JPS621853B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a compressor for an air conditioner or a car cooler that utilizes a vehicle propulsion internal combustion engine as its mechanical drive source. The present invention relates to an automatic compressor disconnection device mounted on a vehicle that allows a certain amount of time for the compressor to return to its function even after disconnection and return to a constant speed rotation state. Air conditioners and car cooler compressors generally use the internal combustion engine used to drive the vehicle as their mechanical drive source. It turns out that he is being eaten by Compretusa,
In particular, when accelerating a vehicle, which requires high efficiency from the internal combustion engine, there are complaints that the acceleration performance is slowed down due to the power loss. Therefore, in an attempt to resolve this dissatisfaction, an electromagnetic clutch placed between the internal combustion engine and the compressor is mechanically disconnected from the internal combustion engine by sensing the negative pressure generated in the intake manifold of the internal combustion engine during acceleration. A device to perform this separation had already been put into practical use. However, this method, which uses pressure-sensitive elements or vacuum switches, requires a special configuration and effort to install, and it is not possible to install it as is without modifying the existing manifold structure. Since it cannot be used, it requires a special design and has the disadvantage of lacking in versatility. Furthermore, since the pressure-sensitive element is exposed to high heat and corrosive environments, countermeasures must be taken to prevent this, and as a result, there is a disadvantage in that the pressure-sensitive element must be manufactured from a dedicated element. Furthermore, with conventional devices like this, the compressor was reconnected immediately after the acceleration state ended, so when driving outside the city, especially when starting and accelerating frequently, such as in low-speed traffic jams, the compressor must be connected frequently each time. The disadvantage was that the compressor clutch, which was repeatedly interrupted and connected to the internal combustion engine, was subject to considerable wear. This drawback is also undesirable from a mechanical stress point of view. The present invention has been made in view of the above, and it electronically detects the acceleration mode of the vehicle or the rotational speed increase mode of the internal combustion engine, and stops the function of the compressor when in this mode. In addition to providing a simple device that mechanically disconnects the internal combustion engine from the internal combustion engine, the present invention aims to prevent the compressor from immediately re-functioning even when the acceleration mode or rotational speed increase mode shifts to the constant speed rotation mode, and the above-mentioned This is intended to reduce the number of times the compressor clutch is engaged in driving conditions with short acceleration/deceleration intervals, thereby extending the life of the clutch and the mechanical system. Hereinafter, one embodiment of the present invention will be described with reference to the attached preferred embodiment. In the device of this embodiment shown in FIG. 1, first, the rotational speed signal of the internal combustion engine is extracted from the primary negative terminal 5 of the ignition coil 1, which forms part of a known ignition device. That is, each time the primary current path of the ignition coil is interrupted or interrupted as is well known, an impulse of several hundreds of volts is generated at the negative terminal 5 of the primary coil, and the pulse repetition period or signal frequency is is proportional to the engine speed. Figure 2A shows this impulse signal S1, and as shown from time T1 to T2, when the engine is rotating at a constant speed, each impulse rising from the reference potential Eo (generally ground potential) also The pulse interval, that is, the frequency is constant, but as shown from time T2 to time T3, when the engine is in the process of increasing the rotational speed, the frequency is also in the process of increasing. In addition, in Fig. 2A, the time axis is viewed from time T3 toward the left, and as the engine speed decreases from time T3 to time T4, the pulse interval gradually widens. (that is, the frequency also decreases), and eventually, when the rotation reaches a constant rotation range from time T4 to time T5, the frequency becomes constant again. Of course, even if it is said that the frequency is constant in a constant rotation range, the value of the frequency will differ if the rotation speed differs. Therefore, the illustrated case starts with a certain constant rotation, for example, idling, goes through an upward and downward process, and then returns to the same constant rotation as before. However, as will become clear from the description below, the present invention does not care about the insulation value at constant rotation, but only whether it is in the process of increasing or increasing, so this diagram is sufficient. Can be generalized. In addition, as mentioned in advance, in the waveform diagrams of the main parts from A to D in FIG. 2, the waveforms are shown in a folded manner from time T3 to T3 to T4 to T5 after passing through time T1 to T2 to T3. On the other hand, in FIGS. 2E to 2G, this is expanded to the right on the time axis t, and a constant rotation range from time T3 to time T3' extending over a certain amount of time is added. Now, the above-mentioned impulse signal S1, whose frequency changes in accordance with the engine speed, cannot be treated directly as an engine speed signal because its level is too high in terms of analog level, and there are too many noise components. , etc., so it is preferable to first shape the waveform in the waveform shaping circuit 6 after applying it to the input In of this device. In the case shown, the signal S1 applied to the input In
After being clipped by a Zener diode 8 to prevent excessive input, it is input to the base of an npn transistor 7, and its collector is used as a waveform shaping output 9, from which a clean waveform engine speed signal S2 is extracted. This waveform, as shown in Figure 2B,
Each time the key switch 3 closes and the ignition coil performs a current cutoff operation, the inverter function of the npn transistor 7 changes the potential Eb of the power supply battery 4 (this is defined as high level H) to the reference potential in this case. Approximately ゞ is the ground potential Eo (this is considered the low level L)
shall be headed for. In order to make the signal S2 into a pulse train signal that is easier to handle, it is input to a conversion circuit or pulse frequency modulation circuit 10 that generates a pulse train signal of a constant width PW that is frequency-modulated in proportion to the engine speed. In this embodiment, a monostable multivibrator 11 is used as the main component of this circuit, and the above-mentioned signal S
2 is applied to the trigger input 13, it is triggered by its high/low transition, and the output terminal 14 has a certain width.
PW pulse appears. This pulse width PW is uniquely determined according to the time constant of the external resistor 15 and capacitor 17, but the frequency of the pulse train signal S3 is proportional to the engine speed. This pulse train signal is then applied to a frequency-to-voltage conversion circuit 1 whose output voltage changes according to the frequency change.
6 is input. In this embodiment, the conversion circuit 16 is assumed to have the simplest configuration, and the capacitor 1
9 and 20 and a resistor 21 as a ripple filter or an integrating circuit, and a pulse train signal is inputted to this circuit after passing through a diode 18. As shown schematically and simply linearly in FIG. 2D, the average voltage value of the converted voltage signal S4 appearing in the output of the integrating circuit 16 is at a certain analog level when the engine speed is constant. When the rotational speed increases, the rotational speed increases from that level, and when the rotational speed decreases, the rotational speed decreases accordingly. This converted voltage output S4 is given to a change direction detection circuit 23 including a two-input comparator 22. One feature of this embodiment is that this change direction detection circuit 23
In addition, by making it possible to use the commonly used comparator 22, the ability to detect the direction of change is achieved with a time constant relationship between both inputs. That is, the voltage output S4 is the positive input (non-inverting input) 31 and negative input (inverting input) 30 of this comparator 22.
However, each input has a different time constant τ ₁ and τ ₂ . In this embodiment, an open collector type output is used for the comparator 22, and as will be described later, when the positive input exceeds the negative input at the analog level, the signal S7 of the output 32 is output at the digital level. The time constant τ _{1 given to the positive input side is selected to be smaller than the time constant τ 2 given} to the negative input side (τ ₁ < τ ₂ ). Specifically, in this case, each time constant is formed by an integrator circuit (resistor 26 and capacitor 27; resistor 29 and capacitor 28) of the respective input, and in the line to the positive input 31, there is a From there, a level shift diode 24 is inserted. Below, if we follow the operation according to the schematic diagram of changes in engine speed in Figure 2E, as shown from time T1 to time T2, when the engine is rotating at a certain constant speed, the above-mentioned From this point, a signal S4 of an analog level Va corresponding to the rotational speed at that time appears at the output terminal 24 of the frequency-to-voltage conversion circuit 16. If this state continues for a relatively long time, the capacitors 27 and 28 on both inputs of the comparator will be fully charged and the potential will be stabilized, but in this state, the capacitor 27 on the negative input side will be approximately is charged to the voltage value Va at this time, whereas the capacitor 28 on the positive input side becomes low level by the forward voltage drop Vt of the inserted level shift diode 25. From now on, if we grasp the average voltage of the potential across this capacitor as a signal over time and represent the input voltage on the positive input side of the comparator as S5 and the input voltage on the negative input side as S6, both signals between times T1 and T2 As can be seen from the above, the potential relationship is schematically expressed linearly as shown in FIG. 2F. Therefore, during this constant speed rotation, since the negative input side potential of the comparator is higher than the positive input side, the signal S7 at the output terminal of the comparator 22 becomes a low level (the open collector transistor turns on and the output terminal or collector to ground). Next, in FIG. 2E, the engine speed is at time T.
During the process of rising or increasing as shown between 2 and T3, the frequencies of the rotational speed signals S1 to S2 and, by extension, the frequency of the vibrator output signal S3 increase, so the output S4 of the integrating circuit 16 is as shown in FIG. 2D. As described above, the potential begins to rise. Therefore, the capacitors 27, 2 at both inputs of the comparator
Both 8 are charged toward a higher voltage value, but as mentioned above, the positive input time constant τ ₁ including the capacitor 28 is shorter than the other τ ₂ , so in such a transient state, for example, a diode 25, the positive input side signal S5 is higher than the negative input side signal S5 as shown in FIG. 2F.
Therefore, the comparison output signal S7 is inverted and becomes H level as shown in FIG. 2G. When the transient state of acceleration or increase in rotational speed ends and the engine rotational speed becomes constant at a certain high level as shown at times T3 to T3', both capacitors 27 and 28 become fully charged again in response to this. If the output potential of the integrating circuit 16 at Vb− lower by directional voltage Vt
Vt, the comparator output is inverted again and becomes L.
level. Next, as shown at times T3' to T4 in FIG. 2E, when the engine speed enters a transient state in which it decreases, the converted voltage output S4 of the integrating circuit 16 changes at times T3' to T4 in FIG. As shown in the figure, a downward transition occurs as seen on the left hand side, and the capacitors on both inputs of the comparator enter the discharge process, but due to the time constant relationship described above, the discharge on the positive input side is always faster. In this transient state, the relationship between the two inputs remains the same as during constant speed rotation, and the comparator output remains at the L level as shown in FIG. 2G. It is already clear that this condition does not change even after the deceleration transition period ends and the engine enters the constant speed rotation range (times T4 to T5) at a lower rotational speed again. The correlation between the above comparator output S7 and each state mode of the internal combustion engine, that is, constant speed mode, increasing mode, and decreasing mode, is as shown in Table 1 below.

[Table] In the end, the comparator output S7 of this device is the engine speed increase mode and the other mode (constant speed, decrease).
It can be seen that he has the ability to discriminate between This comparator output S7 is then input to the compressor function recovery time setting circuit 42. As stated in advance, the output S10 of the return time setting circuit 42 is L as shown in FIG.
Although the rise from the level to the H level is almost at the same time as the comparator output S7, the fall is delayed by an appropriate amount from the fall of the comparator output S7, which is expected in the driving condition with rapid acceleration and deceleration as described at the beginning. Become something. The operation of the recovery time setting circuit 42 in this embodiment will be explained below. In non-acceleration mode, the output S7 of comparator 22
is at L level, the npn transistor 43 at the input of the circuit 42 is in an off state. If this state continues for a certain amount of time, the capacitor 45 inserted between the negative phase input or inverting input of the open collector type comparator 50 similar to the comparator 22 and the ground
is charged to approximately the power supply potential Eb via a variable resistor 44 for reasons to be described later.
On the other hand, the positive phase input side of this comparator 50 has a resistor 4
It receives the divided voltage output of the voltage divider 7 and 48.
If this divided voltage output is S8, this is the reference potential
Es is given to the comparator. This reference potential Es
is set in the following relationship at least with respect to the power supply potential Eb. Eb>Es (1) Therefore, in the non-acceleration state, the output S10 of the comparator 50 is at L level, that is, it is grounded. According to the mechanism described above, when the acceleration mode is entered and the output S7 of the comparator 22 becomes H level as shown in FIG. 2G, the return time setting circuit 4
A resistor 49 is connected to the base of the second input transistor 43,
A base potential is also applied via a bias circuit 49', and this transistor 43 becomes conductive. As a result, the charge accumulated in the capacitor 45 is rapidly discharged through the resistor 46 having a relatively small resistance value, and as shown in FIG.
As the potential of the signal S9 on the negative phase input side rapidly falls below the potential of the signal S8 on the other input side, that is, the reference potential Es, the output S10 of the comparator 50 becomes the signal S7 as shown in FIG. Similarly, it rises to H level.
This time is indicated as time T2' in FIG. Next, as described above, when the acceleration mode ends and the output of the comparator 22 falls as shown at time T3'' in FIG. However, the capacitor 45 is charged through the resistor 44, and it takes time to exceed the reference voltage Es.
In FIG. 2H, the output S of the comparator 50 begins when the potential of the signal S9 exceeds the reference potential at time TD.
10 returns to L level. As can be seen from this function, this circuit 42 has a kind of monostable multivibrator function. The only difference is the duration of H level.
tm is not constant, but changes depending on the time tx during which the output of the comparator 22 is at the H level, that is, the acceleration time (tm=tx+td; tx is variable). However, the time from the end of the acceleration state to the fall
td is constant. And this time td is resistance 4
4 and a capacitor 45. For this purpose, as shown in FIG. 1, the resistor 44 is a variable resistor so that the delay time can be arbitrarily and appropriately set. Of course, the capacitor 45 can be a variable capacitor, but in practice, a resistor is more advantageous.
However, the reference potential Es may be adjusted by using the resistor 47 or the resistor 48 in the voltage dividing circuit that forms the reference potential Es as a variable resistor. In any case, as long as the above recovery time setting or delay output S10 is obtained, by appropriately processing this, it is possible to mechanically connect the compressor and the engine only when this signal S10 is at H level. Detachment arrangements will be readily apparent to those skilled in the art. In this embodiment, such a clutch disconnection circuit 41
As an example, the logic level of the comparator output S10 directly selectively demagnetizes the electromechanical relay 33 as a driver of the electromagnetic clutch that mechanically connects the compressor and the engine.
The power supply path No. 5 is selectively cut off.
That is, a driver relay 33 is inserted in series between the power line 12 and the comparator output terminal 32, and its make contact 34 is inserted into the power supply line 39 extending from the power line 12 to the operating winding 35a of the electromagnetic clutch 35. Therefore, when the engine speed is in the constant speed and decreasing modes, the comparator output S7 is at the L level, which creates a potential difference that causes the operating current to flow across the relay 33, and therefore, the relay 33 is energized. The make contact 34 is closed, current flows through the operating winding 35a of the electromagnetic clutch 35, and the clutch is connected, allowing the compressor to be driven by the engine. When the number increases, the comparator output S7 and the output of the return time setting circuit 42 are reversed to H level, and the potential difference between both ends of the driver relay is lost. Therefore, the make contact 34 opens and the electromagnetic clutch operating winding The electric current to the engine is cut off, and the electromagnetic clutch mechanically disconnects the drive system from the engine. Even after acceleration ends, this state can be maintained until a predetermined time td has elapsed. The above clutch operation is also shown in parentheses in FIG. 2I. Further, the light emitting diode 36 is used for monitoring this operation. However, since this indicator light 36 lights up when the clutch is engaged, it would be better to indicate to the driver when the clutch is disengaged in accordance with the idea of the present invention.
As shown by the imaginary line in FIG. 1, it is preferable to use the break contact 34b of the relay 33 to light the diode 36a. Of course, both may be used together, or they may emit light of different colors. Also, as is obvious from the above functions, the delay time
Although it is important to make td, the method itself is not defined by the present invention. For example, in the above embodiment, a general monostable multivibrator was configured as a discrete unit, but a commercially available IC
It is also possible to use a monostable multivibrator 53 as shown in the third figure. To explain briefly, the output S7 of the comparator in the previous stage is inverted by the inverter 52 and made into the INV (S7) signal,
This signal is intended to trigger the monostable multivibrator 53. As shown in FIGS. 4A and 4C, the resulting relationship between the output signal S11 of the monostable multivibrator 53 and the comparator output signal S7 is, so to speak, a trailing relationship. Therefore, in principle, OR gate 5
4, the required signal S10 shown in FIG. 4D should be obtained, but a hazard may occur in the output signal S10 due to a slight time difference between the falling point of the signal S7 and the rising point of the signal S11. To avoid this, signal S7
If the signal S7' is passed through the analog buffer 51 and the time constant circuit 55 with a slight delay, and this is fed to one input of the OR gate 54, the signal S7' will be as shown in FIG. 4B. As shown in FIG. 4C, the signal S1 crosses the threshold level Et(or) of the OR gate 54 a little later than the falling edge of the signal S7.
It is possible to create an overlapping area where 1 completely rises and then falls, and the above-mentioned hazard does not occur. The required delay time Td for recovering the compressor function is usually determined by varying the resistor 56 that determines the oscillation time of this type of monostable multivibrator IC.
It can be adjusted arbitrarily. The advantage of this second embodiment over the circuit 42 of the previously described embodiment is that when trying to take a considerably long delay time td, the time constant circuit 4 of the previous circuit is
While the electrical capacity of 4 and 45 increases,
There is no such thing. Although the function is different, even though the time constant circuit 55 is required in this second embodiment, the time constant may be extremely small.
It does not hinder miniaturization. In any case, as is clear from both of the above embodiments, the problem with the present invention is that even after the acceleration state ends, the compressor function is not restored until a certain amount of time td has elapsed. This means that under such driving conditions, that is, driving conditions that involve frequent acceleration and deceleration, the number of times the compressor is repeatedly turned on and off can be reduced. Note that in FIG. 1, the circuits 6, 10, and 16 can be considered as one unit, and can be a converted voltage output circuit 40 whose output voltage changes in accordance with changes in engine speed. Accordingly, circuits other than those shown in the illustrated embodiments, such as phase-locked loop circuits, may be used as desired in accordance with known techniques. Further, the compressor intermittent circuit 41 may be electronically formed using a semiconductor element, and other common circuit technology and logic level processing means may be used as desired. Furthermore, the integration circuit 16 may be omitted by having time constant circuits 26, 27; 28, 29 provided at each input of the comparator 22 perform its function. Note that the output pulse width PW of the monostable multivibrator 11 can be adjusted by adjusting the resistance value, for example, if the resistor 15 that determines the time constant is configured to include a fixed resistor 15a and a variable resistor 15b as shown in the figure. can be easily adjusted. In any case, as detailed above, according to the present invention, an electronic system is used as a device to automatically disconnect the compressor from the engine, which can cause mechanical power loss, during acceleration when it is desirable to maximize engine efficiency. In addition to providing a device that is highly reliable, does not require a special sensor, and is easy to integrate into existing electrical systems, it also reduces the number of compressor intermittent cycles under driving conditions that involve frequent acceleration and deceleration. Since it can reduce wear of the compressor clutch and stress on the mechanical system, it is possible to provide a practical device with high commercial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a preferred embodiment of the device of the present invention, FIG. 2 is an explanatory diagram of waveforms of each main part of the device shown in the first diagram, and FIG. 3 is a schematic diagram of main parts of another embodiment. The configuration diagram and FIG. 4 are waveform diagrams of various parts of the circuit shown in the third diagram. In the figure, 1 is an ignition coil, 6 is a waveform shaping circuit, 1
0 is a frequency modulation circuit, 11 is a monostable multivibrator, 16 is a frequency to voltage conversion circuit, 22 is a comparator, 23 is a change direction detection circuit, 40 is an overall engine speed to voltage conversion circuit, 41 is a compressor intermittent circuit, 42 is a compressor recovery time setting circuit, 44 and 45 are time constant circuits for setting delay time,
50 is a comparator, 53 is a monostable multivibrator, and 54 is a NOR gate.

Claims (1)

[Scope of Claims] 1. A rotation speed conversion voltage output generation circuit that extracts a rotation speed signal of an internal combustion engine mounted on a vehicle and generates an output whose voltage changes according to the process of increasing the rotation speed from a constant speed rotation state; A comparator that receives converted voltage outputs at two inputs and inverts the output depending on the magnitude of the two inputs; and a comparator that gives different time constants to the two inputs of the comparator to invert the converted voltage output according to the change in the converted voltage output during the rotation speed increasing process. a time constant circuit for inverting the output of the comparator; a compressor disconnection device for interrupting a mechanical drive system between the internal combustion engine and the compressor by the inverted output of the comparator; A compressor recovery time in which a time delay is provided between the re-inversion of the comparator output upon return to the high speed rotation state and the reconnection of the mechanical drive system between the internal combustion engine and the compressor by the compressor disconnection device. An automatic disconnection device for a vehicle-mounted compressor, comprising a setting circuit;