JPH0143245B2 - - Google Patents

Description

[Detailed description of the invention] <Technical field> The present invention relates to a fuel consumption meter for automobiles.

<Background Art> In recent years, there has been a trend for automobiles to be equipped with fuel efficiency meters either built into drive computers or as standalone items.

By the way, there are two ways to calculate fuel efficiency: (1) dividing the distance traveled during that period by the amount of fuel consumed, and (2) calculating the value when the amount of fuel consumed reaches a certain amount. Another method is to divide the distance traveled up to that point.

Method (1) calculates fuel consumption at regular intervals, so fuel consumption can also be displayed at regular intervals, but method (2) requires that the fuel consumption measurement interval, that is, the display interval, vary depending on the amount of fuel consumed. Become. Therefore, from the driver's perspective, method (1) can be said to be superior.

However, in method (1), in the case of an electronically controlled fuel injection type internal combustion engine, the fuel consumption is measured by integrating the pulse width of the drive pulse to the fuel injection valve. can be measured relatively accurately, but if the distance traveled is measured by counting pulse signals from the speedometer's vehicle speed sensor (which emits a pulse signal synchronized with the rotation of the propeller shaft), As shown in Figure 1, when the speed is low, the number of pulse signals within a certain period of time decreases, so the error portion (A in the diagram) increases accordingly, and the measurement error increases.
This caused the problem that fuel consumption calculations could not be performed accurately.

<Object of the Invention> In view of such conventional problems, an object of the present invention is to enable accurate calculation of fuel efficiency at regular intervals.

<Configuration of the Invention> For this reason, the present invention utilizes a pulse signal from a vehicle speed sensor as a signal every fixed travel distance, and
As shown in the figure, by measuring the amount of fuel consumed during the period T shown in the figure within a certain period of time, it is possible to accurately calculate the fuel consumption.

Specifically, as shown in Fig. 3, there is a means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft, and means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft, and Means for integrating the pulse width of the driving pulses given to the fuel injection valve in between and outputting the integrated result every cycle; Means for accumulating the accumulation result from the accumulation start at 1 to the accumulation result finishing immediately before the next time signal and outputting the accumulation result for each time signal; This configuration includes means for calculating and outputting the calculated result to a display device.

<Example> Examples will be described below.

In FIG. 4, reference numeral 1 denotes a microcomputer, which includes a fuel efficiency calculating section 3. As shown in FIG. It also has a built-in clock 4.

Reference numeral 2 denotes an injection amount calculation unit, which is an electronically controlled fuel injection device, which calculates the fuel injection amount according to the operating conditions of the engine, and sends a corresponding drive pulse to the fuel injection valve (more specifically, the electromagnetic coil for opening the valve) 5. Output against.

A drive pulse to the fuel injection valve 5 is input to the fuel efficiency calculation section 3 . Further, a pulse signal from a vehicle speed sensor 6 in the speedometer is input. That is, a pulse signal is input from a reed switch 9 which is turned on when the S and N poles of the magnet 8, which rotates due to the rotation of the propeller shaft, approach each other via the flexible wire 7. One period of this pulse signal corresponds to 1/2 rotation of the propeller shaft. Further, a time signal is inputted to the fuel efficiency calculating section 3 from the built-in clock 4 at regular intervals.

The digital output from the fuel efficiency calculating section 3 is sent to the display device 10.

Next, the software configuration of the fuel consumption calculation section 3 will be explained based on the flowchart of FIG. 5.

After calculating and displaying the fuel consumption for a certain period of time in S7, which will be described later, and initializing TC, P, and C in S8,
At S1, the rise or fall of a pulse signal from the vehicle speed sensor 6 (hereinafter referred to as vehicle speed pulse) is detected.
For example, if a rising edge is detected,
Proceeding to S2, the integration of the pulse width of the drive pulse to the fuel injection valve 5 (hereinafter referred to as F/I pulse width) is started. Then, in S3, it is determined whether one cycle has passed, that is, whether a rising edge has been detected again,
Also, in S4, it is determined whether a certain period of time has elapsed, that is, whether a time signal has been emitted from the built-in clock 4. If NO in both cases, the process returns to S2 and the F/F/
Continue integrating the I pulse width.

If it is determined in S3 that one cycle has elapsed during this integration, in S5 the previous integrated value C is added to the previous cumulative value TC (initially 0), and this and the new cumulative value are added.
TC. At the same time, the cumulative number P (initially 0) is increased by 1. After that, clear the integrated value C in S6,
Return to S2 and start the second period of integration. Thereafter, in the same manner, integration is performed every cycle until a certain period of time has elapsed, and the integration results are accumulated.

If it is determined in S4 that a certain period of time has elapsed, the process proceeds to S7 and calculates the fuel consumption from the cumulative value TC and the cumulative number of times P. Here, the product of the cumulative number of times P and the distance traveled when the propeller shaft rotates 1/2 corresponds to the distance traveled during period T in FIG. Also, the cumulative value
TC corresponds to the fuel injection amount during the period T.
Therefore, by dividing TC by P and multiplying by an appropriate coefficient, fuel consumption can be calculated. Of course, the calculation results are output to the display device 10. After that, clear all TC, P and C in S8 and return to S1.

<Effects of the Invention> As explained above, according to the present invention, fuel consumption can be calculated accurately at both low and high speeds, and the vehicle speed sensor in the speedometer can be used as is, so costs will not increase.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the conventional fuel efficiency calculation mode, FIG. 2 is a diagram for explaining the fuel efficiency calculation mode of the present invention, and FIG. 3 is a block diagram showing the configuration of the present invention. FIG. 4 is a hardware configuration diagram of an embodiment of the present invention, and FIG. 5 is a flowchart of the same. DESCRIPTION OF SYMBOLS 1... Microcomputer, 2... Electronically controlled fuel injection device, 3... Fuel consumption calculation unit, 4... Built-in clock, 5... Fuel injection valve, 6... Vehicle speed sensor,
10...Display device.

Claims (1)

[Claims] 1. Means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft, and a means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft, and a means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft, and a means for detecting the rise or fall of a pulse signal of a vehicle speed sensor that transmits a pulse signal synchronized with the rotation of the propeller shaft. A means for integrating pulse widths and outputting the integrated result every cycle, and a means for receiving a time signal emitted at fixed time intervals and starting integration immediately after the time signal between the time signals to generate the next time signal from the integrated result. means for accumulating the accumulation results up to the accumulation result that was completed immediately before and outputting the accumulation results for each time signal; and means for calculating the fuel efficiency from the accumulation results and the number of accumulations for each time signal and outputting the result to a display device. Automotive fuel consumption meter.