JPS60153436A - Engine speed controller for industrial hybrid vehicle - Google Patents

Abstract

PURPOSE:To eliminate the wastage of fuel as well as to make highly efficient operation performable, by detecting a mounted engine speed by an actuator at a time when a power generation useless state is judges with a mode judging circuit. CONSTITUTION:In case of an industrial hybrid vehicle which drives a generator by a mounted engine, charging a battery, and performs operation with the generator driven by this electric power, a control position of an operating lever is detected by a lever switch 11, an accelerator pedal's operation by an accelerator switch 12 and a battery's charging state by a voltage sensor 13, respectively, and these detected values are all inputted into a judging circuit 15 by way of an input signal former 14. And, when a power generation useless state if judged, an actuator 16 is driven via a drive circuit 17 while receiving the feedback of a signal out of a travel sensor 18, and a mounted engine speed is decelerated. With this constitution, when the battery is in a state of being overcharged and small in working load, no wastage of fuel occurs, thus highly efficient operation is performable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine rotation speed control device for an industrial hybrid vehicle, especially when the load is small.

2. Description of the Related Art Hybrid type industrial vehicles such as forklifts that use both a gasoline engine and an electric motor are known.

In this method, the engine is operated at a constant rotational speed taking into account its fuel consumption rate, etc., and the generator is driven to charge the battery. The work required of the vehicle is then performed by the electric motor supplied with electric power from the battery.

In this case, in response to changes in the workload, the amount of power generated by the generator is increased or decreased by changing the field current of the generator.
It is designed to control the power supplied to the electric motor.

The constant rotational speed of the engine is set in consideration of the generator drive associated with power consumption during work. Therefore, when the work load is moderately heavy, the fuel consumption rate is reduced and the work can be performed with high efficiency.

However, even when the engine is in an overcharged state and the workload is light, that is, when power generation is not required, the engine is operated at the above-mentioned constant rotational speed. As a result, fuel is wasted, resulting in poor efficiency.

This invention was made in view of the above circumstances,
In an industrial hybrid vehicle in which an onboard engine drives a generator to charge a battery, and the electric power supplied from the battery drives an electric motor that performs work, a lever switch that detects the operating position of a work lever;
an accelerator switch that detects depression of the accelerator pedal; a voltage sensor that detects the state of charge of the battery; and a mode determination circuit that determines whether power generation is unnecessary based on detection signals from the lever switch, the accelerator switch, and the voltage sensor. , and an actuator that reduces the rotational speed of the installed engine according to the determination result of this mode determination circuit, it is possible to perform highly efficient operation without wasting fuel, and also to reduce noise. An object of the present invention is to provide an engine rotation speed control device for an industrial hybrid vehicle that can reduce the engine rotation speed of an industrial hybrid vehicle.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows its configuration, including a lever switch 1 that detects the operating position of each work lever on the vehicle, an accelerator switch 12 that detects the depression of the accelerator pedal, and a voltage sensor 13 that detects the state of charge of the battery. The signals are each input to an input signal former 14 . The input signal generator 14 converts each of the detection signals described above into a form suitable for determining the load condition of the vehicle, and sends the converted signal to the mode determination circuit 15.

The mode determination circuit 15 determines the load state of the vehicle and the state of charge of the battery based on each of the sent detection signals.

As a result, when it is determined that the load is small and the battery is overcharged, that is, when there is no need to generate electricity, a signal is sent to reduce the rotational speed of the engine. This signal is sent to an actuator drive circuit 17 that drives an actuator 16 consisting of, for example, an electric cylinder, which controls the engine as a governor. The actuator drive circuit 17 drives the actuator 16 based on the rotational speed reduction signal and performs governor control to lower the rotational speed of the engine. Note that the amount of movement of the actuator 16 is determined by the amount of movement of the actuator 16 provided in the vicinity of the actuator 16.
The detection signal from the movement sensor 18 causes the actuator drive circuit 17 to:
Ninal so as to control the amount of movement of the actuator 16 by additional value.

Figure 2 shows the generator output and battery characteristics of the vehicle shown in Figure 1. In the figure, A1 to A3 each represent the generator output characteristics, B is the battery discharge characteristic, and C is the battery charging characteristic. Show characteristics. In A1-A3, the amount of current of the exciter of the generator is set in three stages according to the engine rotation speed. This is A when the load required on the vehicle is large, such as during work, and the engine is operated at a constant rotational speed and driven by a generator as in the conventional vehicle. A2 is a case in which the load required on the vehicle is small but the battery needs to be charged, and the engine is operated at a rotation speed lower than the above-mentioned constant rotation speed. When the load required on the vehicle is small and the battery is in an overcharged state, that is, when power generation is not required, the engine rotation speed is lowered even more than in A2, as in A3, to reduce the amount of power generated. .

Figure 3 shows a circuit for controlling the industrial hybrid vehicle shown in Figure W1, and when the lever switch 11 or accelerator switch 12 is turned on, the analog switch 21 is turned on in conjunction with this. . This analog switch 21 includes a potentiometer 22 and a subtractor 23.
When this switch 21 is closed, the potentiometer 22
A voltage signal set in advance is input to the subtracter 23. Here, subtractor 2
3 directly receives the detection signal from the voltage sensor 13 that detects the state of charge of the battery, and inputs the input/? - two analog switches 25 connected via a switch 24;
Two potentiometers 27, 28 intervening 26 are also connected. These two analog switches 25°26
are opened and closed in response to the detection signal of the voltage sensor 13, and along with this opening and closing, the potentiometer 2
From 7.28, a respective preset voltage signal is sent to one input of the subtracter 23. Further, a potentiometer 29 connected to the actuator 16 is connected to the ten-power side of the subtracter 23. Therefore, this subtractor 23 calculates the difference between the ten-man power and the one-man power, and sends the result to one input terminal of the second subtractor 3o and the third subtractor 3o.
Send it to the 10-person force side. The second subtracter 30 is connected to the potentiometer 32 on the power side, and calculates the difference between the voltage signal set in the potentiometer 32 and the output of the subtracter 23, and sends the result to the two inverters. Send on 33.34. Further, one input terminal of the third subtracter 3 is connected to a potentiometer 35 configured in series with the potentiometer 32, and the voltage signal set to the potentiometer 35 and the output of the subtracter 23 are connected to the potentiometer 35. The difference is calculated and the result is sent to two inverters 36 and 37.

Two in/Js connected to the output side of the second subtractor 3θ
The two inverters 36.37 connected to the output side of the third subtractor 31 and 33.34 are connected to the transistors 42, 43 and 44. through diodes 38, 39 and 4.theta. 45 pace terminal. These transistors 42, 43 and 44 transistors 45 constitute a bridge-like circuit 46 that connects the actuator 16, and connects the two inverters 33.
Depending on the output from either 34 or 36.37, either transistor 42゜43 or l@44.45 uses a continuity meter to set the voltage from the actuator 16VC and the power supply terminal 47 to make the engine no longer need to generate power. ,
By comparing this with each detection signal from the lever switch 11, accelerator switch 12, and voltage sensor 13, the governor control is performed so that the actuator 16 is rotated in the forward and reverse directions, and the rotational speed of the engine is accelerated or decelerated.

In the above embodiment, the engine speed is decelerated when power generation is not required, but it is also possible to have a function that automatically or manually stops the engine when power generation is not required. .

As described above, according to the present invention, in an industrial hybrid vehicle in which a generator is driven by an on-board engine to charge a battery, and the electric power supplied from the battery is used to drive an electric motor that performs work, the work lever can be moved. A lever switch that detects the operating position, an accelerator switch that detects the depression of the accelerator pedal, a voltage sensor that detects the state of charge of the battery, and each detection signal from the lever switch, pedal switch, and voltage sensor. The system is equipped with a mode determination circuit that determines whether power generation is required or not, and an actuator that reduces the rotational speed of the engine according to the determination result of this mode determination circuit, especially when the battery is overcharged and the workload is small. To provide an engine rotation speed control device for an industrial hybrid vehicle that can perform highly efficient operation without wasting fuel, reduce noise, and prevent deterioration of a generator. I can do it.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an engine rotation speed control device for an industrial hybrid vehicle according to an embodiment of the present invention, and FIG.
1 is a diagram showing the characteristics of the device shown in FIG. 1, and FIG. 3 is a diagram showing the control circuit of the device shown in FIG. 11... Lever switch, 12... Accelerator switch 1
0- switch, 13... Voltage sensor, 14... Input signal former, 15... Mode determination circuit, 16... Actuator, 17... Actuator drive circuit, 18...
Movement amount sensor, 21, 25.26... Analog switch, 22, 27.2B, 29, 32.35... Potentiometer, 23, 30.31... Subtractor. Applicant Sub-Agent Patent Attorney Takehiko Suzue 11- Sango

Claims (1)

[Claims] In an industrial hybrid vehicle that uses an onboard engine to drive a generator and a parallel power source to drive an electric motor to perform work, a lever switch that detects the operating position of a work lever, an accelerator switch that detects the depression of an accelerator pedal, A voltage sensor that detects the state of charge of the battery; a mode determination circuit that determines whether power generation is unnecessary based on detection signals from the lever switch, accelerator switch, and voltage sensor; An engine rotational speed control device for an industrial hybrid vehicle, comprising an actuator that reduces the rotational speed of the installed engine.