JPH0115413B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a function to disengage the compressor latch of an air conditioner or car cooler that utilizes a vehicle propulsion internal combustion engine as its mechanical drive source when the internal combustion engine rotational speed increases beyond a specific set rotational speed. The present invention relates to an automatic disconnection device for a compressor clutch mounted on a vehicle. Air conditioners and car cooler compressors generally use the internal combustion engine used to drive the vehicle as their mechanical drive source. This has led to complaints that acceleration performance is slowed down due to power loss, especially when accelerating a vehicle that requires high efficiency from the internal combustion engine. 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. Further, in such prior art systems, the compressor clutch was disengaged as soon as the engine speed increased. Therefore, when driving outside the city, especially in low-speed traffic jams, you may start or accelerate from a stop (idling), then immediately decelerate and accelerate again.
When the above-mentioned process is repeated frequently, the compressor clutch has the disadvantage that it repeatedly engages and disconnects each time, resulting in significant 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 vehicle acceleration mode or the internal combustion engine rotation speed increasing mode, and when in this mode, the compressor function is stopped, that is, the clutch is disengaged. In principle, the compressor is mechanically disconnected from the internal combustion engine, but this function is not activated when the engine speed does not reach a predetermined set speed, and the The object of the present invention is to provide a simple device that can reduce the number of times the compressor clutch is engaged and extend the life of the clutch and mechanical system. An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the main configuration of a basic embodiment of the present invention, and FIG. 2 shows a slightly more specific circuit configuration as an example. First, the internal combustion engine ignition timing signal detection circuit 1 detects Extract the ignition timing detection signal Si. In the second illustrated embodiment, this signal Si is extracted from the primary negative terminal Ti ^- of the ignition coil, which forms part of a known ignition device. As is well known, each time the primary current path of the ignition coil is interrupted in accordance with the ignition timing, an impulse of several hundreds of volts is generated at the negative terminal Ti ^- of the primary coil, which is The pulse repetition period or signal frequency is proportional to the engine speed. Therefore, this impulse is included in the signal Si in the form of engine rotational speed information embodied in frequency information. Figure 3 shows this impulse signal Si, and when the engine is rotating at a constant speed, each impulse that rises in the negative direction from a reference potential (generally ground potential) also has a constant pulse interval, that is, a constant frequency. However, when the engine is in the process of increasing rotation speed,
The frequency also increases. In addition, in FIG. 3, if the time axis is viewed in a folded manner toward the left, as the engine's rotational speed is in the process of decreasing, the pulse interval will gradually widen (that is, the frequency will also decrease). In this way, the impulse signal Si, whose frequency changes in accordance with the engine speed, is too high in analog level to be handled directly.
Furthermore, since it is not desirable because there are too many noise components, etc., it is preferable to first shape the waveform using the waveform shaping circuit 2. In the case shown in the second figure, the signal Si applied to the input Ti ^- is clipped by the Zener diode 21 to prevent excessive input, and then input to the base of the npn transistor 22, and the collector is used as the waveform shaping output. Engine ignition timing signal with a clean waveform from
Si′ is extracted. In order to make this signal Si' into a pulse train signal that is easier to handle, a monostable multivibrator 31 with a constant pulse width Pw is used to obtain a pulse train Sb whose frequency is proportional to the engine speed (the third
figure). This pulse train signal Sb is then processed so that the output voltage changes according to the change in frequency. In the embodiment shown in the second figure, the conversion circuit is configured as a ripple filter or an integrating circuit including capacitors 32, 33 and a resistor 34 as the simplest example of the configuration. As mentioned above, monostable multivibrator 31
The average voltage value of the converted voltage signal _Sv0 appearing at the output of the frequency-to-voltage conversion (F-V conversion) circuit 3, which includes ripple filters 32, 33, and 34, is
As shown schematically and simply linearly by the two-dot chain line in the figure, when the engine speed increases from a constant engine speed Vi, the level increases, and when it decreases, the level decreases. becomes. This converted voltage output Sv ₀ is given to both the positive input (non-inverting input) and negative input (inverting input) of the comparator 6, but each input has different time constants τ ₁ and τ ₂ . be done. In the embodiment shown in the second figure, the comparator 6 uses an open collector type output, and as described later, when the positive input exceeds the negative input at the analog level, the output signal Sc is at the digital level. Since the output voltage is set to a high level "H" (this is defined as logic "1"), 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 the integrator circuits 4 and 5 of the respective inputs, each consisting of a simple CR circuit, but in the line to the positive input of the comparator, there is a For the reason,
A level shift diode 41 is inserted. Below, if we follow the operation according to the schematic diagram of engine rotational speed change shown in Figure 4, when the engine is rotating at a certain rotational speed, the output of the frequency-to-voltage conversion circuit 3 will change as described above. An analog level signal Sv ₀ corresponding to the rotational speed at that time appears at the terminal. If this state continues for a relatively long time, the capacitors 42 and 52 on both inputs of the comparator become fully charged and their potentials are determined, but in this state, the capacitor 52 on the negative input side is approximately While the capacitor 42 on the positive input side is charged to the current voltage value of ₀ , the level becomes low by the forward voltage drop Vt of the inserted level shift diode 41. From now on, by grasping the average voltage of the potential across this capacitor as a signal over time, and expressing the input voltage on the positive input side of the comparator as Sv ₁ and the input voltage on the negative input side as Sv ₂ , first, this constant speed rotation Sometimes, the potential of the comparator negative input side is higher than the positive input side
The signal Sc at the output terminal of is at a low level (the open collector transistor is turned on and conducts the output terminal or collector to ground). Next, in FIG. 3, during the process of increasing the engine speed, the ignition timing signal Si or
The frequency of Si′ and hence the vibrator output signal Sb
Since the frequency increases, the potential of the output Sv ₀ of the frequency-to-voltage conversion circuit 3 is in the process of rising from the point already mentioned, as shown in FIG. Therefore, both capacitors 42 and 52 at both inputs of the comparator are charged toward a higher voltage value, but as mentioned above, the positive input time constant τ ₁ including the capacitor 42 is faster than the other τ ₂ . Because of their short duration, in these transient conditions,
Even if there is a voltage drop due to the intervention of the diode 41, the positive input side signal Sv ₁ exceeds the potential of the negative input side signal Sv ₂ as shown after time Ta in FIG. 4, and therefore the comparison output The signal Sc is inverted and becomes "H" level. When the transient state of acceleration or RPM is over and the engine RPM becomes constant at a higher level than before,
In response, both capacitors 42 and 52 are fully charged again, the signal potential on the positive input side becomes lower than the negative input side by the forward voltage Vt of the level shift diode 41, and the comparator output is again inverted and becomes "L". ' level. When entering a transient state in which the engine speed decreases, the capacitors on both inputs of the comparator begin a discharging process, but due to the time constant relationship described above, the discharge on the positive input side is always faster, so in that transient state, The relationship between both inputs remains the same as during constant speed rotation, and the comparator output remains at the "L" level. The correlation between the comparator output Sc and each state mode of the internal combustion engine is as shown in Table 1 below.

[Table] As a result, it can be seen that the output Sc of the comparator 6 of the present device has the ability to discriminate between the engine speed increase mode and the other mode (constant speed, decrease; ie, non-increase mode). Therefore, if the comparator output Sc is used as the clutch disconnection command signal Sc to operate the compressor clutch disconnection circuit 8, and the compressor is deactivated when the signal Sc is "H" in this case,
Power loss during acceleration can be kept small. However, one of the objects of the present invention, as stated at the beginning, is not to immediately disconnect the compressor clutch whenever the engine enters the speed increasing mode, but to disengage the compressor clutch until the engine reaches a predetermined set speed. Sometimes I leave it connected while it is not working. Therefore, in the present invention, a gate circuit 7 is provided for the comparator output Sc, and unless information indicating that the rotation speed exceeds the set rotation speed is given to one input of this gate 7, the comparator output Sc will be It is arranged so that it does not function as a clutch disconnection command signal. In other words, the output signal S ₀ of the gate 7 becomes the activated clutch disengagement command signal. In order to make this gate 7 function as described above, in this embodiment, this gate 7 is configured as a two-input AND gate, and one input is given the above-mentioned comparator output signal Sc, while the other An output Ss from a second comparator or a set rotation speed reaching detection circuit 10, which indicates that the engine rotation speed has exceeded the set rotation speed, is applied to the input. To explain this point in detail, a comparator 10 having two inputs, a positive input and a negative input, is prepared, and one input of the comparator 10 is
In this case, a potential Es corresponding to the output Sv ₀ of the frequency-to-voltage conversion circuit 3 at the lowest rotation speed at which it is considered better to disconnect the compressor clutch is applied to the negative input from the minimum rotation speed setting circuit 9, and the other The output Sv ₀ of the frequency-to-voltage conversion circuit 3 is applied to the input, that is, the positive input in this case. In the end, whether or not the current engine rotation speed exceeds the set rotation speed is converted into a voltage and monitored.
However, monitoring in terms of current or resistance is also possible. As shown in FIG. 2, when monitoring by voltage, the reference potential Es corresponding to the set rotational speed can actually be obtained from a potentiometer 91 that divides the power supply potential. In such a circuit configuration, as shown in Fig. 4, even in the process where the engine speed increases from speed Vi to speed Vs, the frequency remains constant before reaching the predetermined speed Vs. Since the potential of the output Sv ₀ of the voltage conversion circuit 3 is lower than the reference voltage Es, the output of the second comparator or the set rotation speed attainment detection circuit 10 is "L", and therefore the gate 7 is closed. Therefore, even if the output from the comparator 6 having a rising mode detection function is an "H" level signal indicating the rising mode, this gate 7 cannot be passed. That is, gate 7
The output S ₀ of is "L". In the engine speed increase mode, when the engine speed exceeds the set speed Vs, the second comparator or the set speed reaching detection circuit outputs.
Ss becomes "H", gate 7 is opened, and the output signal S ₀ is "H" and significant as a clutch disengagement command signal.
is enabled. In this way, the object of the invention could be achieved. Under special conditions, such as when driving in a city area, the clutch can be disconnected reliably to prevent frequent engagement of the clutch and enable continuous acceleration, and under conditions where the engine's energy needs to be used as effectively as possible. It is from. Those skilled in the art will be able to freely configure the circuit configuration for operating the clutch disconnection circuit 8 using the output of the gate 7 or the clutch disconnection command signal _S0 using this type of logic circuit technology and logic level and power level conversion technology. You can assemble things. In the present invention, therefore, there is no direct limitation on this point, but an example will be shown based on the embodiment shown in the second figure. However, although shown in phantom lines in FIG. 1, in the specific embodiment shown in FIG.
In order to effectively utilize the present invention as a practical device, a clutch reconnection delay circuit 11 is also provided to provide a time delay in reconnecting the clutch, although this is not essential. Therefore, although the compressor clutch disconnection circuit 8 is not directly activated by the clutch disconnection command signal _S0 , the output _S0 ' of the clutch reconnection delay circuit 11 is connected to the gate 7 for clutch disconnection. Output S has the same logical information as ₀ . Therefore, the details of the clutch reconnection delay circuit 11 will be omitted here, and the operation of the compressor clutch disconnection circuit 8 will be described first. It is easy to configure the output S ₀ to S ₀ ′ to be obtained from an open collector type output section, and in that case, the drive relay 81
A working winding is inserted in series between the power supply and the open collector type output part, and its break contact 83
Power may be supplied to the active winding 84 of the electromagnetic clutch 82 via the electromagnetic clutch 82. As a result, when _the engine speed increases beyond the set speed, relay ₈
1 can be demagnetized and the clutch can be disconnected. If a monitor light 85 is provided in parallel with the electromagnetic clutch winding, the operation of this circuit can be notified to the driver. If you want to visually indicate when the clutch is disengaged, you can use the make contact of the drive relay 81. Next, the clutch reconnection delay circuit 11, which is not essential but would be desirable, will be briefly described. This circuit 11 also includes a third comparator 112, whose positive phase input is supplied with an appropriate potential Er lower than the power supply potential via a voltage dividing resistor network.
The negative input is supplied with an inverted signal of the output of the gate 7 via a switching inverter formed by a transistor 111, and is also supplied with a time constant determined by a time constant circuit comprising a resistor 113 and a capacitor 114. In the initial state, the capacitor 114 is considered fully charged and the negative input side is at a higher potential, so
The output of the comparator 112 is "L", but when the clutch disconnection command signal _S0 is applied to the input of this circuit 11, the transistor 111 is turned on and the charge in the capacitor 114 is rapidly discharged, so that the positive phase input is As a result, the output S ₀ ' of this circuit 11 rises rapidly, similar to the output S ₀ of the gate 7, and the clutch disconnection circuit 8 is activated by the mechanism described above. The clutch is immediately disengaged. However, even when the engine speed increase mode ends and the output of the gate 7 becomes "L", the output S ₀ ' of this circuit 11 does not fall suddenly. This is because charging of the capacitor 114 starts from the turn-off of the transistor 111, and a certain amount of time according to the above-mentioned time constant is required until the capacitor 114 exceeds the reference potential Er. This certain period of time may already be obvious, but
An appropriate value can be selected depending on the setting of the time constant of the resistor 113 and the capacitor 114 and the setting of the reference potential Er. This arrangement has the advantage that even when the vehicle is frequently decelerated and then accelerated again immediately after a short delay, the number of times the clutch is engaged and engaged does not need to be excessively increased. Therefore, by adopting this circuit 11 in addition to the configuration of the present invention that allows the clutch to be disengaged due to acceleration in consideration of the set rotation speed, a more practical compressor control device can be constructed. . Even if a delay time is to be created, those skilled in the art can think of various ways to create it. For example, in the above embodiment, the circuit 11 is configured as a discrete circuit, but it is possible to create a delay time using a monostable multivibrator using a commercially available IC. It is also possible to adopt a configuration in which the trigger is triggered by the falling edge of the output S ₀ of the gate 7. Further, the compressor clutch disconnection circuit 8 may be electronically formed using a semiconductor element, and other conventional means for circuit technology and logic level processing may be used as desired. Furthermore, even if one of the output signals Sv ₁ and Sv ₂ of the first and second integrating circuits 4 and ₅ is applied to the positive phase input side of the comparator 10 instead of the signal Sv 0, the reference potential It is possible to perform the same function as above by adjusting Es. As detailed above, according to the present invention, an electronic and 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 addition to providing a device that has high performance and does not require a special sensor and can be easily integrated into existing electrical systems, it also reduces the number of times the compressor clutch is repeatedly disconnected under driving conditions that involve frequent acceleration and deceleration. Therefore, wear of the compressor clutch and stress on the mechanical system can be reduced, and a practical device with high commercial value can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the main circuits of a basic embodiment of the device of the present invention, FIG. 2 is a circuit diagram of a slightly more specific example of the circuit configuration of the device shown in FIG. 3, and FIG. FIG. 4 is an explanatory diagram of frequency conversion, and is an explanatory diagram of changes in engine speed and voltage waveforms of main parts. In the figure, 1 is an engine ignition timing signal detection section, 2 is a waveform shaping circuit, 3 is a frequency-to-voltage conversion circuit, 4 and 5 are first and second integration circuits, 6 is a comparator, 7 is a gate circuit, and 8 is a 9 is a compressor clutch disconnection circuit, 9 is a clutch disconnection minimum rotation speed setting circuit, and 10 is a set rotation speed reaching detection circuit.

Claims (1)

[Scope of Claims] 1. A converted voltage output generation circuit that detects an ignition timing signal of an internal combustion engine mounted on a vehicle and generates an output whose voltage changes in accordance with the process of increasing the rotational speed from a constant speed rotation state; A comparator that receives outputs at two inputs and inverts the output depending on the magnitude of the two inputs, and gives different integration time constants to the two inputs of the comparator,
According to the change in the converted voltage output during the rotation speed increasing process, the difference in the integral time constant is used to make the comparator output, since the magnitude relationship of the two inputs is reversed during the rotation speed increase process. a compressor clutch disconnection device that receives the inverted output of the comparator as a clutch disconnection command signal and disconnects the clutch between the internal combustion engine and the compressor; a set rotation speed reaching detection circuit that issues an arrival detection signal when the set rotation speed reaches a predetermined set rotation speed; and a circuit that disables the clutch disengagement command signal when the set rotation speed reaching detection signal is not received, and disables the compressor clutch intermittently. An automatic disconnection device for a compressor clutch for use in a vehicle, comprising: a gate circuit that prevents the device from disengaging the clutch.