FUEL SUPPLY APPARATUS IN CONSTRUCTION MACHINE

Abstract

A fuel supply apparatus able to stop actuating of a fuel supply pump without mounting a special fuel supply sensor when the fuel supply is stopped or becomes slow, includes a control section which calculates an amount of the fuel in the fuel tank based upon a signal from a fuel gauge, and outputs the result to a fuel meter. The control section also calculates from the fuel gauge signal the amount of the supplied into the fuel tank per unit of time, and if the amount of the fuel supplied per unit of time is determined to be less than a set supply rate, the fuel supply pump is stopped so that a malfunction of the fuel supply can be detected without mounting a special fuel supply sensor.

Claims

1. A fuel supply apparatus in a construction machine including a fuel tank, the apparatus comprising: a fuel supply pump for supplying fuel to the fuel tank, a strainer that filters the fuel supplied to the fuel tank, and a control section for calculating a remaining amount of fuel in response to a signal from a fuel gauge measuring the amount of fuel remaining in the fuel tank, and for outputting the calculated remaining amount to a fuel meter for displaying the amount, wherein the control section further includes: fuel supply determining means for determining whether or not fuel is being fed into the fuel tank using the signal from the fuel gauge when the fuel supply pump is active, and fuel supply pump stopping means for stopping the fuel supply pump based upon an indication by the fuel supply determining means.

2. The fuel supply apparatus in a construction machine according to claim 1, wherein the fuel supply determining means determines the fuel being supplied unit of time, and when the fuel supply amount per unit of time is not larger than a set supply rate, the fuel supply pump stopping means stops the fuel supply pump.

3. The fuel supply apparatus in a construction machine according to claim 1, further comprising notification means, wherein the control means outputs a notification instruction to said notification means to give a notification when the fuel supply pump stopping means stops the fuel supply pump.

4. The fuel supply apparatus in a construction machine according to claim 1, wherein the control section includes timer control means for instructing the fuel supply pump stopping means to stop the fuel supply pump when a fuel supply stoppage condition has lasted for a preset timer time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a general side view of a hydraulic excavator;

[0019] FIG. 2 is a side view of a fuel tank;

[0020] FIG. 3 is a block circuit diagram of a control system; and

[0021] FIG. 4 is a flowchart of the control system.

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] An embodiment of the present invention will be described based on the drawings. As depicted in the drawings, a hydraulic excavator that is an example construction machine is configured as in the case of the related art. The hydraulic excavator includes a traveling machine body 1. The traveling machine body 1 includes a lower traveling body 2 like a crawler and an upper slewing body 3 mounted on the lower traveling body 2 so as to be able to slew around a vertical axis. The upper slewing body 3 has various member apparatuses such as a front working section 4 with a boom 4a, an arm 4b, and a bucket 4c, an operation room (cab) 5, an engine room 6, a counterweight 7, a fuel tank 8, and a hydraulic oil tank 9.

[0023] A hose 10 for fuel supply is connected to a fuel supply port 8a of the fuel tank 8. The hose 10 is connected to a supply port of a fuel supply pump 12 integrated with a strainer 11 set in the fuel supply port 8a. Fuel is fed into the fuel tank 8 as follows. With a tip of the hose 10 inserted into a fuel container 13 such as a drum, a fuel supply switch 14 provided in the operation room 5 is turned on. This operation signal is input to a control section CPU including a microcomputer. Based on the operation signal, the control section CPU outputs an operation instruction to the fuel supply pump 12. The fuel supply pump 12 is thus actuated to feed the fuel into the fuel tank 8 via the strainer 11. In this case, the fuel supply pump 12 and the strainer 11 may of course be separated from each other instead of being integrated together.

[0024] A fuel gauge 15 is provided on a side surface plate 8b of the fuel tank 8. A gauge main body 15a of the fuel gauge 15 extending into the fuel tank 8 has an arm 15c that pivots around a support shaft 15b in an up-down direction. Afloat 15d is provided at a tip of the arm 15c. A potentiometer 15e converts, into an electrical signal, a pivoting amount (pivoting angle) by which the arm 15c pivots in conjunction with up-down movement of the float 15d floating on a surface of the fuel remaining in the fuel tank 8. The signal is input to the control section CPU, which then calculates the amount of the fuel remaining in the fuel tank 8 based on the input electrical signal. The control section CPU outputs a control instruction to a fuel meter 16 to allow the fuel meter 16 to display the result of the calculation.

[0025] When the fuel supply switch 14 is turned on, the control section CPU controls determination of a fuel supply amount. A procedure for this determination control will be described below using a flowchart in FIG. 4. As described above, when the fuel supply switch 14 is turned on, a fuel supply amount determination control routine is started. First, the control section CPU determines whether or not fuel has been supplied, in other words, whether or not an electrical signal from the potentiometer 15e has changed to a fuel increase side (S1). When the result of the determination is NO, indicating that no fuel has been supplied, whether or not a first timer 17 has been set is determined (S2). When the result of the determination is NO, indicating that the first timer 17 has not been set (the first timer 17 has been reset), the control section CPU sets the first timer 17 (S3) and returns to S1 where whether or not fuel has been supplied is determined. Then, when the control section CPU determines again in S2 that no fuel has been supplied and the determination result in S2 is YES, indicating that the first timer 17 has been set, the control section CPU determines whether or not a count time C1 counted by the first timer 17 exceeds a timer time (for example, five seconds) T1 (C1>T1) (S4). When the determination result is NO, indicating that the count time C1 does not exceed the timer time T1. The control section CPU returns again to determination of whether or not fuel has been supplied in S1. On the other hand, when the determination result in S4 is YES, indicating that the count time C1 exceeds the timer time T1, the control section CPU determines that no fuel has been supplied to output a stoppage instruction to the fuel supply pump 12 (S5), while outputting a notification instruction to first notification means 18 such as a buzzer (S6).

[0026] In contrast, when the determination result in S1 is YES, indicating that fuel has been supplied, the control section CPU calculates a supply amount (an increase amount) U per unit time (S7) to determine whether or not the supply amount U is larger than a preset set supply amount X per unit time (U>X?) (S8). When the determination result is NO, indicating that the supply amount U is not larger than the set supply amount X, the control section CPU determines whether or not a second timer 19 has been set (S9). When the determination result is NO, indicating that the second timer 19 has not been set, the control section CPU sets the second timer 19 (S10) and returns to S1 where the control section CPU determines whether or not fuel has been supplied. In contrast, when the determination result in S9 is YES, indicating that the second timer 19 has been set, the control section CPU determines whether a count time C2 counted by the second timer 19 exceeds a preset timer time (for example, 10 seconds) T2 (C2>T2) (S11). When the determination result is NO, indicating that the count time C2 does not exceed the timer time T2, the control section CPU returns to S1 where the control section CPU determines whether or not fuel has been supplied. On the other hand, when the determination result in S11 is YES, indicating that the count time C2 in the second timer 19 exceeds the timer time T2 (C2>T2), the control section CPU determines that the fuel supply amount is smaller than the set supply amount to output the stoppage instruction to the fuel supply pump 12 (S12). The control section CPU also outputs the notification instruction to second notification means 20 (S13).

[0027] On the other hand, when the determination result in the above-described S8 is YES, indicating that the fuel supply amount U per unit time is larger than the preset set supply amount X per unit time (U>X), the control section CPU determines whether or not the fuel tank 8 has been filled up (the fuel tank 8 is full) (S14). When the determination result is NO, indicating that the fuel tank 8 is not full, the control section CPU returns again to S1 where the control section CPU determines whether or not fuel has been supplied. When the determination result is YES, indicating that the fuel tank 8 is full, the control section CPU outputs the stoppage instruction to the fuel supply pump 12 (S15), while outputting the notification instruction to third notification means 21 (S16), thus notifying an operator that the fuel supply operation has ended.

[0028] The first, second, and third notification means 18, 20, and 21 may be single notification means. The single notification means allows the operator to recognize that the fuel supply pump 12 has been stopped, by varying the contents of the notification according to the situation.

[0029] In the embodiment of the present invention configured as described above, if the fuel container 13 becomes empty to disrupt fuel supply started by turning on the fuel supply switch 14, the fuel supply pump 12 is automatically stopped and can thus be prevented from being seized. The automatic stoppage of the fuel supply pump 12 is based on the determination, by the control section CPU, of whether or not fuel has been supplied based on the signal from the fuel gauge 15, which monitors the amount of fuel remaining in the fuel tank 8. This eliminates the need for a dedicated sensor that monitors fuel supply. As a result, the number of components can be reduced, and the maintenance of the sensor is not needed.

[0030] Furthermore, in the embodiment, when the fuel supply amount is determined to be excessively small during fuel supply, the strainer 11 is determined to be clogged, and this is determined to be abnormal. Then the fuel supply pump is automatically stopped. As a result, measures for dealing with the clogged strainer 11 can be immediately taken to improve workability. Determination of whether or not the strainer 11 is clogged is made based on calculation by the control section CPU, which makes determination for the case where fuel supply has been disrupted. This eliminates the need for a dedicated sensor that detects the clog, thus reducing the number of components and enhancing maintainability.

[0031] Moreover, if such abnormalities occur, the first and second sensors 18 and 20 give notifications to the operator to allow the operator to immediately recognize that fuel supply has been abnormal.

[0032] Furthermore, determination of whether or not fuel supply has been abnormal is made when the preset timer time is exceeded. As a result, possible malfunction can be prevented when an abnormality signal is input due to noise or the like.

INDUSTRIAL APPLICABILITY

[0033] The present invention can be utilized in the field of a fuel supply apparatus in a construction machine such as a hydraulic excavator.

EXPLANATION OF REFERENCE NUMERALS

[0034] 1 Traveling machine body

[0035] 8 Fuel tank

[0036] 11 Strainer

[0037] 12 Fuel supply pump

[0038] 13 Fuel container

[0039] 14 Fuel supply switch

[0040] 15 Fuel gauge

[0041] 16 Fuel meter

[0042] 17 First timer

[0043] 18 First notification means

[0044] 19 Second timer

[0045] 20 Second notification means

[0046] CPU Control section