JP2917794B2 - Electronic odometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic odometer and, more particularly, to an electronic odometer having both odometer and trip meter functions.

[0002]

2. Description of the Related Art Conventionally, an electronic mileage integrator for a vehicle is configured as shown in FIG.

In FIG. 6, reference numeral 1 denotes a vehicle speed sensor that generates a vehicle speed pulse having a frequency proportional to the vehicle speed.
The vehicle speed sensor 1 is connected to the interrupt input port iNT of the CPU 3 via the interface 2.

The CPU 3 includes an IG power supply 5 that outputs +5 V when the ignition switch 4 is on, and a + B power supply 7 that outputs +5 V when the on-vehicle battery 6 is connected regardless of whether the ignition switch 4 is on or off. , Connected to both.

A display drive circuit 8 is connected to an output port of the CPU 3, and a display 9 is connected to the display drive circuit 8. The display 9 is a display that displays both the odd value and the trip value.

A reset switch 11 for a trip meter is connected to an input port I _{1 of the} CPU 3 via an interface 10. This reset switch 11
Is a switch operated by the occupant when resetting the trip value, as is well known.

Further, the CPU 3 has a nonvolatile memory 1
2 are connected.

The CPU of the electronic odometer shown in FIG.
3 calculates the odd value by counting the vehicle speed pulse from the vehicle speed sensor 1, stores the odd value in the nonvolatile memory 12, and sets C every time the reset switch 11 is turned on.
Reset the trip value on the RAM 13 inside the PU3,
Thereafter, a trip value is calculated by counting the vehicle speed pulse, and processing for storing the trip value in the RAM 13 is executed.

[0009]

However, when the ignition switch 4 is turned off, the trip value on the RAM 13 is cleared because the CPU 3 is connected to the + B power supply 7 when the ignition switch 4 is turned off. Although no trouble occurs, when the battery 6 is replaced, the trip value in the RAM 13 is cleared because the + B power supply 7 is in a non-power supply state, and there is a problem that an accurate trip value cannot be displayed after the battery 6 is connected.

[0010] The electronic mileage integrator may be a CP.
There is a problem that it cannot be applied to a vehicle in which it is difficult to connect the + B power supply 7 to the U3, for example, a vehicle such as a motorcycle or an electric vehicle in which a large-capacity battery cannot be mounted as the vehicle-mounted battery 6.

The present invention solves these problems and can display an accurate trip value after battery replacement, and can be easily applied to a vehicle in which a + B power supply cannot be connected to a CPU. The main object of the present invention is to provide an electronic odometer that can be used.

By the way, in order to solve the above problems,
A method of sequentially storing trip values in addition to odd values in the nonvolatile memory 12 is conceivable. However, according to such a method, as shown in FIG. 7, the number of rewrite cycles of the minimum bit representing the trip value data becomes extremely large, and in order to secure the reliability of the nonvolatile memory 12, the number of rewrite cycles is increased. Must be limited (for example, if the number of rewrites is 1
Limit to 10,000 times. ). Another object of the present invention is to solve such a problem and to improve the reliability of the nonvolatile memory by reducing the number of times of rewriting of the nonvolatile memory.

[0013]

In order to solve the above-mentioned problems, an electronic odometer according to the present invention comprises: a nonvolatile memory for storing a current odometer value and an odometer value at zero reset; comprising a CPU for determining the trip value from the current odometer value memory by subtracting the odometer value at the zero-reset, and the non
The volatile memory stores at least the zero-time odd value as at least
Stores the most recent zero-zero value and the immediately preceding zero-value.
And the CPU calculates the latest zero return value from the current odd value.
It is characterized in that a trip value is obtained by subtracting a time odd value .

[0014]

[0015]

According to the electronic odometer of the present invention , since the odometer value at the time of return to zero (when the reset switch is turned on) is stored in the non-volatile memory in addition to the current odometer value, it can be used when the battery is replaced. Odd value is not cleared at home.
For this reason, the CPU can obtain an accurate trip value by subtracting the return-time odd value from the current odd value after battery replacement. Therefore, an accurate trip value can be displayed after battery replacement. Further, even for a vehicle in which the + B power supply cannot be connected to the CPU, even when the ignition switch is turned off, the return value at the time of return to zero is not cleared, so that the present invention can be easily applied. Furthermore, since the odd value at the time of return to zero of the nonvolatile memory is rewritten only at the time of return to zero, the number of times of rewriting of the nonvolatile memory is reduced, and the reliability of the nonvolatile memory is improved. Further
, According to the electronic travel distance totalizer according to the present invention, the
In addition to the effects described above , the following effects can be obtained. That is, when the nonvolatile memory is configured to always store only the latest zero-zero value, the reset switch is turned on and the ignition switch is turned off while the nonvolatile memory is being cleared and rewritten. Then, the current odd value is not stored in the non-volatile memory as the zero-time odd value, and the subsequent trip value may not be an accurate value. However, as in the case of the electronic odometer according to the present invention , when the nonvolatile memory stores at least the latest zero return value at the time of zero return and the immediately preceding zero return value at the same time, the current odd value is stored. Since the ignition switch is turned off as described above, even if the latest zero return value is stored in the nonvolatile memory without being stored in the nonvolatile memory as the zero return value,
An accurate trip value can be calculated and displayed by using the latest zero return value at the time of return to zero.

[0016]

[0017]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an electronic odometer according to one embodiment.

In FIG. 1, reference numeral 1 denotes a vehicle speed sensor 1 for generating a vehicle speed pulse having a frequency proportional to the vehicle speed. The vehicle speed sensor 1 has a CPU via an interface 2
3 is connected to the interrupt input port iNT.

The CPU 3 is connected only to the IG power supply 5 that outputs +5 V when the ignition switch 4 is in the ON state, and is not connected to the + B power supply 7 as shown in FIG.

A display drive circuit 8 is connected to an output port of the CPU 3, and a display 9 is connected to the display drive circuit 8. The display 9 is a display that displays both the odd value and the trip value.

A reset switch 11 for a trip meter is connected to an input port I _{1 of the} CPU 3 via an interface 10. This reset switch 11
Is a switch operated by the occupant when resetting the trip value, as is well known.

A write switch 14 is connected to an input port I _{2 of the} CPU 3 via an interface 15. Here, since the number of vehicle speed pulses generated per unit distance does not match between the vehicle speed sensors 1, the write switch 14 determines the number of vehicle speed pulses generated per unit distance generated by the vehicle speed sensor 1 to be used by the interface 16. and a switch which is operated when entered set inside CPU3 through the input port I _S.

Further, a non-volatile memory (NVM) 12 is connected to the CPU 3.

Next, the processing of the CPU 3 will be described with reference to FIGS. 2 and 3 show the processing contents of a series of main routines. FIG. 2 corresponds to the first half and FIG. 3 corresponds to the second half. FIG. 4 shows the processing contents of the interrupt routine. FIG. 5 shows the NVM1
2 and the configuration of the RAM 13.

(1) Main Routine (FIGS. 2 and 3) The main routine is executed when the ignition switch 4 is turned on (step 100).

First, the CPU 3 clears the RAM 13,
Initialize various flags, registers, and ports (step 101).

Next, the display is cleared (step 1).
02).

Thereafter, the CPU 3 sets the number of vehicle speed pulses per unit distance (steps 103 to 111) and calculates a trip value to be displayed first (steps 112 to 1).
17), display of trip value and odd value every elapse of 50 milliseconds (steps 118 to 119), reset switch 1
Updating of the odometer value at the time of return when 1 is turned on (step 12
0 to 129), and update the odd value and trip value for each 0.1 km of travel (steps 130 to 136). Hereinafter, each processing content will be described in order.

The unit distance setting of the vehicle speed pulse number per whether (step 103-111) the write switch 14 is on, in other words, the input port I ₂ determines whether "0" level (step 103).

If I ₂ = 0, wait for all the bits of the vehicle speed pulse number data per unit distance, which is a serial signal, to be input to the input port I _S (step 10).
4), this serial signal is converted into parallel data (pulse set value)
And set it in the register MR17 (step 10).
5) The pulse set value is stored in the pulse set value storage area RK (see FIG. 5) on the RAM 13 and the pulse set value storage area NK (see FIG. 5) on the NVM 12 (steps 106 and 107).

On the other hand, if I ₂ ≠ 0, the pulse set value is read from NK (step 108), and whether this pulse set value is “0”, in other words, whether the pulse set value is not set Is determined (step 109).
When the pulse set value is “0”, the general “100” as the number of vehicle speed pulses per unit distance is stored in the NK as the pulse set value (step 110), while the pulse set value has already been set. In this case, the process ends.

[0033] Thus, in step 103-111, when the write switch 14 is turned on, the pulse setting value inputted via the input port I _S stores in NK, whereas, write switches When 14 is off, the pulse set value of NK is maintained as it is, or the numerical value “100” is stored in NK as the pulse set value.

Here, according to the method of setting the number of vehicle speed pulses per unit distance, the degree of freedom is significantly improved as compared with the conventional setting method by switching input ports. That is, since the number of vehicle speed pulses per unit distance usually varies depending on the combination of sensors, tire diameters, transmissions, etc., the conventional setting method makes the number of input ports insufficient or sets a new number of pulses. However, according to the setting method as in this embodiment, two input ports I ₂ and I _S are sufficient, and the input port I
_Since various pulse set values can be input via _S , various vehicle speed pulse numbers can be handled and the degree of freedom is significantly improved.

Calculation of the Trip Value to be Displayed First
Steps 112 to 117) Current odd value storage area NOD on NVM 12 (see FIG. 5)
Read the current odd value from the current odd
Store in the value store area ROD (see FIG. 5) (step
112), Odd value storage area NO at zero return on NVM 12
DT₁ Reads the odd value at the time of return from (see FIG. 5) RAM
13 Odd value store area RODT on zero ₁ (See Figure 5
(Step 113), and store on NVM 12
Odd value store area NODT at zero_Two (See Fig. 5)
Read the odd value at the other return time at another return time on the RAM 13
Odd value store area RODT_Two (See Figure 5)
(Step 114).

Next, the odd value at the time of return of RODT ₁ and ROD
Other return midnight odo value of T ₂ to magnitude comparison (step 11
5). In other words, the return-time odd value of RODT ₁ and RODT _{1
It is determined which of the two} other return zero od values is the latest return zero od value.

If the return zero od value of RODT ₁ is greater than or equal to the other return zero od values of RODT ₂ , in other words, ROD 1
If the zero od value of T ₁ is the latest zero od value,
The register RTP stores the current odd value of ROD in RODT _1.
Is stored as a result of subtraction of the zero-time odd value at step 116 (step 116).

On the other hand, the other odd value at the time of RODT ₂ is R
If the Odd value of ODT ₁ is larger than the zero-time od value, in other words,
If the other return zero od value of RODT ₂ is the latest return zero od value, a trip value which is the result of subtracting the other return od value of RODT ₂ from the current od value of ROD is stored in the register RTP. Is stored (step 117).

As described above, in steps 112 to 117, the trip value to be displayed on the display 9 immediately after the ignition switch 4 is turned on is calculated by subtracting the latest odometer value at the time of return from the current odometer value. I do.

Display of trip value and odd value every 50 milliseconds have elapsed (steps 118 to 119) It is determined whether 50 milliseconds have elapsed since the ignition switch 4 was turned on (step 118). If it is determined that the elapsed time has elapsed, the trip value and the current odd value stored in the register RTP in step 116 or 117 are displayed on the display 9 (step 119).

Thereafter, every time 50 milliseconds elapse, the current odd value calculated in step 132 described later and the trip value calculated in step 135 or 136 are displayed on the display 9 (step 119).

As described above, in steps 118 to 119, immediately after the ignition switch 4 is turned on,
The current odd value and the trip value calculated above are displayed on the display 9.
, And thereafter, the updated odd value and trip value are displayed on the display 9.

[0043] whether the update of the null midnight odo value when the reset switch 11 is turned on (step 120 to 129) the reset switch 11 is turned on, in other words, whether the input port I ₁ is "0" level A judgment is made (step 120).

If I ₁ ≠ 0, the chattering check flag FI ₁ is cleared and the process is terminated (step 121).

On the other hand, if I ₁ = 0, it is determined whether the chattering check flag FI ₁ is “1” (step 122).

If FI ₁ ≠ 1, chattering flag F
Set the I ₁ ends the process (Step 12
3).

On the other hand, when FI ₁ = 1, the magnitude of the return-time odd value of RODT ₁ is compared with the other return-time odd value of RODT ₂ (step 124).

The odometer value at the zero-reset of RODT ₁ may be less than at odo value other zero-reset of RODT _2, the current odometer value ROD, store the RODT ₁ and NODT ₁ (step 125 and 126). In other words, if the other return zero od value of RODT ₂ is the latest return zero od value before the present reset switch 11 is turned on, the old return zero od value is stored in the RODT ₁ and NODT ₁ stored therein. The current odd value when the reset switch 11 is turned on this time is stored.

On the other hand, when the odd value at the time of return of RODT ₁ is ROD
If it is another zero-reset time odo value above T _2, the current odometer value of ROD to determine equality with odo value at the zero-reset of RODT ₁ (step 127).

[0050] Current odo value ROD is equal to the odo value at the zero-reset of RODT _1, since there is no need to update the odometer value at the zero-reset, the process ends.

Meanwhile, the current odometer value ROD is not equal to the odo value at the zero-reset of RODT _1, the current odometer value ROD, stores the RODT ₂ and NODT ₂ (step 128, 129). In other words, if the return zero od value of RODT ₁ is the latest return zero od value before the present reset switch 11 is turned on, the old return zero od value is stored in RODT ₂ and NODT ₂ which are stored. The current odd value at the time when the reset switch 11 is turned on is stored.

As described above, in steps 120 to 129, when the reset switch 11 is turned on, the oldest zero return value stored at this time is stored in R
The current odds value is stored as the latest zero-return odds value in the return-time odds-value storage areas on the AM 13 and the NVM 12.

In the present embodiment, two zero-value odd-value store areas on the NVM 12 are provided.
One is enough. However, if there is only one odd-value storage area at the time of return to zero, the reset switch 11 is turned on and the NVM1
When the ignition switch 4 is turned off during the clearing and rewriting of the data 2, the current odd value becomes NVM1.
2, the trip value is not stored in the return-time odd value storage area, so that the subsequent trip value may not be an accurate value. However, when two trip values are provided as in this embodiment, the current odd value is not stored. Even if is not stored in one of the zero-value-zero storage areas, the latest zero-value is stored in the other zero-value storage area. Thus, an accurate trip value can be calculated.

Updating of the odd value and trip value for every 0.1 km (steps 130 to 136) It is determined whether or not the flag F0.1k is "1" (step 130). Here, the flag 0.1k is a flag that is set each time it is determined that the vehicle has traveled the unit traveling distance (0.1 km), as described later in the interrupt routine shown in FIG.

If the flag F0.1k ≠ 1, the process ends, and the routine goes to step 118.

On the other hand, when the flag F0.1k = 1, the flag F0.1k is reset (step 131), and the current odd value which is the result of adding "0.1 km" to the current odd value of the ROD is stored in the ROD. (Step 13
2) The current odds value obtained by adding "0.1 km" to the current odds value of the NOD is stored in the NOD (step 133).

Next, the odometer value at the time of return of RODT ₁ and ROD
Other return midnight odo value of T ₂ to magnitude comparison (step 13
4). In other words, the return-time odd value of RODT ₁ and RODT _{1
It is determined which of the two} other return zero od values is the latest return zero od value.

If the return zero od value of RODT ₁ is greater than or equal to the other return zero od values of RODT ₂ , in other words, RODT
If the zero od value of T ₁ is the latest zero od value,
The register RTP stores the current odd value of ROD in RODT _1.
Is stored (step 135).

On the other hand, the other odd value at the time of RODT ₂ is R
If the Odd value of ODT ₁ is larger than the zero-time od value, in other words,
If the other return zero od value of RODT ₂ is the latest return zero od value, a trip value which is the result of subtracting the other return od value of RODT ₂ from the current od value of ROD is stored in the register RTP. Is stored (step 136).

As described above, in steps 130 to 136, the current odometer value is updated by adding "0.1 km" to the current odometer value for each unit mileage (0.1 km) travel, thereby updating the current odometer value. ROD and N
The trip value is updated by storing the updated trip value by subtracting the latest zero value at the time of return from the updated current odd value, and storing the updated trip value in the register RTP. The trip value stored in the register RTP is displayed on the display 9 in step 119.

(2) Interrupt Routine (FIG. 4) The interrupt routine is executed by detecting the falling of the vehicle speed pulse generated by the vehicle speed sensor 1 (step 200).

First, the number of vehicle speed pulses in the vehicle speed pulse number storage area CN (see FIG. 5) on the RAM 13 is incremented, and the result is stored in CN (step 201).

Next, the number of CN vehicle speed pulses is subtracted from the RK pulse set value (step 202).

Next, it is determined whether or not the result obtained by subtracting the CN vehicle speed pulse number from the RK pulse set value is "0" or more (step 203). In other words, it is determined whether the vehicle speed pulse number has reached the pulse set value.

If the vehicle speed pulse number has not reached the pulse set value, the routine returns to the main routine (step 20).
4).

On the other hand, if the vehicle speed pulse number has reached the pulse set value, the flag F0.1k is set (step 20).
5), the number of vehicle speed pulses of CN is set to "0" (step 206), and the process returns to the main routine (step 2).
04).

As described above, in the interrupt routine, the flag F0.1k is set for each unit traveling distance (0.1 km).
Is set.

As described above, according to the present embodiment,
Since the Odd value at the time of return in addition to the current Od value is stored in the NVM 12, the Od value at the time of the return is not cleared when the battery 6 is replaced. For this reason, after replacing the battery 6, the CPU 3 can obtain an accurate trip value by subtracting the return-time odd value from the current odd value. Therefore,
An accurate trip value can be displayed on the display 9 after the replacement of the battery 6. Further, even for a vehicle in which the + B power supply cannot be connected to the CPU 3, even when the ignition switch 4 is turned off, the return value at the time of return to zero is not cleared, so that the present invention can be easily applied. Furthermore, N
Since the odd value at the time of return of the VM 12 is rewritten only at the time of the return to zero, the number of rewrites of the NVM 12 is reduced, and the reliability of the NVM 12 is improved.

Further, according to the present embodiment, since the NVM 12 stores the latest zero return value at the time of zero return and the immediately preceding zero return value at the time of zero return, the reset switch 11 is turned on and the N
If the ignition switch 4 is turned off while the VM 12 is being cleared and rewritten, the current odd value becomes N
Since the latest zero return value is stored in the NVM 12 even if it is not stored in the VM 12 as the zero return value, an accurate trip value is calculated and displayed using the latest zero return value. Will be able to

Further, according to the present embodiment, since the number of vehicle speed pulses per unit distance is set using the _two input ports I ₂ and I _S , the conventional setting method by input port switching and In comparison, shortage of input ports, software change, ROM mask change, and the like do not occur, and the degree of freedom is significantly improved.

In the above-described embodiment, the two return zero od values, the latest return od value and the immediately preceding return od value, are set to N
Although stored in the VM 12, only the latest zero-return-time odd value may be stored, or three or more zero-return-time odd values may be stored.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electronic odometer according to an embodiment;

FIG. 2 is a flowchart of a first half of a main routine executed by a CPU;

FIG. 3 is a flowchart of the latter half of the main routine.

FIG. 4 is a flowchart of an interrupt routine.

FIG. 5 is a configuration diagram of an NVM and a RAM.

FIG. 6 is a configuration diagram of a conventional electronic odometer.

FIG. 7 is an explanatory diagram for explaining a problem of the present invention.

[Explanation of symbols]

 3 CPU 12 Non-volatile memory (NVM)

Claims (1)

(57) [Claims] A non-volatile memory for storing a current odd value and a zero reset odd value; a CPU for subtracting the zero reset value from the current odd value of the non-volatile memory to obtain a trip value; wherein the non-volatile memory as odo value at the zero-reset, low
At least the most recent zero-zero value at the time of return
The CPU stores the latest zero return time from the current odd value.
An electronic mileage integrator that calculates a trip value by subtracting a trip value .