JPS6150803B2 - - 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 a vehicle-mounted compressor automatic disconnection device. Compressors for air conditioners and car coolers generally use the internal combustion engine used to drive the vehicle as their mechanical drive source.Conversely speaking, if you look at the internal combustion engine, some of its power energy is used as a compressor. As a result, there are complaints that the power loss slows acceleration performance, especially when accelerating a vehicle that requires high efficiency from the internal combustion engine. Conventionally, an attempt has been made to resolve this dissatisfaction by sensing the negative pressure generated in the internal combustion engine's intake manifold during acceleration and activating an electromagnetic clutch placed between the internal combustion engine and the compressor. A device that can be used to disconnect internal combustion engines from internal combustion engines has already been put into practical use. However, this method, which uses a pressure sensitive element or vacuum switch, requires a special configuration and time to install it to the intake manifold, and also requires no modification to the existing manifold structure. Since it cannot be installed as is, it requires a special design, which has the disadvantage of lacking in versatility. Furthermore, since the pressure-sensitive element is placed in a high heat and corrosive environment, countermeasures for this are required, and in the end, it is necessary to start manufacturing from a dedicated element. The present invention has been made in view of the above, and is capable of purely electronically controlling the acceleration mode of a vehicle or the rotation speed increase mode of an internal combustion engine, and also using a rotation speed sensor already installed in an existing vehicle, if necessary. The present invention aims to provide an automatic compressor disconnection device that can be reused and therefore easily retrofitted into existing vehicles. Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the device of the present invention, first, the rotation speed signal of the internal combustion engine is adopted, but this rotation speed signal can be transmitted to the ignition device, which generates an ignition signal in synchronization with the rotation of the internal combustion engine, without the need for a separate dedicated sensor. The ignition signal from the ignition signal, the angle signal from the angle signal generator that informs the position or angular deviation in synchronization with the camshaft or crankshaft of the internal combustion engine, or the rotation of the propulsion shaft or drive shaft of the vehicle. The angular velocity signal from a device that generates an angular velocity signal, etc., and the rotational speed corresponding signal from an existing sensor or circuit system can be used. In the illustrated embodiment, as shown in FIG. 1, an impulse-like rotational speed signal S _i is extracted from the primary end 5 of an ignition coil 1 forming a part of an ignition device. That is, each time the primary current path of the ignition coil is interrupted, as is well known, an impulse of several hundred volts is generated at one end 5 of the primary coil, and the pulse repetition period or signal frequency of this pulse is generally equal to several hundred volts at the analog level. It is proportional to the number of rotations. Figure 2A shows this impulse signal S _i , which rises from the reference potential E ₀ (generally ground potential) when the engine is rotating at a constant speed, as shown from time T ₁ to T ₂ . Each impulse also has a constant pulse interval, that is, a constant frequency, but the time
As shown from T ₂ to T ₃ , when the engine is in the process of increasing the rotational speed, the frequency is also in the process of increasing. Also,
In Fig. 2A, the time axis is viewed from time _T3 toward the left, and as the engine begins to decrease in rotational speed from time _T3 to _T4 , the pulse interval gradually widens. As the rotation continues (that is, the frequency also decreases), and eventually reaches a constant rotation range from time T ₄ to T ₅ , 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 absolute value of the rotation speed at a constant rotation, but whether it is rising or in the process of increasing.
Since the only question is whether this is the case, this figure can be sufficiently generalized. Also, to state in advance, in Figure 2, A to D
In the waveform diagrams of the main parts up to this point, the waveforms are shown in a folded manner from time T ₁ to T ₂ to T ₃ and from time T ₃ to T ₃ to _{T 4} to _{T 5.} On the other hand, in Fig. 2 E to G, This is expanded on the right hand side along the time axis t, and a constant rotation range from time T ₃ to time T ₃ ' extending over a certain amount of time is added. Now, regarding the above-mentioned impulse signal S _i whose frequency changes in accordance with the engine speed, it would be too high in analog level to handle it directly as an engine speed signal, and it would contain too many noise components. , etc., so first,
If applied to the device input I _o , the waveform shaping circuit 6
It is best to shape the waveform with . In the illustrated case, the signal S _i applied to the input I _o
is clipped with a Zener diode 8 to prevent excessive input, and then inputted to the base of an npn transistor 7, whose collector is used as a waveform shaping output 9, from which a clean waveform engine speed signal S _i ' 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 potential of the power supply battery 4 E _B due to the inverter function of the NPN transistor 7.
(this is referred to as a high level H) to a reference potential, in this case approximately the ground potential E ₀ (this is referred to as a low level L). In order to convert this signal S _i 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 S _f that is frequency-modulated with respect to the engine rotational speed. In this example, monostable multivibrator 1
1 as the main constituent, and the above signal S
Every time _i ' is applied to the trigger input 13, it is triggered by its low-high transition, and the output terminal 14 has a constant width P.
_{A W} pulse appears. This pulse width P _W is uniquely determined according to the time constant of the external resistor 15 and capacitor 17, but in this pulse train signal S _f , as shown in FIG. 2C, each pulse width P _W is It is stable and the frequency is proportional to the engine speed. This pulse train signal S _f is then input to a frequency-to-voltage conversion circuit 16 whose output voltage changes in accordance with changes in frequency. In this embodiment, the conversion circuit 16 has the simplest configuration as a ripple filter or integration circuit consisting of capacitors 19, 20 and a resistor 21, and the pulse train signal S _f is inputted to this circuit after passing through a diode 18. I'm letting you do it. As shown in FIG. 2D, the converted voltage signal S appearing at the output 24 of the integrating circuit 16 is at a certain analog level when the engine speed is constant, and as the engine speed increases, it rises from that level. , if it goes down, it will go down accordingly. This converted voltage output S is given to a change direction detection circuit 23 including a two-input comparator 22. One feature of the present invention is that this change direction detection circuit 23
By making it possible to use a general-purpose comparator 22, it is possible to detect the direction of change with a time constant relationship between both inputs. That is, the voltage output S〓 is the positive input (non-inverting input) 31 and the negative input (inverting input) 30 of this comparator 22.
However, each input has different time constants τ ₁ and τ ₂ . In this embodiment, the comparator 22 uses an open collector type output, and as described later, when the positive input exceeds the negative input at the analog level, the signal S ₀ of the output 32 is digital. Since it is set to a high level H (logic “1”),
The time constant τ ₁ on the positive input side is selected to be smaller than the time constant τ ₂ on the negative input side (τ ₁ <τ ₂ ).
Specifically, in this case, each time constant is determined by each input integrating circuit (resistor 26 and capacitor 27; resistor 29
and a capacitor 28), and a level shift diode 25 is inserted in the line to the positive input 31 for reasons explained later. Below, if we follow the operation according to the schematic diagram of changes in engine speed in Figure 2E, as shown from time T ₁ to T ₂ , when the engine is rotating at a certain rotation speed, From the above, the frequency-to-voltage conversion circuit 16
At the output terminal 24 of , a signal S〓 of an analog level υ _a corresponding to the rotational speed at that time appears. If this state continues for a relatively long time, the capacitors 27 and 28 on both inputs of the comparator will be charged and the potential will become stable. The voltage value V at this time is
In _contrast , 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 understand the potential across this capacitor as a signal over time and represent the input voltage signal on the positive input side of the comparator as S〓 ⁺ and that on the negative input side as S〓 ^- , then between time T ₁ and T ₂ As mentioned above, the relationship between both signal potentials is as shown in FIG. 2F. Therefore, during this constant speed rotation, the signal _S0 at the output terminal 32 of the comparator 22 is at a low level because the negative input side potential of the generator circuit is higher than the positive input side (the open collector transistor is turned on and the output terminal or conduct the collector to ground). Next, in Figure 2 E, the engine speed is
During the process of rising or increasing as shown between T ₂ and _{T 3} , the frequencies of the rotational speed signals S _i to S _i ′ and, by extension, the frequency of the vibrator output signal S _f increase, so that the output S of the integrating circuit 16 As shown in FIG. 2D, although there is a slight delay, the potential begins to rise from the point already described. Therefore, both the capacitors 27 and 28 at both inputs of the comparator are charged toward a higher voltage value, but as described above, the time constant τ ₁ on the positive input side including the capacitor 28 is higher than the other τ ₂ , so in such a transient state,
Even if there is a voltage drop due to the presence of a diode, the positive input side signal S _i
⁺ exceeds the potential of the negative input side signal S _i ^- , so the comparator output signal S ₀ is inverted and becomes H level as shown in FIG. 2G. After the transient state of acceleration or increase in rotation speed is over,
As shown at times _T3 to _T3 ', when the engine speed becomes constant at a certain high level, both capacitors 27 and 28 become fully charged again, and the output S of the integrating circuit 16 at this time If the potential of 〓 is V _b , then
As before, the potential of the comparator negative input signal S ^- is approximately V _b , whereas the potential of the positive input signal S ⁺ is V _b lower by the forward voltage V _t of the level shift diode 25 _-Vt , the comparator output _S0 is again inverted and becomes L level. Next, as shown at times _T3 ' to _T4 in Fig. 2E, when the engine speed enters a transient state where it decreases, the converted voltage output S〓 changes to As shown on the left hand side, a downward transition occurs, and therefore the capacitors on both inputs of the comparator enter the discharge process, but the discharge on the positive input side is always faster than that due to the time constant relationship mentioned earlier. In the transient state, the relationship between the two inputs remains the same as during constant speed rotation, and the comparator output _S0 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 a constant speed rotation region (time T ₄ to _{T 5} ) with a reduced rotation speed again. The correlation between the above comparator output S ₀ 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] After all, the comparator output S ₀ of this device is the output for discriminating between the engine speed increase mode and other modes (constant speed, decrease), that is, the engine speed increase mode detection output, so such an output As long as you can get
Process this logically and then turn it into a power level,
Those skilled in the art can conceive of various circuits for disengaging the electromagnetic clutch between the compressor and the engine only during the process of increasing the rotational speed. In this embodiment, as an example, the logic level of the comparator output _S0 directly selectively demagnetizes the electromechanical relay 33 as a driver for the electromagnetic clutch, thereby selectively cutting off the power supply path to the electromagnetic clutch 35. There is. That is, the power supply line 12 and the comparator output terminal 32
A driver relay 33 is inserted in series between them, and its make contact 34 is inserted into a power supply line 39 extending from the power line 12 to the operating winding 35a of the electromagnetic clutch 35, so that the engine speed is constant and constant. When in the drop mode, the comparator output S ₀ is at the L level, which creates a potential difference that causes the operating current to flow across the relay 33. Therefore, the relay 33 is energized, the make contact 34 is closed, and the electromagnetic Current flows through the operating winding 35a of the clutch 35, resulting in the clutch being connected, and the compressor being driven by the engine. However, when the vehicle requires acceleration and the engine speed increases, the comparator output S H of ₀
With the reversal to level, the potential difference across the driver relay 33 is substantially lost, so the make contact 34 opens and the current in the electromagnetic clutch winding 35a is cut off. The purpose is achieved by blocking it.
The above clutch operation is also shown in parentheses in FIG. 2G. By the way, when we examine the above-mentioned embodiments, we find that
As a specific circuit, a waveform shaping circuit 6 and a pulse frequency modulation circuit 10 are used to facilitate pulse-like handling, but as a result,
In this embodiment, the signals S _i , S _i ', and S _f have the same information content, which is converted into voltage information S〓. Therefore, as shown in the output S of the integrating circuit 16, it is sufficient to obtain a voltage output corresponding to the transient state of the rotational speed. Therefore, the circuits 6, 10, and 16 can collectively form a converted voltage output circuit 40 that receives a rotational speed signal and whose output voltage changes in accordance with a change in the rotational speed. In this way, a similar converted voltage output S can be obtained in other embodiments as shown in the third diagram. In this embodiment, from the input signal S _i the detection signal
Assuming that FIG _{. 1} is used for the other circuits, the converted voltage output circuit 40 that generates a voltage output according to the change in rotational speed in this second embodiment is as follows.
It is configured as a phase locked loop. The input terminal I _o of this embodiment receives a frequency signal S _i corresponding to the engine speed (or equivalently the already described S _i ', S _f modified to be easily processed), which also has the following characteristics: It is added to one input of the phase comparator (φ/D) 42. The output of a voltage controlled oscillator (VCO) 43 is given to the other input of the phase comparator 42, and the output of the phase comparator 42 is fed to an integrator circuit or a low-pass filter 1.
6 to the control voltage input of the VCO, and the converted voltage output S for this device is extracted from the output of the integrating circuit and inputted to the change direction detector 23, which may be similar to the first embodiment described above. ing. However, a DC bias voltage V _B is applied to the phase locked loop 41 system, and the reference potential within the loop is increased by V _B due to the reference potential (E ₀ ; ground) of the entire system. This is because, as will be described later, the output S is not brought to zero potential during loop lock, that is, when the rotational speed is constant. The operation will be explained with reference to each schematic waveform in FIG. As is well known, Phase Locked Loop 4
1, when a frequency difference or a phase difference occurs between both inputs of the phase comparator 42, the comparator output has VCO
43, a control signal that changes the oscillation frequency in the direction of eliminating the phase difference appears, and therefore, if the input frequency is stable, that is, the engine rotational speed changes from time T ₁ to T in FIG. 4A. When the voltage is constant as shown between ₂ and 2, no control signal appears at the phase comparator output, and the integrating circuit output S is also stable at the bias voltage _VB . Therefore, due to the mechanism in the previous embodiment, at both inputs of the comparator 22 in the change direction detection circuit 23, the potential of the positive input signal S ⁺ is at a level higher than the potential _VB of the negative input signal S ⁺ . shift diode 2
Therefore, _the output _S0 is at L level. As shown between times T ₂ and T ₃ in FIG. 4, when the rotational speed begins to increase, the frequency of the input signal S _i increases, so the output of the phase comparator 42
A control signal is generated to cause the output frequency of the VCO 43 to follow this, and the integrating circuit output S has an increasing voltage tendency as shown in FIG. 4B. Therefore, the positive and negative input signals S〓 ⁺ , S of the comparator 22
〓 ^- potential changes over time from positive input side time constant τ ₁ <negative input side time constant τ ₂ as described above, to positive input side potential S〓
⁺ becomes high, and the output _S0 of the comparator 22 becomes H level (FIG. 4D). In the constant speed rotation region again shown in the section T ₃ to T ₃ ′,
The phase-locked loop becomes locked again, the error voltage S becomes zero in the loop system, the bias voltage becomes _VB in the entire system, and the comparator output _S0 becomes L again.
level, and thereafter, as shown in sections T ₃ ′ to T ₄ and T ₄ to T ₅ , the condition of S〓 ⁺ <S〓 ⁻ does not change until the rotation speed decreases and settles to a constant rotation. Comparator output S ₀ remains at L level. In this way, it is shown that in this embodiment as well, the process of increasing the engine speed can be detected, and the output S ₀ can be used in the same way as in the first embodiment. In both embodiments described above, the driver 33 (not shown in the second embodiment with reference to FIG. 1)
is not limited to relays, but may also be semiconductor power switching circuits such as thyristor circuits, and
Each of the already mentioned signals S _i , S _i ′, S _f , S〓, S ₀ is
Process in inverted state or comparator output
The time constant relationship on the input side and the series insertion position of the level shift diode are reversed to the relationship in this embodiment so that only _S0 is inverted, and the electromagnetic clutch is disconnected at the L level of the output _S0 . Any common means in circuit technology such as
is an integrating circuit (26, 27;
28, 29) can also serve as this. In addition, in the first embodiment, the response characteristics at the time of transition to the rotation speed increasing mode are determined by the time constant circuits 15 and 17 that determine the pulse width P _W of the output pulse train S _f of the monostable multivibrator 11. As shown in the figure, the resistor 15 is composed of a fixed resistor 15a and a variable resistor 15b, and by adjusting the variable resistor, the pulse width P _W can be adjusted and controlled. In addition, the light emitting diode 36 connected in parallel with the electromagnetic clutch winding 35a in FIG. It's convenient, but of course it's better without it. Contact 37 in series in power supply line 12
is a contact point of an air temperature detection sensor normally provided at the air outlet 38 of the air conditioner cooler, and if this contact point is open, there is no need to do so, and the device of the present invention does not operate. As described above, according to the present invention, an electronic and highly reliable device is used 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 particular, an extremely practical device that does not require a dedicated sensor and can be easily retrofitted into an existing electrical system can be obtained. In the above embodiment, the engine speed signal is extracted from a part directly related to the engine, so it operates even when revving (of course, there is no problem with that), but the drive system If the engine speed signal is extracted indirectly from the engine speed signal, it will truly operate only when the vehicle is accelerating.

[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 and state transitions of various parts related to the device shown in the first diagram, and FIG. 3 is a schematic diagram of the main list configuration of the second embodiment. , FIG. 4 shows waveforms of various parts of the second embodiment,
It is an explanatory diagram of state transition. In the figure, 1 is an ignition coil, 4 is a power supply battery, 6 is a waveform shaping circuit, 10 is a pulse frequency modulation circuit for engine speed, 11 is a monostable multivibrator, 12 is a power supply line, and 16 is a frequency-to-voltage conversion circuit. , 22 is a comparator, 23 is a change direction detection circuit, 3
5 is an electromagnetic clutch, 40 is an output circuit for a voltage corresponding to the rotational speed as a whole, and 41 is a phase locked
42 is a phase comparator, and 43 is a voltage controlled oscillator.

Claims (1)

[Scope of Claims] 1. A device for mechanically disconnecting a compressor mounted on a vehicle from the internal combustion engine as the engine speed increases during vehicle acceleration, which includes at least an internal combustion engine speed signal when the vehicle is running. a rotation speed conversion voltage output generation circuit that generates an output whose voltage changes according to the rotation speed increasing process; and a rotation speed conversion voltage output generation circuit that receives the converted voltage output at two inputs and inverts the output according to the magnitude of the two inputs. a comparator; giving different time constants to the two inputs of the comparator;
a time constant circuit that inverts the output of the comparator due to a change in the converted voltage output during the process of increasing the rotational speed; and an electromagnetic clutch that interrupts the mechanical drive system between the internal combustion engine and the compressor based on the inverted output of the comparator. An automatic compressor disconnection device for vehicle installation, characterized in that it consists of the following.