JPS6255418A - Engine with pressure wave supercharger - Google Patents

Abstract

PURPOSE:To constantly keep high the blowby ratio of a fresh air, which blows through from a fresh air passage to an exhaust passage via a pressure wave supercharger, and to keep the pressure wave supercharger's adiabatic efficiency high by controlling a revolving speed ratio variable means in accordance with the fresh air blowby ratio. CONSTITUTION:The fresh air blowby ratio etasp of the fresh air, which blows through from an intake air passage 2 to an exhaust passage 3 via a pressure wave supercharger 4, is calculated by a computer 22, according the following formula: etasp={21-[O2]3/21-[O2]4}-1 where [O2]3, [O2]4, and 21 represent the oxygen concentration at O2-sensors 20and 21 and of the atmosphere, respectively. In case etasp<100%, a pulley 5 is moved so that the adiabatic efficiency is heightened. A difference E in the fresh air blowby ratio etasp between the previous time an this time is computed. In case E>5 or E<-5, the pulley ratio is varied by a predetermined amout so that the E-value becomes -5<=E<=5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvement of an engine equipped with a pressure wave supercharger, and particularly to measures for improving the supercharging capacity of a pressure wave supercharger.

(Prior Art) A pressure wave supercharger has been known as one of the superchargers for supercharging intake air into an engine (Japanese Patent Publication No. 38-1
(See Publication No. 153). This pressure wave supercharger is rotatably driven by an engine and is disposed across the exhaust passage and intake passage of the engine, and has a large number of chambers rotatably supported within a case. A rotor with partition walls arranged radially, an intake inlet and an intake outlet formed in a case on one end of the rotor, and an exhaust inlet and an exhaust outlet formed in a case on the other end of the rotor. As the rotor rotates in accordance with the engine speed, the intake air drawn into the small chamber of the rotor from the intake inlet is caused to flow into the small chamber from the exhaust inlet, and the pressure between the two is reduced. The difference compresses and accelerates the intake air, which is then discharged from the intake and discharge ports. In other words, by transmitting the pressure waves and energy of the exhaust gas to the intake air, the intake air is supercharged, while the exhaust gas remaining in the small chamber is discharged through the exhaust discharge port, and the air is drawn into the small chamber from the intake inlet. By introducing air, the scavenging process is repeated.

(Problems to be Solved by the Invention) By the way, in an engine equipped with a pressure wave supercharger as described above, the supercharging capacity of the pressure wave supercharger strongly depends on its adiabatic efficiency, and when the adiabatic efficiency is high, has increased supercharging capacity,
This is preferable because it is possible to further improve the engine output, and also to suppress the temperature rise of the pressure wave supercharger, thereby improving its reliability. However, the adiabatic efficiency of a pressure wave supercharger changes depending on various factors, such as the engine speed and load, the ratio of the pressure wave supercharger's speed to other engine speeds, the flow resistance of the intake and exhaust system, and the intake passage. Cooling efficiency of supercharged intake air when an intercooler is installed in
It shows characteristics that change over time in response to changes in actual driving conditions such as exhaust energy.

Therefore, when maintaining and controlling the adiabatic efficiency of the pressure wave supercharger at a high level in order to improve the supercharging capacity, a disadvantage arises in that the configuration becomes quite complicated.

However, if the control factors of adiabatic efficiency are limited to the main ones and prospective control is performed according to the engine speed and load, the control accuracy will decrease, and it will be difficult to improve the supercharging capacity and suppress the temperature rise. I can't expect much.

The present invention has been made in view of this point, and in the scavenging process in a pressure wave supercharger, fresh air introduced from the intake passage upstream of the pressure wave supercharger is discharged together with the exhaust gas downstream of the pressure wave supercharger. It blows through into the side exhaust passage. It focuses on the phenomenon of so-called fresh air blowing through. In other words, the adiabatic efficiency of a pressure wave supercharger is closely related to the amount of fresh air vented, or the rate of fresh air vented in a pressure wave supercharger. In addition to the engine speed and load factors, the change characteristics of the adiabatic efficiency change depending on actual driving conditions such as the rotation speed ratio of the pressure wave supercharger to the engine speed and the circulation resistance of the intake and exhaust system. We focused on the fact that the higher the ratio, the higher the adiabatic efficiency of the pressure wave supercharger. Fresh air blowing in a pressure wave supercharger changes the ratio of the pressure wave supercharger's rotation speed to the engine speed according to the rate, so it can be adjusted not only to changes in engine speed and load but also to actual driving conditions. Detection control is performed in response to changes to maintain the adiabatic efficiency of the pressure wave supercharger at a high level at all times, further improving supercharging capacity and more effectively suppressing the rise in Wm of the pressure wave supercharger. It's about doing.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides an engine equipped with a pressure wave supercharger as described above. a rotation speed ratio variable means for changing the ratio of rotation speeds; first and second exhaust gas concentration detection means for detecting exhaust gas concentrations in the upstream and downstream exhaust passages of the pressure wave supercharger, respectively; The atrium of fresh air that reaches the output of the detection means and is blown from the intake passage to the exhaust passage through the pressure wave supercharger is sieved by means for sieving the rate; The fresh air vent calculated by the rate calculation means is provided with a control means for controlling the rotation speed ratio variable means in accordance with the rate.

(Function) With the above configuration, in the present invention, the rate of fresh air blowing from the intake passage to the exhaust passage via the pressure wave supercharger is determined by the change in the engine speed and load. Although it tends to change in size according to changes in actual running conditions such as system flow resistance and exhaust energy, this fresh air vent does not exhibit the characteristic that as the rate increases, the adiabatic efficiency of the pressure wave supercharger also decreases. However, when the rate of this fresh air vent is calculated by the rate calculation means based on the output of the first and second exhaust 81 degree detection means, the rate of this fresh air vent is calculated by the pressure wave supercharger so that the bow is higher. Since the rotation speed ratio is controlled by the control means, the adiabatic efficiency of the pressure wave supercharger is always maintained high, and as a result, the supercharging capacity is increased and the engine output is further improved, and the pressure wave supercharger is The temperature rise of the feeder is effectively suppressed and its reliability is improved.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows the overall schematic configuration of an engine with a pressure wave supercharger. 1 is a 4-cylinder engine having the first to fourth cylinders 1a to 1d, and 2 is a four-cylinder engine with an upstream end opening to the atmosphere and a downstream end having four branches. An intake passage 3 opens to each cylinder 1a to 1d of the engine 1 through passages 2a to 2d and supplies intake air to each cylinder 1a to 1d of the engine 1, and 3 has an upstream end connected to the engine through branch passages 38 to 3d. This is an exhaust passage that opens into each of the cylinders 1a to 1d of the engine 1 and whose downstream end opens to the atmosphere to discharge exhaust gas from each of the cylinders 1a to 1d of the engine 1.

Iζ,4 is a pressure wave supercharger disposed across the intake passage 2 and exhaust passage 3, and the pressure wave supercharger IR4
is rotationally driven by a girder belt transmission mechanism 7 (1) wrapped around a belt 6 via pulleys 5, 5 between its rotating shaft 4a and the output shaft 1e of the engine 1, and its internal configuration is as follows:
As is well known, it has a rotor rotatably supported within a case, and a number of partition walls are arranged radially around the outer periphery of the rotor, and a number of small chambers are formed in the circumferential direction on the outer periphery of the rotor by the partition walls. has been done. An intake inlet 4b and an intake outlet 4c are formed in the case at one end of the rotor, the intake inlet 4b is upstream of the pressure wave supercharger 4 in the intake passage 2, and the intake outlet 4c is in the intake passage The two pressure wave superchargers 4 are connected downstream. Further, an exhaust inlet 4d and an exhaust outlet 4e are formed in the case on the other end side of the rotor, and the pressure wave supercharger 4 of the exhaust passage 3 is connected to the exhaust passage 3, respectively.
It communicates with the upstream and downstream sides. As the rotor rotates, when high-pressure exhaust gas flows into the small chamber in which low-pressure intake air is confined through the exhaust passage 3 on the upstream side of the pressure wave supercharging 14, the pressure difference causes A pressure wave (compression shock wave) is generated and propagated inside the small chamber, and the pressure wave energy of the exhaust gas is transmitted to the intake air, thereby compressing and accelerating the intake air and moving it from the intake discharge port 4c to the downstream side of the pressure wave supercharger 4. The exhaust gas flowing into the small chamber is then discharged from the exhaust outlet 4e to the exhaust passage 3 on the downstream side of the pressure wave supercharger 4, and pressure wave supercharging is performed. Intake air from the intake passage 2 on the upstream side of the machine 4 is transferred to the intake inlet 4
It is configured to repeatedly introduce the air into the small chamber via b and scavenge the exhaust air. Here, in order to scavenge the exhaust air, fresh air is introduced from the intake passage 2 on the upstream side of the pressure wave supercharger 4 and blows through to the exhaust passage 3 on the downstream side of the pressure wave supercharger 4. The coefficient exhibits a characteristic that the higher the adiabatic efficiency of the pressure wave supercharger 4, the higher the coefficient becomes.

The pulley 5 on the pressure wave supercharger 4 side of the belt transmission mechanism 7 has a fixed flange 5a fixed to the end of the rotating shaft 4a of the pressure wave supercharger 4, as shown in detail in FIG. It consists of a movable flange 5b facing the fixed flange 5a, and a double spring 5c compressed between the flanges 5a and 5b to urge the movable flange 5b to the right in FIG. Also, in the vicinity of the pulley 5, there is a pulley ratio control device 10#l that moves the movable flange 5b in the axial direction! ii!
It is placed. The pulley ratio control device 10 has a bearing 12 that rotatably supports the movable flange 5b of the pulley 5, and a fixed plate fixed to the pressure wave supercharger 4 via a screw member 13 fixed to the central part of the back surface of the bearing 12. The screw member 13 is attached to the stepping motor 16 via a speed reduction mechanism 15 made of gears.
is rotatably connected to. Therefore, the rotation of the screw member 13 by the stepping motor 16 causes the bearing 12 to be rotated.
By moving the movable 7 flange 5b of the pulley 5 in the axial direction by moving it in the left-right direction in FIG. A rotation speed ratio variable means 17 is configured to change the ratio of the rotation speed of the pressure wave supercharger 4 to the rotation speed of the pressure wave supercharger 4.

Furthermore, on the upstream and downstream sides of the pressure wave supercharger 4 of the exhaust passage 3 in FIG. First and second 02 sensors 20.21 as means are interposed, and the first and second 02
Detection signals from the sensors 20 and 21 are input to a computing machine 22, and the stepping motor 16 of the pulley ratio control device 10 is driven by the computing machine 22. In FIG. 1, reference numeral 23 denotes an air-cooled intercouple disposed downstream of the pressure wave supercharger 4 in the intake passage 2, which is used to collect high-temperature intake air supercharged by the pressure wave supercharger 4. The system cools the vehicle by exchanging heat with outside air (driving wind).

Next, drive control of the stepping motor 16 by the computer 22 will be explained based on the flowchart of FIG. First, it starts after running for a predetermined time (for example, 10 seconds), and in step S1, the first and second 02 sensors 20,
Based on the output from 21, the oxygen concentration in the exhaust gas on the upstream and downstream sides of the pressure wave supercharger 4 in the exhaust passage 3, respectively [0□]
3 and [02]4 (expressed as %), in step S2, based on the above-mentioned oxygen concentrations [0213, [0214] and atmospheric oxygen 111 [(21%), The amount of fresh air blown from the intake passage 2 to the exhaust passage 3 is calculated based on the following formula.

η5l)-((21-[0213)/(21[02]4)) 1 After that, in step S3, the fresh air vent compares the rate ηsp with a large predetermined value K (for example, 100%), η
If sp≧ is YES, it is determined that the adiabatic efficiency of the pressure wave supercharger 4 is high, and the process immediately ends. On the other hand, ηSt)<K
If the answer is No, step S4 is performed to increase the insulation efficiency.
After moving the movable flange 5b of the pulley 5 in the axial direction to increase or decrease the boolean ratio by the setting IIfI (for example, 0.1), step Ss and Ss move the movable flange 5b of the pulley 5 in the axial direction. 3 Pressure wave supercharger 4 Oxygen S degree in the exhaust gas on the upstream and downstream sides [
02]3 and [02]4, and at the same time, the fresh air atrium calculates the skewer ηsp. Then, in step S7, the fresh air vent is set to the difference η5p(n)−η5 between the current and previous rate ηsp.
I) Calculate (n-+>), and if the difference E is E>5 or E-5, that is, if the adiabatic efficiency of the pressure wave supercharger 4 can be expected to improve further, proceed to step S4 above. Go back and repeat roughly changing the pulley ratio by a predetermined value. Then, if the difference E falls within the range of -5≦E≦5 in step S7, the adiabatic efficiency of the pressure wave supercharging 1114 is It decides that the price has become high and ends the transaction.

Therefore, in the operation flow shown in FIG. 3 above, step S
+ , Sz , Ss , 86, the pressure wave supercharger 4 is activated based on the outputs of the first and second 02 sensors 20.21.
The fresh air blowing out from the intake passage 2 to the exhaust passage 3 via the air vent constitutes a spitting means 24 for calculating the skew ηsp.

Further, in step Sy, 84, the fresh air vent calculated by the skewer calculation means 23 is adjusted so that the difference E falls within the range of 15≦E≦5 according to the rate ηsp. 1. The control means 25 is configured to perform the following functions.

Therefore, in the above embodiment, the intake air in the intake passage 2 flows into the pressure wave supercharger 4, and is compressed and accelerated within the pressure wave supercharger 4 by receiving the pressure wave energy of the exhaust gas from the exhaust passage 3. After being discharged into the intake passage 2 on the downstream side of the pressure wave supercharger 4, the air is cooled to an appropriate temperature by the intercooler 23, and then sucked into the engine 1.

At this time, the exhaust gas that has transferred pressure wave energy to the intake air is scavenged by fresh air from the intake passage 2 on the upstream side of the pressure wave supercharger 4 to the exhaust passage 3 on the downstream side of the pressure wave supercharger 4. This new air venting rate ηsp is determined by various factors, such as ■ When the engine speed changes ■ When the engine load changes ■ The rotation speed of the pressure wave supercharger 4 relative to the engine speed ■ When the cooling efficiency of the supercharged intake air of the intercooler 23 changes depending on changes in vehicle speed or outside temperature ■ When the pressure loss increases due to smoke adhering to the inside of the intercooler 23, etc. When the flow resistance of the intake passage 2 on the downstream side of the pressure wave supercharger 4 changes due to ■ When the exhaust energy changes due to a change in the pressure and temperature r in the exhaust passage 3 on the upstream side of the pressure wave supercharger 4■ If smoke accumulates inside the pressure wave supercharger 4, etc., the fresh air blower will tend to change over time, but if the fresh air vent becomes higher by η5ptfi, the pressure wave supercharger Since the adiabatic efficiency of 4 also becomes ^, this fresh air vent has a skewer ηsp.When the calculation means 24 shuts out the air, the boost ratio of the belt transmission mechanism 7 is controlled in magnitude by the control means 25, and the engine The ratio of the rotational speed of the pressure wave supercharger 4 to the rotational speed is changed over time, and the fresh air blowing is performed at a rate ηsp.
is always controlled to be high, the adiabatic efficiency of the pressure wave supercharger 4 is maintained high, the supercharging capacity is improved, the engine output is improved, and the temperature rise of the pressure wave supercharger is suppressed to a small level. That will happen.

Here, the fresh air blowing rate ηsp to the exhaust passage 3 on the downstream side of the pressure wave supercharging 114 is determined by the changes in the actual running conditions from ■ to ■ in addition to the changes in engine speed and load in ■ and ■ above. Nevertheless, the rotational speed ratio of the pressure wave supercharger 4 is always maintained by the control means 25 as described in (1) above, so that the adiabatic efficiency of the pressure wave supercharger 4 can be controlled to maintain a high value with high precision. Therefore, it is possible to further improve the engine output, and it is also possible to reliably suppress the 1 degree rise in the pressure wave supercharger, thereby improving its reliability.

Moreover, the fresh air blowing in the pressure wave supercharger 4 can be controlled to keep the adiabatic efficiency at a high value, taking into account changes in actual driving conditions, by simply controlling the rate ηsp to maintain a high value, so the configuration can be simplified. can do.

In addition, the rate ηsp of the new air atrium usually has a variation range of 0 to 10.
Since it is as large as 0% or more, the control accuracy of the adiabatic efficiency of the pressure wave supercharging I14 can be increased. Moreover,
The first and second 02 sensors 20.21 are typically 200
Although it has the characteristic of operating normally only under high temperature conditions of ℃ or higher, since it is placed in the exhaust passage 3 which is a
There is little need for heating, and the detection refinement of the exhaust gas 111m is high. From the above, the control accuracy of the control to maintain a high value of the adiabatic efficiency of the pressure wave supercharger 4 is extremely high, and it is possible to further improve the engine output and the reliability of the pressure wave supercharger 4.

In the above embodiment, each of the first and second exhaust gas concentration detection means is composed of a 02 sensor, but it goes without saying that they may also be composed of other CO2 sensors.

(Effects of the Invention) As explained above, according to the pressure wave supercharged engine of the present invention, the pressure wave supercharger is controlled by variable control of the ratio of the rotation speed of the pressure wave supercharger to the engine rotation fault. The rate of fresh air blowing from the intake passage to the exhaust passage is maintained at a high rate and the adiabatic efficiency of the pressure wave supercharger is maintained at a high level. As a detection control that responds to changes in actual running conditions such as flow resistance in the intake and exhaust system, it is possible to stably increase the supercharging capacity of the pressure wave supercharger, and also to increase the temperature of the pressure wave supercharger. It is possible to effectively suppress the increase in pressure, thereby contributing to further improvement in engine output and reliability of the pressure wave supercharger.

Moreover, the rate of fresh air venting has a wide variation range, and the exhaust gas 1112 detection means can be operated normally without heating, so it is possible to improve the control accuracy of the adiabatic efficiency of the pressure wave supercharger. This can contribute more significantly to the improvement of the engine output and the reliability of the pressure wave supercharger.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall schematic diagram, FIG. 2 is an enlarged view of main parts showing the configuration around the pulley ratio control device, and FIG. 3 is an operation of the pulley ratio control device using vin*. FIG. 3 is a flowchart diagram showing control. 1... Engine, 2... Intake passage, 3... Exhaust passage, 4... Pressure wave supercharger, 5... Pulley, 5b...
- Movable flange, 6... V belt, 7... Belt transmission VJ mechanism, 10... Pulley ratio control device, 16... Stepping motor, 17... Rotation speed ratio variable means, 20
...first 02 sensor, 21...second 02 sensor, 22...computer, 23...intercooler, 24
...The atrium is the rate calculation means, 25...the control means.

Claims (1)

[Claims] (1) A pressure wave that is rotationally driven by the engine and is disposed astride the exhaust passage and intake passage of the engine, and supercharges the intake air by transmitting the pressure wave energy of the exhaust gas in the exhaust passage to the intake air in the intake passage. In an engine equipped with a supercharger, a rotation speed ratio variable means for changing the ratio of the rotation speed of the pressure wave supercharger to the rotation speed of the engine; and exhaust passages on the upstream side and downstream side of the pressure wave supercharger. first and second exhaust concentration detection means for respectively detecting exhaust concentration;
blow-through rate calculation means for calculating a fresh air blow-through rate of fresh air blowing through from the intake passage to the exhaust passage via the pressure wave supercharger based on the outputs of the both exhaust gas concentration detection means; An engine with a pressure wave supercharger, comprising: a control means for controlling the rotation speed ratio variable means according to the calculated fresh air blow-through rate.