JPH04325736A - Exhaustion preventing method for battery of vehicle - Google Patents

Abstract

PURPOSE:To prevent exhastion of a battery used in a vehicle in which an elec tric auxiliary driving system for an internal combustion engine is mounted. CONSTITUTION:An electric auxiliary driving system for an internal combustion engine is provided in a such a constitution that auxiliary torque is given from an electric machine (an alternating current rotator 3) to an internal combustion engine (a diesel engine 1) at the time of starting and accelerating of a vehicle. In this system, charging condition of a battery 8 is detected by a battery condition detector 14 so as to find out the charging rate alpha of the battery 8 (step S103). An auxiliary torque amount able to be supplied from the alternating current rotator 3 to the diesel engine 1 is calculated on the basis of the charging rate alpha (step S104). A fuel amount given to the diesel engine 1 and a load ratio of the alternating current rotator 3 are changed by the auxiliary torque amount capable of being supplied (step S105 to S108). It is thus possible to prevent exhaustion of the battery 8 when the charging rate alpha becomes in a low level, without using the alternating current rotator 3 as the electric machine even if the auxiliary torque is necessitated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing a battery from draining in a vehicle equipped with an internal combustion engine/electrical auxiliary drive system.

0002

BACKGROUND OF THE INVENTION This type of internal combustion engine/electrical auxiliary drive system incorporates a thin AC rotating machine in the flywheel housing of a large diesel engine, and controls the operation of the AC rotating machine with an inverter. Regenerates brake energy as electricity and charges the battery.
It has been proposed as a device that assists the diesel engine with torque when starting and accelerating a vehicle.

[0003] In a vehicle equipped with this system, when going uphill, etc., the AC rotary machine is used as an electric motor by an inverter device, and by supplying energy from the battery to the electric motor, the electric motor gives auxiliary torque to the diesel engine. By providing auxiliary torque to the diesel engine in this manner, it is possible to reduce the load on the engine when the vehicle starts or accelerates, and to reduce exhaust black smoke.

0004

[Problems to be Solved by the Invention] However, in the case of a vehicle equipped with the above-mentioned system, for example, if a long uphill climb continues, the drive assistance time of the electric motor becomes longer, and the ratio of fuel and auxiliary drive during auxiliary drive becomes lower than that of the battery. Since it is constant regardless of the charging state, there is a problem that there is a concern that the battery will run out.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for preventing a vehicle battery from draining, which eliminates the above-mentioned disadvantages and prevents the battery from draining.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the method for preventing the rise of a vehicle battery according to the present invention provides an internal combustion engine/electric motor equipped with an electric motor that provides auxiliary torque to the internal combustion engine when starting or accelerating the vehicle. In the auxiliary drive system, a state of charge of the battery is detected, an amount of auxiliary torque that can be supplied from the electric motor to the internal combustion engine is calculated based on the detected state of charge, and fuel is supplied to the internal combustion engine from the amount of auxiliary torque that can be supplied. This changes the amount and the load ratio of the electric motor.

[0007]

[Operation] The present invention calculates the amount of auxiliary torque that can be supplied from the electric motor to the internal combustion engine based on the charging rate α of the battery, and calculates the amount of fuel to be supplied to the internal combustion engine and the burden ratio of the electric motor from the amount of auxiliary torque that can be supplied. Therefore, if the charging rate α becomes small, no current is supplied from the battery to the electric motor even if auxiliary torque is required, thereby preventing the battery from dying.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the illustrated embodiments.

FIG. 1 is a block diagram showing an engine-electrical auxiliary drive system that implements an embodiment of the method for preventing the rise of a vehicle battery according to the present invention.

In FIG. 1, a large diesel engine 1
A thin AC rotating machine (induction machine) 3 is built into a flywheel housing 2. A transmission 4 is provided at the rear of the flywheel housing 2. A rotation sensor 5 is provided on the rotation shaft of the diesel engine 1. The AC rotating machine 3 is connected to an inverter device 6, and the inverter device 6 includes a resistor 7,
Battery 8 is connected. This inverter device 6 is controlled by a control circuit 10. In addition, the control circuit 10
consists of a processing unit (CPU), a memory that stores necessary processing programs, etc., and an input/output device that inputs and outputs signals to and from the outside. This control circuit 10 stores necessary diagrams and the like (diagrams in FIGS. 3 to 5, which will be described later) in advance, and is configured to obtain necessary data from the input detection signal. The control circuit 10 also receives a rotation detection signal from the rotation sensor 5, a signal from the retarder adjustment lever 11, an accelerator opening signal from the accelerator sensor 12, a signal from the starter switch 13, and the state of charge of the battery 8. A detection signal from a battery state detector 14 capable of detecting the detection signal is inputted to the battery state detector 14, respectively. In addition, accelerator sensor 1
The accelerator opening signal No. 2 is input to the electronic governor 15 so that the fuel injection pump 16 can be driven. The control circuit 10 also instructs the electronic governor 15 to stroke the fuel lever.

In such a system, when starting the engine, the control circuit 10 receives a signal from the starter switch 13 and drives and controls the inverter device 6 to operate the AC rotating machine 3 as a starter. When the vehicle starts or accelerates, the control circuit 10 receives a signal from the accelerator sensor 12 and controls the drive of the inverter device 6 to operate the AC rotating machine 3 as a torque assist motor. Furthermore, when braking the vehicle, the control circuit 10 receives a signal from the retarder adjustment lever 11 and drives and controls the AC rotating machine 3 to retarder (
It operates as a regenerative brake. At this time, if the regenerative braking is insufficient, braking energy is consumed by the resistor 7. Further, the battery 8 is charged by driving and controlling the inverter device 6 by the control circuit 10 to generate regenerative energy from the AC rotating machine 3, or by operating the AC rotating machine 3 as an alternator.

Next, an explanation will be given of the operation for preventing the battery from running out in the above system.

First, the drawings used in the explanation of this operation will be explained. FIG. 2 is a flowchart for explaining the operation of preventing the vehicle battery from draining. 3 and 4 are explanatory diagrams for explaining that the battery state can be detected by the battery state detector. The charging rate α is detected by the terminal voltage, as shown in Figure 4.
The charging rate α is detected by measuring the temperature and specific gravity of the battery fluid in the battery 8. FIG. 5 is an explanatory diagram showing the relationship between torque and engine speed.

In these figures, when the control circuit 10 is informed by the depression amount signal from the accelerator sensor 12 that the fuel pedal has been depressed (step S101),
Based on the depression amount signal, it is determined whether torque assistance is required (step S102). If it is determined that torque assistance is not necessary (step S102), the control circuit 10 returns to the original process without performing any particular torque assistance operation (step S101).

Here, if it is determined that torque assistance is necessary (step S102), the control circuit 10 controls the battery state detector 14 when the battery state detector 14 obtains the charging rate α based on the terminal voltage of the battery 8. Compare the detection signal from the battery status detector 1 with the characteristic diagram in Fig.
4 obtains the charging rate α based on the specific gravity of the electrolyte of the battery 8, the charging rate α of the battery 8 is determined by comparing the detection signal from the battery state detector 14 with the characteristic diagram of FIG. 4 (step S103). . This charging rate α is determined as follows. Detecting the voltage of the battery 8 with the battery status detector 14,
The charging rate α is calculated based on which point on the characteristic V in FIG. 3 the detected voltage is located. At this time, the characteristic V is the capacity at 25°C, C25, and the capacity at a certain temperature t, Ct.
When the coefficient is k, from the relationship C25=Ct/{1+k(t-25)}, 25
The charging rate α can be obtained by determining the capacity at an arbitrary temperature t from the capacity at °C. Or battery 8
The specific gravity is determined, and the charging rate α at the temperature t is determined from the relationship between specific gravity and charging rate α shown in FIG. 4 at a temperature of 25°C.

Next, in the control circuit 10, the charging rate α
The range that can be assisted by the motor 7 is determined from the relationship between the amount of torque and the rotational speed shown in FIG. 5, which is stored in advance (step S104). In addition, in FIG. 5, if the maximum torque of the engine is Tm, the range assisted by the AC rotating machine 3 is S,
Further, the output range of the diesel engine 1 is indicated by Pw. Further, as shown in Table 1, the range of the auxiliary torque decreases as the charging rate α decreases.

[0017]

[Table 1]

The control circuit 10 also calculates the torque to be generated by the diesel engine 1 by subtracting the auxiliary torque from the required torque (step S105).
, instructs the fuel lever stroke based on the calculation result (step S106), and instructs the inverter device 6 to specify the amount of power to be supplied to the AC rotating machine 3 (step S107). Next, the control circuit 10 checks whether the required output is generated (step S108), and if it is not generated, the process goes to step S105, and if it is generated, the process returns to step S101.

Note that when the depression amount signal from the accelerator sensor 12 becomes smaller than the previous time, or when the battery 8
When the torque is on the verge of rising, the current assistance is unnecessary (step S102), and generation of the assistance torque from the AC rotating machine 3 is stopped (step S109).

As described above, in this embodiment, during the auxiliary torque operation, the ratio between the amount of fuel supplied to the diesel engine 1 and the auxiliary torque is controlled by the inverter device 6 according to the state of charge of the battery 8. Since the auxiliary torque is not generated when the state of charge of the battery 8 is deteriorated, the battery 8 does not run down.

[0021]

[Effects of the Invention] As explained above, the present invention uses an inverter to adjust the ratio between the amount of fuel supplied to the diesel engine and the auxiliary torque during auxiliary torque operation according to the state of charge of the battery. Since the auxiliary torque is not generated when the state of charge of the battery is deteriorated, there is an effect that the battery will not run out of power.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a system for implementing an embodiment of a method for preventing battery aging of a vehicle according to the present invention.

FIG. 2 is a flowchart for explaining an embodiment of the present invention.

FIG. 3 is a diagram for determining the charging rate of the battery from the battery terminal voltage detected by the battery status detector in the embodiment of the present invention.

FIG. 4 is a diagram for determining the charging rate of the battery from the specific gravity of the battery solution detected by the battery status detector in the embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between torque and rotational speed in an embodiment of the present invention.

[Explanation of symbols]

1 Diesel engine 2 Flywheel housing 3 AC rotating machine 5 Rotation sensor 6 Inverter device 8 Battery 10 Control circuit 12 Accelerator sensor 15 Electronic governor

Claims (1)

[Claims] 1. In an internal combustion engine/electrical auxiliary drive system that includes an electric motor that provides auxiliary torque to the internal combustion engine when starting or accelerating a vehicle, the state of charge of the battery is detected,
The amount of auxiliary torque that can be supplied from the electric motor to the internal combustion engine is calculated based on the detected state of charge, and the amount of fuel to be supplied to the internal combustion engine and the load ratio of the electric motor are changed from the amount of auxiliary torque that can be supplied. How to prevent vehicle batteries from rising.