JPH04350330A - Driving signal conversion method for instrument - Google Patents

Abstract

PURPOSE:To set a constant K in the relationship theta=K.R for determining the indicating theta of an indicating instrument in relation to the number of revolutions R of engine to a value which is not changed by increasing or decreasing the number of cylinders, namely by the pulse rate. CONSTITUTION:The relationship theta=K.P can be converted into the following equation: theta=K.(1/(P.T)) (where P: pulse rate, T: TA pulse period), where P.T can be regarded as the time required for one revolution of an engine. Count value (n) determined by the number of cylinders is added from a count value output circuit 2 to a period counter 3 for every sampling signal of fixed period T (SK) outputted from a sampling clock circuit 1 to calculate a counting value N. The addition is performed in nearly in one cycle period of the engine, and in the following period, a counting value N of the period counter 3 is reset so as for the operation to be performed again. The counting value N becomes equal to P.T. Besides, the value N can be represented by the following equation: N=(T/T(SK)).n, and the value remains the same regardless of the number of cylinders. That is, because the relationship for P.T is similarly established, a constant K can be definitely set as K=theta.N.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting the indicated angle of an analog meter such as a crossed coil meter.

0002

[Prior Art] Generally, when the engine speed is indicated using an analog meter, the cycle of the signal output from the spark plug of the engine is measured, and θ=K・(1/T)(θ
: indicated angle, T: spark plug period, K: constant of proportionality). The constant K is a proportional constant that determines the indicated angle θ with respect to 1/T (=f), and determines the characteristics of the indicated angle θ with respect to the frequency f.

[0003] Therefore, in order to indicate the indicated angle θ, it is first necessary to determine the constant K. For example, if a meter is set to indicate 180 degrees at 5000 rotations/minute, this value is the period T at 5000 rotations and the indicated angle θ at that time.
(=180 degrees), it can be uniquely determined as K=T・180 degrees.

0004

[Problem to be Solved by the Invention] However, when the type of engine, in this case the number of cylinders, changes, an instrument with the same rotation speed and the same indication angle characteristic (an instrument whose indication angle is determined for a certain rotation speed) changes to the constant K. You have to change the value of . To explain specifically, if the signal output from the engine plug due to the difference in the number of cylinders is expressed as the number of pulses per revolution, that is, the pulse rate P, the signal output from the engine plug due to the difference in the number of cylinders is expressed as the number of pulses per revolution, or the pulse rate P.
．． 5 (pulse/rev), 2.0 (pu
lse/rev ), 2.5 (pulse/r
ev),... Here, when we look at the indicated angle θ as a function of the rotation speed R, it is expressed as θ=K'・R, and this formula is: θ=K'・R =K'・(f/P) =K'・(1/P)・(1/T), and the constant K of the above θ=K・(1/T) is K=
K'・(1/P). In other words, the constant K becomes a constant that changes as the number of cylinders increases or decreases, and when used in various types of engines, it is necessary to have a constant suitable for each engine.

[0005] These processes are carried out using a digital circuit custom IC.
Alternatively, in the case of using a CPU or the like, it is not appropriate to have a large number of constants K because the circuit or program data ROM becomes large and the cost increases. Therefore, the constant K usually has a limited value within a certain range. For example, a meter with the same rotation speed and the same indicated angle, specifically a pulse rate P of 2.0 (pul
se/rev), in response to an input of 200 (Hz), the position of the 6000 revolutions per minute number on the dial design can be changed from 200 degrees to 300 degrees in 2 degree steps based on the 0 degree position of the number. When setting at this position, θ=K
・From f, the constant K is 1 in steps of 0.01 from 1.00.
．． Must have 51 pieces of data up to 50. i.e.

However, if the pulse rate P is 2.
0(pulse/rev) and 2.5(pulse/r
ev ), each frequency is 200
(Hz) and 250 (Hz). At this time, if each indicates 252 degrees, the pulse rate P is 2
．． The constant K of 0 (pulse/rev) is 1.26, while the pulse rate P is 2.5 (pulse/r
The constant K of ev ) satisfies 252 (degrees) = 1.008・250 (Hz)
=1.008.

However, since the constant K is set in steps of 0.01, K=1.008 cannot be realized under this setting. Therefore, the constant K is 0.0
It is possible to set it to 01 steps, but this minute ROM
The data will increase, and if K=1.008 is rounded to K=1.00, the instruction accuracy will decrease.

[0008]

[Means for Solving the Problems] The present invention provides that when the indicating angle θ of the indicating instrument is viewed as a function of the rotation speed R, that is, θ
=K・R =K・(f/P) =K・(1/P)・(1/T) =K・(1/P・T) If we focus on the formula conversion, we can calculate the pulse rate P and
The product of spark plug periods, i.e. P(pulse/re
v)×T(min/pulse) is the time per revolution (min/rev). This time is determined by adding up (counting up) a reference signal n determined by the number of cylinders of the engine every sampling clock of a constant period.

[0009]

[Operation] Since the time per revolution is a value that is not affected by changes in the pulse rate P, that is, changes in the number of cylinders B, the constant K is set at any indicated angle θ and at this time regardless of changes in the pulse rate P. It can be uniquely determined by substituting the count value N. An indicating instrument that can be applied to any number of cylinders can be obtained by simply multiplying this uniquely determined constant K by the reciprocal 1/N of the number of signals. In addition, please refer to Japanese Patent Publication No. 61-57580 as a prior document.

0010

[Embodiment] A preferred embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 shows a sampling clock circuit which outputs a pulse signal (sampling signal) with a constant period. 2 is a reference signal circuit, which is provided with a terminal or switch for setting the number of cylinders, and by inputting or switching data regarding the number of cylinders to this terminal or switch, the reference signal n
is set. 3 is a period counter which adds a reference signal n every time a sampling signal is output, and calculates a total addition value N. Reference numeral 4 denotes a reset circuit which inputs a signal output from the ignition plug of the engine and resets the count value N of the period counter 3 approximately every cycle of this ignition signal. The count value N before being reset is the aforementioned θ=K・(1/N)
and make the indicating instrument indicate the value.

FIG. 2 is an explanatory diagram of the operation of FIG. A sampling signal is output at a constant cycle regardless of the cycle of the ignition signal. At the rising edge a of the sampling signal next to the sampling signal including the rising edge A of the ignition signal, the reference signal n is added to the period counter, the count value N is outputted from the period counter 3, and the period counter 3 is reset. Furthermore, the period counter 3 starts counting and adding at the next rising edge b of the sampling signal, and repeats the addition until there is the next rising edge B of the ignition signal.
It is reset after outputting the count value N in the same way as when outputting.

That is, if the period of the ignition signal is T and the period of the sampling signal is T (SK), the period counter 3
The count value N at is expressed as N=(T/T(SK))·n.

As a specific example, the ignition signal period T(
1) at 2.0 (msec/pulse), the reference signal n(
1) is set to 1, and the ignition signal period T(2
) is 1.0 (msec/pulse), and the reference signal n (2
) is set to 2, the sampling signal period T(SK
) is constant for both cylinders, so the count value N at this time is N(1) = (2.0/T
(SK))・1=2.0/T(SK)
N(2)=(1.0/T(SK))・2=2.
0/T(SK), and it can be seen that N(1)=N(2). This count value N is the same for any number of cylinders, and from the relational expression θ=K・R between the indicated angle θ of the indicator and the rotation speed R, that is, its modified form θ=K・(1/N), K is K=θ・N=θ・(2.
0/T(SK)), and is a value that is unrelated to the pulse rate P, which differs depending on the number of cylinders.

In the above embodiment, the reference signal n is added to the period counter 3 for each sampling signal, but the point is that the value determined by the number of cylinders is added to the period counter 3 within the period of the sampling signal. It is sufficient if the number is counted, and a method may be used in which the counted value N is calculated by counting and adding pulse signals corresponding to this value.

[0015]

[Effects of the Invention] The present invention takes the indicated angle θ of the indicating instrument as a function of the rotation speed R, and when the formula is transformed to θ=K・(1/N), N is a number that does not depend on the increase or decrease in the number of cylinders. Since it can be calculated, the constant K can be uniquely determined.
The indicating angle of the indicating instrument can be easily set without increasing the ROM. Furthermore, by changing the constant K, the designated angle relative to the engine speed can be easily set. Furthermore, even if the pulse rate P is different, if the engine speed and vehicle speed are the same, the count value N during one period of the ignition signal is the same, so
It can be used to determine the rotation speed of various engines and vehicle speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a preferred embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of FIG. 1;

[Explanation of symbols]

1 Sampling clock circuit 2 Reference signal circuit 3 Period counter 4 Reset circuit

Claims (1)

[Claims] Claim 1: A reference signal n output during a period of a signal output due to engine rotation, such as a plug ignition signal.
, and based on this count value N, convert the rotation angle θ of the indicating instrument by θ=K・(1/N) (K is a constant),
The reference signal n is determined by the number of cylinders of the engine, and the count value N has a constant period regardless of the signal outputted by the rotation of the engine. 1. A method for converting an indicating angle of an indicating instrument, characterized in that a reference signal n is counted and added for each period of a sampling clock outputted by a sampling clock.