JPS5874846A - Controlling method of internal-combustion engine - Google Patents

Abstract

PURPOSE:To increase air-fuel ratios, allow an internal-combustion engine to drive close to lean side and raise the efficiency of combustion and the cost effectiveness by driving the internal-combustion engine on the basis of set driving conditions meeting the humidity detection signal of intake air by a humidity sensor. CONSTITUTION:The relative humidity of intake air A coming into the air inlet path 2 of an engine 1 is detected by a humidity sensor 3, and a humidity signal S corresponding to the relative humidity is sent to a control unit 6 from which a control signal I for making it suitable to the set driving conditions corresponding to each humidity signal S is sent to a driving condition sensor 5. By this, larger timing control amount of ignition time can be kept within a range that no knocking occurs in engine 1 and the engine 1 can be controlled all the time with an optimum value at which the air-fuel ratios can be reduced. As said driving condition setter 5, distributor, fuel injector, etc., may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine drive control method for driving an internal combustion engine under conditions that match the humidity of outside air.

Until now, the influence of the humidity of intake gas on the performance of internal combustion engines, such as gasoline engines (hereinafter simply referred to as engines), has not been empirically known to some extent, and there has also been no correlation between the required octane number of fuel and relative humidity. Recognized.

By the way, lower fuel consumption is required as one aspect of engine performance.

This reduction in fuel efficiency requires the engine to be used frequently in a high load range, requires high torque, and requires a high engine compression ratio, making it necessary to control engine drive more strictly than before. . In this case, it is necessary to use various sensors to detect whether or not the engine is being driven properly, and to control the engine under the driving conditions that are most suitable for low fuel consumption under each situation. For this reason, various sensors detect the rotation speed, atmospheric pressure, load level, air-fuel ratio, cooling water temperature, etc. of the conventional i engine, and drive conditions that are suitable for each situation are determined.
For example, the ignition timing and fuel flow rate are controlled to set values to cause combustion within the cylinder. However, in order to further improve fuel efficiency, it is necessary to increase the amount of advance of each ignition timing within a range that does not cause non-king, or to further reduce the fuel flow rate. It is necessary to rigorously detect such situations and set more rational driving conditions.

Here, we will discuss the limits of use of conventionally used means for detecting knocking using a knock sensor VC to ensure normal combustion within the cylinder. This knock sensor is a device that detects knock and retards the ignition timing based on a stiff signal, but if this is used to rapidly and significantly retard the ignition timing from a certain operating state, it will cause a sudden drop in output.

When a knock sensor is used for such reasons in terms of driving feeling, it becomes necessary to perform angle retard control for each minute angle.

In addition, even for knock sensors in systems that perform retard control proportional to the knock intensity, a delay circuit is sometimes installed to prevent large retards during activation due to noise. It takes time to return to a state where there is no knocking.

For this reason, once a knock occurs, it lasts a long time.

There is a risk of causing noise and engine damage.

Therefore, the inventor of the present invention focused on the relative humidity of the intake gas when setting the driving conditions for the enflation, and conducted the following experiment.

First, the influence of the humidity of the intake gas on the knock limit is
The experiment was carried out using a 1600 cc engine.

This engine has a compression ratio of (10,1:1).

A two-el injector is used for each cylinder to adjust the air-fuel ratio (
A/F=12) and was driven with the throttle fully open. As a result, Figure 1 (a), (b), (c
).

As shown in (b), overall, the relative humidity has a linear relationship with the knock limit ignition timing over almost the entire engine speed range, and it is possible to advance the knock limit ignition timing by increasing the relative humidity. found. In addition,
Among the measured values recorded in the diagram for each rotation speed, the (Δ, ○, ◇) 0) marks indicate the outside temperature of 100.
, 20°C, and 30°C.

Next, using the same engine used in the experiment described above,
The influence of air-fuel ratio on knock limit was investigated. in this case,
The outside air conditions for adults are temperature 20±0.5℃ and humidity 60±
It was set at 5 yen. Then, with the throttle fully open, we measured the knock limit ignition timing when changing the air-fuel ratio using the engine speed as a parameter. As a result, as shown in Fig. 2.

As the value became lower than the stoichiometric air-fuel ratio (14.5 in A/F), the knock limit ignition timing increased in advance, and the kneading showed a similar tendency at each rotation speed.

In this way, based on the results not obtained in Figures 1 and 2, the air-fuel ratio (A/F) is used as a parameter and the knock limit ignition timing is estimated when the relative humidity is changed. You can create the line diagram shown in the figure. That is, in the two experiments mentioned above, engine 7 was the most likely to cause knocking. Looking at the results in Figure 3 with reference to the high load range of 1500 rpm, it is possible to keep the knock limit ignition timing constant by adjusting the air-fuel ratio or relative humidity. Furthermore, by adjusting the air-fuel ratio or ignition timing, it is possible to drive the engine without knocking at various relative humidity levels.

The above experiment shows that if the ignition timing is controlled to always advance close to the knock limit ignition timing in response to the relative humidity of the outside air, the engine's output can always be extracted in the most reasonable way, resulting in improved fuel efficiency. It is assumed that it can be measured. Furthermore, when the air-fuel ratio is increased in order to improve fuel efficiency, the knock limit ignition timing is retarded and knocking is more likely to occur. However, by increasing the relative humidity of the outside air, knocking can be prevented and the engine It is also speculated that it is possible to normalize the driving of.

An object of the present invention is to provide a drive control method for an internal combustion engine that can improve fuel efficiency.

A drive control method for an internal combustion engine according to the present invention uses a humidity sensor that detects the humidity of intake air flowing into an intake passage of an internal combustion engine and generates a humidity signal, detects the humidity signal, and sets drive according to the humidity signal. The system is configured to drive the internal combustion engine based on conditions.

According to this internal combustion engine drive control method, the following effects can be obtained. The internal combustion engine can be operated in response to the humidity of each intake air, and the ignition timing can be moved closer to the knock limit ignition timing within a range where knocking does not occur, and the air-fuel ratio can be made larger, that is, closer to the combustion side. It is possible to drive the engine, and it is possible to constantly burn the engine with good movement, so that output can be extracted rationally, and fuel efficiency can be improved.

The present invention will be described below with reference to the accompanying drawings.

FIG. 4 schematically shows a drive control method for an internal combustion engine (hereinafter simply referred to as a drive control method). In this drive control method, the relative humidity of the intake air A flowing into the intake passage 2 of the engine 1 is detected by the humidity sensor 31C. in this case,
The engine 1 is driven by the load condition from the load section 4, the intake A
Humidity 1 varies depending on driving conditions such as ignition timing, air-fuel ratio, pressure of intake air A, and cooling water temperature. Therefore, humidity sensor 3
The humidity signal S'Y corresponding to the relative humidity of the intake air A from Send control signal I to bring it closer. By kneading, each drive condition setting means 5
Always keep the ignition timing advance as large as possible without causing knock ignition, and also reduce the air-fuel ratio.

The engine 1 is controlled with the optimum set value.

An example of the humidity sensor 3 used in such a drive control method is shown in FIG. This humidity sensor 3 has a humidity-sensitive ceramic 302 mounted on a ceramic substrate 301, and the electrical resistance changes due to the influence of water molecules adsorbed on the surface of the humidity-sensitive ceramic 302 (see Figure 6). (showing a characteristic diagram). Note that there are electrode films on both sides of the moisture-sensitive ceramic 3020, and an annular heater 303 is provided with a predetermined gap therebetween. This heater 303 is provided to provide a self-cleaning mechanism to the humidity sensor 3, which is sensitive to contamination. This is to prevent the humidity sensor 3 from being contaminated.

It is located behind the air cleaner 7 in the intake passage 2,
Moreover, in order to prevent malfunction due to fuel vapor, the fuel supply device 8. For example, it is desirable to arrange it upstream of a capretor, injection nozzle, etc.

Figure 7 shows an engine l to which the drive control method according to the present invention is applied. This engine 1 can operate with good fuel efficiency by varying the amount of advance of the ignition timing as a set drive condition based on the relative humidity of the intake air A. That is, the engine 1 is provided with a fuel supply device 8 above the gathering portion of the intake manifold 9, and provided with an air cleaner 7 upstream of the fuel supply device 8 via the intake passage 2. A humidity sensor 3 similar to that shown in FIG. 5 is attached to the intake passage 2, and this humidity sensor 3 is connected to a control unit 6.

The output end of the control unit 6 is connected to a distributor 10 serving as drive condition setting means 5 for the engine 1. This destination repeater 10 is.

A control pulse generated by the electromagnetic pickup (see Fig. 8) 11 by rotation of a signal rotor (not shown) is sent to the amplifier 13 via the retard angle control circuit W812, and further.

The power transistor 14 causes an output current corresponding to the control pulse to flow to the primary side of an ignition coil (not shown). In this case, the output current of the power transistor 14 is not detected by the current control circuit 15 and is adjusted to an appropriate value. The control unit 6 that sends the control signal IY to the retard angle control circuit 12 basically calculates the control signal I value based on the engine speed 'p intake pressure, etc., but it also calculates the control signal ■ value based on the humidity signal S. to correct. For this reason, the retard angle control circuit 12
By receiving control signal I, at the relative humidity indicated by intake air A, the engine is ignited to the maximum within a range that does not cause knocking.

Figure 1 (a) # (b)
), '(e) and (d) are set based on the same engine characteristics as shown in) 1. It is possible to rationally perform combustion in the engine 1 and achieve low fuel consumption. Note that the humidity sensor 3 was placed in the intake passage 2, but depending on the situation.

It may also be installed on the surface of the vehicle body that comes into direct contact with the outside air.

FIG. 9 shows an engine 16 as another embodiment to which the drive control method according to the present invention is applied.

The engine 16 can operate with good fuel efficiency by varying the air-fuel ratio as a set driving condition based on the relative humidity of the intake air A. That is, this engine 16 is the engine 1. shown in the off-line diagram. A fuel injector 17 is provided above the gathering part of the intake manifold 9, and an air cleaner 7 is provided upstream of the fuel injector 17 via the intake passage 2. A humidity sensor 3 is attached to the intake passage 2, and the output end of this control unit is connected to a two-el injector 17 as a drive condition setting means 5. The fuel injector 17 has a fuel injection amount control circuit 18, to which the control unit 6 sends a control signal I. The control unit 6 basically calculates the control signal ■ value based on the engine speed, throttle position, intake air amount, etc., but based on the humidity signal S.

Furthermore, the control signal ■ value is corrected. For this reason, by receiving the control signal ■, the injection amount control circuit 18 reduces the fuel flow rate within a range that does not cause knocking at the relative humidity indicated by the intake air, and sets the air-fuel ratio as large as possible, as shown in FIG. 3. Set based on engine characteristics)1
The engine 16 is combusted in a rational manner to achieve lower fuel consumption.

Figure 10 shows an engine 19 as another embodiment to which the drive control method according to the present invention is applied.

In order to improve fuel efficiency, this engine 19 maintains a relatively large fuel ratio, and when the relative humidity of the outside air decreases and knocking becomes more likely to occur, the relative humidity is forcibly increased to reach the knock limit. Keep the ignition timing advance amount at the specified value (
(See Figure 3).

That is, the engine 19 has the same members as the engine 1 shown in FIG. In the intake passage 2, there are intake air temperature sensors 20. A humidifier 21 is arranged as a humidity sensor 3° drive condition setting means 5. The intake temperature sensor 20 and the humidity sensor 3 are connected to a control unit (61C1), and the output end of this control unit is connected to the humidification control circuit 22 of the humidifier 21. The control unit 6 receives input of intake air temperature and humidity from both sensors 20 and 3.

Then, when the engine 19 is driven, the control unit 6 operates so that the advance amount does not exceed the knock limit or ignition timing at an air-fuel ratio maintained at a predetermined value. That is, the control unit 6 that has detected the low humidity region sends a control signal I to the humidification control circuit 22. As a result, the humidifier 21 adds water vapor to the intake air A, increasing the relative humidity of the intake air.

It is possible to measure the increase in the amount of advance of the knock limit ignition timing at that point (operation shown by the broken line in Figure 3).

As a result, the engine 19 can be driven without reducing the air-fuel ratio, resulting in lower fuel consumption.

Figure 11 shows an engine 23 as another embodiment to which the drive control method according to the present invention is applied.

This engine 23 can operate with good fuel efficiency by varying the supercharging pressure, which is a factor of the fuel-fuel ratio, based on the relative humidity of the intake air A. That is, this engine 23 has a supercharger 27 equipped with a waste gate pulp 26 that opens and closes a bypass passage 25 on the exhaust pipe 24 side.

The waste gate pulp 26 as the driving condition setting means 5 is operated by the supercharging pressure P that is led from the intake passage 28 to the diaphragm chamber 30 via the conduit 29. This supercharging pressure P is applied to the diaphragm chamber 30 by opening and closing a lenoid valve 31 attached to the conduit 29, and an output end of a control unit 6 similar to that shown in FIG. 7 is connected to this lenoid valve 31. On the other hand, a fuel injector 33 is attached to the gathering part of the intake manifold 32, and a humidity sensor 34 is attached on the intake passage 28 on the upstream side of the fuel injector 33, and a humidity signal S from the humidity sensor 34 is applied to the control unit 6. The control unit 6 constantly detects the relative humidity of the intake air A using a humidity signal S, and when the relative humidity falls below a set value, it applies a control signal (2) to the renoid valve 31 to open the waste gate pulp 26.

By kneading, the boost pressure is reduced, that is, the air-fuel ratio is reduced, and the advance amount of the knock limit ignition timing is maintained at a predetermined amount even in low humidity, preventing a reduction in engine output due to knocking, and as a result, the engine output is reduced throughout the season. It is possible to measure fuel efficiency in In addition.

In some cases, a knock sensor (not shown) is attached to the intake manifold 32 side of the engine 23, and by using this sensor uniformly, the knock limit ignition timing can be detected by multiple means, and the boost pressure can be controlled accurately based on the stiffness. It's okay.

In each of the above embodiments, the distributor 10. is used as a drive condition setting means. Fuel injector 17. Humidifier 21. The wastegate pulp 26 and other factors are varied to improve the fuel efficiency of each engine. Similarly,
The temperature of the engine's cooling water is controlled based on relative humidity, and this cooling water is used to cool the combustion chamber, and the engine is driven by increasing the amount of advance of the intermediate fire timing within a range that does not cause knocking. It's okay. By kneading, it is possible to maintain the advance angle amount at a predetermined value in a low humidity region and improve fuel efficiency.

[Brief explanation of drawings]

Figure 1 (a) I (b) I (e) , (
Figure d) is a knock limit ignition timing-relative humidity characteristic diagram, Figure 2 is a knock limit ignition timing-air fuel ratio characteristic diagram, and Figure 3 is a knock limit ignition timing-air fuel ratio characteristic diagram.
The figure is a knock limit ignition timing-relative humidity characteristic diagram using air-fuel ratio as a parameter, and Figure 1'4 is a block diagram for schematically explaining the drive control method according to the present invention. Figure 5 is a perspective view of the humidity sensor, and Figure 6 is an AC resistance value-relative humidity characteristic diagram and off-line diagram of the same humidity sensor. The drive control method according to the present invention is applied to FIG. 19, FIG. 10, and FIG. 11. FIG. 8 is a schematic plan view of an engine as a different embodiment, and FIG. 8 is a block diagram of a retard angle control circuit used in the engine shown in FIG. 7. 1...Engine, 2...Intake passage, 3...Humidity sensor. 5... Drive condition setting means, 10... Distributor, 17... Fuel injector, 21... Humidifier, 26... Waste gate valve, A... Intake,
S... Humidity signal bow 5) Shape δ Diagram relative; l Melon (%) 92A

Claims (1)

[Claims] 1. Using a humidity sensor that detects the humidity of intake air flowing into the intake passage of an internal combustion engine and generates a humidity signal, detects the humidity' signal, and sets drive conditions that match this humidity signal. A drive control method for an internal combustion engine that drives an internal combustion engine based on the method. , 2. 2. A drive control method for an internal combustion engine according to claim 1, wherein the set drive condition is a stagnation period of the internal combustion engine. 3. The drive control method for an internal combustion engine according to claim 1, wherein the set drive condition is an air-fuel ratio of the internal combustion engine.