GB2076973A

GB2076973A - Fuel economy indicator

Info

Publication number: GB2076973A
Application number: GB8115347A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1980-05-26
Filing date: 1981-05-19
Publication date: 1981-12-09
Also published as: JPS56172724U; FR2483075A1; DE3120976A1

Abstract

A fuel economy indicator has a divider 4 for obtaining travelling distance per unit amount of fuel consumption from a distance counter 13 and a fuel flow counter 32 and a display means 52 for displaying the result of the arithmetic operation. The counters 13, 32 and the display means 52 are operated at respectively different given timings by timers 22, 23 which give outputs at different counts of pulses from clock 21. Further, the fuel economy indicator includes a fuel flow sensor comprising a fuel velocity responsive means to generate an output having a frequency proportional to the flow velocity and a switch means for alternately switching the flow direction of the fuel through a passage containing a float whose oscillations are sensed photo-electrically (Figs 2 and 3). <IMAGE>

Description

SPECIFICATION Fuel economy indicator for an automotive vehicle The present invention relates to a fuel economy indicator for an automotive vehicle for determining and displaying vehicle-travel distance per unit amount of fuel. More particularly, the invention relates to a fuel economy indicator capable of performing arithmetic operations for obtaining the travel distance of the vehicle per unit amount of fuel consumed and displaying the obtained result at independent time intervals.

The fuel economy indicator has been applied to an automotive vehicle for controlling the cruising of the vehicle to adapt the vehicle driving to most economical condition. As is well known, the fuel economy can be obtained by dividing the travelled distance by the fuel amount consumed for travelling distance.

Conventionally, the fuel economy indicator effect the arithmetic operations at a given interval and display the result of the arithmetic operation simukane ously. Since such a conventional fuel economy indicator has the same timing for performing the arithmetic operations and displaying the result, it may not accurately determine the amount of fuel consumed, particularly while the vehicle is being driven at a relatively low speed. Furthermore, if the display is changed at intervals determined by the amount of fuel consumed, the interval of change of the display varies according to the condition of the vehicle.

Therefore, it is an object of the present invention to provide a fuel economy indicator capable of performing the arithmetic operations and displaying the result at respectively independent time intervals.

Another object of the invention is to provide the fuel economy indicator having a fuel flow sensor responsive to the amount of the fuel flowing through the fuel supply circuit of the engine.

To accomplish the above-mentioned and other objects, there is provided a fuel-economy indicator having an arithmetic means for performing the arithmetic operations for obtaining the travelling distance per the unit amount of fuel consumed and a display means for displaying the result of the arithmetic operations. Respective arithmetic means and the display means are respectively operated at respectively independent given timings. Further, the fuel economy indicator includes a fuel flow sensor responsive to the amount of the fuel flowing through the fuel-supply circuit. The fuel-flow sensor comprises a fuel-flow-amount responsive means to generate an output having a frequency proportional to the determined amount of fuel flow and a switch means for switching the flow direction of the fuel flowing through the fuel-amount-responsive means.

According to one embodiment of the invention, there is provided a fuel economy indicator for an automotive vehicle comprising a first means for determining travelling distance of the vehicle and producing a first signal indicative of the determined travel distance, a second means for determining a fuel amount of fuel consumed for travelling the determined travel distance and producing a second signal indicative of the determined fuel amount, an arithmetic means for receiving said first and second signals at a first given interval and performing arithmetic operations for determining the travel distance per unit amount of the fuel consumed, the arithmetic means producing a third signal indicative of the determined travelling distance per unit amount of the fuel, and a display means for receiving the third signal from the arithmetic means at a second given interval to display the determined travelling distance per the unit amount of the fuel consumed.

The present invention will become more fully understood from the detailed description given hereinbelow and from the accompanying drawings of the preferred embodiment of the present invention, which however, should not be taken as limitative to the present invention but for elucidation and explanation only.

In the drawings: Fig. 1 is a schematic block diagram of a preferred embodiment of a fuel economy indicator according to the present invention; Fig. 2 is a longitudinal section of a fuel flow sensor applied in the fuel economy indicator of Fig. 1, in which the sensor is in a position allowing the fuel flow in one direction; and Fig. 3 is a similar view to Fig. 2 but showing the sensor position allowing the fuel flow in the other direction.

Referring now to the drawings, particularly to Fig.

1, there is illustrated a preferred embodiment of a fuel economy indicator according to the present invention. A travelling distance sensor 11 produces a sine-wave signal having a frequency proportional to the vehicle speed. The sine-wave signal is fed to a shaping circuit 12 to be shaped into a rectangular pulse train therein. The frequency of the shaped pulse train is substantially the same as that of the sine-wave signal and, therefore, is proportional to the vehicle speed. A counter 13 receives the shaped pulse train outputted by the shaping circuit 12 and counts up the number of pulses. This distance sensor 11, the shaping circuit 12 and the counter 13 constitute a travelling distance determining means 1.

A timer circuit 2 comprises a clock generator 21 and timers 22 and 23. The clock generator 21 produces a clock signal having a given pulse duration, for example 1 second. The clock signal is fed to the timers 22 and 23 which count up the number of pulses and output gate signals when the counted pulse numbers becomes equal to the respectively predetermined values. In other words, the timer 22 outputs a gate signal every predetermined period of time, for example every 30 sec. Likewise, the timer 23 generates a gate signal every predetermined period oftime.

A fuel amount determining circuit 3 includes a fuei-flow sensor 31 generates a pulse train having a frequency proportional to the flow amount of the fuel flowing therethrough. The pulse train representative of the fuel-flow amount is fed to a counter 32 in which the pulse number is counted.

Both of the counters 13 and 32 are respectively responsive to the gate signal generated by the timer 22 to output respective outputs indicative of the counted values. Both outputs of the counters 13 and 32 are inputted to a divider 4. The divider divides the output of the counter 13 representative of the deter mined travelling distance by the output of the counter 32 representative of the determined fuel amount in order to obtain the travelling distance of the vehicle per the unit amount of fuel. The divider output is fed to a memory 51. The memory 51 is coupled with a display unit 52 to feed the value obtained by the dividing operation in the divider4 for display. The memory 51 is responsive to the gate signal of the timer 22 to update the storage according to the output received from the divider 4.The memory unit 51, in turn, produces an output indicative of the stored value to be fed to the display unit 52, in response to the gate signal fed from the timer 23. Also, the display unit 52 is responsive to the gate signal ofthe timer 23 to vary the content on the display corresponding to the input from the memory 51. The memory 51 and the display unit 52 constitute a display circuit 5.

It is to be noted that the predetermined values in the timers 22 and 23 define respectively time intervals for the arithmetic operations and the display and are independent of each other and can be varied, if necessary. In the preferred embodiment of the present invention, the value preset in the timer 22 is adapted to the frquency of performance of arithmetic operations for obtaining the travel distance of the vehicle per unit amount of fuel consumed and the preset value in the time 23 is adapted to the interval in which the driver can easily perceive the indicated fuel economy.

Referring to the drawings Figs. 2 and 3, there are illustrated a preferred embodiment of the fuel flow sensor to be applied for the fuel economy indicator of the present invention.

As shown in Fig. 2, the fuel flow sensor 31 includes an electric circuit which has been shown in blockform. The fuel flow sensor 31 generally comprises a flow sensitive means 100 into which is introduced the fuel and which is responsive thereto, and a switching valve means 200 which is cooperatively connected with the flow-sensitive means 100 and is interposed between a fuel tank (not shown) incorporating a fuel pump and the flow sensitive means Generally, the flow sensitive means 100 comprises a cylinder bore 102 formed within a sensor housing 104. The bore 102 is straight and is open at both ports 106 and 108. The bore 102 is communicates through ports 106 and 108 with a fuel passage connected to the fluid source, such as the fuel tank and a fuel injector or a float chamber of a carburetor.Adjacent to each port 106 and 108, the housing 104 is formed with pairs of stepped openings 114 and 116, and 118 and 120. Each of the openings has a larger diameter in its outer section, respectively 122,124, 126, and 128. Each pairof openings 114 and 116, and 118 and 120 are aligned radially with respect to the cylinder bore 102. The pairs of inner sections, 130 and 132, and 134 and 136 respectively open to the bore 102 and oppose one another.

In the outer sections 122 and 126 of the openings 114 and 118, light emitting elements 138 and 140 such as photo-emitting diodes are received, and in the outer sections 124 and 128 of the openings 116 and 120 are received photo-senstive elements 142 and 144 such as photo-sensitive transistors. The light emitting elements 138 and 140 respectively and continuously emit light through the inner sections 130 and 134. The photo-sensitive elements 142 and 144 are respectively connected to a switching circuit 302 through amplifiers 304 and 306.

A movable element 146 such as a ball member, as shown in the Figs. 2 and 3, is movably received within the cylinder bore 102. In the preferred embodiment, the movable element 146 is a ball member having a diameter slightly smaller than that of the cylinder bore 102 and being made of a material having a specific gravity which is substantially the same as that of the fuel to be measured.

A switching valve means 200 is interposed within a fuel passage to introduce the fuel to orto drain the fuel from the fluid flow sensitive means 100. The switching valve means 200 is responsive to a signal generated in the switching circuit 302, which signal is fed to switch the direction of the fuel flow between a first direction from the port 106 to the port 108 and a second direction from port 108 to the port 106. As shown in Figs. 2 and 3, the switching value means 200 comprises a cylinder bore 202 formed in the housing 104 and a spool valve member 214 disposed within the cylinder bore 202. The spool valve member 214 is normally urged toward the bottom of the cylinder bore 202 by a spring 222. An electromagnetic actuator 224 is provided at the end of the cylinder bore 202 remote from the bottom thereof.The acturator 224 is electrically connected with the switching means 302 which energizes and deenergizes the former. The cylinder bore 202 communicates with an inlet port 240 opening thereto. On the other hand, the cylinder bore 202 communicates with an outlet port 246 through passages 248 and 250. The inlet port 240 and the outlet port 246 respectively communicate with the fuel tank and the fuel injection valve or the float chamber of the carburetor. On the other hand, the cylinder bore 202 communicate with both ports 106 and 108 of the cylinder bore 102 via passages 254 and 252.

The spool valve 214 is formed with lands 216 and 218definingannulargrooves 219,220 and 221 therebetween.The lands 216 and 218 are located so that either one of them closes the corresponding passage 254 and 252 respectively depending on the position ofthe spool valve 214, and the other passages remain open to communicate with each corresponding annular groove 219,220, and 221. Specifically, when the the actuator 224 is in the deenergized condition and therefore the spool valve 214 uged toward right, as shown in Fig. 2, in the cylinder bore 202 communicates with the outlet port 246 through the passage 248. At this time, the passage 250 is blocked communication with the outlet port 246 by the corresponding land 218.Thus the fuel introduced from the fuel tank flows through the inlet bort 240, the annular groove 220, the passage 252, the cylinder bore 102, passage 254, the annular groove 221, the passage 248, and the outlet port 246 to the fuel injection valve or float chamber of the carburetor. That is, the fuel in the cylinder bore 102 flows from right to left in the drawing. Following the fuel flow within the cylinder bore 102, the ball member 146 is moved in the first direction and finally reaches the position opposing inner sections 130 and 132 ofthe openings 114 and 116. Thereby, the light emitted from the light emitting elements 138 is interrupted. Responsive to the interruption of the light, the photo-sensitive element 142 generates a signal to be fed to the switching circuit 302 through the amplifier 304.Responsive to the signal fed from the photo-sensitive element 142, the switching means 302 generates a signal which energizes the actuator 224. The spool valve 214 is pulled toward the actuator 224 against the spring force, as shown in Fig. 3. In this spool valve position, the groove 220 communicates with the passage 250. At this time, the passage 248 is blocked the communication with the outlet port 246 by the land 216. Thereby, the direction of the fluid flow is alternated to move the ball member 146 in opposite direction, from left to right.

The alternation of the flow direction is counted up by a counter 32 connected with respective amplifiers 304 and 306 through an OR gate. Therefore, the counter 32 is responsive to outputs of either of the photo-sensitive elements 142 and 144. It should be noted that, in the preferred construction, the counter 32 becomes operative when the switching valve means 200 is switched to energized position and counts up the occurances of energization of the actuator 224.

Since the occurrences of turning on and off of the actuator 224 are proportional to the fuel velocity, the fuel amount can be calculated by multiplying the counted value by a predetemined constant.

In operation, the distance sensor 11 sequentially determines the vehicle speed and generates the sine-wave signal having the frequency proportional to the vehicle speed. The sine-wave signal is con verted into the rectangular pulse train by the shaping circuit 12 and then inputted to the counter 13. The counter 13 is responsive to the gate signal outputted from the timer 22 at the given time interval to output the counted value to the divider 4. At the same time, the counter 32 totals the fuel amount determined by the fuel flow sensor 31 and outputs the counted value in response to the gate signal fed from the timer 22 at the given interval to the divider 4.

In the divider 4, the travelled distance is divided by the fuel amount to obtain the travelling distance per the unit fuel amount. The divider 4 outputs the result of the dividing operation to the memory 51. In response to the divider output, the memory 51 clears its storage thereof and then latches the output value of the divider 4. The timer 23 outputs the gate signal at a given interval different from that of the gate signal of the timer 22. The gate signal fed from the timer 23 is inputed to the memory 51 to induce the ilatterto output the latched value to the display unit 52. As apparent from Fig. 1, the display unit 52 displays the determined travelling distance per unit fuel amount in digital form.

It is to be noted that the given interval of the timer 22 is to be preset comparably longer than that of conventional. For example, the interval is preset about 30 sec. On the other hand, the fuel flow sensor pulse may correspond to icc per 1 cycle of the pulse.

The time interval of the timer 23 can be preset in consideration of convenience of observation of the display unit. Preferably, the preset interval of the timer 23 can be varied according to the desire of the driver.

Thus, the invention fulfills all of the objects and advantages sought therefor.

While the invention has been illustrated in the specific embodiment of the invention by way of example, the invention should not be understood as limited to the hereabove given specific embodiment but should be understood as including any possible modifications for the whole or for in part thereof without departing from the principle of the invention.

Claims

1. A fuel economy indicator for an automotive vehicle comprising: a first means for determining travelling distance of the vehicle and producing a first signal indicative of the determined travelling distance; a second means for determining a fuel amount consumed for travelling the determined travelling distance and producing a second signal indicative of the determined fuel amount; an arithmetic means for receiving said first and second signals at a first given interval and effecting arithmetic operation for determining the travelling distance per consumption of unit amount of the fuel, said arithmetic means producing a third signal indicative of the determined travelling distance per unit amount of the fuel; and a display means for receiving said third signal from said arithmetic means at a second given interval to display the determined travelling distance per the unit amount of fuel.

2. A fuel economy indicator for an automotive vehicle comprising: A first means for determining travelling distance of the vehicle and producing a first signal indicative of the determined travelling distance; a second means for determining a fuel amount consumed for travelling the determined distance and producing a second signal indicative of the determined fuel amount; an arithmetic means for arithmetically operating said first and second signals for determining the travelling distance per consumption of unit amount of the fuel, said arithmetic means producing a third signal indicative of the determined travelling distance per unit amount of the fuel; a display means receiving said third signal and updating the storage thereof by the inputted third signal, said display means including a display unit for displaying the determined travelling distance per unit amount of fuel;; a first command generator for generating a first command to be fed to said first and second means and said arithmetic means at a first given interval for make them operative; and a second command generatorforgenerating a second command to be fed to said display means at a second given interval for make the latter operative to display the result of arithmetic operation.

3. An indicator asset forth in claim 1 or 2, wherein said second means includes a fuel flow sensor comprising: a fuel passage formed in straight and introducing therein the fuel so that the fluid flows alternatively in first and second direction therethrough; a movable member movably disposed within said fuel passage; sensor means provided in said fuel passage adjacent both to each end of the passage, said sensor means detecting the positipn of said movable member while the latter moves therethrough and generating a signal responsive to the detection of said movable member; a fuel flow direction switching means responsive to a signal of said sensor means and operative to switch flow direction of said fuel in the fuel passage;; a counter means responsive to said fuel flow direction switching means and counting up the occurrences of switching operation in said fluid flow direction switching means.

4. A indicator as setforth in claim 3, said fuel flow direction switching means comprises a valve means interpositioned between said fuel passage and inlet and outlet ports, which valve means is operative by means of an electromagnetic actuator for switching flow direction of the fuel between first and second directions, said actuator is responsive to said sensor signal to alternate the position between energized and deenergized positions.

5. An indicator as set forth in claim 4, wherein said sensor means comprises two pairs of photo emitting member and photo sensitive member, each pair of the members are located adjacent the end of the fluid passage, said photo sensitive members are responsive to interruption of the photo emitted from said photo emitting members and generates a signal responsive thereto.

6. A indicator as set forth in claim 3, wherein said second interval of operating said display means is variable.

7. A method for indication of a travelling distance per unit amount of fuel consumed in driving ofthe vehicle comprising: determining a travelling distance ofthevehicle; determining a fuel amount consumed for travelling the determined distance; arithmetically operating to determinethe travelling distance per consumption of unit amount of the fuel based on the determined travelling distance and the fuel amount, said operation being effected at a first given interval; displaying the determined travelling distance per unit amount of the fuel at a second given interval.

8. A method as setforth in claim 7, wherein said second given interval is variable according to the convenience of observation of the display by the driver.

9. A method as set forth in claim 7 or 8, wherein the consumed fuel amount is determined by a method comprising: introducing the fuel a straight fluid passage and alternatively flowing the fuel therewithin in first gnd second direction; detecting the presence of a movable member at either end of said straightfluid passage and switching flow direction of the fuel in said fluid passage in response to detection of the movable member; generating a counter pulse indicative of one cycle of alternation of flow direction of the fuel in said fluid passage; and counting said counter pulse to determine the vel- ocity and amount of the fluid based thereon.