This application is based on Japanese Patent Application No. 2015-89882 filed on Apr. 24, 2015, Japanese Patent Application No. 2015-210147 filed on Oct. 26, 2015, Japanese Patent Application No. 2015-222770 filed on Nov. 13, 2015, and Japanese Patent Application No. 2015-222771 filed on Nov. 13, 2015, the disclosures of which are incorporated herein by reference.
The present disclosure relates to a control device for a high-pressure pump including an electromagnetic valve that moves a quantity control valve of the high-pressure pump to open and close.
Direct injection engines, which inject fuel into each cylinder directly, atomize the injected fuel using high injection pressure. To do so, such an engine employs an electric low-pressure pump to supply fuel from a fuel tank to a high-pressure pump, which is driven by the power of the engine, so that the high-pressure pump discharges high-pressure fuel to fuel injection valves.
Such a high-pressure pump includes a quantity control valve to open and close the suction port of the high-pressure pump and an electromagnetic valve to move the quantity control valve for the opening and closing. Energization of the electromagnetic valve is controlled to control a period over which the quantity control valve is closed and thereby control the quantity of fuel to be discharged by the high-pressure pump and thus the fuel pressure.
When the electromagnetic valve is being closed, its movable portion strikes its stopper portion, generating a vibration, which may lead to an unpleasant noise. A solution for this is described in Patent Literature 1 (JP 2010-533820 A). A current value to be used when an electromagnetic valve of a high-pressure pump is energized so as to be closed is a minimum current value that can close the valve, so that the valve closing speed is reduced and thereby the vibration generated during valve closing control is inhibited. To determine the minimum current value, an actual fuel pressure of a pressure reservoir that stores the high-pressure fuel supplied from the high-pressure pump is compared to a target fuel pressure. The minimum current value is determined on the basis of a current value at which the deviation of the actual fuel pressure from the target fuel pressure exceeds a threshold value.
The technique described in Patent Literature 1, however, may be affected by variations in characteristic of the high-pressure pump resulting from individual differences (manufacturing variability) and environmental changes. Thus, this technique may have difficulty in setting the minimum current value accurately and hence may not be able to reduce the noise of the high-pressure pump sufficiently.
The applicant of the present application has been studying a technique to reduce the noise from a high-pressure pump in a manner that is unlikely to be affected by individual differences and environmental changes, in the form of a system as described below. It is determined whether the high-pressure pump is operated (whether a movable portion of an electromagnetic valve is moved to a closed position) when the electromagnetic valve is energized. If it is determined that the high-pressure pump is operated, the electric power to be supplied to the electromagnetic valve is reduced by a predefined amount. This processing is repeated to reduce the supply power gradually. Then, if it is determined that the high-pressure pump is not operated, the supply power is increased by a predefined amount. In this manner, the supply power to the electromagnetic valve can be set to a valve-closing marginal power (a minimum supply power that can close the electromagnetic valve).
The system described above, however, requires the supply power to be reduced until it is determined that the high-pressure pump is not operated and thus may cause issues such as an intermittent noise resulting from the non-operation of the high-pressure pump and a reduction in fuel pressure.
An object of the present disclosure is to provide a control device for a high-pressure pump that can reduce a noise from the high-pressure pump while restricting issues resulting from non-operation of a high-pressure pump.
According to an aspect of the present disclosure, a high-pressure pump includes: a pump chamber having a suction port and a discharge port for fuel; a plunger configured to reciprocate in the pump chamber; a quantity control valve configured to open and close the suction port; and an electromagnetic valve configured to move the quantity control valve for opening and closing. The high-pressure pump is configured to energize the electromagnetic valve to move a movable portion of the electromagnetic valve to a closed position to close the quantity control valve. A control device for the high-pressure pump includes: a determination unit configured to determine whether the movable portion of the electromagnetic valve has been moved to the closed position to close the electromagnetic valve when the electromagnetic valve is energized; an acquisition unit configured to acquire, as an electromagnetic-valve response time, a period of time from a start of the energization of the electromagnetic valve until when it is determined that the electromagnetic valve has been closed; and an electric power setting unit configured to set a supply power to the electromagnetic valve by repeating a process in which the supply power to the electromagnetic valve is reduced so as to be smaller than a previous value until the electromagnetic-valve response time reaches a predefined upper limit value.
A reduction in supply power to the electromagnetic valve leads to a reduction in the valve closing speed of the electromagnetic valve (the moving speed of a movable portion), increasing electromagnetic-valve response time. Because of such a relationship, by monitoring the electromagnetic-valve response time during the energization of the electromagnetic valve and repeating processing in which the supply power to the electromagnetic valve is reduced so as to be smaller than a previous value until the electromagnetic-valve response time reaches a predefined upper limit value, the supply power to the electromagnetic valve can be reduced to a lower limit supply power that corresponds approximately to the upper limit value of the electromagnetic-valve response time. In this manner, the valve closing speed of the electromagnetic valve can be reduced and thereby the noise from the high-pressure pump can be reduced.
In this case, the supply power to the electromagnetic valve can be set to the lower limit supply power without being affected by variations in characteristic of the high-pressure pump (including variations in characteristic of the electromagnetic valve) resulting from individual differences and environmental changes. Thus, the noise from the high-pressure pump can be reduced without being affected significantly by the individual differences and environmental changes. Moreover, instead of reducing the supply power until it is determined that the high-pressure pump is not operated (that is, the electromagnetic valve does not close), the supply power is reduced until the electromagnetic-valve response time reaches its upper limit value; hence, issues such as intermittent noise resulting from the non-operation of the high-pressure pump and a reduction in fuel pressure can be restricted.
According to an aspect of the present disclosure, a high-pressure pump includes: a pump chamber having a suction port and a discharge port for fuel; a plunger configured to reciprocate in the pump chamber; a quantity control valve configured to open and close the suction port; and an electromagnetic valve configured to move the quantity control valve for opening and closing. The high-pressure pump is configured to energize the electromagnetic valve to move a movable portion of the electromagnetic valve to a closed position to close the quantity control valve. A control device for the high-pressure pump includes: a determination unit configured to determine whether the movable portion of the electromagnetic valve has been moved to the closed position to close the electromagnetic valve when the electromagnetic valve is energized; an acquisition unit configured to acquire, as an electromagnetic-valve response time, a period of time from a start of the energization of the electromagnetic valve until when it is determined that the electromagnetic valve has been closed; a target setting unit configured to set a target value of the electromagnetic-valve response time as a target electromagnetic-valve response time; and an electric power control unit configured to control a supply power to the electromagnetic valve such that the electromagnetic-valve response time becomes equal to the target electromagnetic-valve response time.
With such a configuration, the electromagnetic-valve response time can be controlled so as to agree with a desired target electromagnetic-valve response time accurately without being affected significantly by individual differences and environmental changes. Also in this manner, issues resulting from non-operation of the high-pressure pump can be restricted and the noise from the high-pressure pump can be reduced.
A first embodiment will now be described with reference to
As described in
As illustrated in
The electromagnetic valve 27 includes a movable portion 28, a spring 29 that urges the movable portion 28 to an open position (see
As illustrated in
As illustrated in
The energization of the electromagnetic valve 27 (the solenoid 30) is controlled to achieve the following. As illustrated in
Here, the timing to start energizing the electromagnetic valve 27 (the solenoid 30) is controlled to control a period over which the quantity control valve 23 is closed and thereby control the quantity of fuel to be discharged from the high-pressure pump 14 and thus the fuel pressure. To increase the fuel pressure, for example, the timing to start energizing the electromagnetic valve 27 is advanced, so that the timing to start closing the quantity control valve 23 is advanced. In this way, the period over which the quantity control valve 23 is closed is prolonged and thereby the discharge flow rate of the high-pressure pump 14 is increased. To reduce the fuel pressure, the timing to start energizing the electromagnetic valve 27 is retarded, so that the timing to start closing the quantity control valve 23 is retarded. In this way, the period over which the quantity control valve 23 is closed is shortened and thereby the discharge flow rate of the high-pressure pump 14 is reduced.
As illustrated in
The engine is also provided with an airflow meter 37, which measures the quantity of intake air, and a crank angle sensor 38, which outputs a pulse signal for every predefined crank angle in synchronization with the rotation of a crankshaft (not shown). The crank angle and the engine rotation speed are sensed on the basis of the output signal of the crank angle sensor 38. Furthermore, a cooling water temperature sensor 39 for sensing the temperature of a cooling water (cooling water temperature) is disposed at a cylinder block of the engine. A current sensor 42 senses the current passing through the electromagnetic valve 27 (the solenoid 30) of the high-pressure pump 14.
The output of such sensors is input to an electronic control unit (hereinafter referred to as an ECU) 40. The ECU 40, which includes a microcomputer as its main component, executes various engine control programs stored in a built-in ROM (a storage medium) to control the quantity of fuel injection, ignition timing, throttle opening (the quantity of intake air), and the like in accordance with the operating conditions of the engine.
As shown in
During the valve closing control, the movable portion 28 of the electromagnetic valve 27 may strike a stopper portion 41 (see
In the present embodiment, normal control is performed when a predefined condition to execute noise reduction control is unsatisfied (for example, when the noise generated during the valve closing control on the high-pressure pump 14 is unlikely to be heard by a driver). As illustrated in (a) of
The noise reduction control is performed when the predefined condition to execute the noise reduction control is satisfied (for example, when the noise generated during the valve closing control on the high-pressure pump 14 is likely to be heard by a driver) to reduce the noise generated during the valve closing control. As illustrated in
Here, the ECU 40 executes routines in
When the electromagnetic valve 27 is energized (when the solenoid 30 is energized), it is determined whether the movable portion 28 of the electromagnetic valve 27 has been moved to the closed position (hereinafter referred to as “the electromagnetic valve 27 has been closed”). A period of time from start of the energization of the electromagnetic valve 27 until when it is determined that the electromagnetic valve 27 has been closed is acquired as an electromagnetic-valve response time. Then, processing is repeated in which the supply power to the electromagnetic valve 27 is reduced so as to be smaller than a previous value until the electromagnetic-valve response time reaches a predefined upper limit value to set the supply power to the electromagnetic valve 27.
The upper limit value of the electromagnetic-valve response time is preset to an electromagnetic-valve response time with which the supply power to the electromagnetic valve 27 is a minimum supply power that can close the electromagnetic valve 27 or a value shorter than that by a predefined value, on the basis of the characteristic of the electromagnetic valve 27 (for example, an electromagnetic valve having a standard characteristic).
As illustrated in
A method to determine whether the electromagnetic valve 27 has been closed will now be described.
As illustrated in
Because of such a characteristic, the current through the solenoid 30 of the electromagnetic valve 27 is sensed by the current sensor 42, the speed of the current (for example, a differentiated value) is calculated, and it is determined that the electromagnetic valve 27 has been closed (the movable portion 28 has moved to the closed position) when the speed of the current falls below a predefined valve-closure criterion value in the first embodiment.
Additionally, in the first embodiment, to reduce the supply power to the electromagnetic valve 27 until the electromagnetic-valve response time reaches the upper limit value, processing is performed, if the electromagnetic-valve response time is shorter than the upper limit value, in the following manner: the supply power to the electromagnetic valve 27 is reduced so as to be smaller than a previous value each time when the number of times determining that the electromagnetic valve 27 has been closed reaches a predefined determination count.
Here, in case where the determination count is a constant value as illustrated in (a) of
Hence, in the first embodiment, as illustrated in (b) of
The routines in the
A valve closing control routine described in
If it is determined in step 101 that the electromagnetic valve 27 has been closed during the previous energization, the routine proceeds to step 102. In step 102, the determination count is calculated in accordance with the electromagnetic-valve response time (or the supply power) exhibited during the previous energization by referencing a table of the determination count illustrated in
Then, the routine proceeds to step 103, where it is determined whether the electromagnetic-valve response time during the previous energization is shorter than the predefined upper limit value. Here, the upper limit value is preset to an electromagnetic-valve response time with which the supply power to the electromagnetic valve 27 is a minimum supply power that can close the electromagnetic valve 27 or a value shorter than that by a predefined value, on the basis of the characteristic of the electromagnetic valve 27 (for example, an electromagnetic valve having a standard characteristic).
If it is determined in step 103 that the electromagnetic-valve response time is less than the upper limit value, it is determined that the electromagnetic-valve response time has not reached the upper limit value. Then, the routine proceeds to step 104, where the consecutive number of times it is determined that the electromagnetic valve 27 has been closed is counted as the valve closing count.
Then, the routine proceeds to step 105, where it is determined whether the valve closing count is equal to or greater than the determination count. If it is determined in step 105 that the valve closing count is less than the determination count, the routine proceeds to step 106, where the forthcoming supply power to the electromagnetic valve 27 is set to a value identical with the previous value.
Subsequently, if it is determined in step 105 described above that the valve closing count is equal to or greater than the determination count, the routine proceeds to step 107, where the forthcoming supply power to the electromagnetic valve 27 is set to a value obtained by reducing the previous value by a predefined value. Then, the routine proceeds to step 108, where the valve closing count is reset to “0.”
Subsequently, if it is determined in step 103 described above that the electromagnetic-valve response time is equal to or greater than the upper limit value, it is determined that the electromagnetic-valve response time has reached the upper limit value. Then, the routine proceeds to step 106, where the supply power is set to a value identical with the previous value.
In this manner, the processing to reduce the supply power to the electromagnetic valve 27 from a previous value is repeated every time the valve closing count reaches the determination count until the electromagnetic-valve response time reaches the upper limit value. The processing from steps 101 to 108 serves as an electric power setting unit.
If it is determined in step 101 described above that the electromagnetic valve 27 has not been closed during the previous energization, the routine proceeds to step 109, where the supply power is set to a value obtained by increasing the previous value by a predefined value.
Subsequently, the routine proceeds to step 110 in
Then, the routine proceeds to step 111, where, when the timing to start the energization of the electromagnetic valve 27 is reached, the energization of the electromagnetic valve 27 is started with the PWM control being performed to periodically switch on and off the voltage to actuate the solenoid 30 of the electromagnetic valve 27 at the duty ratio set in step 110 described above.
As illustrated in
Then, the routine proceeds to step 112, where a response time calculation routine in
Then, the routine proceeds to step 113, where it is determined whether the PWM control has been continued for a predefined time Tp (or whether the current through the solenoid 30 exceeds a predefined value I1). At a point in time when it is determined in step 113 that the PWM control has been continued for the predefined time Tp (or when it is determined that the current through the solenoid 30 exceeds the predefined value I1), the routine proceeds to step 114, where the PWM control is switched to a first constant current control and the first constant current control is performed. In the first constant current control, the current passing through the solenoid 30 is set to the predefined value I1.
Then, the routine proceeds to step 115, where it is determined whether the first constant current control has been continued for a predefined time T1. At a point in time when it is determined that the first constant current control has been continued for the predefined time T1, the routine proceeds to step 116, where the first constant current control is switched to a second constant current control and the second constant current control is performed. In the second constant current control, the current passing through the solenoid 30 is set to a predefined value I2, which is less than the predefined value I1.
Then, the routine proceeds to step 117, where it is determined whether the second constant current control has been continued for a predefined time T2. At a point in time when it is determined that the second constant current control has been continued for the predefined time T2, the routine proceeds to step 118, where the energization of the electromagnetic valve 27 is stopped, and this routine is finished.
The response time calculation routine described in
Then, the routine proceeds to step 202, where the current passing through the solenoid 30 and detected by the current sensor 42 is read. Then, the routine proceeds to step 203, where the speed of the current passing through the solenoid 30 (for example, a differentiated value) is calculated.
Then, the routine proceeds to step 204, where it is determined whether the speed of the current passing through the solenoid 30 falls below the predefined valve-closure criterion value. If the speed of the current passing through the solenoid 30 is not less than the valve-closure criterion value, the routine reverts back to step 202 described above.
At a point in time when it is determined in step 204 described above that the speed of the current passing through the solenoid 30 is less than the valve-closure criterion value, the routine proceeds to step 205. In step 205, it is determined that the electromagnetic valve 27 has been closed (the movable portion 28 has moved to the closed position), and the valve closure determination flag FCL is set to “1.”
Then, the routine proceeds to step 206, where the period of time from start of the energization of the electromagnetic valve 27 until when it is determined that the electromagnetic valve 27 has been closed is calculated as the electromagnetic-valve response time, and this routine is finished.
In the first embodiment described above, the noise reduction control is executed when a predefined condition to execute the noise reduction control is satisfied. During the noise reduction control, it is determined whether the electromagnetic valve 27 has been closed during the energization of the electromagnetic valve 27, and a period of time from start of the energization of the electromagnetic valve 27 until when it is determined that the electromagnetic valve 27 has been closed is acquired as the electromagnetic-valve response time. Then, processing is repeated in which the supply power to the electromagnetic valve 27 is reduced so as to be smaller than a previous value until the electromagnetic-valve response time reaches a predefined upper limit value to set the supply power to the electromagnetic valve 27. In this manner, the supply power to the electromagnetic valve 27 can be reduced to a lower limit supply power that corresponds approximately to the upper limit value of the electromagnetic-valve response time. Thus, the valve closing speed of the electromagnetic valve 27 can be reduced and thereby the noise from the high-pressure pump 14 can be reduced.
In this case, the supply power to the electromagnetic valve 27 can be set to the lower limit supply power without being affected even by variations in characteristic of the high-pressure pump 14 (including variations in characteristic of the electromagnetic valve 27) resulting from individual differences and environmental changes. Thus, the noise from the high-pressure pump 14 can be reduced without being affected significantly by the individual differences and environmental changes. Moreover, instead of reducing the supply power until it is determined that the high-pressure pump 14 is not operated (that is, the electromagnetic valve 27 does not close), the supply power is reduced until the electromagnetic-valve response time reaches its upper limit value; hence, issues such as intermittent noise resulting from the non-operation of the high-pressure pump 14 and a reduction in fuel pressure can be prevented.
Additionally, in the first embodiment, to reduce the supply power to the electromagnetic valve 27 until the electromagnetic-valve response time reaches the upper limit value, processing is performed, if the electromagnetic-valve response time is shorter than the upper limit value, in the following manner: the supply power to the electromagnetic valve 27 is reduced so as to be smaller than a previous value every time when the number of times it is determined that the electromagnetic valve 27 has been closed reaches a predefined determination count. In this manner, the supply power to the electromagnetic valve 27 can be reduced after the number of times determining that the electromagnetic valve 27 has been closed reaches a predefined determination count and it is thereby ensured that the electromagnetic valve 27 is closed with the supply power provided this time.
Furthermore, in the first embodiment, the determination count is increased as the electromagnetic-valve response time becomes longer or the determination count is increased with a reduction in the supply power to the electromagnetic valve 27. In this way, when the supply power to the electromagnetic valve 27 is still large with a short electromagnetic-valve response time, the determination count is reduced, so that the supply power to the electromagnetic valve 27 can be reduced swiftly. Subsequently, when the supply power to the electromagnetic valve 27 becomes small with a long electromagnetic-valve response time and a region in which the electromagnetic valve 27 does not close is approaching, the determination count is increased, so that the reliability of the valve closure determination on the electromagnetic valve 27 can be enhanced. In this manner, the time taken to reduce the supply power to the electromagnetic valve 27 to a lower limit supply power can be reduced while the reliability of the valve closure determination on the electromagnetic valve 27 is maintained. Thus, the noise from the high-pressure pump 14 can be reduced swiftly.
Additionally, in the first embodiment, the upper limit value of the electromagnetic-valve response time is preset to an electromagnetic-valve response time with which the supply power to the electromagnetic valve 27 is a minimum supply power that can close the electromagnetic valve 27 or a value shorter than that by a predefined value, on the basis of the characteristic of the electromagnetic valve 27 (for example, an electromagnetic valve having a standard characteristic). In this manner, the supply power to the electromagnetic valve 27 can be reduced to approximately a minimum supply power (the minimum supply power or its vicinity). Thus, the effect of reducing the noise from the high-pressure pump 14 can be enhanced.
While the determination count is changed in accordance with the electromagnetic-valve response time (or the supply power) in the first embodiment described above, this is not limitative. The determination count may be fixed to a constant value. Furthermore, the processing to determine the valve closing count may be omitted and the supply power to the electromagnetic valve 27 may be reduced so as to be smaller than a previous value every time when it is determined that the electromagnetic valve 27 is closed (or every time when a predefined period of time elapses) until the electromagnetic-valve response time reaches the upper limit value.
A second embodiment will now be described with reference to
In the second embodiment, an ECU 40 executes routines in
The routines in the
A fuel pressure F/F control quantity calculation routine described in
When this routine is started, a fuel pressure F/F control quantity [° C.A] is calculated in step 301 from a map or the like in accordance with a target fuel pressure, a required quantity of fuel injection, engine rotation speed, and the like. The target fuel pressure and the required quantity of fuel injection are each calculated from a map or the like in accordance with operating conditions of the engine (for example, engine rotation speed, load, and the like).
A fuel pressure F/B control quantity calculation routine described in
When this routine is started, a deviation of an actual fuel pressure (a fuel pressure sensed by the fuel pressure sensor 36) from a target fuel pressure is calculated as a fuel pressure deviation [MPa] in step 401.
Fuel pressure deviation=Target fuel pressure −Actual fuel pressure
Then, the routine proceeds to step 402, where the fuel pressure deviation is multiplied by a proportional gain to obtain a proportional term [° C.A].
Proportional term=Fuel pressure deviation×Proportional gain
Then, the routine proceeds to step 403, where the integral term [° C.A] for this time is calculated using the fuel pressure deviation, an integral gain, and the previous integral term (i−1) on the basis of the following equation.
Integral term=Integral term (i−1)+Fuel pressure deviation×Integral gain
Then, the routine proceeds to step 404, where the fuel pressure F/B control quantity [° C.A] is calculated using the proportional term and the integral term on the basis of the following equation.
Fuel pressure F/B control quantity=Proportional term+Integral term
A target electromagnetic-valve response time calculation routine described in
When this routine is started, a timing to request valve closure [° C.A] is calculated in step 501 using the fuel pressure F/F control quantity and the fuel pressure F/B control quantity on the basis of the following equation.
Timing to request valve closure=Fuel pressure F/F control quantity+Fuel pressure F/B control quantity
The timing to request valve closure is set in the form of an advancement quantity from a reference position (for example, a position that corresponds to the top dead center of the plunger 18) (see
Then, the routine proceeds to step 502, where the timing to start energization [° C.A] is calculated using a high-pressure pump discharge interval and a heat resistance factor on the basis of the following equation.
Timing to start energization=High-pressure pump discharge interval×Heat resistance factor
The timing to start energization is set in the form of an advancement quantity from a reference position (see
Then, the routine proceeds to step 503, where a target electromagnetic-valve response period [° C.A] is calculated using the timing to start energization and the timing to request valve closure on the basis of the following equation (see
Target electromagnetic-valve response period=Timing to start energization−Timing to request valve closure
Then, the routine proceeds to step 504, where the target electromagnetic-valve response period [° C.A] is converted to the target electromagnetic-valve response time [ms] using the current engine rotation speed Ne [rpm] on the basis of the following equation.
Target electromagnetic-valve response time [ms]=Target electromagnetic-valve response period [° C.A]×1000÷6÷Ne
In this manner, the target electromagnetic-valve response time is set such that the electromagnetic-valve response time is maximized within a range that can prevent overheating of the electromagnetic valve 27 and thereby the noise from the high-pressure pump 14 is reduced.
An electromagnetic-valve response time control routine described in
When this routine is started, an actuation duty F/F term [%] for the electromagnetic valve 27 is calculated in step 601 from a map or the like in accordance with the target electromagnetic-valve response time.
Then, an actuation duty F/B term for the electromagnetic valve 27 is calculated in steps 602 to 605 such that the deviation of an actual electromagnetic-valve response time (an electromagnetic-valve response time calculated during previous energization) from the target electromagnetic-valve response time is reduced.
First, in step 602, the deviation of the actual electromagnetic-valve response time from the target electromagnetic-valve response time is calculated as a response time deviation [ms].
Response time deviation=Target electromagnetic-valve response time−Actual electromagnetic-valve response time
Then, the routine proceeds to step 603, where the response time deviation is multiplied by a proportional gain to obtain a proportional term [%] of the actuation duty F/B term.
Proportional term=Response time deviation×Proportional gain
Then, the routine proceeds to step 604, where an integral term [%] for this time of the actuation duty F/B term is calculated using the response time deviation, the integral gain, and the previous integral term (i−1) on the basis of the following equation.
Integral term=Integral term (i−1)+Response time deviation×Integral gain
Then, the routine proceeds to step 605, where the actuation duty F/B term [%] is calculated using the proportional term and the integral term on the basis of the following equation.
Actuation duty F/B term=Proportional term+Integral term
Then, the routine proceeds to step 606, where the actuation duty [%] for the electromagnetic valve 27 is calculated using the actuation duty F/F term and the actuation duty F/B term on the basis of the following equation.
Actuation duty=Actuation duty F/F term+Actuation duty F/B term
In this manner, the actuation duty for the electromagnetic valve 27 is calculated such that the deviation of an actual electromagnetic-valve response time from the target electromagnetic-valve response time is reduced.
Then, the routine proceeds to step 607, where it is determined whether the electromagnetic valve 27 has been closed during the previous energization. If it is determined in step 607 that the electromagnetic valve 27 has been closed during the previous energization, the routine proceeds to step 608, where a lower limit guard value of the actuation duty is set to a value identical with a previous value.
If it is determined in step 607 described above that the electromagnetic valve 27 has not been closed during the previous energization, the routine proceeds to step 609, where the lower limit guard value of the actuation duty is set to a value obtained by increasing the previous value by a predefined value.
Then, the routine proceeds to step 610, where the actuation duty is restricted to the lower limit guard value. That is, if the actuation duty is greater than the lower limit guard value, the actuation duty is used as it is. If the actuation duty is equal to or less than the lower limit guard value, the actuation duty is set to the lower limit guard value.
After the actuation duty for the electromagnetic valve 27 has been set in the manner described above, the ECU 40 executes processing associated with valve closing control (for example, the processing of step 111 to 118 in
As shown in
In the second embodiment, the target electromagnetic-valve response time is set such that overheating of the electromagnetic valve 27 is prevented. In this manner, overheating of the electromagnetic valve 27 can be prevented and thereby thermal degradation of the electromagnetic valve 27, for example, damage to the covering of the solenoid 30 (coil) and the like can be prevented from occurring.
Moreover, the target electromagnetic-valve response time is set on the basis of the timing to request valve closure, which is set in accordance with the fuel pressure F/B control quantity, and on the basis of the timing to start energization, which is set such that overheating of the electromagnetic valve 27 can be prevented. Here, the target electromagnetic-valve response time is set such that the electromagnetic-valve response time is maximized within a range that prevents overheating of the electromagnetic valve 27 and thereby the noise from the high-pressure pump 14 is reduced. In this manner, the accuracy with which the fuel pressure of the high-pressure pump 14 is controlled can be maintained, overheating of the electromagnetic valve 27 can be prevented, and the noise from the high-pressure pump 14 can be reduced.
A third embodiment will now be described with reference to
In the third embodiment, an ECU 40 executes a target electromagnetic-valve response time calculation routine in
The routine in
In the target electromagnetic-valve response time calculation routine in
Then, the routine proceeds to step 502a, where a temperature of the electromagnetic valve 27 is acquired. Here, for example, a temperature sensor may be disposed to sense a temperature of the electromagnetic valve 27 (for example, the temperature of a solenoid 30), so that the temperature of the electromagnetic valve 27 is sensed by this temperature sensor. Alternatively, a temperature of the electromagnetic valve 27 (for example, the temperature of the solenoid 30) may be estimated on the basis of fuel temperature, cooling water temperature, current through the electromagnetic valve 27, or the like.
Then, the routine proceeds to step 502b, where the timing to start energization [° C.A] is calculated from a map or the like in accordance with the temperature of the electromagnetic valve 27. To prevent overheating of the electromagnetic valve 27, the map or the like of the timing to start energization is set such that the timing to start energization is retarded (the target electromagnetic-valve response time is reduced) with an increase in temperature of the electromagnetic valve 27 in a region with the temperature of the electromagnetic valve 27 being equal to or greater than a predefined value.
Then, the routine proceeds to step 503, where a target electromagnetic-valve response period [° C.A] is calculated using the timing to start energization and the timing to request valve closure. Then, the routine proceeds to step 504, where the target electromagnetic-valve response period [° C.A] is converted to the target electromagnetic-valve response time [ms] using the current engine rpm Ne [rpm].
In the third embodiment described above, the target electromagnetic-valve response time is changed in accordance with the temperature of the electromagnetic valve 27. In this manner, the target electromagnetic-valve response time can be set to an appropriate value in accordance with a change in temperature of the electromagnetic valve 27 as the change occurs. For example, when the temperature of the electromagnetic valve 27 is low and thus overheating is unlikely, the target electromagnetic-valve response time can be prolonged to enhance the effect of reducing the noise from the high-pressure pump 14. When the temperature of the electromagnetic valve 27 is high, the target electromagnetic-valve response time can be shortened to prevent the overheating of the electromagnetic valve 27 reliably.
While the target electromagnetic-valve response time is set such that overheating of the electromagnetic valve 27 is prevented in the second and third embodiments described above, this is not limitative. The target electromagnetic-valve response time may be changed as appropriate. For example, the target electromagnetic-valve response time may be set to the upper limit value of the electromagnetic-valve response time described in the first embodiment. In this manner, issues resulting from non-operation of the high-pressure pump 14 can be prevented and the noise from the high-pressure pump 14 can be reduced. Alternatively, the target electromagnetic-valve response time can be set such that the frequency of the electromagnetic valve 27 during the energization is outside the natural frequency range of the high-pressure pump 14 (its resonance frequency range).
A fourth embodiment will now be described with reference to
As described in
Additionally, an ECU 40 executes a routine in
The routine in the
A valve-closure criterion value setting routine described in
Then, the routine proceeds to step 702, where the temperature of the electromagnetic valve 27 is calculated using a map, a mathematical expression, or the like on the basis of the cooling water temperature and the lubricant temperature to estimate the temperature of the electromagnetic valve 27. The processing in steps 701 and 702 serves as an information acquisition unit.
Then, the routine proceeds to step 703, where the valve-closure criterion value is calculated using a map, a mathematical expression, or the like on the basis of the temperature of the electromagnetic valve 27 and the battery voltage. The map, the mathematical expression, or the like of the valve-closure criterion value is set such that, for example, the valve-closure criterion value is reduced with a reduction in current through a solenoid 30 of the electromagnetic valve 27. The current through the solenoid 30 is reduced with an increase in temperature of the electromagnetic valve 27 (that is, an increase in resistance of the solenoid 30) and a reduction in battery voltage. The map, the mathematical expression, or the like of the valve-closure criterion value is prepared in advance on the basis of test data, design data, or the like and stored in a ROM of the ECU 40. The processing in step 703 serves as a criterion-value setting unit.
While the valve-closure criterion value is directly obtained from the temperature of the electromagnetic valve 27 and the battery voltage in this routine, this is not limitative. For example, a correction value may be calculated using a map, a mathematical expression, or the like on the basis of the temperature of the electromagnetic valve 27 and the battery voltage, and the correction value may be used to correct a base valve-closure criterion value to obtain the valve-closure criterion value.
In the fourth embodiment described above, the temperature of the electromagnetic valve 27 and the battery voltage are obtained, and the valve-closure criterion value is set on the basis of the temperature of the electromagnetic valve 27 and the battery voltage. In this manner, the valve-closure criterion value is changed with a change in characteristic of the electromagnetic valve 27 (for example, a current changing characteristic during energization). The change in characteristic of the electromagnetic valve 27 occurs in accordance with the temperature of the electromagnetic valve 27 and the battery voltage. Thus, the valve-closure criterion value can be set to an appropriate value that corresponds to a change in characteristic of the electromagnetic valve 27 as the change occurs. In this manner, the accuracy with which it is determined whether the electromagnetic valve 27 has been closed can be enhanced.
Additionally, in the fourth embodiment, the temperature of the electromagnetic valve 27 is estimated on the basis of the cooling water temperature and the lubricant temperature. In this manner, the need to add a temperature sensor to sense the temperature of the electromagnetic valve 27 is eliminated, and thereby demand for cost reduction can be satisfied.
In the case of a system including a fuel temperature sensor for sensing the temperature of fuel (fuel temperature), the temperature of the electromagnetic valve 27 may be estimated on the basis of the cooling water temperature, the lubricant temperature, and the fuel temperature. Alternatively, the temperature of the electromagnetic valve 27 may be estimated on the basis of one or two of the cooling water temperature, the lubricant temperature, and the fuel temperature. Here, a temperature sensor may be disposed to sense a temperature of the electromagnetic valve 27 (for example, the temperature of the solenoid 30), so that the temperature of the electromagnetic valve 27 is sensed by this temperature sensor.
Additionally, in the fourth embodiment described above, the valve-closure criterion value is set on the basis of both of the temperature of the electromagnetic valve 27 and the battery voltage. This, however, is not limitative. The valve-closure criterion value may be set on the basis of one of the temperature of the electromagnetic valve 27 and the battery voltage.
While the temperature of the electromagnetic valve is used as the information related to the temperature of the electromagnetic valve in the fourth embodiment described above, this is not limitative. In place of the temperature of the electromagnetic valve, at least one of the cooling water temperature, the lubricant temperature, the fuel temperature, and the like may be used.
Moreover, the method of determining whether the electromagnetic valve 27 has been closed is not limited to the method described in the foregoing first embodiment and may be changed as appropriate. Whether the electromagnetic valve 27 has been closed may be determined by comparing the valve-closure criterion value to a parameter that changes in accordance with the behavior of the electromagnetic valve 27 (the solenoid 30), such as the current and voltage to actuate the electromagnetic valve 27.
When the initial value of the supply power to the electromagnetic valve 27 is set to a preset fixed value (for example, a value obtained by providing a wide margin from the lower limit supply power for system variations and the like) every time the engine is started, the following is likely. The time taken to set the supply power to the electromagnetic valve 27 by repeating the processing to reduce the supply power to the electromagnetic valve 27 until the electromagnetic-valve response time reaches a predefined upper limit value (that is, the time taken to reduce the supply power to the electromagnetic valve 27 to the lower limit supply power) may be prolonged every time.
As a solution, the ECU 40 executes routines in
In this manner, the initial value of the forthcoming supply power to the electromagnetic valve 27 can be set to an appropriately small value (for example, a value slightly greater than the lower limit supply power) with reference to a learned value of the previous supply power to the electromagnetic valve 27 with consideration given to a change in characteristic of the electromagnetic valve 27 due to the change in temperature of the electromagnetic valve 27 (that is, the change in resistance of the solenoid 30) and the change in battery voltage.
The routines in the
A learning and halt-time information acquisition routine described in
If it is determined in step 801 described above that the engine is being operated, the routine proceeds to step 802. The supply power to the electromagnetic valve 27 set in step 106 of
Then, the routine proceeds to step 803, where it is determined whether an engine stop command has been generated. If it is determined in step 803 that the engine stop command has not been generated, this routine is finished without executing the processing in step 804 and subsequent steps.
If it is determined in step 803 described above that the engine stop command has been generated, the routine proceeds to step 804. A cooling water temperature sensed by the cooling water temperature sensor 39 is acquired as a halt-time cooling water temperature in step 804. A lubricant temperature sensed by the lubricant temperature sensor 43 is also acquired as a halt-time lubricant temperature. A battery voltage sensed by the battery voltage sensor 44 is also acquired as a halt-time battery voltage.
Then, the routine proceeds to step 805, where the temperature of the electromagnetic valve 27 at the time of the halt is calculated using a map, a mathematical expression, or the like on the basis of the halt cooling water temperature and the halt lubricant temperature to estimate a halt temperature of the electromagnetic valve 27. The processing in steps 804 and 805 serves as a halt-time information acquisition unit.
While the halt-time information (for example, the temperature of the electromagnetic valve 27 and the battery voltage) is acquired when the engine stop command is generated in this routine, this is not limitative. The halt-time information may be acquired immediately before the engine is stopped (for example, while the engine rpm is decreasing) or immediately after the engine has stopped.
Then, the routine proceeds to step 806, where the halt temperature of the electromagnetic valve 27 and the halt battery voltage are stored in the nonvolatile memory, such as the backup RAM of the ECU 40.
A start-time information acquisition and initial value setting routine described in
If it is determined in step 901 described above that the engine start command has been generated, the routine proceeds to step 902. In step 902, the learned value of the previous supply power to the electromagnetic valve 27 (that is, the lower limit supply power learned during the previous operation of the engine) is read from the nonvolatile memory, such as the backup RAM of the ECU 40.
Then, the routine proceeds to step 903, where the previous halt temperature of the electromagnetic valve 27 and the previous halt battery voltage are read from the nonvolatile memory, such as the backup RAM of the ECU 40.
Then, the routine proceeds to step 904, where a cooling water temperature sensed by the cooling water temperature sensor 39 is acquired as a start cooling water temperature. A lubricant temperature sensed by the lubricant temperature sensor 43 is also acquired as a start lubricant temperature. A battery voltage sensed by the battery voltage sensor 44 is also acquired as a start battery voltage.
Then, the routine proceeds to step 905, where the temperature of the electromagnetic valve 27 at the time of the start is calculated using a map, a mathematical expression, or the like on the basis of the start cooling water temperature and the start lubricant temperature to estimate a start temperature of the electromagnetic valve 27. The processing in steps 904 and 905 serves as a start-time information acquisition unit.
While the start-time information (for example, the temperature of the electromagnetic valve 27 and the battery voltage) is acquired when the engine start command is generated in this routine, this is not limitative. The start-time information may be acquired while the engine is being started (for example, during cranking) or immediately after the engine has started.
Then, the routine proceeds to step 906, where a difference between the previous halt temperature of the electromagnetic valve 27 and the present start temperature of the electromagnetic valve 27 is calculated as a temperature difference ΔT. A difference between the previous halt battery voltage and the present start battery voltage is calculated as a voltage difference ΔV.
Then, the routine proceeds to step 907, where a supply power correction value in accordance with the temperature difference ΔT and the voltage difference ΔV is calculated using a map, a mathematical expression, or the like. The map, the mathematical expression, or the like of the supply power correction value is prepared in advance on the basis of test data, design data, or the like and stored in the ROM of the ECU 40.
Then, the routine proceeds to step 908, where the learned value of the previous supply power to the electromagnetic valve 27 is corrected using the supply power correction value to obtain the initial value of the forthcoming supply power to the electromagnetic valve 27. The processing from steps 906 to 908 serves as an initial value setting unit.
In the fourth embodiment described above, the supply power to the electromagnetic valve 27 (that is, the lower limit supply power) is learned while the engine is being operated, and, when the engine is stopped, the halt-time information (for example, the temperature of the electromagnetic valve 27 and the battery voltage) is obtained. Then, when the engine is started, the start-time information (for example, the temperature of the electromagnetic valve 27 and the battery voltage) is acquired. The learned value of the previous supply power to the electromagnetic valve 27 is corrected on the basis of the halt-time information and the start-time information to set the initial value of the forthcoming supply power to the electromagnetic valve 27. In this manner, the initial value of the forthcoming supply power to the electromagnetic valve 27 can be set to an appropriately small value (for example, a value slightly greater than the lower limit supply power) with reference to the learned value of the previous supply power to the electromagnetic valve 27 with consideration given to a change in characteristic of the electromagnetic valve 27 due to the change in temperature of the electromagnetic valve 27 and the change in battery voltage. As a result, the time taken to set the supply power to the electromagnetic valve 27 by repeating the processing to reduce the supply power to the electromagnetic valve 27 until the electromagnetic-valve response time reaches the predefined upper limit value (that is, the time taken to reduce the supply power to the electromagnetic valve 27 to the lower limit supply power) can be shortened.
Additionally, in the fourth embodiment, the temperature of the electromagnetic valve 27 is estimated on the basis of the cooling water temperature and the lubricant temperature. In this manner, the need to add a temperature sensor to sense the temperature of the electromagnetic valve 27 is eliminated, and thereby demand for cost reduction can be satisfied.
In the case of a system including a fuel temperature sensor for sensing the temperature of fuel (fuel temperature), the temperature of the electromagnetic valve 27 may be estimated on the basis of the cooling water temperature, the lubricant temperature, and the fuel temperature. Alternatively, the temperature of the electromagnetic valve 27 may be estimated on the basis of one or two of the cooling water temperature, the lubricant temperature, and the fuel temperature. Here, a temperature sensor may be disposed to sense a temperature of the electromagnetic valve 27 (for example, the temperature of the solenoid 30), so that the temperature of the electromagnetic valve 27 is sensed by this temperature sensor.
Additionally, in the fourth embodiment described above, the learned value of the previous supply power to the electromagnetic valve 27 is corrected on the basis of both of the temperature difference ΔT and the voltage difference ΔV to set the initial value of the forthcoming supply power to the electromagnetic valve 27. This, however, is not limitative. The learned value of the previous supply power to the electromagnetic valve 27 may be corrected on the basis of one of the temperature difference ΔT and the voltage difference ΔV to set the initial value of the forthcoming supply power to the electromagnetic valve 27.
While the temperature of the electromagnetic valve is used as the information related to the temperature of the electromagnetic valve in the fourth embodiment described above, this is not limitative. In place of the temperature of the electromagnetic valve, at least one of the cooling water temperature, the lubricant temperature, the fuel temperature, and the like may be used.
The functions executed by the ECU 40 may be partially or entirely configured in the form of hardware using one or more ICs or the like in each of the first to fourth embodiments.
Various modifications, for example, changes to the configuration of the high-pressure pump and the configuration of the fuel supply system, may be made as appropriate to each of the embodiments within the scope not departing from the spirit of the present disclosure.
Number | Date | Country | Kind |
---|---|---|---|
2015-089882 | Apr 2015 | JP | national |
2015-210147 | Oct 2015 | JP | national |
2015-222770 | Nov 2015 | JP | national |
2015-222771 | Nov 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2016/001892 | 4/4/2016 | WO | 00 |