If the intake oxygen concentration determined based on the sensor information is smaller than this optimal value, the intake throttle valve is throttled and the intake negative pressure applied to the oxygen enrichment device becomes too large, causing the oxygen enrichment device to generate less oxygen. The amount of oxygen is increased to bring this amount of oxygen to the optimal value.

Furthermore, when the intake oxygen amount is larger than the optimum value, the intake throttle valve is opened and the intake negative pressure is reduced, reducing the generated oxygen amount and bringing this oxygen amount to the optimum value as well.

[Example] An example of the present invention will be described below based on FIGS. 1 to 5.

FIG. 1 shows an example of an intake system for an internal combustion engine according to the present invention.

1 is an engine, to which an intake pipe 3 for supplying general air via an air cleaner 2 is connected. An oxygen enrichment device 4 is interposed in the middle of this intake pipe 3, and generates oxygen-enriched air from fresh air supplied from a blower fan 5 using engine intake negative pressure, and merges it with general air. It is designed to be supplied into the engine 1. The engine supply negative pressure applied to the oxygen enrichment device 4 can be varied by adjusting the valve opening degree of an intake throttle valve 6 attached to the intake pipe 3 on the upstream side. The opening degree of the intake throttle valve 6 is adjusted by a throttle valve actuator 8 that is operated by an operation signal output from a controller 7.

On the input side of the controller 1 to the roller 7, there is a load sensor 10 that detects the load from the injection pump. Rotation sensor 11 for detecting engine rotation speed. A pressure sensor 12 is installed in the intake pipe 3 on the downstream side of the M element enrichment device 4 and is supplied to the engine 1. An oxygen concentration sensor →)-13 that detects the oxygen concentration of the combined air, and a temperature sensor 14 that is attached to the fresh air introduction path of the oxygen enrichment device 4 and detects the temperature of the fresh air are connected, and the temperature obtained from these various sensors is connected. Based on the information, an actuation signal for the actuator is output. Note that the oxygen concentration sensor 13
is not required.

The various functions of the controller 7 are as shown in FIG.

By the way, in the intake device configured in this way, the entire system in which the oxygen concentration device 4 is interposed in the intake pipe 3 is
Its characteristics are as shown in Figures 4 and 5, and the oxygen concentration and outflow of the combined air obtained downstream of the oxygen enrichment device 4 are determined by the engine intake negative pressure (absolute field). These are also determined by the temperature of the air supplied by the blower fan 5.

Now, the effects of the above-mentioned configuration and various functions will be explained with reference to FIG.

The engine rotation speed N and engine load, which represent the engine operating state, are each detected by a rotation sensor 11. It is detected by the load sensor 10, and the detection data is input to the controller 7. In addition, the intake negative pressure P applied to the oxygen enrichment device 4 and the fresh air temperature T supplied to the oxygen enrichment device @4 are detected by the pressure sensor 12 and temperature sensor 14, respectively, and the detected data is also input to the controller 7. be done. These data are input at regular intervals as is normally done.

After inputting the detection data from each of these sensors,
It is determined whether the engine rotational speed N is zero or not, and the engine 1
Since the throttle valve is controlled only when the engine is rotating, proceed to the next step and set the oxygen concentration according to the engine operating state. In this embodiment, the oxygen 'a stage setting is set to a high oxygen concentration A when the detected engine load is greater than a predetermined 1iaLo from the map shown in FIG. B, two types are set depending on the engine load condition, but the number of types of concentration settings may be further increased, or the engine speed may be added to the setting conditions.

Note that regardless of whether the oxygen concentration is set to A or B, the operation flow after setting is the same, so here we will use the oxygen concentration A.
I will continue to discuss the case where it is set to .

After setting the oxygen concentration Δ, the total intake air ff1Q, which is a mixture of general air and M-enriched air and is supplied to the engine 1, is calculated based on the intake negative pressure P. Further, the oxygen mo2o required for the engine 1 is calculated g1 from the engine speed N and the engine load. Then, from these and the characteristic data maps shown in FIGS. 4 and 5, the oxygen enrichment device 4
Determine the intake negative pressure PA, which is the operating condition. This decision is made as follows.

The oxygen concentration of the current intake air supplied to engine 1 is A
Assuming that, MNFlr02 supplied to engine 1
is 02=QXA based on the calculated intake air fmQ
<1). However, the oxygen concentration A can be expressed as A = f (P) Q (T) (21) from the characteristics shown in Figures 4 and 5. Therefore, by substituting formula (2) into formula (1),
=Qf (P) Q (T)
(3) is obtained.

On the other hand, the currently required oxygen envelope can be found from the calculation results as mentioned above, and is 02=020 (4), so assuming that equations (3) and (4) are equal, f (P)
=020/Q-Q (T) (5) is obtained. The intake negative pressure that satisfies this equation is the required intake negative pressure P=PA.

Therefore, from equation (5), PA = f'' (020/Q-Q (T) ) (
6+ gets 1. Note that Q (T> is known because the fresh air temperature T has been detected.

In this way, assuming that the current intake air ff1Q does not change, in order to make the oxygen concentration A, the intake negative pressure P=PA
It is necessary to decide.

When the intake negative pressure PA is determined as described above, controllers 1 to 1
After outputting an activation signal to the throttle valve actuator 8, the roller 7 determines whether or not the intake negative pressure P is equal to or higher than the determined intake negative pressure PA.If not, the actuator is activated and the subsequent determination described above is repeated. In this case, the process proceeds to the next step and determines whether the oxygen concentration has reached the set value of oxygen concentration Δ. This oxygen concentration is detected by the oxygen concentration sensor 13. When A is reached, this control ends and returns to the routine of reading the first detection data, but if not, the process returns to the actuator actuation step and does not repeat the subsequent steps.

That is, when the actuator is actuated by an actuation signal from the controller 7 and the valve opening degree of the intake throttle valve 6 is adjusted thereby, the intake negative pressure applied to the oxygen enrichment device 4 is controlled accordingly. This reduced intake negative pressure P (<O)
is determined to be greater than the negative intake pressure pA (<0), that is, when the aperture is still insufficient and PA has not been reached, check whether the oxygen concentration has already reached the set value A before reaching PA. In each case, if Δ is not reached, the valve opening of the intake throttle valve 6 is further reduced, and the target oxygen concentration A is reached before P=PA (if I try not to perform 4-engine intake throttling.

On the other hand, when the controlled intake negative pressure P is smaller than PA, the valve opening of the intake throttle valve 6 is opened, and by setting P=PA, the target oxygen concentration A is similarly reached. That's what I do.

In this way, in addition to feedback control of the intake negative pressure, feedback control of the oxygen concentration is also supplementary to this, so that the optimal oxygen-enriched air, that is, the necessary amount of oxygen, is always supplied to the engine. Can be done.

Note that when the oxygen concentration sensor 13 is not used, the intake negative pressure is simply determined by P=
It is sufficient to change it to PA or not and omit the concentration determination.

Furthermore, in the above embodiment, basically, the oxygen amount is indirectly controlled by the intake negative pressure, but instead of the pressure sensor 12, the oxygen concentration sensor 13 is actively used, and the oxygen concentration sensor 13 is used to detect the oxygen concentration. Directly adjust the throttle valve actuator 8 so that the oxygen concentration reaches the set temperature 1iIII21! You may also do so.

[Effects of the Invention] In short, according to the present invention, the intake throttle valve is controlled so that the amount of intake oxygen determined from sensor information becomes the optimum value according to the engine operating condition, thereby achieving oxygen enrichment. Since the intake negative pressure, which determines the amount of oxygen generated by the device, is appropriately adjusted, air can be supplied with the optimal oxygen concentration and flow rate according to the tlf3[] operating state.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an intake system for an internal combustion engine reformer according to an embodiment of the present invention, Fig. 2 is a flowchart explaining various functions of the controller shown in Fig. 1, and Fig. 3 is a flowchart of Fig. 2. Load characteristic diagram showing the contents of the program to obtain the optimum oxygen concentration according to the operating condition of the adopted engine, Part 4
5 and 5 are characteristic diagrams of an oxygen enrichment device installed in the intake system. In the figure, 1 is the engine, 3 is the intake pipe, 4 is the oxygen enrichment device,
6 is an intake throttle valve; 7.8 is a controller and throttle valve actuator constituting a control means; 12.13 is a pressure sensor and an oxygen concentration sensor for detecting intake information.

Claims (3)

[Claims] (1) A sensor is installed on the downstream side of the oxygen enrichment device installed in the intake system to detect the intake air information, and the intake air is adjusted so that the amount of intake oxygen determined from the sensor information is the optimal value according to the engine operating condition. An intake system for an internal combustion engine that is equipped with a control means for controlling a throttle valve. (2) The intake system for an internal combustion engine according to claim 1, wherein the sensor is a pressure sensor that detects intake negative pressure applied to the oxygen enrichment device. (3) The intake system for an internal combustion engine according to claim 1, wherein the sensor is an oxygen concentration sensor that detects the oxygen concentration in intake air flowing downstream of the oxygen enrichment device.