JPH01237320A - Auxiliary air feeder for rotary piston engine - Google Patents

Abstract

PURPOSE:To improve exhaust air characteristics, in an air feeder for preventing exhaust gas from getting into an intake air operation chamber with replacement air supplied into an exhaust air operation chamber at the time of idling operation, by introducing air into an exhaust air port when a water temperature is low in an idling operation range. CONSTITUTION:An air control device 40 provided with the first/-second changeover valves 37, 38 operated by intake air negative pressure, is provided on the passage 36 of pressurized air ejected from an air pump 34 driven by an engine. In addition it is selected by the first changeover valve 37 whether pressurized air is supplied to a scavenging port 31 through a passage 45, or supplied to the second changeover valve 38 side. On the other hand, it is selected by the second changeover valve 38 whether the pressurized air is supplied to the air port 33 opening to an exhaust air port 16 through a passage 46, or supplied to the air port 33 inside a catalyst converter 19 through a passage 47. When water temperature is low in an idling operation range, each of valves 37, 38 is changeover-controlled so as to supply pressurized air into the air port 33.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an auxiliary air supply device for a rotary piston engine equipped with a rotor that performs planetary rotation within a housing having a trochoidal inner peripheral surface.

(Prior Art) Conventionally, in a low-return piston engine, especially in the idle operating range and light load range where the intake pressure is negative, a relatively large amount of exhaust gas is brought into the intake operating chamber due to the overlap of intake and exhaust, and this exhaust gas ( Since the air-fuel mixture is diluted by the guillion gas, there is a problem that ignition errors occur and combustion becomes unstable.As a countermeasure, extra fuel is supplied, which improves fuel efficiency in the idling range and light load range. There were drawbacks that worsened the

Therefore, conventionally, as disclosed in JP-A-59-18233, for example, a scavenging port that opens on the leading side of the exhaust port and the trailing side of the intake port is formed in the housing, and the exhaust air is exhausted from this scavenging port. By supplying air into the working chamber, the exhaust gas in the exhaust working chamber is replaced with fresh air, preventing exhaust gas from entering the intake working chamber, stabilizing combustion, and improving fuel efficiency. However, if displacement air is supplied from the scavenging port in a light load region, internal EGR
Since the amount of nitrogen oxides decreases and the amount of nitrogen oxides increases, the supply of the replacement air is limited to the idle operation region.

However, due to the supply of displacement air from the exhaust port, if combustion is completed in a short time and the so-called engine water temperature is low, the exhaust gas temperature decreases and HC in the exhaust gas
(hydrocarbons), which not only worsened the emission characteristics but also caused problems in that it took a long time to warm up.

(Objective of the Invention) Therefore, an object of the present invention is to provide an auxiliary air supply device for a rotary piston engine that improves emission characteristics and warm-up performance at low water temperatures.

(Structure of the Invention) The present invention provides a rotary piston engine configured to supply replacement air through a first air supply passage into an exhaust operation chamber in an idle operating region to replace dilution gas with fresh air. A second air supply passage that opens into the exhaust port is provided, and when the engine water temperature is below a predetermined value in the idling operation region, the first air supply passage is provided.
A switching means is provided for stopping the supply of replacement air to the second air supply passage and instead switching the supply of air from the replacement air supply source to the second air supply passage.

(Effects of the Invention) In the present invention, by stopping the supply of replacement air from the first air supply passage when the water temperature is low, aftergrowth occurs and the temperature of the exhaust gas increases. Therefore, it is possible to improve emission characteristics and warm-up performance.

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

In Fig. 1, reference numeral 1 denotes the main body of a rotary piston engine, and the casing of the engine main body 1 consists of a rotor housing 2 having a trochoid inner circumferential surface 2a, and a pair of side housings 3 (one side housing is not shown in the drawing). The rotor 4 is housed in such a casing and performs planetary rotational motion.

Between the casing and the rotor 4 there are three working chambers 5.6.
7 is defined. The volumes of these three working chambers 5,6,7 change sequentially as the rotor 4 slides against the inner circumferential surface 2a of the rotor housing 2 and makes planetary rotational movement in the clockwise direction in the figure. It goes through the intake, compression, explosive expansion, and exhaust strokes, and in Fig. 1, the working chamber 5 is in the intake stroke, the working chamber 6 is in the final state of the compression stroke, and the working chamber 7 is in the exhaust stroke. Indicates a case in progress.

An intake port 8 is formed in the side housing 3,
In the intake passage 9 on the upstream side of the intake port 8, a fuel injector 10, a throttle valve 11, an intercooler 12, a turbocharger compressor 13, and an air flow meter 14 are arranged in order from the intake port 8 side, and an air cleaner 15 is installed. It has been reached. Further, an exhaust port 16 is formed in the rotor housing 2 on the trailing side of the intake port 8, and an 02 sensor 18 and a catalyst converter 19 for exhaust purification are arranged in an exhaust passage 17 downstream of the exhaust port 16. There is. Further, a turbine for driving a turbocharger is disposed in the exhaust passage 17, but this turbine is omitted in FIG. 1.

The fuel injector 10 includes a fuel tank 20
Fuel is supplied from the engine via a fuel pump 21 and a fuel filter 22. The pressure of fuel supplied to the fuel injector 10 is regulated by a pressure regulator 23. 24 is a water temperature sensor, 25 is a throttle opening sensor that detects the opening of the throttle valve 11, 26 is a pressure sensor that detects negative pressure in the intake passage 8 on the downstream side of the throttle valve 11, and 27 is a sensor that detects the engine rotation speed. These sensors, the 02 sensor 18 and the flow meter 14
Based on the signal output from the control device 28, the control device 28 outputs a fuel injection pulse to the fuel injector 10. The control device 28 also sends a signal to the igniter coil 29 to control the ignition timing of the spark plug 30.

On the other hand, the rotor housing 2 is formed with a scavenging port 31 that opens into the working chamber 7 on the leading side of the exhaust port 16 and the trailing side of the intake port 8, and further includes an air port 32 that opens into the exhaust port 16. An air port 33 that opens into the catalytic converter 19 is provided to supply air to the catalyst to enhance its exhaust gas purification function. Reference numeral 34 denotes an air pump that sucks and pressurizes air from the intake passage 9 through the air passage 49. This air pump 34 is driven by the engine via an electromagnetic clutch 35 that is controlled on and off by the control device 28. There is. In the passage 36 of the pressurized air discharged from the air pump 34, first and second switching valves 37 and 38 each operated by the negative pressure in the intake passage 9 are provided.
Each of the switching valves 37 and 38 is provided with a negative pressure passage 41 connected to the intake passage 9.
．． Negative pressure for driving the switching valves is supplied from 42 through solenoid valves 43 and 44, respectively. The solenoid valves 43, 44 are controlled by a control device 28. Assist air is supplied to the fuel injector 10 from the intake passage 9 on the upstream side of the throttle valve 11 through the air passage 39.
A solenoid valve (not shown) operated by the control device 28 is also provided in the middle of the air passage 39, so that the air passage 39 is closed when replacement air is supplied from the scavenging port 31.

The first switching valve 37 allows pressurized air supplied from the air pump 34 to pass through the air supply passage 45 to the scavenging port 31.
supply as displacement air to the air port 32 or
It is a switching valve that selects whether to supply it to Further, the second switching valve 38 is provided on the downstream side of the first switching valve 37, and supplies pressurized air to the air port 32 in the exhaust port 16 through the air supply passage 46 as port air, or This is a switching valve that selects whether to supply sprint air to the air port 33 in the catalytic converter 19 through the air supply passage 47.

Note that an air pump 3 is provided in the air supply passages 45 to 47.
A check valve 48 is provided for preventing backflow of exhaust gas when the engine 4 is stopped.

In addition, in the configuration shown in FIG. 1, the air flow meter 14
Air is supplied to the air pump 34 through the air passage 49 from the intake passage 9 downstream of the compressor 13 of the turbocharger and upstream of the compressor 13 of the turbocharger. is directly transmitted to the air flow meter 14, and the air flow meter 14
As a result, air-fuel ratio control may become inaccurate and combustion may become unstable. If there is such a possibility, as indicated by the broken line 49' in FIG.
By providing an air outlet for the air pump 34 in the intake passage 9 on the downstream side of the compressor 13 of the turbocharger and on the upstream side of the ink cooler 12, the compressor 13
becomes an interference wall, and the pulsation of the suction air of the air pump 34 is not transmitted to the air flow meter 14, and the air flow meter 1
4 variations can be prevented. In addition, by supplying air to the air pump 34 from the downstream side of the compressor 13, the pressure on the downstream side of the compressor 13 decreases, and the impeller rotation speed of the turbocharger increases by that amount, improving the responsiveness of the turbocharger during acceleration. It also has the effect of improving.

Furthermore, in the configuration shown in FIG. 1, the first switching valve 37 for supplying replacement air to the scavenging port 31 is provided upstream of the second switching valve 38; This is because it is advantageous to supply replacement air, which has a large effect on idle stability and has the largest air flow rate, with as little passage resistance as possible. The split air supply passage with the lowest flow rate is located on the most downstream side.

The above is the configuration of one embodiment of the auxiliary air supply device for a rotary piston engine according to the present invention. In such a configuration, the control device 28 controls the solenoid valves 43 and 44 in the manner shown in FIG. Scavenging port 3
1 and air ports 32 and 33.

Below, regarding the flowchart in Figure 2, Figures 3 and 4 will be explained.
This will be explained with reference to the map shown in the figure. In addition, Figure 3 shows
Showing the air supply state to the air ports 31 to 33 in each operating range when the engine water temperature is higher than 50°C,
FIG. 4 shows the state of air supply to the airport ports 31 and 32 when the engine water temperature is below 50° C., that is, in a semi-warmed-up state before completion of warm-up.

In FIG. 2, first, in steps 31 to S4, the engine water temperature THW from the water temperature sensor 24, the throttle opening TVO from the throttle opening sensor 25, the intake pipe internal pressure P from the pressure sensor 26, and the engine rotation from the crank angle sensor 27. Enter the number Ne and proceed to step S.
5, engine speed Ne and throttle opening TVO
A deceleration line D3 is set. Next, in step S6, the engine water temperature THW is read, and in step S7, it is determined whether the engine water temperature THW is higher than 50°C.

If the determination in step S7 is rYEsJ, the throttle opening T V○, engine speed Ne, and intake pipe pressure P are read in steps 88 to SIO, and the engine speed Ne is set to a predetermined value (iRl (lower than 10100Qrp, for example). In the next step S12, it is determined whether the throttle opening degree TVO is smaller than a predetermined value TVOI.If the determinations in steps Sll and 312 are both rYEsj, the process advances to steps S13 and S14. , the solenoid valve 43 is turned ON to guide pressurized air to the air supply passage 45 and supply displacement air to the scavenging port 31. (idle operation region A in Fig. 3) 6 On the other hand, the determination in step Sll is "NO". In this case, it is determined in step S15 whether or not the deceleration line is below D3, and if the determination in step 515 is rYEsJ, the process proceeds to steps S16 and S17, and the solenoid valve 44 is turned to O.
Pressurized air is introduced into the air supply passage 46 to supply port air to the air port 32 (fuel cartridge area and light load area B in FIG. 3).

If the determination in step 515 is rNOJ, step S1
8, the intake pipe internal pressure P reaches a predetermined value P1 (for example, -10
0 mHg), and further in the next step S19, the engine rotation speed Ne is lower than a predetermined value R2 (for example, 3
500 rpm), and step S1
8. When the determinations in S19 are both rYEsJ, proceed to steps S20 and S21 and turn off the solenoid valve 44.
Pressurized air is guided to the air supply passage 47, and sprint air is supplied to the air port 33 (feedback area C in FIG. 3). If the determination in step 318 is "NO", the process proceeds to steps S22 and S23, where the air pump electromagnetic clutch 35 is turned off to perform air cutting (area D in FIG. 3).

Step 32 also when the determination in step S19 is "NO"
2. Proceed to S23 and cut the air (area E in Figure 3)
.

On the other hand, if the determination in step 312 is 1NO, the process advances to step S24, where it is determined whether or not the intake pipe internal pressure P is lower than the predetermined value P1.If this determination is rYESJ, the process advances to step S16, where the next In step S17, port air is supplied to the air port 32 (area F in FIG. 3). If the determination in step S24 is rNOJ, the process moves to step S22 and air cut is performed (area G in FIG. 3).
).

The above flow is for a case where the engine water temperature T)IW is higher than 50° C., and displacement air is supplied from the scavenging port 31 only in the idle operation region A to improve fuel efficiency.

Next, a description will be given of the flow when the determination in step S7 is 1NO, that is, in a semi-warmed state where the engine water temperature THW is 50° C. or less. In this case, step S2
5. In S26, the engine speed Ne and the intake pipe internal pressure P are read, and in step S27 it is determined whether the intake pipe internal pressure P is lower than a predetermined value P1.
If NO, the process proceeds to steps S22 and S23 to perform air cutting (areas A and G in FIG. 4).

Further, when the determination in step S27 is rYEsJ, the process advances to the next step S28 and the engine rotation speed Ne is set to the predetermined value R2.
If the determination is rYEsJ, the process proceeds to steps S16 and S17, and the airport 32
Supply port air to (areas A, B-1, and C in Figure 4)
and F). - On the other hand, when the determination in step 32B is rNOJ, the process advances to step S29 to determine whether the deceleration line is below D3, and when this determination is rYEsj, the process advances to steps S16 and S17 to set the port air to the airport 32. (area B-2 in FIG. 4).

Further, when the determination in step S29 is "NO", the process proceeds to step S22 and air cut is performed (area E in FIG. 4).
).

The above flow is for a case where the engine water temperature THW is in a semi-warmed up state of 50° C. or less, and the supply of replacement air through the air supply passage 45 in the idle operation region A is stopped, and instead, the supply of displacement air is passed through the air supply passage 46 to the air port 32. It is designed to supply port air to the

Then, by stopping the supply of the replacement air, afterburn occurs in the idling operation region and the temperature of the exhaust gas increases, so that it is possible to improve the emission characteristics and the warm-up performance.

FIG. 5 is a logic port showing conditions for supplying replacement air from the scavenging port 31.

Although omitted in the above explanation, one of the air pumps 34
Since the next air is taken out from the downstream side of the air flow meter 14, it is necessary to correct the measured value of the air flow meter 14 when the air pump 34 is activated. When supplying replacement air, the entire amount of air passing through the air pump 34 is supplied to the scavenging port 31, so the fuel injection amount of the fuel injector 10 may be increased by a predetermined amount. However, since relief passages are provided in the port air and split air passages, and a portion of the air passing through the air pump 34 is supplied, it is necessary to measure the amount of air, especially for the port air. For this reason, although not shown in FIG. 1, an orifice is actually provided downstream of the switching valve 37 and upstream of the check valve 48 in the port air passage, and a differential pressure sensor is used to locate the orifice upstream of the orifice. The flow rate of port air is detected by measuring the pressure difference between the air flow meter 14 and the downstream side, and this air flow rate is subtracted from the measured value of the air flow meter 14 to control the air-fuel ratio. Regarding the supply of split air in the feedback area, the amount of air required is small, so
A preset amount is corrected using a map of engine speed Ne and throttle opening TVO.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic overall configuration diagram of a rotary piston engine equipped with an auxiliary air supply device according to the present invention, FIG. 2 is a flowchart of control executed by the control device, FIG. FIG. 4 is a map showing the auxiliary air supply state in each operating range when the engine water temperature is high and low, respectively, and FIG. 5 is a logic diagram showing the supply conditions of 1-comer air. 1 - Engine body 2 - Rotor housing, 8 - Intake port 9 - Intake passage 11 - Throttle valve 12 - Intercooler 13 - Turbocharger compressor 14 - Air flow meter 16 - Exhaust port 19 - Catalyst converter 24 - Water temperature sensor 25 - Throttle Opening sensor 26 - Pressure sensor 27 - Crank angle sensor 31 - Scavenging port 32. 33 - Air port 34 - Air pump 35 - Electromagnetic clutches 37 to 39 - Switching valve
40-Air control device 43.44-Solenoid valve

Claims (1)

[Claims] A rotor that performs planetary rotation within a housing having a trochoidal inner circumferential surface is provided, and a first air supply passage that opens on the leading side of the exhaust port and on the trailing side of the intake port is provided in the housing. In the rotary piston engine, the exhaust port is configured such that displacement air is supplied into the exhaust working chamber through the first air supply passage in the idle operating region to prevent exhaust gas from being brought into the intake working chamber. A second air supply passage is provided that opens inward, and when the engine water temperature is below a predetermined value in the idle operating region, the supply of the displacement air to the first air supply passage is stopped, and the displacement air is supplied instead. An auxiliary air supply device for a rotary piston engine, comprising a switching means for switching to guide air from the supply source to the second air supply passage.