JP2008057349A - Engine system - Google Patents

Abstract

In an engine system including a variable valve timing device and an auxiliary machine operated by rotation of a camshaft, the capacity of an electric motor which is an actuator of the variable valve timing device is reduced.
An intake camshaft 1120 is provided with a cam 1125 for opening and closing an intake valve, and further a VVT mechanism 2000 having an electric motor as an actuator is attached. Intake camshaft 1120 and exhaust camshaft 1130 are connected to the crankshaft by timing chain 1005. The pump cam 1150 that drives the high-pressure fuel pump avoids the intake camshaft 1120 so that the rotational resistance of the electric motor does not increase due to an increase in the rotational load of the intake camshaft 1120 with the operation of the high-pressure fuel pump. Provided on the camshaft 1130.
[Selection] Figure 13

Description

  The present invention relates to an engine system, and more particularly to an engine system including a variable valve timing device using an electric motor as an actuator.

  Conventionally, variable valve timing (VVT) is known in which the phase (crank angle) at which an intake valve or an exhaust valve opens and closes is changed according to the operating state. In general, in a variable valve timing device, the phase is changed by rotating a camshaft for opening and closing an intake valve and an exhaust valve relative to a sprocket or the like. The camshaft is rotated by an actuator such as a hydraulic pressure or an electric motor.

  In addition, a configuration is known in which auxiliary equipment (auxiliary equipment) is operated using the rotational force of a camshaft that is rotated with the rotation of the engine as a power source.

  For example, Japanese Patent Laid-Open No. 2005-23942 (Patent Document 1) discloses a high-pressure fuel pump that is operated by a pump drive cam attached to a camshaft of an exhaust valve. In the configuration of Patent Document 1, the crank angle is set so that the high-pressure fuel pump promotes the increase in fuel pressure from the start of the engine, shortens the start of the engine, reduces exhaust gas substances, and improves the engine output. The drive signal is output at least twice to the high-pressure fuel pump from the time when the sensor output signal is detected to the time when the phase of the crank angle sensor and the cam angle sensor that detects the position of the pump drive cam is determined. It is said. Moreover, in the structure of patent document 1, while the variable valve timing apparatus is provided in the camshaft of an intake valve, a pump drive cam is provided in the camshaft of an exhaust valve.

  Similarly, FIG. 12 of Japanese Patent Application Laid-Open No. 10-176508 (Patent Document 2) shows the same for an intake camshaft in which a pump cam for driving a fuel injection pump is formed in a valve operating apparatus for an internal combustion engine. A configuration in which a valve timing changing mechanism for changing the rotational phase of the shaft is provided is disclosed. In particular, in the valve operating apparatus for an internal combustion engine disclosed in Patent Document 2, the rotation timing of the camshaft is changed by the valve timing changing mechanism by forming a pump cam on the camshaft whose rotation phase is changed by the valve timing changing mechanism. Even in such a case, the angular phase of the camshaft torque fluctuation and the pump driving torque fluctuation is changed synchronously. Thereby, it can suppress that the fluctuation | variation of valve drive torque is amplified by the fluctuation | variation of pump drive torque.

  Alternatively, Japanese Patent Laid-Open No. 2003-343381 (Patent Document 3) discloses that a pump cam rotates with a sprocket wheel as a high-pressure supply pump that does not affect the operation of continuous phase control means corresponding to a variable valve timing device. Disclosed is a configuration in which the pump portion is driven so that the operating load of the pump portion does not act on the camshaft.

Japanese Patent Laying-Open No. 2004-1000055 (Patent Document 4) discloses another example of an auxiliary machine driven by a camshaft, in order to generate a negative pressure in the intake pipe even when the throttle valve opening is large. A configuration in which a pressure pump is driven by a cam provided on a camshaft is disclosed.
Japanese Patent Laid-Open No. 2005-23942 JP-A-10-176508 JP 2003-343181 A JP 2004-1000055 A

  By the way, in a variable valve timing device using hydraulic pressure as a drive source, there is a problem in that the hydraulic pressure is insufficient or the responsiveness of the hydraulic control is lowered at the time of cold or engine start, and the accuracy of the variable valve timing is lowered. A variable valve timing device using an electric motor as an actuator has been proposed.

  Thus, in the mechanism that changes the phase of the camshaft by the rotation of the electric motor, reducing the rotational resistance of the electric motor greatly affects the downsizing of the actuator. That is, as the rotational resistance of the electric motor increases, the capacity of the electric motor necessary to ensure a constant valve timing change speed increases, which may cause problems in terms of space saving, cost, and fuel consumption.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a variable valve in an engine system including a variable valve timing device and an auxiliary machine operated by rotation of a camshaft. It is to reduce the capacity of the electric motor that is the actuator of the timing device.

  An engine system according to the present invention includes an engine that generates a driving force by fuel combustion, an intake valve and an exhaust valve that are provided on the engine and are driven to open and close by a camshaft, and an opening / closing timing of one of the intake valve and the exhaust valve. A variable valve timing device for changing the above and an auxiliary device configured to operate using the rotational force of one of the camshafts as a power source. The variable valve timing device includes an electric motor as an actuator and a changing mechanism. The changing mechanism changes the rotational phase difference of one camshaft that drives the one valve with respect to the crankshaft by a change amount corresponding to a relative rotational speed difference of the electric motor with respect to the camshaft. It is configured to change the valve opening / closing timing. The auxiliary device is configured to operate by the rotational force of the other camshaft that drives the other valve on which the variable valve timing device is not disposed.

  According to the engine system described above, the camshaft that drives the intake valve and the exhaust valve is not the one camshaft provided with the variable valve timing device using the electric motor as an actuator, but the auxiliary device (compensation) by the rotation of the other camshaft. Operating energy can be obtained. For this reason, the rotation resistance of one camshaft to which the variable valve timing device is attached is increased by the operation of the auxiliary machine, and the rotation resistance of the electric motor is not increased. Compared with a configuration for obtaining energy, it is possible to reduce the electric motor power necessary to ensure the same actuator operation amount (motor rotational speed). As a result, the capacity of the motor required to obtain a predetermined valve opening / closing timing speed can be reduced, and the fuel consumption can be improved by downsizing the apparatus and reducing the power consumption of the variable valve timing apparatus.

Preferably, the auxiliary device includes a fuel pump that operates in accordance with the rotation of the other cam.
As a result, the fuel pump can be operated as an auxiliary machine without increasing the capacity of the electric motor that is the actuator of the variable valve timing device.

  Preferably, the auxiliary device is a negative pressure pump that operates in accordance with the rotation of the other camshaft.

  Accordingly, the negative pressure pump can be operated as an auxiliary machine without increasing the capacity of the electric motor that is an actuator of the variable valve timing device.

  According to the engine system of the present invention, in an engine system having a variable valve timing device using an electric motor as an actuator and a load operated by the rotation of a camshaft, the capacity of the electric motor can be reduced, and the device can be downsized. The fuel consumption can be improved by reducing the power consumption of the variable valve timing device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a vehicle engine system equipped with a variable valve timing device according to an embodiment of the present invention will be described.

  The engine 1000 is a V-type 8-cylinder engine in which a first bank 1010 and a second bank 1012 are each provided with a group of four cylinders. The application of the present invention is not limited to the engine type, and the variable valve timing device described below can be applied to an engine of a type other than the V-type 8-cylinder.

  Engine 1000 receives air from air cleaner 1020. The intake air amount is adjusted by a throttle valve 1030. The throttle valve 1030 is an electronic throttle valve that is driven by a motor.

  Air is introduced into the cylinder 1040 through the intake passage 1032. Air is mixed with fuel inside the cylinder 1040 (combustion chamber). Fuel is directly injected from the injector 1050 into the cylinder 1040. That is, the injection hole of the injector 1050 is provided in the cylinder 1040.

  Fuel is injected during the intake stroke. Note that the timing of fuel injection is not limited to the intake stroke. In this embodiment, engine 1000 will be described as a direct injection engine in which an injection hole of injector 1050 is provided in cylinder 1040. In addition to direct injection injector 1050, a port injection injector is provided. May be. Further, only a port injection injector may be provided.

  The air-fuel mixture in the cylinder 1040 is ignited by the spark plug 1060 and burned. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 1070 and then discharged outside the vehicle. When the piston 1080 is pushed down by the combustion of the air-fuel mixture, the crankshaft 1090 rotates. The rotational speed of a rotating body such as a shaft is generally expressed by the number of rotations per unit time (typically, the number of rotations per minute: rpm). In terms of rotational speed, it is also simply expressed as “rotational speed”.

  An intake valve 1100 and an exhaust valve 1110 are provided at the top of the cylinder 1040. Intake valve 1100 is driven by intake camshaft 1120. The exhaust valve 1110 is driven by an exhaust camshaft 1130. Intake camshaft 1120 and exhaust camshaft 1130 are connected by a chain, a gear, or the like, and rotate at the same rotational speed (half the rotational speed of crankshaft 1090). The rotational speed of a rotating body such as a shaft is generally expressed by the number of rotations per unit time (typically, the number of rotations per minute: rpm). In terms of rotational speed, it is also simply expressed as “rotational speed”.

  The phase (opening / closing timing) of intake valve 1100 is controlled by intake VVT mechanism 2000 provided on intake camshaft 1120. The phase of the exhaust valve 1110 is controlled by an exhaust VVT mechanism 3000 provided on the exhaust camshaft 1130.

  In the present embodiment, intake camshaft 1120 and exhaust camshaft 1130 are rotated by the VVT mechanism, whereby the phases of intake valve 1100 and exhaust valve 1110 are controlled. The method for controlling the phase is not limited to this.

  Intake VVT mechanism 2000 is operated by electric motor 2060 (shown in FIG. 3). The electric motor 2060 is controlled by an electronic control unit (ECU) 4000. The current and voltage of the electric motor 2060 are detected by an ammeter (not shown) and a voltmeter (not shown), and are input to the ECU 4000. The exhaust VVT mechanism 3000 is operated by hydraulic pressure.

  ECU 4000 receives signals representing the rotational speed and crank angle of crankshaft 1090 from crank angle sensor 5000. ECU 4000 also receives a signal representing the phases of intake camshaft 1120 and exhaust camshaft 1130 (the position of the camshaft in the rotational direction) from cam position sensor 5010.

  Further, the ECU 4000 receives from the water temperature sensor 5020 a signal indicating the water temperature (cooling water temperature) of the engine 1000 and receives from the air flow meter 5030 a signal indicating the intake air amount of the engine 1000 (the amount of air sucked into the engine 1000). Is done.

  Based on signals input from these sensors, a map stored in a memory (not shown), and a program, ECU 4000 controls throttle opening, ignition timing, fuel injection so that engine 1000 can be in a desired operating state. The timing, fuel injection amount, intake valve 1100 phase, exhaust valve 1110 phase, and the like are controlled.

  In the present embodiment, ECU 4000 refers to a map that determines a target phase in advance by referring to a parameter that indicates an engine operating state, typically, the engine speed NE and the intake air amount KL corresponding to the parameter. The target phase of intake valve 1100 corresponding to the state is sequentially determined. Generally, a plurality of the above maps for determining the target phase of the intake valve 1100 are stored for each water temperature.

  Hereinafter, intake VVT mechanism 2000 operated by an electric motor will be further described. In contrast to the present embodiment, the exhaust VVT mechanism 3000 may have the same configuration as the VVT mechanism 2000 described below, and the intake VVT mechanism may be hydraulically operated.

  As shown in FIG. 3, intake VVT mechanism 2000 includes sprocket 2010, cam plate 2020, link mechanism 2030, guide plate 2040, speed reducer 2050, and electric motor 2060.

  The sprocket 2010 is connected to the crankshaft 1090 via a chain or the like. The number of rotations of the sprocket 2010 is a half of the number of rotations of the crankshaft 1090 as with the intake camshaft 1120 and the exhaust camshaft 1130. An intake camshaft 1120 is provided so as to be concentric with the rotation axis of the sprocket 2010 and to be rotatable relative to the sprocket 2010.

  Cam plate 2020 is connected to intake camshaft 1120 by pin (1) 2070. The cam plate 2020 rotates integrally with the intake camshaft 1120 inside the sprocket 2010. The cam plate 2020 and the intake camshaft 1120 may be formed integrally.

  The link mechanism 2030 includes an arm (1) 2031 and an arm (2) 2032. A pair of arms (1) 2031 is provided in the sprocket 2010 so as to be point-symmetric with respect to the rotation axis of the intake camshaft 1120, as shown in FIG. Each arm (1) 2031 is connected to the sprocket 2010 so as to be swingable around a pin (2) 2072.

  As shown in FIG. 5 which is a BB cross section in FIG. 3 and FIG. 6 which is a state where the phase of the intake valve 1100 is advanced from the state of FIG. 5, the arm (1) 2031 and the cam plate 2020 include: It is connected by an arm (2) 2032.

  The arm (2) 2032 is supported so as to be swingable with respect to the arm (1) 2031 about the pin (3) 2074. The arm (2) 2032 is supported so as to be swingable with respect to the cam plate 2020 around the pin (4) 2076.

  By the pair of link mechanisms 2030, the intake camshaft 1120 rotates relative to the sprocket 2010, and the phase of the intake valve 1100 is changed. Therefore, even if any one of the pair of link mechanisms 2030 is broken due to damage or the like, the phase of the intake valve 1100 can be changed by the other link mechanism.

  Returning to FIG. 3, a control pin 2034 is provided on the surface of each link mechanism 2030 (arm (2) 2032) on the guide plate 2040 side. The control pin 2034 is provided concentrically with the pin (3) 2074. Each control pin 2034 slides in a guide groove 2042 provided in the guide plate 2040.

  Each control pin 2034 is moved in the radial direction by sliding in the guide groove 2042 of the guide plate 2040. By moving each control pin 2034 in the radial direction, the intake camshaft 1120 is rotated relative to the sprocket 2010.

  As shown in FIG. 7 which is a CC cross section in FIG. 3, the guide groove 2042 is formed in a spiral shape so that each control pin 2034 is moved in the radial direction when the guide plate 2040 rotates. The shape of the guide groove 2042 is not limited to this.

  The more the control pin 2034 is radially away from the axis of the guide plate 2040, the more retarded the phase of the intake valve 1100 is. That is, the amount of change in phase becomes a value corresponding to the amount of operation of the link mechanism 2030 due to the control pin 2034 changing in the radial direction. Note that the phase of the intake valve 1100 may be further advanced as the control pin 2034 moves away from the axis of the guide plate 2040 in the radial direction.

  As shown in FIG. 7, when the control pin 2034 contacts the end of the guide groove 2042, the operation of the link mechanism 2030 is limited. Therefore, the phase at which the control pin 2034 contacts the end of the guide groove 2042 is the most retarded angle or most advanced angle phase.

  Returning to FIG. 3, the guide plate 2040 is provided with a plurality of recesses 2044 for connecting the guide plate 2040 and the speed reducer 2050 on the surface of the speed reducer 2050 side.

  The reduction gear 2050 includes an external gear 2052 and an internal gear 2054. The external gear 2052 is fixed to the sprocket 2010 so as to rotate integrally with the sprocket 2010.

  The internal gear 2054 is formed with a plurality of convex portions 2056 that are received in the concave portions 2044 of the guide plate 2040. The internal gear 2054 is supported so as to be rotatable about an eccentric shaft 2066 of a coupling 2062 formed eccentrically with respect to the shaft center 2064 of the output shaft of the electric motor 2060.

  A DD cross section in FIG. 3 is shown in FIG. The internal gear 2054 is provided such that some of the plurality of teeth mesh with the external gear 2052. When the output shaft rotational speed of the electric motor 2060 is the same as the rotational speed of the sprocket 2010, the coupling 2062 and the internal gear 2054 rotate at the same rotational speed as the external gear 2052 (sprocket 2010). In this case, the guide plate 2040 rotates at the same rotational speed as the sprocket 2010, and the phase of the intake valve 1100 is maintained.

  When the coupling 2062 is rotated relative to the external gear 2052 around the axis 2064 by the electric motor 2060, the entire internal gear 2054 rotates (revolves) around the axis 2064, The internal gear 2054 rotates around the eccentric shaft 2066. Due to the rotational movement of the internal gear 2054, the guide plate 2040 is rotated relative to the sprocket 2010, and the phase of the intake valve 1100 is changed.

  The phase of intake valve 1100 changes when the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 (the amount of operation of electric motor 2060) is decelerated in reduction gear 2050, guide plate 2040, and link mechanism 2030. . The phase of intake valve 1100 may be changed by increasing the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010. The output shaft of the electric motor 2060 is provided with a motor rotation angle sensor 5050 that outputs a signal representing the rotation angle of the output shaft (the position of the output shaft in the rotation direction). The motor rotation angle sensor 5050 is generally configured to generate a pulse signal every time the output shaft of the electric motor 2060 rotates by a predetermined angle. Based on the output of the motor rotation angle sensor 5050, the rotation speed of the output shaft of the electric motor 2060 (hereinafter also simply referred to as the rotation speed of the electric motor 2060) can be detected.

  As shown in FIG. 9, the reduction ratio R (θ) of intake VVT mechanism 2000 as a whole, that is, the ratio of the relative rotational speed between output shaft of electric motor 2060 and sprocket 2010 with respect to the amount of change in phase is the value of intake valve 1100. It can take a value according to the phase. In the present embodiment, the greater the reduction ratio, the smaller the amount of phase change with respect to the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010.

  When the phase of intake valve 1100 is in the first region from the most retarded angle to CA (1), the overall reduction ratio of intake VVT mechanism 2000 is R (1). When the phase of intake valve 1100 is in the second region from CA (2) (CA (2) is an advance angle side of CA (1)) to the most advanced angle, the entire intake VVT mechanism 2000 is decelerated. The ratio is R (2) (R (1)> R (2)).

  When the phase of intake valve 1100 is in the third region from CA (1) to CA (2), the reduction ratio of intake VVT mechanism 2000 as a whole is set to a predetermined rate of change ((R (2) -R (1)) / (CA (2) -CA (1))).

  The operation of intake VVT mechanism 2000 of the variable valve timing device according to the present embodiment, which is expressed based on the above structure, will be described.

  When the phase of the intake valve 1100 (intake camshaft 1120) is advanced, when the electric motor 2060 is operated and the guide plate 2040 is rotated relative to the sprocket 2010, the intake valve 1100 is shown in FIG. The phase of is advanced.

  When the phase of intake valve 1100 is in the first region between the most retarded angle and CA (1), the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 is reduced by reduction ratio R (1). Thus, the phase of intake valve 1100 is advanced.

  When the phase of intake valve 1100 is in the second region between CA (2) and the most advanced angle, the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 is reduced by reduction ratio R (2). Thus, the phase of intake valve 1100 is advanced.

  When retarding the phase of the intake valve 1100, the output shaft of the electric motor 2060 is rotated relative to the sprocket 2010 in the opposite direction to that when the phase is advanced. When the phase is retarded, the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010 is reduced in the first region between the most retarded angle and CA (1), as in the case of the advance. Decelerated by the ratio R (1), the phase is retarded. In the second region between CA (2) and the most advanced angle, the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010 is decelerated by the reduction ratio R (2), and the phase is retarded. The

  Thus, as long as the relative rotation direction of the output shaft of the electric motor 2060 and the sprocket 2010 is the same, the first region between the most retarded angle and CA (1) and the most advanced angle of CA (2). The phase of intake valve 1100 can be advanced or retarded in both regions of the second region between the two. At this time, in the second region between CA (2) and the most advanced angle, the phase can be advanced or retarded more greatly. Therefore, the phase can be changed in a large range.

  Further, in the first region between the most retarded angle and CA (1), since the reduction ratio is large, the output shaft of electric motor 2060 is generated by the torque acting on intake camshaft 1120 as engine 1000 is operated. A large torque is required to rotate the. Therefore, even when the electric motor 2060 is stopped or the like, even when the electric motor 2060 does not generate torque, the rotation of the output shaft of the electric motor 2060 due to the torque acting on the intake camshaft 1120 can be suppressed. it can. Therefore, it is possible to suppress the actual phase from changing from the control phase. In addition, when energization of the electric motor 2060 which is an actuator is stopped, it is possible to suppress an unintended phase change from occurring in which the actual phase changes from the control phase.

  By the way, when the phase of intake valve 1100 is in the third region between CA (1) and CA (2), the output shaft and sprocket of electric motor 2060 have a reduction ratio that changes at a predetermined rate of change. The relative rotational speed with respect to 2010 is decelerated, and the phase of intake valve 1100 is advanced or retarded.

  As a result, when the phase changes from the first region to the second region or from the second region to the first region, the phase changes with respect to the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010. The amount can be gradually increased or decreased. Therefore, it is possible to suppress the phase change amount from changing suddenly in steps, and to suppress the phase from changing suddenly. As a result, the phase controllability can be improved.

  As described above, according to the intake VVT mechanism of the variable valve timing apparatus according to the present embodiment, when the phase of the intake valve is in the region from the most retarded angle to CA (1), the intake VVT mechanism 2000 The overall reduction ratio is R (1). When the phase of the intake valve is in the region from CA (2) to the most advanced angle, the overall reduction ratio of intake VVT mechanism 2000 is R (2), which is smaller than R (1). As a result, as long as the rotation direction of the output shaft of the electric motor is the same, the first region between the most retarded angle and CA (1) and the second region between CA (2) and the most advanced angle. In both areas, the phase of the intake valve can be advanced or retarded. At this time, in the second region between CA (2) and the most advanced angle, the phase can be advanced or retarded more greatly. Therefore, the phase can be changed in a large range. Further, in the first region between the most retarded angle and CA (1), the reduction ratio is large, so that the output shaft of the electric motor is rotated by the torque acting on the intake camshaft as the engine operates. Can be suppressed. Therefore, it is possible to suppress the actual phase from changing from the control phase. As a result, the phase can be changed in a large range, and the phase can be controlled with high accuracy.

  FIG. 11 is a schematic block diagram illustrating the control configuration of the intake valve phase by the variable valve timing device according to the present embodiment.

  Referring to FIG. 11, as described with reference to FIG. 1, the engine 1000 uses the intake camshaft 1120 and the exhaust cam via the sprockets 2010 and 2012 by the power from the crankshaft 1090 via the timing chain 1005 (or timing belt). It is configured to be transmitted to the shaft 1130. A cam position sensor 5010 that outputs a cam angle signal Piv for each predetermined cam angle is attached to the outer periphery of the intake camshaft 1120. On the other hand, a crank angle sensor 5000 that outputs a crank angle signal Pca at every predetermined crank angle is attached to the outer peripheral side of the crankshaft 1090. A motor rotation angle sensor 5050 that outputs a motor rotation angle signal Pmt at every predetermined rotation angle is attached to a rotor (not shown) of the electric motor 2060. These cam angle signal Piv, crank angle signal Pca, and motor rotation angle signal Pmt are input to ECU 4000.

  ECU 4000 further provides an output required for engine 1000 based on the output of the sensor group for detecting the state of engine 1000 and the driving conditions (driver pedal operation, current vehicle speed, etc.). 1000 operations are controlled. As part of the engine control, ECU 4000 sets target phases of intake valve 1100 and exhaust valve 1110 based on the map shown in FIG. Further, ECU 4000 generates a rotation speed command value Nmref of electric motor 2060 that is an actuator of intake VVT mechanism 2000 so that the actual phase of intake valve 1100 matches the target phase.

This rotational speed command value Nmref is determined in correspondence with the relative rotational speed between the output shaft of electric motor 2060 corresponding to the actuator operation amount and sprocket 2010 (intake camshaft 1120), as will be described below. The electric motor EDU (Electronic Drive Unit) 4100 controls the rotational speed of the electric motor 2060 in accordance with the rotational speed command value Nmref from the ECU 4000.
(Auxiliary equipment that obtains power from the camshaft)
Next, the arrangement of auxiliary equipment that obtains power by rotation of the camshaft will be described.

  FIG. 12 is a block diagram showing a configuration of a high-pressure fuel pump shown as an example of such an auxiliary machine.

  Referring to FIG. 12, low-pressure fuel pump 1170 discharges fuel that has sucked fuel in fuel tank 1165 at a predetermined pressure (low pressure set value). Discharged fuel from the low pressure fuel pump 1170 is pumped to the low pressure fuel passage 1190 via the fuel filter 1175 and the fuel pressure regulator 1180. The fuel pressure regulator 1180 is opened when the fuel pressure of the low-pressure system increases, and the fuel existing in the vicinity of the fuel pressure regulator 1180 in the low-pressure fuel passage 1190, that is, the fuel just pumped up by the low-pressure fuel pump 1170. Form a path back in. As a result, the fuel pressure in the low pressure fuel passage 1190 is maintained at a predetermined pressure.

  The high-pressure fuel pump 1200 is attached to a cylinder head (not shown), and the plunger 1220 in the pump cylinder 1210 is driven to reciprocate by the rotational drive of the pump cam 1150 provided on the exhaust camshaft 1130. High-pressure fuel pump 1200 further includes a high-pressure pump chamber 1230 defined by pump cylinder 1210 and plunger 1220, a gallery 1245 connected to low-pressure fuel passage 1190, and an electromagnetic spill valve 1250. The electromagnetic spill valve 1250 is an open / close valve that controls communication disconnection between the gallery 1245 and the high-pressure pump chamber 1230.

  The discharge side of the high-pressure fuel pump 1200 is connected via a high-pressure fuel passage 1260 to a delivery pipe (not shown) that distributes fuel to the injector 1050 shown in FIG. The high-pressure fuel passage 1260 is provided with a check valve (check valve) 1240 that restricts fuel from flowing back to the high-pressure fuel pump 1200 side. The suction side of the high-pressure fuel pump 1200 is connected to a low-pressure fuel pump 1170 provided in the fuel tank 1165 via a low-pressure fuel passage 1190.

  In the suction stroke in which the lift amount of the plunger 1220 decreases as the pump cam 1150 rotates, the volume of the high-pressure pump chamber 1230 increases due to the reciprocating drive of the plunger 1220. In the intake stroke, the electromagnetic spill valve 1250 is maintained in the open state. Since the gallery 1245 and the high-pressure pump chamber 1230 are in communication during the opening period of the electromagnetic spill valve 1250, fuel is sucked into the high-pressure pump chamber 1230 from the low-pressure fuel passage 1190 via the gallery 1245 during the intake stroke. .

  On the other hand, in the discharge stroke in which the lift amount of the plunger 1220 increases as the pump cam 1150 rotates, the volume of the high-pressure pump chamber 1230 is reduced by the reciprocating drive of the plunger 1220. In the discharge stroke, opening / closing of the electromagnetic spill valve 1250 is controlled by an opening / closing control signal from an ECU (not shown).

  During the valve opening period of the electromagnetic spill valve 1250 during the discharge stroke, the gallery 1245 and the high pressure pump chamber 1230 are in communication with each other, so that the fuel sucked into the high pressure pump chamber 1230 passes through the gallery 1245 to the low pressure fuel passage. Overflow to 1190 side. That is, the fuel is discharged back to the low-pressure fuel passage 1190 via the gallery 1245 without being pumped to the high-pressure fuel passage 1260.

  On the other hand, the gallery 1245 and the high-pressure pump chamber 1230 are not in communication during the opening period of the electromagnetic spill valve 1250. For this reason, the fuel pressurized in the discharge stroke is pumped to the high-pressure fuel passage 1260 without flowing back to the gallery 1245. Therefore, the amount of fuel discharged from the high-pressure fuel pump 1200 and the fuel pressure are controlled by setting the open / close period (duty ratio) of the electromagnetic spill valve 1250.

  Referring to FIG. 13, intake camshaft 1120 is provided with a cam 1125 for opening / closing drive of intake valve 1100. Similarly, exhaust camshaft 1130 is provided with a cam 1135 for driving opening / closing of exhaust valve 1110. Is provided. Intake camshaft 1120 and exhaust camshaft 1130 are connected to crankshaft 1090 (FIG. 1) by timing chain 1005. Further, as described above, VVT mechanism 2000 is provided with respect to intake camshaft 1120.

  Here, a pump cam 1150 for driving the high-pressure fuel pump 1200 shown in FIG. 12 is provided on the exhaust camshaft 1130. As a result, the rotational resistance of the electric motor 2060, which is the actuator of the VVT mechanism 2000, does not increase due to an increase in the rotational load of the intake camshaft 1120 provided with the VVT mechanism 2000 along with the operation of the high-pressure fuel pump 1200. . Therefore, compared with the configuration in which the pump cam 1150 is provided on the intake camshaft 1120, it is possible to reduce the power consumption required to obtain the same rotational speed of the electric motor 2060, and to achieve a predetermined intake valve phase change speed. The capacity of the electric motor 2060 required for securing can be reduced. As a result, fuel efficiency can be improved by downsizing the device and reducing power consumption of the variable valve timing device.

  FIG. 14 shows an engine system in which a negative pressure pump 1400 is added to the engine system shown in FIG. Negative pressure pump 1400 is shown as another example of an accessory driven by a camshaft.

  The negative pressure pump 1400 is arranged to generate a negative pressure in the intake pipe even when the throttle valve opening is large. For example, in an engine system equipped with a variable valve lift mechanism that controls the amount of air introduced into the combustion chamber by variably controlling the valve lift amount of the intake valve while maintaining the throttle valve in a large opening state. The arrangement of the negative pressure pump 1400 is required. It should be noted that any of a configuration in which the valve lift amount is continuously variable, a configuration in which the valve lift amount is switched in two steps, a configuration in which only some of the cylinder valves are opened, etc. can be applied to the variable valve lift mechanism.

  Referring to FIG. 14, negative pressure supply passage 1330 for supplying intake negative pressure generated in surge tank 1022 to brake booster 1310 is connected to surge tank 1022. The negative pressure supply passage 1330 is provided with a check valve 1340 that restricts the flow of gas from the surge tank 1022 side to the brake booster 1310 side. The brake booster 1310 is further connected to a negative pressure supply passage 1350 that supplies negative pressure from the negative pressure pump 1400. The negative pressure supply passage 1350 is provided with a check valve 1360 that restricts the flow of gas from the negative pressure pump 1400 side to the brake booster 1310 side. The negative pressure pump 1400 operates by driving the pump drive shaft 1160 to rotate.

  The brake booster 1310 is connected to the brake pedal 1320 and uses the negative pressure supplied from the surge tank 1022 and the negative pressure pump 1400 to reduce the depression force of the brake pedal 1320 and increase the vehicle braking force.

  Referring to FIG. 15, pump drive shaft 1160 of negative pressure pump 1400 is connected to exhaust camshaft 1130, and rotates together with the rotation of exhaust camshaft 1300.

  Thus, the rotational resistance of the electric motor 2060, which is the actuator of the VVT mechanism 2000, does not increase due to an increase in the rotational load of the intake camshaft 1120 provided with the VVT mechanism 2000 in accordance with the operation of the negative pressure pump 1400. . Therefore, compared with the configuration in which the pump drive shaft 1160 is provided on the intake camshaft 1120, it becomes possible to reduce the power consumption required to obtain the same rotational speed of the electric motor 2060, and a predetermined intake valve phase change speed can be reduced. The capacity of the electric motor 2060 required for securing can be reduced. As a result, fuel efficiency can be improved by downsizing the device and reducing power consumption of the variable valve timing device.

  In the present embodiment, the high pressure fuel pump and the negative pressure pump are illustrated as examples of the auxiliary machine driven by the camshaft. However, the limitation of the present invention is not limited to such an example. In other words, in an engine system provided with a variable valve timing device using an electric motor as an actuator for one of the intake valve and the exhaust bubble, the arrangement of the cam or drive shaft for driving the auxiliary machine driven by the camshaft The present invention can be applied regardless of whether a variable valve timing device driven by an electric motor is disposed on the valve, and the type of auxiliary machine.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram showing an engine system of a vehicle equipped with a variable valve timing device according to an embodiment of the present invention. It is a figure which shows the map which defined the phase of the intake camshaft. It is sectional drawing which shows the VVT mechanism for intake. It is AA sectional drawing of FIG. FIG. 4 is a cross-sectional view taken along the line BB in FIG. 3 (part 1). FIG. 4 is a BB cross-sectional view (part 2) of FIG. 3. It is CC sectional drawing of FIG. It is DD sectional drawing of FIG. It is a figure which shows the reduction ratio as the whole VVT mechanism for intake. It is a figure which shows the relationship between the phase of the guide plate with respect to a sprocket, and the phase of an intake camshaft. It is a schematic block diagram explaining the control structure of the intake valve phase by the variable valve timing apparatus which concerns on this Embodiment. It is a block diagram which shows the structure of the high pressure fuel pump which is an example of an auxiliary machine. It is the schematic explaining the arrangement | positioning of the pump cam which drives a high pressure fuel pump. It is a schematic block diagram which shows arrangement | positioning of the negative pressure pump which is another example of an auxiliary machine. It is the schematic explaining the arrangement | positioning of the drive shaft of a negative pressure pump.

Explanation of symbols

  1000 engine, 1005 timing chain, 1010, 1012 bank, 1020 air cleaner, 1022 surge tank, 1030 throttle valve, 1032 intake passage, 1040 cylinder, 1050 injector, 1060 spark plug, 1070 three-way catalyst, 1080 piston, 1090 crankshaft, 1100 Intake valve, 1110 exhaust valve, 1120 intake camshaft, 1125 cam (intake valve), 1130 exhaust camshaft, 1135 cam (exhaust valve), 1150 pump cam, 1160 pump drive shaft, 1165 fuel tank, 1170 low pressure fuel pump, 1175 Fuel filter, 1180 Fuel pressure regulator, 1190 Low pressure fuel passage, 1 200 High-pressure fuel pump, 1210 Pump cylinder, 1220 Plunger, 1230 High-pressure pump chamber, 1245 Gallery, 1250 Electromagnetic spill valve, 1260 High-pressure fuel passage, 1300 Exhaust camshaft, 1310 Brake booster, 1320 Brake pedal, 1330 Negative pressure supply passage, 1340 , 1360 Check valve, 1350 Negative pressure supply passage, 1400 Negative pressure pump, 2010, 2012 Each sprocket, 2020 Cam plate, 2030 Link mechanism, 2034 Control pin, 2040 Guide plate, 2042 Guide groove, 2044 Recess, 2050 Reducer, 2052 External gear, 2054 Internal gear, 2056 Convex, 2060 Electric motor, 2062 Coupling, 2064 Axle, 2066 Eccentric shaft, 3000 VVT Structure (exhaust valve), 5000 crank angle sensor, 5010 cam position sensor, 5020 water temperature sensor, 5030 air flow meter, 5050 motor rotation angle sensor, Nmref rotation speed command value, Pca crank angle signal, Piv cam angle signal, Pmt motor rotation angle signal.

Claims (3)

An engine that generates driving force by fuel combustion;
An intake valve and an exhaust valve provided in the engine and driven to open and close by camshafts;
A variable valve timing device for changing the opening and closing timing of one of the intake valve and the exhaust valve;
The variable valve timing device is
An electric motor as an actuator;
The one valve shaft is opened and closed by changing the rotational phase difference of one camshaft driving the one valve with respect to the crankshaft by an amount of change corresponding to the relative rotational speed difference of the electric motor with respect to the one camshaft. A change mechanism configured to change timing;
An auxiliary device configured to operate using the rotational force of any of the camshafts as a power source;
The engine system is operated by the rotational force of the other camshaft that drives the other valve on which the variable valve timing device is not disposed.   The engine system according to claim 1, wherein the auxiliary device includes a fuel pump that operates in accordance with rotation of a cam mounted on the other camshaft.   The engine system according to claim 1, wherein the auxiliary device is a negative pressure pump that operates in accordance with rotation of the other camshaft.

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