JPH01170722A - Fuel injection equipment of rotary piston engine - Google Patents

Abstract

PURPOSE:To provide an optimum running property over the whole running region by opening a jet of a fuel injection nozzle opened on a slide surface of a side housing selectively to positions of an operating chamber in the intake stroke and a space section surrounded by a side seal or the like of rotor side. CONSTITUTION:A jet 26 of a fuel injection nozzle 12 is opened to the slide surface 3a of a side housing 3 at the intake port 10 forming side. The opening position of jet 26 is set to a position offset to the leading side in the rotational direction of rotor in an operating chamber 43 to which the intake port 10 is opened at the end of intake stroke. Also, when the operating chamber 43 to which the intake port 10 is opened is in the beginning of intake stroke, the jet 26 is set to open to a space section 45 surrounded by a side seal 6 and coiled seal 7. The fuel injection period is set to that when the jet 26 is adjacent the leading side portion of operating chamber 43 in the end of intake stroke within the service running region and to that when the jet 26 is adjacent the space section 45 within a specified running region.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection device for a rotary piston engine.

(Prior art) As a fuel injection device for a rotary piston engine, from the viewpoint of improving combustibility by stratifying the air-fuel mixture (stratified combustion) and improving fuel efficiency, for example, Japanese Patent Application Laid-Open No. 13010/1983 As disclosed, a fuel injection device using a direct injection method has been proposed in which the injection port of a fuel injection nozzle is opened on a side housing and fuel is directly injected into an operating chamber.

However, although such stratified combustion is effective in improving fuel efficiency in normal operating ranges, it is effective in improving fuel efficiency in operating ranges where high output is required, such as during high load or acceleration, or during warm-up or startup. In the operating range where atomization of the particles is required (in the following description, these operating ranges are collectively referred to as a specific operating range), this is not preferable for the following reasons. That is, under high load or acceleration, if stratified combustion is used, the combustion speed will decrease and sufficient output will not be obtained. Therefore, in an operating range where such high output is required, it is necessary to promote mixing of the air-fuel mixture to equalize the air-fuel mixture concentration and improve the combustion rate.

On the other hand, during warm-up or startup, fuel atomization is required to improve ignitability. However, when a direct injection type fuel injection device is adopted, the atomization (atomization) and vaporization of the fuel are insufficient due to the short distance the fuel travels between the time it is injected and the time it ignites. If this is not done properly, warm-up or starting performance will deteriorate as a result.

In a rotary piston engine equipped with a direct injection fuel injection device, it is difficult to obtain good combustion characteristics over a wide operating range that spans both the normal operating range and the specific operating range. Therefore, for example, in a rotary piston engine, in addition to a direct injection type fuel injection device, an intake manifold type fuel injection device that injects fuel into the intake manifold is installed side by side, and these two fuel injection devices are installed together. Techniques have also been proposed in which the engine is used differently depending on the operating condition of the engine. Specifically, the direct injection method is used in the normal driving range to improve fuel efficiency, and the intake manifold injection method is used in the specific driving range to homogenize the air-fuel mixture or atomize the fuel.

However, in this case, the structure of the fuel injection device becomes complicated, and a shock may occur when switching the injection method, or percolation may occur in the fuel supply system of the direct injection method during operation using the intake manifold injection method. There is a risk that new problems may occur.

(Object of the Invention) In view of the above-mentioned problems, the present invention provides a low-return piston engine equipped with a direct injection fuel injection system that can obtain optimal operating characteristics throughout the entire operating range with a simple configuration. It was done for that purpose.

(Technical Background of the Invention) In the process of researching a means to achieve the above object, the inventors of the present application found that by utilizing a structure unique to rotary piston engines, as described below, they were able to improve fuel efficiency and improve air-fuel mixture. The idea was to achieve equalization and atomization of the fuel. In other words, in a side port intake type rotary piston engine in which the intake port is opened on the sliding surface of the side housing, a substantially triangular rotor rotates planetarily around an eccentric shaft within the trochoidal inner peripheral surface of the engine casing. In this case, the intake port is formed by the inner peripheral surface of the trochoid of the rotor housing, the sliding surfaces of the pair of left and right side housings, a side seal provided on the side surface of the rotor, and two apex seals located at both ends of the side seal. A space surrounded by a working chamber, three side seals, three corner seals, an oil seal located on the rotor axis side, a sliding surface of the side housing, and a rotor land portion on the side surface of the rotor. Communicate alternately with each other. Therefore, the opening position of the fuel injection nozzle opening on the sliding surface of the rotor housing is set at a position where it can face the leading side position in the rotor rotational direction of the working chamber at the end of the intake stroke and the above-mentioned space. Then, the fuel is injected when the injection port faces the space. In this way, the fuel injected into the space is drawn into the intake port from the space when the space faces the intake port, and is transferred from the intake port toward the working chamber during the next intake stroke. We came up with the idea that this would lengthen the travel distance of the fuel from injection to ignition, promote atomization of the fuel, and improve the mixing effect between fuel and air. It is something.

(Means for Achieving the Object) The present invention is based on such a technical idea, and as a means for achieving the above object, an intake port and a fuel injection nozzle nozzle are provided on the sliding surface of the side housing. In a rotary piston engine, the nozzle of the fuel injection nozzle is connected to the working chamber which is in the intake stroke as the rotor rotates, the sliding surface of the side housing, the side surface of the rotor, and the outer periphery of the side surface of the rotor. It opens at a position where it can selectively face the space surrounded by the side seal provided in the inner circumferential portion and the oil seal provided in the inner peripheral portion,
In the normal operating range of the engine, the nozzle of the fuel injection nozzle faces the leading side of the working chamber in the rotor rotational direction at the end of the intake stroke, and in the specific operating range, the nozzle faces the space. The fuel injection timing is set so that fuel injection is performed at each of the following times.

(Function) In the present invention, by the above means, (1) In the normal operating range of the engine, fuel is injected into the leading side portion of the working chamber in the rotor rotational direction at the end of the intake stroke; (2) In specific operating ranges of the engine, fuel is injected into a space separated from the intake port through the side seal. is drawn into the intake passage through the intake port when it faces the space as the rotor rotates, and then is drawn into the intake passage when the intake port faces the following working chamber in the next intake stroke. Since fuel is drawn into the working chamber from the intake port along with air, (a) During high load or acceleration when particularly high output is required within a specific operating range, fuel is drawn into the working chamber together with air. Mixing of air and fuel in the room is promoted, increasing the combustion rate and increasing the output of the engine. (b) During warm-up or startup when the ignitability of the air-fuel mixture is particularly required within a specific operating range. In some cases, the atomization (atomization) of the fuel is promoted because the fuel travels a long distance between injection and ignition.
In addition, since it comes into contact with high temperature parts such as the rotor land portion for a long period of time, its vaporization is promoted, thereby improving the ignitability of the air-fuel mixture.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 5.

(a: Configuration) FIG. 1 shows an intake/exhaust system diagram of a rotary piston engine l equipped with a fuel injection device according to an embodiment of the present invention. 2a is a rotor housing, 3 is a side housing that closes both sides of the rotor housing 2, 4 is an eccentric shaft provided passing through the side housing 3,
A substantially triangular rotor 5 is attached to the eccentric shaft 4. This rotor 5 has an apex seal 8 and a corner seal 9 attached to each of its three top parts, while arcuate side seals 6, 6, 6, 6, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, , , , ,, , , , , , , 6, also
Annular oil seals 7 are respectively attached to the radially inner portions of the rotor land portions 5a.

This rotor 5 has three apex seals 8.8.
8 is the trochoid inner peripheral surface 2 of the rotor housing 2, respectively.
By planetary rotation around the eccentric shaft 4 while in sliding contact with a, three working chambers 41, 42, 43 partitioned in the rotational direction by respective apex seals 8, 8.8 are formed around it, and Sliding surface 3 of left and right side housing 3
a, 3 Rotor land portion 5 of both a and rotor 5
A flat cavity-like space 45.45 surrounded by each side seal 6 and oil seal 7 is formed between the side seals 6 and 5a.

Further, an intake port 10 is opened in the sliding surface 3a of the side housing 3. In addition, a surge tank 14 is provided in the intake passage 13 connected to the outer end of the intake port IO.
is formed, and a throttle valve 15 and an air flow meter 1 are installed on the intake upstream side of the surge tank 14.
6 and an air cleaner 17 are provided in this order.

Further, on the sliding surface 3a of the site nozzle 1 housing 3 on the side where this intake port IO is formed, there is a nozzle 2 facing the fuel injection nozzle 12.
6 is open. The opening position of the nozzle 26 is set as follows by applying the present invention. That is, as shown in FIG. 2, at the end of the intake stroke just before the intake port 10 is closed by the rotor 5, the intake port 1
0 faces the working chamber 43, and when the working chamber 43 facing the intake port 10 is in the early stage of the intake stroke as shown in FIGS. The opening position of the nozzle 26 is set relative to the rotor 5 so that it is open.

The fuel injection nozzle 12 is connected to the fuel tank 30 via a fuel supply pipe 31 including a fuel pump 34 and a fuel filter 35, and a fuel return pipe 32 including a pressure regulator 37.

On the other hand, the rotor housing 2 has a trochoid inner peripheral surface 2a.
An exhaust port 11 is provided which opens to the exhaust port 11, and an exhaust passage 18 equipped with an exhaust purification device 19 is connected to the exhaust port 11.

Furthermore, two spark plugs 27 are provided on the side wall of the rotor housing 2 on the side facing the exhaust port 11.

Further, in this fuel injection system, the fuel injection amount and fuel injection timing are each controlled by an electronic control unit 20, and for this purpose, in addition to the air flow meter 16, a throttle opening sensor 21 and a water temperature sensor 22 are installed. 02
A sensor 23, a rotation angle sensor 24, and a rotation speed sensor 25 are provided.

(b: Operation explanation) Next, the operation and effect of this fuel injection device will be explained, but for the convenience of explanation, this will first be explained from the hardware aspect of fuel injection timing control with reference to FIGS. 1 to 4. Then, this will be explained from a software perspective with reference to FIG. Note that the control of the fuel injection amount is not the gist of the present invention and is based on a conventionally known control method, so a description thereof will be omitted.

The fuel injection device of this embodiment has the characteristics of a direct injection type fuel injection device, which is originally adopted with a focus on improving fuel efficiency through stratified combustion, and an intake manifold injection type fuel injection device, which is originally adopted with a focus on increasing output. This improves fuel efficiency through stratified combustion in the normal operating range, while
In a specific operating range, the system promotes homogenization of the air-fuel mixture or atomization of fuel, thereby increasing engine output and improving startability. This will be explained in detail below with reference to the drawings.

As the engine operates, the rotor 5 changes from Fig. 1 to Fig. 2-3.
Move in the order of Figure-4. And each working chamber 41, 4
2.43 faces the intake port IO until communication with the intake port 10 is cut off, the intake port 10
Air is introduced into the working chamber and fuel is sequentially supplied. In this case, in this embodiment, by controlling the fuel injection timing, the fuel injection method is actually changed to a direct injection method even though the fuel injection device is a direct injection method in terms of its form. It is possible to arbitrarily change between the intake manifold injection method and the intake manifold injection method.

That is, in the normal operating range where improvement in fuel efficiency is required, when the nozzle 26 opens toward the leading side in the rotor rotational direction of the working chamber 41 at the end of the intake stroke, as shown in FIG. Directly through the working chamber 4
Carry out fuel injection within 1 hour. In this case, a rich air-fuel mixture layer is locally formed in a part of the working chamber 41 at the end of the intake stroke (stratification of the air-fuel mixture). Therefore, by igniting this rich mixture vaporized layer, even if the mixture as a whole is lean, the mixture can be effectively combusted (stratified combustion), and the fuel efficiency is improved accordingly.

On the other hand, in a specific operating range, as shown in FIGS. 1 and 4, when the nozzle 26 faces the space 45, the fuel injection nozzle 1
Fuel injection starts from step 2. Then, this space 45
When the rotor 5 rotates further and the space 45 faces the intake port 10 (the state shown in FIG. 3)
, the intake passage 1 passes from the space 45 through the intake port 10.
After flowing out to the 3 side, when this intake port IO again faces the working chamber 43 in the subsequent intake stroke as shown in FIG. Ru. That is, in this case, the fuel injection nozzle 12
The fuel injected from the space 45 is not directly injected into the working chamber, but flows through the space 45 into the intake passage 13 side through the intake port 10, and then travels through a relatively long path, reaching the working chamber side. Mixing of fuel and air and atomization of fuel (from where it is sucked into the working chamber together with air)
In addition, since the period during which the fuel is in contact with high-temperature members such as the rotor 5 is long, the heat promotes its vaporization, thereby increasing the combustion rate or improving the ignitability. Therefore, it is possible to increase the output of the engine during high load or acceleration, improve startability during starting, and promote warm-up during warm-up.

In this way, in the fuel injection system of this embodiment, by controlling the injection timing according to the operating conditions of the engine (regular operating range and specific operating range), the injection timing is optimized for each operating state throughout the entire operating range of the engine. This makes it easy to obtain excellent driving characteristics.

Next, the injection timing control system in the fuel injection device of this embodiment will be explained with reference to the control flowchart shown in FIG.

First, after starting the control, the engine speed, intake air amount,
Detect the engine cooling water temperature (step S,
). Based on these detected values, it is determined whether the current operating range is a regular operating range or a specific operating range. That is, if the engine speed is below a predetermined value, it is determined that the engine is starting (step S)), and if the water temperature is below a predetermined water temperature t°C, it is determined that the engine is warming up (step S3), and the intake air amount is If the change in the throttle opening is greater than a predetermined value, it is determined that the vehicle is under high load (Step S), and if the change in throttle opening is greater than a predetermined value, it is determined that the vehicle is accelerating (Step SS). At times (i.e., specific operating range), the fuel injection amount and injection timing are selected from values set corresponding to the specific operating range, and at other times (i.e., regular operating range), the fuel injection amount and injection timing are selected from the values set corresponding to the specific operating range. Select the injection timing to a value set corresponding to the normal operating range.

First, as a result of the determination in Steps St to Step S5, if it is determined that the current state is in the regular operation range, the flow from Step S to Step S is executed. That is, first, in step S, the injection pulse width (i.e., fuel injection amount) in the normal operating range is calculated, and the process waits until the injection timing in the normal operating range is reached (step S,
). Then, when the injection timing in the regular operating range is reached, it is determined whether this is the first time the specific operating range has been shifted to the regular operating range, or whether the specific operating range has already been shifted to the regular operating range from the previous time (step S
,).

The judgment in this step is necessary for the following reasons. That is, in a specific operating range, fuel is injected into the space, whereas in a regular operating range, fuel is injected directly into the operating chamber. The fuel injected into the space is then sucked into the working chamber in the next intake stroke. Therefore, when combustion is injected into the working chamber at the injection timing in the first regular operating range when the specific operating range shifts to the regular operating range for the first time, in addition to this fuel in the working chamber, there is also fuel from the previous specific operating range. The fuel injected into the space is sucked together with air through the intake port 10, resulting in an excessively rich mixture and poor combustibility.

Therefore, when moving from the specific operating range to the regular operating range for the first time, it is necessary to cancel the injection at the first injection timing in the regular operating range to maintain the mixture concentration appropriately.

For this reason, as a result of the determination in step S, if it is the first time since the transition from the specific operating range to the regular operating range, fuel injection will not be performed, and only if it is not the first time, the fuel injection will be performed at the injection timing in the regular operating range. Fuel injection is performed (step S9).

On the other hand, as a result of the determinations in steps S and -S, if it is determined that the current operation is in the specific operating range, control proceeds to step S1° and subsequent steps. That is, first, an injection pulse (injection amount) is selected from values set corresponding to a specific operating range (step S1°).

Next, contrary to step S8 above, it is determined whether the regular operating range has shifted to the specific operating range for the first time, or whether the specific operating range has already been shifted from before the previous time (step S, . . . ). The judgment in step 11 is necessary for the following reasons. That is, the fuel injected at the injection timing in the specific operating range is sucked into the working chamber in the next intake stroke. Therefore, if fuel injection is performed at the injection timing in the specific operating range from the first time after changing from the normal operating range to the specific operating range, there will be no fuel in the working chamber that will undergo the first intake stroke after the shift to the operating range. It will not be supplied. In order to prevent the occurrence of such a working chamber where fuel is not supplied, it is necessary to perform normal operation at the same time as fuel injection at the injection timing in the specific operating area only once after the transition from the normal operating area to the specific operating area. Therefore, it becomes necessary to perform fuel injection at injection timing within the range.

For this reason, first, as a result of the determination in step S11, if it is the first time since the normal operating range has been shifted to the specific operating range, first, the injection pulse width corresponding to the normal operating range is calculated in step S1. ), and sets flag a to 1 (step S1.). First, when the injection timing in the specific operating range has come (step 8.4), an amount of fuel corresponding to the specific operating range is injected into the space (step S1), and at the same time, the injection timing in the normal operating range is injected. When the timing is reached (step S7), an amount of fuel corresponding to the normal operating range is injected into the operating chamber (step S,
).

Furthermore, if it is the second time or later after changing from the regular operating range to the specific operating range, since flag a is cleared (step 517), only combustion injection is performed at the injection timing in the specific operating range.

(Effects of the Invention) The present invention provides a rotary piston engine in which an intake port and a fuel injection nozzle opening are respectively opened on the sliding surface of a side housing. and a space surrounded by the side housing sliding surface, the rotor side surface, a side seal provided on the outer periphery of the rotor side surface, and an oil seal provided on the inner periphery of the rotor side surface. In addition, in the normal operating range of the engine, the nozzle of the fuel injection nozzle faces the leading side of the working chamber in the rotor rotational direction at the end of the intake stroke, and in the specific operating range, the The present invention is characterized in that the fuel injection timing is set so that the fuel injection is performed at the time when the nozzle port faces the space. Therefore, according to the fuel injection device for a rotary piston engine of the present invention, fuel efficiency is improved by stratified combustion in the normal operating range, and fuel efficiency is improved in the specific operating range by promoting homogenization of the air-fuel mixture or atomization of the fuel. Although it is a direct injection type combustion injection device with a simple structure, it has the effect of providing optimal operating characteristics for each operating condition throughout the entire operating range of the engine, such as improved output, warm-up performance, and startability. There is.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of the intake/exhaust system of a rotary piston engine equipped with a fuel injection device according to an embodiment of the present invention;
4 through 4 are state change diagrams of the rotary piston engine shown in FIG. 1, and FIG. 5 is a control flowchart of the fuel injection device shown in FIG. 1. l...Fist...Rotary piston engine 2...Rotor housing 3...Side housing 4...Eccentric shaft 5...Rotor 6...Side seal 7. ... Oil seal 8 ... Apex seal 9 ... Corner seal 10 ... Intake port 11 ... Exhaust port 12 ... Fuel injection nozzle 13 ... Intake Passage 14... Surge tank 15... Throttle valve 16... Air flow meter 17... Air cleaner 20... Electronic control unit 21... Throttle opening sensor 22... Water temperature sensor 23...0! Sensor 26... Nozzle 27... Spark plugs 41 to 43... Working chamber 45... Space part

Claims (1)

[Claims] 1. In a rotary piston engine in which an intake port and a fuel injection nozzle nozzle are respectively opened on the sliding surface of a side housing, the fuel injection nozzle nozzle is located in a working chamber in which the intake stroke is performed as the rotor rotates. and an opening at a position that can selectively face the space surrounded by the side housing sliding surface, the rotor side surface, the side seal provided on the outer periphery of the rotor side surface, and the oil seal provided on the inner periphery. In addition, in the normal operating range of the engine, the injection port of the fuel injection nozzle faces the leading side of the rotor rotation direction of the working chamber at the end of the intake stroke, and in the specific operating range, the injection port faces the space. 1. A fuel injection device for a rotary piston engine, characterized in that fuel injection timing is set so that fuel injection is performed at each point in time.