DE102014213547A1 - ELECTRONIC CONTROL UNIT FOR A COMBUSTION ENGINE - Google Patents

Abstract

An electronic control unit for an internal combustion engine is provided. The electronic control unit comprises: measuring means (52) for measuring a signal period of a crank angle signal; prediction means (54) for predicting, each time a crank angle signal is input, the signal period until the input of a next crank angle signal based on a past signal period measured by the measuring means (52); and generating means (56, 58) for generating, in the predicted signal period, a detailed crank angle signal. If the predicted signal period is shorter than the past signal period, the generating means (56, 58) generates the detailed crank angle signal such that the signal interval of the detailed crank angle signal gradually becomes shorter in the predicted signal period.

Description

The present invention relates to an electronic control unit for an internal combustion engine. More particularly, the present invention relates to an electronic control unit that generates a detailed crank angle signal indicative of a more accurate rotational angular position of the crankshaft than the crank angle signal based on a crank angle signal generated at a certain rotational angle interval associated with rotation of a crankshaft of the internal combustion engine.

The JP 2001-263150 A discloses a conventional engine control unit which measures a pulse interval of a pulse train of a crank angle signal and generates a multiplication signal having a frequency of an integer multiple of the pulse interval until the next pulse. The engine control unit controls an engine control actuator to perform fuel injection and ignition based on the multiplication signal.

Specifically, to execute engine control with a small error in engine rotation, this engine control unit predicts the next pulse interval based on a temporary change of a pulse interval in the crank angle signal, and the engine control unit corrects a generation interval of the multiplication signal or a control value such as an ignition timing and an injection timing ,

The following problem may arise in the prior art. The in the JP 2001-2631501 A As described above, the described engine control unit predicts the next pulse interval and corrects the generation interval of the multiplication signal. In this way, the engine control unit may generate a predetermined number of multiplication signals until the next pulse of the crankshaft signal and detect a rotational position of the crankshaft with higher accuracy by the multiplication signal.

In the above technology, the generation interval of the multiplication signal in the predicted pulse interval is constant. This is equivalent to the following: An angular velocity of the crankshaft is assumed to be constant in the predicted pulse interval. In reality, however, even in the pulse interval of the crankshaft signal, the angular velocity of the crankshaft is changed in some cases. For this reason, in the engine control unit of JP 2001-263150 A even if the next pulse interval can be properly predicted, since a change in the angular velocity of the crankshaft is not taken into account, an error in the rotational position of the crankshaft caused by the multiplication signal is caused.

The present invention has been made in view of the above difficulties. It is an object of the present invention to provide an electronic control unit for an internal combustion engine which can reduce an error of a detailed crank angle signal indicative of a more accurate rotational angular position of a crankshaft than a crank angle signal.

According to a first aspect, an electronic control unit for an internal combustion engine comprises a measuring device, a prediction device and a generation device. The measuring means inputs a crank angle signal generated at a certain rotational angle interval of a crankshaft accompanied with rotation of the crankshaft of the internal combustion engine, and measures a signal period of the input crank angle signal. Each time the crank angle signal is input, the predictor predicts the signal period until the input of a next crank angle signal based on a past signal period measured by the measuring device. In the Signal period, which is predicted by the predictor, the generating means generates a detailed crank angle signal at a signal interval which is smaller than the predetermined rotational angle interval, wherein the detailed crank angle signal indicates a rotational angular position of the crankshaft. If the predicted signal period is shorter than the past signal period and the rotation of the crankshaft can be considered accelerated, the generating means generates the detailed crank angle signal such that the signal interval of the detailed crank angle signal generated in the signal period predicted by the predictor, of a first signal interval, which is the signal interval first appearing in the signal period predicted by the predictor, gradually becoming shorter.

According to a second aspect, an electronic control unit for an internal combustion engine comprises a measuring device, a prediction device and a generation device. The measuring device inputs a crank angle signal generated at a certain rotational angle interval of a crankshaft accompanied with rotation of the crankshaft of the internal combustion engine, and measures a signal period of the crank angle signal. Each time the crank angle signal is input, the predictor predicts a signal period until the input of a next crank angle signal based on a past signal period measured by the meter. In the signal period predicted by the predictor, the generator generates a detailed crank angle signal at a signal interval that is less than the determined rotational angle interval, the detailed crank angle signal indicating a rotational angular position of the crankshaft. If the predicted signal period is longer than the past signal period and the rotation of the crankshaft can be assumed to be delayed, the generating means generates the detailed crank angle signal such that the signal interval of the detailed crank angle signal generated in the signal period predicted by the predictor, from a first signal interval, which is the signal interval first appearing in the signal period predicted by the predictor, gradually becomes longer.

In the electronic control units described above, the signal interval of the detailed crank angle signal in the predicted signal period is changed in accordance with a change in angular velocity of the crankshaft. More specifically, in the event that the predicted signal period is shorter than the past signal period and the rotation of the crankshaft can thus be assumed to be accelerated, the detailed crank angle signal is generated such that the signal interval of the detailed crank angle signal generated in the predicted signal period becomes gradually shorter from the first signal interval. Further, in the event that the predicted signal period is longer than the past signal period and the rotation of the crankshaft can thus be assumed to be delayed, the detailed crank angle signal is generated such that the signal interval of the detailed crank angle signal generated in the predicted signal period of becomes gradually longer at the first signal interval. Consequently, as compared with the case where the signal interval of the detailed crank angle signal is constant, the amount of error in the detailed crank angle signal can be reduced. For this reason, the rotational angular position of the crankshaft can be detected with high accuracy from the detailed crank angle signal.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings shows:

1 an illustration illustrating a configuration with an electronic control unit for an internal combustion engine according to an embodiment and parts and devices with respect to the electronic control unit;

2 a block diagram illustrating a schematic configuration of an angle measuring part;

3 an exemplary map for illustrating an error when multiplication signal (detailed crank angle signal) is generated, under a condition that an angular velocity is assumed to be constant;

4 Fig. 4 is a diagram for illustrating a cause of generation of an error when an angular velocity is assumed to be constant;

5 Fig. 14 is an illustration showing an example of how a cranking angle detailed signal period T _μ (n) is changed when the rotation of a crankshaft is delayed;

6 a configuration for illustrating an example of a detailed internal configuration of a period calculation part; and

7 a diagram illustrating a technical effect, which is brought about by the embodiment.

Hereinafter, an electronic control unit for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings. 1 shows a configuration with an electronic control unit for an internal combustion engine according to embodiments and parts and devices thereof.

An internal combustion engine controlled by the electronic control unit (hereinafter referred to as an engine ECU) 20 for an internal combustion engine of the present embodiment is, for example, a diesel engine. This is because in the diesel engine, when fuel injection control is performed in accordance with a crank angle, the accuracy of the crank angle has a great influence on fuel consumption and exhaust gas characteristic. However, the internal combustion engine is not limited to a diesel engine but may be, for example, a gasoline engine. In the case where the internal combustion engine is a gasoline engine, fuel injection and ignition may be performed at an appropriate timing, and thus fuel economy and exhaust gas characteristics may be improved as in the case of the diesel engine.

In the present embodiment, a four-cylinder engine is used as a diesel engine provided by the engine ECU 20 is controlled. In this four-cylinder engine, pistons in A cylinder # 1 and a cylinder # 4 are moved in the same phase, and pistons in a cylinder # 2 and a cylinder # 3 are moved in the same phase. The order of a compression operation is, for example, as follows: Cylinder # 1 → Cylinder # 3 → Cylinder # 4 → Cylinder # 2. A combustion cycle of the cylinder # 1 and a combustion cycle of the cylinder # 4 are shifted from each other by 360 ° CA, and a combustion cycle of the cylinder # 2 and a combustion cycle of the cylinder # 3 are shifted from each other by 360 °.

The internal combustion engine ECU 20 controls an amount of fuel to be injected into the diesel engine, based on measurement signals from various types of sensors that measure an engine speed, an accelerator opening, a water temperature, an exhaust gas component and a fuel pressure, and an input signal from a switch or the like , More precisely, the ECU 20 gives a drive signal to open a valve flap of each injector 50 synchronous with a timing at which fuel injection is started. Subsequently, when the time has elapsed according to the amount of fuel to be injected, the valve of the injector is exhausted 50 closed.

Whether or not the timing for starting the fuel injection is reached is determined based on a rotational position (crank angle) of a crankshaft of the engine. In order to measure this crank angle and the engine speed, in the present embodiment, a camshaft sensor 2 and a crankshaft sensor 10 intended.

The crankshaft sensor 10 is a sensor of the electromagnetic pickup type, which is a signal rotor 14 and an electromagnetic pickup 16 having. The signal rotor 14 is in the crankshaft 12 fitted. The electromagnetic transducer 16 lies on an outer periphery of the signal rotor 14 opposite and grasps teeth, which are in the outer periphery of the signal rotor 14 are formed at equal intervals of, for example, 10 ° CA. However, instead of the electromagnetic pickup, another measuring means such as a magnetic resistor may be used.

The signal rotor 14 has a toothless portion where two teeth are missing at a location of the outer periphery. When the crankshaft is rotated to a crank angle corresponding to an upper compression dead center of the # 1 cylinder and the # 4 cylinder, this toothless portion is located at a position that includes a predetermined number of teeth in a rotational direction of the crankshaft with respect to the position of teeth of the signal rotor 14 opposite the electromagnetic transducer 16 is removed. The crankshaft sensor 10 there, as in 3 1, a pulse signal as a crank angle signal at every certain crank angle (such as 10 ° CA) in accordance with the rotation of the crankshaft except the crank angle corresponding to the toothless portion. When the rotational position of the crankshaft 12 ie the toothless portion of the signal rotor 14 a position opposite the electromagnetic pickup 16 reached, gives the crank angle sensor 10 a reference pulse signal having a larger pulse width than the other pulse signal.

The camshaft sensor 2 has a signal rotor 6 and an electromagnetic pickup 8th on. The signal rotor 6 is on a camshaft 4 of the internal combustion engine, which rotates at a reduced speed at a ratio of ½ to the rotation of the crankshaft. The electromagnetic transducer 8th is opposite to an outer periphery of the signal rotor 6 and outputs a pulse signal corresponding to teeth on the outer periphery of the signal rotor 6 are formed. As in the case of the crankshaft sensor 10 For example, a measuring device other than the electromagnetic pickup may be used.

The signal rotor 6 of the camshaft sensor 2 points as in 1 shown several teeth formed on it. The plurality of teeth are formed such that, in the case where the crankshaft is rotated twice and the crankshaft sensor 10 twice a reference pulse signal outputs, a pulse signal of the camshaft sensor 2 becomes a high level in synchronism with the output of one of the reference pulse signals, and the pulse signal of the camshaft sensor 2 goes low in synchronism with the output of the other of the reference pulse signals. In this way, if the crankshaft sensor 10 the reference pulse signal is output, it is determined whether the reference pulse signal is output at a time when the cylinder # 1 is in the compression process or at a time when the cylinder # 4 is in the compression process.

The internal combustion engine ECU 20 has an input circuit 22 , an EEPROM 24 as an electrically rewritable nonvolatile memory, a microcomputer 26 , an output circuit 42 and a power supply circuit 44 on. The internal combustion engine ECU 20 receives a crank angle signal from the crankshaft sensor 10 is output, and a cam angle signal from the camshaft sensor 2 is output, so that the crank angle signal and the cam angle signal via the input circuit 22 to the microcomputer 26 are given. The measurement signals from the other sensors and an input signal from the switch are via the input circuit 22 to the microcomputer 26 given. Further, to drive signal in the microcomputer 26 is generated to the injection valve 50 to drive, and an output signal to the other ECU via the output circuit 42 output. The EEPROM 24 stores various types of correction values and learning values. The microcomputer 26 reads the correction values and the learned values from the EEPROM as needed 24 and uses them for control. Furthermore, the microcomputer writes 26 the updated learning values into the EEPROM 24 , The power supply circuit 44 receives a power supply from a battery 18 and generates a voltage to activate the input circuit 22 , the EEPROM 24 , the microcomputer 26 and the output circuit 42 and provides the tension for these parts.

The microcomputer 26 has an input / output circuit (I / O circuit) 28 , an A / D converter 30 , a timer 32 , a CPU 36 , a ROM 38 and a ram 40 on, which are connected via an internal bus. In the microcomputer 26 leads the CPU 36 various types of processing in accordance with in ROM 38 stored programs, whereby the drive signal of the injection valve 50 and output signals to the other ECU based on the various types of measurements and input signals described above.

This is where the microcomputer generates 26 In the present embodiment, in order to increase the accuracy of the timing for starting the fuel injection, a detailed crank angle signal generated at an angular interval (such as 1 ° CA) that is more accurate than an angular interval (such as 10 ° CA), for example Generation of a crank angle signal is. It is determined whether or not the timing for starting the fuel injection is reached based on the detailed crank angle signal.

The detailed or accurate crank angle signal is from an angle measuring part 34 generated in the timer 32 is provided. Below are the configuration and operation of the angle measuring part 34 described in more detail with reference to the drawings. 2 shows a block diagram illustrating a schematic configuration of the angle measuring part 34 , The angle measuring part 34 points as in 2 shown a periodic measuring part 52 , a period prediction part 54 , a signal interval calculating part 56 and a detail crank angle signal generating part 58 on. The periodic measuring part 52 may correspond to a measuring device. The period forecasting part 54 may correspond to a predictor. The signal interval calculation part 56 and the detail crank angle signal generating part 58 may correspond to detail crank angle signal generating means (abbreviated as generating means).

The periodic measuring part 52 measures a period of the crank angle signal (also referred to as a crank angle signal period) based on the input crank angle signal. More specifically, every time the pulse of the crank angle signal is input, the period measuring part measures 52 a time interval between the rising edges of two consecutive pulses of the crank angle signal as a period of the crank angle signal. The measured crank angle signal period T (i) is applied to the period prediction part 54 and the signal interval calculating part 56 output.

Based on a past crank angle signal period from the periodic measurement part 52 is measured, the period prediction part wins 54 a predicted next crank angle signal period T '(i + 1) which is a crank angle signal period T (i + 1) until a pulse of the next crank angle signal is input. The period forecasting part 54 For example, an angular acceleration (angular deceleration) of rotation of the crankshaft is obtained from two past crank angle signal periods T (i), T (i-1) and adds (or subtracts) the obtained angular acceleration (angular deceleration) to (or from) the last crank angle signal period T (i). whereby a predicted next crank angle signal period T '(i + 1) can be obtained. At this time, the period prediction part can 54 the angular acceleration (angular deceleration) of three or more past crank angle signal periods T (i), T (i-1), T (i-2), ... win. Furthermore, the period prediction part 54 to add (or subtract) the angular acceleration (angular deceleration) not to (from) the last crank angle signal period T (i), but to (from) a mean (weighted average) of a plurality of past crank angle signal periods so as to predict a predicted next crank angle signal period T '(i + 1) to win or receive.

The signal interval calculation part 56 calculates a signal interval that determines an interval at which a detailed crank angle signal in the next crank angle signal period T '(i + 1) generated by the period prediction part 54 is predicted is generated.

Here, as described in the background paragraph and the paragraph on the problem in the prior art to be solved by the present invention, there is proposed a prior art method which predicts a next crank angle signal period and a detailed crank angle signal (Multiplication signal) is generated in the next crank angle signal period. In the prior art, an interval for generating the However, in the predicted next crank angle signal period, as in FIG. 11, the detailed crank angle signal (multiplication signal) is used 3 shown, constant.

In reality, however, the angular velocity of the crankshaft is also changed within a crank angle signal period. For this reason, for example, when the rotation of the crankshaft is accelerated, the detailed crank angle signal (multiplication signal) which is outputted first becomes an error B occurring in the 3 is shown generated before the time at which an actual crank angle is changed. On the other hand, when the rotation of the crankshaft is decelerated, the detailed crank angle signal (multiplication signal) which is outputted first becomes an error A occurring in the 3 is shown after the time at which the actual crank angle is changed.

These errors are caused because the conventional method makes an angular velocity in the predicted crank angle signal period as in FIG 4 shown to be constant or approximated. These errors are how clear from the 4 can be seen larger as a change in the angular velocity increases, ie, an angular acceleration (angular deceleration) increases. However, every time the rising edge of the pulse of the crank angle signal is input, we, as in 4 detected, a correct crank angle detected, so that the error is reset to zero.

Consequently, in the present embodiment, a signal interval that is from the signal interval calculating part 56 is calculated, changed in accordance with the acceleration or deceleration of the rotation of the crankshaft. Specifically, in the case that a predicted crank angle signal period T '(i + 1) is shorter than a past crank angle signal period T (i) and therefore the rotation of the crankshaft can be regarded as being accelerated, the signal interval calculating part calculates 56 a signal interval such that the signal interval of the first detailed crank angle signal is the longest and the signal interval of the subsequent detailed crank angle signals gradually becomes shorter. In the case that the predicted crank angle signal period T '(i + 1) is longer than the past crank angle signal period T (i), and therefore the rotation of the crankshaft can be regarded as being delayed, the signal interval calculating part calculates 56 a signal interval such that the signal interval of the first detailed crank angle signal is the shortest and the signal interval of the subsequent detailed crank angle signals then gradually becomes longer.

Subsequently, the detail crank angle signal generating part gives 58 every time that of the signal interval calculation part 56 calculated signal interval elapses, a detailed crank angle signal. In this way, the detail crank angle signal generating part 58 , as in 3 shown to output a detailed crank angle signal in which an error is reduced compared with the prior art.

In this regard, the signal interval calculating part receives 56 from the detail crank angle signal generating part 58 Information regarding the number N of detailed crank angle signals to be output in each crank angle signal period T, and calculates the signal interval calculating part 56 every crank angle signal interval. When the signal interval calculating part 56 however, the information about the number N of detailed crank angle signals to be output but not has to be outputted to the signal interval calculating part 56 does not receive the information regarding the number N of detailed crank angle signals to be output. Further calculates signal interval calculation part 56 every time the detailed crank angle signal from the detail crank angle signal generating part 58 is output, a signal interval provided until the next detailed crank angle signal is output. For this, the signal interval calculation part is detected 56 the number n of detailed crank angle signals already provided by the detail crank angle signal generating part 58 is output, and receives the detailed crank angle signal itself.

Below is a specific calculation method for calculating a signal interval in the signal interval calculation part 56 described.

The signal interval calculation part 56 calculates a signal interval T _μ (n) of the detailed crank angle signal using the following mathematical equation 1. (Mathematical Equation 1)

A first term of the mathematical equation 1 describes a basic component of a period of the detailed crank angle signal, whereas a second term of the mathematical equation 1 describes a correction component according to an angular acceleration (angular deceleration) of the rotation of the crankshaft. T _μ0 in the first term is calculated from the following mathematical equation 2.

(Mathematical Equation 2)

• T _μ0 = T '(i + 1) + T (i) / 2

T _μ0 is calculated as an average of the past crank angle signal period T (i) and the predicted crank angle signal period T '(i + 1) as shown in Mathematical Equation 2.

Here, let us assume the case that the rotation of the crankshaft can be regarded as being accelerated (i.e., considered to be accelerated). In this case, when a value obtained by dividing the past crank angle signal period T (i) by the total number N of detailed crank angle signals is used, the first signal interval of the detailed crank angle signal in the predicted crank angle signal period is too long. When a value obtained by dividing the predicted crank angle signal period T '(i + 1) by the number N of all of the detailed crank angle signals is used, the first signal interval of the detailed crank angle signal in the predicted crank angle signal period is too short. Further, let us consider another case where the rotation of the crankshaft can be considered to be retarded (i.e., can be considered to be retarded). In this case, when a value obtained by dividing the past crank angle signal period T (i) by the total number N of detailed crank angle signals is used, the first signal interval of the detailed crank angle signal in the predicted crank angle signal period is too short. When a value obtained by dividing the predicted crank angle signal period T '(i + 1) by the number N of all of the detailed crank angle signals is used, the first signal interval of the detailed crank angle signal is too long in the predicted crank angle signal period.

In this sense, in the present embodiment, a value obtained by dividing a mean value T _{μ0 of} the past crank angle _{signal period} T (i) and the predicted crank angle signal period T '(i + 1) by the total number N of detailed crank angle signals, is used as the basic component of the signal interval of the detailed crank angle signal. Subsequently, the correction term of the second term is added (or subtracted) to (or from) the basic component so as to calculate a signal interval T _μ (n) of the detailed crank angle signal.

The correction _component T _μd included in the second term is calculated by the following mathematical equation 3.

(Mathematical Equation 3)

• T _μd = T '(i + 1) - T _μ0 = T' (i + 1) - T (i) / 2

As described above, T _μd is calculated by _subtracting a mean value T _{μ0 of} the past crank angle _{signal period} T (i) and the predicted crank angle signal period T '(i + 1) from the predicted crank angle signal period T' (i + 1). For this reason, T _{μd is changed} in accordance with the amount of angular acceleration (angular _deceleration ) of the rotation of the crankshaft. More specifically, when the rotation of the crankshaft is accelerated, T _{μd assumes} a negative value, and as the angular acceleration increases, an absolute value of T _{μd becomes} larger. Thus, when the rotation of the crankshaft is accelerated, the signal interval T _μ (n) of the detailed crank angle signal is calculated by subtracting the correction component corresponding to the angular acceleration of the second term from the fundamental component of the first term. On the other hand, when the rotation of the crankshaft is decelerated, T _{μd becomes} a positive value, and as the angular acceleration (angular _deceleration ) increases, an absolute value of T _{μd becomes} larger. Consequently, when the rotation of the crankshaft is decelerated, the signal interval T _μ (n) of the detailed crank angle signal is calculated by adding the correction component corresponding to the angular acceleration of the second term to the fundamental component of the first term.

Further, since T _{μd is} calculated by subtracting the average value T _μ0 from the predicted crank angle signal period T '(i + 1), a correction _component corresponding to an actual angular acceleration (actual angular deceleration) with high accuracy can be obtained from the second term T _μd contains, are calculated. More specifically, the average value T _μ0 describes a crank angle _{signal interval} at a time point at which the past crank angle signal period T (i) is changed to the predicted crank angle signal period T '(i + 1). For this reason, the crank angle _{signal period} described by the average value T _μ0 describes a crank angle _{signal period} at a timing closer to the predicted crank angle signal period T '(i + 1) than the past crank angle signal period T (i). Thus, the correction component corresponding to the actual angular acceleration (actual angular deceleration) with high accuracy can be calculated by using the difference between the predicted crank angle signal period T '(i + 1) and the crank angle _{signal period} described by the average value T _μ0 ,

According to another configuration, T _μd can be calculated by the past Crank angle signal period T (i) is subtracted from the predicted crank angle signal period T '(i + 1). Further, the past crank angle signal period T (i) describing a factor for calculating T _μ0 and T _{μd may be} the predicted crank angle _{signal period} itself, which is one before the predicted crank angle signal period T '(i + 1), or a crank angle signal period is calculated from a mean value (weighted average) of some past crank angle signal periods.

In the present embodiment, the signal interval T _μ (n) of the detailed crank angle signal is obtained by using the mathematical equation 1 described above. Consequently, in the event that the rotation of the crankshaft is accelerated, the respective signal intervals T _μ (n) can be calculated such that the signal interval T _μ (1) of the first detailed crank angle signal becomes the longest and that the subsequent signal intervals T _μ (n ) gradually become shorter in accordance with the degree of acceleration. In contrast, in the event that the crankshaft rotation is delayed, the respective signal intervals T _μ (n) are calculated such that the signal period T _μ (1) of the first detailed crank angle signal becomes the shortest and that the following signal periods T _μ ( n) gradually become longer in accordance with the degree of delay. Of course, the total value of the signal intervals of all the detailed crank angle signals is equal to the predicted crank angle signal period T '(i + 1).

Further, in the case that the rotation of the crankshaft is accelerated, the signal interval T _μ (1) of the first detailed crank angle signal calculated using the mathematical equation 1 can be made shorter than a value obtained by the past one Crank angle signal period T (i) is divided by the number N of all the detailed crank angle signals, and designed to be longer than a value obtained by dividing the predicted crank angle signal period T '(i + 1) by the number N of all the detailed crank angle signals. Moreover, in the case where the rotation of the crankshaft is decelerated, the signal interval T _μ (1) of the first detailed crank angle signal calculated using Mathematical Equation 1 can be made longer than the value obtained by the past crank angle signal period T (i) is divided by the number N of all the detailed crank angle signals, and shorter than the value obtained by dividing the predicted crank angle signal period T '(i + 1) by the number N of all the detailed crank angle signals ,

5 FIG. 16 shows an example of how the signal interval T _μ (n) of the detailed crank angle signal calculated using Mathematical Equation 1 changes. Further shows 5 an example in which the predicted crank angle signal period T '(i + 1) becomes longer than the past crank angle signal period T (i) and the rotation of the crankshaft is assumed to be delayed. In the 5 It is assumed that the number of detailed crank angle signals output in the crank angle signal period T is six.

In the in the 5 In the example shown in FIG. 1, the correction component in the mathematical equation 1 assumes a positive value, and thus the signal interval T _μ (n) of the detailed crank angle signal can be calculated by adding the correction component to the fundamental component. The amount of the correction component is calculated so that when the position (first, second, third, etc.) of the signal interval becomes later, the amount of the correction component increases. For this reason, the signal interval T _μ (1) of the first detailed crank angle signal becomes the shortest. The signal interval T _μ (n) of the detailed crank angle period is calculated so that when the position (first, second, third, etc.) of the signal period becomes later, the signal interval T _μ (n) of the detailed crank angle period gradually becomes longer.

Below is an internal configuration of the signal interval calculation part 56 with reference to the 6 described. The past crank angle signal period T (i) and the predicted crank angle signal period T '(i + 1) become, as in FIG 6 shown to a subtractor 60 and to an adder 64 given.

The subtractor 60 outputs a subtraction result (T '(i + 1) _-T (i) = 2T _μd ) obtained by subtracting the past crank angle signal period T (i) from the predicted crank angle signal period T' (i + 1).

A multiplier 62 multiplies the subtraction result (2T _μd ) by 1 / (N + 1). A multiplication result (2T _μd / (N + 1)) of the multiplier 62 goes to an adder 74 given.

An addition result (T '(i + 1) + T (i)) of the adder 64 is in a multiplier 66 multiplied by ½. For this reason, a multiplication result of the multiplier becomes 66 equal to the mean T _μ0 . The average value _T0 is applied to an input _{terminal of} a selector 68 given. A signal is sent to the other input terminal of the selector 68 given by a signal interval register 70 which holds a signal interval T _μ (n) × N, that of the signal interval calculation part 56 is issued. In this regard, the value of the signal interval T _μ (n) × N, that of the signal interval register 70 is kept updated every time the detail crank angle signal generating part 58 outputs the detailed crank angle signal.

A command unit 72 gives commands to the voter 68 which input value is to be output. The command unit 72 gives the commands in accordance with the number n of outputs of the detailed crank angle signal generated by the detail crank angle signal generating part 58 provided. More specifically, when a rising edge of a pulse of a crank angle signal is input, the number n of outputs of the detailed crank angle signal is reset to "1". Then instructs the command unit 72 the voter 68 to output the mean value T _μ0 . When the number n of outputs of the detailed crank angle signal becomes greater than or equal to 2, the command unit instructs 72 the voter 68 to output the signal interval T _μ (n) × N from the signal interval register 70 is held.

Here, the mathematical equation 1 described above can be transformed into the following mathematical equation 4. (Mathematical Equation 4)

More specifically, in the case that the signal interval T _μ (n) of the detailed crank angle signal is multiplied by the number N of signals, the first signal interval T _μ (1) × N can be calculated by dividing the average value T _μ0 by 2T _μd / (N + 1) is added. Further, a multiplied value between a second or subsequent signal _interval and the number N of signals can be calculated by adding 2T _μd / (N + 1) to a value obtained by precisely measuring the signal interval T _μ (n-1) before the signal interval T _μ (n) is multiplied by the number of N of signals.

If the average T _μ0 as described above, by the voter 68 is selected, the mean value T _{μ0 is} determined by the adder 74 added to 2T _μd / (N + 1). Consequently, a value obtained by multiplying the first signal interval T _μ (1) by the number N of signals is inputted from the adder 74 output. In contrast, in the event that an input value from the signal interval register 70 by the voter 68 is selected, a value obtained by multiplying the last signal interval T _μ (n-1) by the number N of signals from the selector 68 to the adder 74 output. For this reason, 2T _μd / (N + 1) will be in the adder 74 is added to the output value (T _μ (n-1) × N), and thus a value obtained by multiplying the signal interval T _μ (n) of that time by the number N of signals is output.

In this connection, a value obtained by multiplying the signal interval T _μ (n) by the number N of signals under the given circumstances may be applied to the detail crank angle signal generating part 58 can be output and the detail crank angle signal generating part 58 multiply the obtained value (T _μ (n) × N) by 1 / N. Alternatively, a multiplier for multiplying the obtained value (T _μ (n) × N) by 1 / N in the signal interval calculating part 56 be provided.

A simulation was performed for an error of the detailed crank angle signal calculated in this way. The simulation confirms how in 7 shown that the error can be significantly reduced compared to the conventional technology.

Above, the embodiment of the present invention is described. However, the present invention is not limited to the embodiment described above, but can be modified variously within its scope.

In the embodiment described above, the angle measuring part 34 for example, constructed of hardware and the detailed crank angle signal is generated by hardware. However, the detailed crank angle signal may be due to software in the microcomputer 26 be generated.

Further, in the above-described embodiment, the signal interval of the detailed crank angle signal is changed both for the case that the rotation of the crankshaft is accelerated and for the case that the rotation of the crankshaft is decelerated. In some cases, a crank angle where fuel is in the However, the internal combustion engine is injected, but to be nearly constant and the accuracy of the detailed crank angle signal at this crank angle can be sufficiently ensured by the signal interval of the detailed crank angle signal is changed in accordance with either the acceleration or the deceleration of the rotation of the crankshaft. In this case, the signal interval of the detailed crank angle signal may be changed in accordance with either the acceleration or the deceleration of the rotation of the crankshaft.

Above, an electronic control unit for an internal combustion engine is described.

An electronic control unit for an internal combustion engine is provided. The electronic control unit comprises: a measuring device 52 for measuring a signal period of a crank angle signal; a predictor 54 for predicting, each time a crank angle signal is input, the signal period until the input of a next crank angle signal based on a past signal period provided by the measuring device 52 is measured; and a generator 56 . 58 for generating, in the predicted signal period, a detailed crank angle signal. If the predicted signal period is shorter than the past signal period, the generating means generates 56 . 58 the detailed crank angle signal such that the signal interval of the detailed crank angle signal gradually becomes shorter in the predicted signal period.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• JP 2001-263150 A [0002, 0005]
• JP 2001-2631501 A [0004]

Claims (9)

Electronic control unit for an internal combustion engine, comprising: - a measuring device ( 52 ) for inputting a crank angle signal generated at a certain rotational angle interval of a crankshaft accompanied with rotation of the crankshaft of the internal combustion engine and for measuring a signal period of the input crank angle signal; A predictive device ( 54 ) for predicting, each time the crank angle signal is input, the signal period until an input of a next crank angle signal based on a past signal period detected by the measuring device (12); 52 ) is measured; and a generating device ( 56 . 58 ) in the signal period generated by the predictor ( 54 ), a detailed crank angle signal at a signal interval that is less than the determined rotational angle interval, wherein the detailed crank angle signal indicates a rotational angular position of the crankshaft, wherein - when the predicted signal period is shorter than the past signal period and the rotation of the crankshaft as accelerated can be considered, the generating device ( 56 . 58 ) generates the detailed crank angle signal such that the signal interval of the detailed crank angle signal generated in the signal period obtained by the predicting means ( 54 ) is predicted by a first signal interval, which is the signal interval that first appears in the signal period, that is generated by the predictor ( 54 ) is gradually becoming shorter. Electronic control unit according to claim 1, characterized in that - the generating device ( 56 . 58 ) generates a predetermined number N of detailed crank angle signals in the predicted signal period, where N is an integer; and - if the predicted signal period is shorter than the past signal period and the rotation of the crankshaft can be considered accelerated, the generating means ( 56 . 58 ) the first signal interval of the detailed crank angle signal generated in the signal period output by the predictor ( 54 ) is set such that the first signal interval is shorter than a value obtained by dividing the past signal period by N and longer than a value obtained by dividing the predicted signal period by N. Electronic control unit according to claim 2, characterized in that - the generating device ( 56 . 58 ) the first signal interval of the detailed crank angle signal generated in the signal period output by the predictor ( 54 ) is calculated by subtracting a value corresponding to an angular acceleration of the rotation of the crankshaft from a value obtained by dividing an average of the past signal period and the predicted signal period by N. Electronic control unit according to claim 2 or 3, characterized in that - when the generating device ( 56 . 58 ) calculates a second or subsequent signal interval of the detailed crank angle signal generated in the signal period to be generated by the predictor (16). 54 ), the generating device ( 56 . 58 ) calculates the second or subsequent signal interval, which is the signal interval to be calculated, by subtracting a value corresponding to an angular acceleration of rotation of the crankshaft from a reference signal interval that is the signal interval that precedes the signal interval to be calculated by one. Electronic control unit for an internal combustion engine, comprising: - a measuring device ( 52 ) for inputting a crank angle signal generated at a certain rotational angle interval of a crankshaft accompanied with rotation of the crankshaft of the internal combustion engine and measuring a signal period of the crank angle signal; A predictive device ( 54 ) for predicting, every time the crank angle signal is input, a signal period up to an input of a next crank angle signal based on a past signal period detected by the measuring device (12); 52 ) is measured; and a generating device ( 56 . 58 ) in the signal period generated by the predictor ( 54 ), a detailed crank angle signal at a signal interval that is less than the determined rotational angle interval, wherein the detailed crank angle signal indicates a rotational angular position of the crankshaft, wherein when the predicted signal period is longer than the past signal period and retards the rotation of the crankshaft as can be assumed, the generating device ( 56 . 58 ) generates the detailed crank angle signal such that the signal interval of the detailed crank angle signal generated in the signal period obtained by the predicting means ( 54 ) is predicted by a first signal interval, which is the signal interval that first appears in the signal period, that is generated by the predictor ( 54 ) is gradually getting longer. Electronic control unit according to claim 5, characterized in that - the generation facility ( 56 . 58 ) generates a predetermined number N of detailed crank angle signals in the predicted signal period, where N is an integer; and - if the predicted signal period is longer than the past signal period and the rotation of the crankshaft can be considered as being delayed, the generating means ( 56 . 58 ) the first signal interval of the detailed crank angle signal generated in the signal period output by the predictor ( 54 ) is set such that the first signal interval is longer than a value obtained by dividing the past signal period by N and shorter than a value obtained by dividing the predicted signal period by N. Electronic control unit according to claim 6, characterized in that - the generating device ( 56 . 58 ) the first signal interval of the detailed crank angle signal generated in the signal period output by the predictor ( 54 ) is calculated by adding a value corresponding to an angular acceleration of the rotation of the crankshaft to a value obtained by dividing an average of the past signal period and the predicted signal period by N. Electronic control unit according to claim 6 or 7, characterized in that - when the generating device ( 56 . 58 ) calculates a second or subsequent signal interval of the detailed crank angle signal generated in the signal period to be generated by the predictor (16). 54 ), the generating device ( 56 . 58 ) calculates the second or subsequent signal interval, which is the signal interval to be calculated, by adding a value corresponding to an angular acceleration of rotation of the crankshaft to a reference signal interval, which is a signal interval preceding the signal interval to be calculated by one. Electronic control unit according to one of claims 1 to 7, characterized in that - the generating device ( 56 . 58 ) calculates an nth signal interval T _μ (n) of the detailed crank angle signal in accordance with the following mathematical equation:

Where n is a number indicating that the nth signal interval is the signal interval to be calculated, N is a number of detailed crank angle signals, T '(i + 1) is the predicted signal period, and T (i ) is the past signal period.

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