JPS593162A - Fuel pressure adjustment mechanism for injector - Google Patents

Abstract

PURPOSE:To accurately regulate fuel pressure in response to various engine operational conditions, by providing a pressure sensor in the fuel chamber of an electromagnetic fuel-pressure regulating valve, and regulating an opening degree of the valve in response to an output signal from the pressure sensor and the operational parameter of an engine. CONSTITUTION:An electromagnetic fuel-pressure regulating valve 13 is provided in the return passage of a fuel circulating line 2 communicating a fuel tank (not shown) with an injector 1. The fuel-pressure regulating valve 13 is constituted in such a manner that a magnetic plate 15 is attracted to or repulsed from an iron core 16 by energizing or de-energizing an exciting coil 17 in response to an input signal from a control circuit 19, and thereby to open and close an outlet passage 9. The control circuit 19 regulates an opening degree of the electromagnetic fuel- pressure regulating valve 13 in response to an engine operational parameter such as the amount of intake air or the like, while receiving a signal from a pressure sensor 18 for sensing the pressure in a fuel chamber 5, and thereby to feedback- control the fuel pressure so that the pressure may become a desired value with respect to a manifold vacuum.

Description

[Detailed description of the invention] It is something to do.

Currently, electronically controlled fuel injection systems are becoming widely used in internal combustion engines for vehicles, but the dynamic range of conventional injectors does not allow for the fuel supply required in the case of 5PI (single point injection). It is difficult to satisfy the range of fuel supply, and even in the case of MPI (multipoint injection), as the range of fuel supply required for motorcycles becomes wider, a highly accurate injector is required to meet the demand. Therefore, there was a problem of high cost. Further, in a conventional fuel injection device, as shown in FIG. 1, for example, a fuel circulation path 2 connects a fuel tank (not shown) and an injector 1 (disposed in an intake manifold (not shown)).
A fuel pressure regulating valve 3 is provided in the middle of the return path, and the nuclear fuel pressure regulating valve 3 includes a regulating valve body 4, a diaphragm 7 that divides the inside of the regulating valve body 4 into a fuel chamber 5 and a negative pressure chamber 6, and a fuel chamber 5. a fuel cell 8 connecting the fuel chamber 5 and the fuel circulation path 2;
and a fuel outlet passage 9 which is connected to the valve seat 9a and which is fixed to the lower surface of the diaphragm 7 and has a valve seat 9a formed at its inner end.
a spring 11 that is installed between the ceiling surface of the negative pressure chamber 6 and the diaphragm 7 and gives the valve plate 10 the habit of moving toward the valve seat 9a, and an intake manifold (not shown). F and a negative pressure passage 12 communicating with the negative pressure chamber 6, and when the manifold negative pressure is high, the valve plate 10 rises against the elasticity of the spring 11 and opens the fuel outlet passage 9, so that the injector 1 When the nuclear fuel pressure decreases and the manifold negative pressure is low, the valve plate 10 descends due to the elasticity of the spring 11 and closes the fuel outlet passage 9, so the nuclear fuel pressure increases, resulting in a difference between the fuel pressure and the manifold negative pressure. Pressure (
Although the fuel injection pressure (fuel injection pressure) was always kept constant, this did not make the differential pressure variable and widen the range of the amount of fuel supplied by the injector 1 beyond the range achieved by the ξ nose width control. Further, with a negative pressure operated type fuel pressure regulating valve 3, it is difficult to accurately adjust the fuel pressure according to various operating conditions.

In view of the above-mentioned problems, the present invention provides an electromagnetic fuel pressure regulating valve provided in the return path of a fuel circulation path connecting a fuel tank and an injector, and a pressure regulating valve provided in a fuel chamber of the electromagnetic fuel pressure regulating valve. The fuel pressure is set to a target value with respect to the manifold negative pressure by adjusting the opening degree of the electromagnetic fuel pressure regulating valve according to the operating parameters of the engine including at least the amount of intake air while receiving a signal from the pressure sensor. For an injector, the injector is equipped with a control circuit that performs feedback control so that the fuel pressure and the manifold negative pressure are controlled, and the differential pressure between the fuel pressure and the manifold negative pressure is made variable so that the width of the amount of fuel supplied by the injector is wider than the width by pulse width control. Although the present invention is intended to provide a fuel pressure adjustment mechanism, the same members as those in the conventional example will be described with the same reference numerals based on the illustrated embodiment. In FIG. 2, 13 indicates the fuel pressure adjustment mechanism. An electromagnetic fuel pressure regulating valve is provided in place of the regulating valve 3 on the return path of the fuel circulation path 2, 14 is an atmospheric chamber formed in place of the negative pressure chamber 6, and 15 is an electromagnetic fuel pressure regulating valve provided on the upper surface of the diaphragm 7. A fixed magnetic plate 16 is an iron core fixed to the ceiling wall of the atmospheric chamber 14.
Reference numeral 7 designates an excitation coil that is wound around the iron core 16 and connected to the output side of a control circuit, which will be described later. The outlet side passage 9 is opened and closed by being attracted to or separated from the iron core 16. A pressure sensor 18 is fixed to the inner wall of the fuel chamber 5 and connected to the input side of a control circuit to be described later. FIG. 3 shows a block circuit diagram of the control system of this fuel pressure adjustment mechanism, and 19 is an electromagnetic fuel pressure adjustment according to the intake air amount, which is one of the operating parameters of the engine, while receiving a signal from the pressure sensor 18. Valve 13
This is a control circuit that performs feedback control of the fuel pressure to a target value with respect to the manifold negative pressure by adjusting the opening degree of the injector 1, and also controls the nose width of the injector 1.

Note that the target value is relative to the manifold negative pressure, and the relative value is determined in advance according to the intake air amount through experiments or the like.

The injector fuel pressure adjustment mechanism according to the present invention is configured as described above, and electronically feedback-controls the fuel pressure according to the intake air amount so that it becomes a target value with respect to the manifold negative pressure. It is possible to make the differential pressure between the fuel pressure and the negative pressure of the manifold 1 variable. Therefore, if the target value of the fuel pressure to be adjusted with respect to the Mayuhole 1 negative pressure is set so that the differential pressure between the fuel pressure and the Mayuhole 1 negative pressure changes in proportion to the width of the injector 1, it is possible to As shown in Figure 4, the rate of increase in the fuel supply amount QF due to this fuel pressure adjustment mechanism (the slope of the solid line a) is the same as the rate of increase (the slope of the dotted line) when the differential pressure between the conventional fuel pressure and the manifold negative pressure is kept constant. Become more of a dog. That is, as a result, the width of the fuel supply amount QFO by the injector 1 is made wider than the width of the fuel supply width control.

Therefore, the fuel supply amount range required in the case of SPI can be fully satisfied. In addition, it can fully accommodate the expansion of the fuel supply range required when a turbocharger or supercharger is installed on the engine. Also, MPI
In this case, the dynamic range unique to the injector 1, that is, the fuel supply width by the nozzle width control, does not need to be made so wide, so the injector IK does not require so high precision, and as a result, the cost can be reduced. becomes.

Furthermore, since the fuel pressure regulator 13 is of an electromagnetic type, it is possible to accurately adjust the fuel pressure according to various operating conditions.

FIG. 5 shows another embodiment, in which 20 is a fuel circulation path 2.
This is an electromagnetic pump installed on the way out. FIG. 6 shows a block circuit diagram of the control system of this embodiment. In this case, the control circuit 19 controls electromagnetic control not only according to the amount of intake air but also according to the throttle opening and the engine speed, or the torque and the engine speed. Not only the opening degree of the fuel pressure regulating valve 13 but also the electromagnetic pump 2
The rotation speed at 0 is also controlled. It is assumed that the opening degree of the electromagnetic fuel pressure regulating valve 13 and the rotation speed of the electromagnetic pump 200 are controlled independently of each other. Therefore, in this embodiment, since fuel pressure control is performed by both the electromagnetic fuel pressure regulating valve 13 and the electromagnetic pump 20, the control speed is higher than in the above embodiments. Furthermore, since not only the intake air amount but also the throttle opening and the engine rotational speed or the torque and the engine rotational speed are added to the engine operating parameter ξ, control accuracy is also improved.

In the first embodiment as well, it goes without saying that not only the intake air amount but also the throttle opening and the engine speed or the torque and the engine speed may be added to the engine operating speed meter.

As described above, according to the fuel pressure adjustment mechanism for an injector according to the present invention, the width of the fuel supply amount by the injector can be made wider than the width by ξ pulse width control.
It can fully satisfy the fuel supply width required in the case of SPI or when a turbocharger is installed, and in the case of MPI, the cost is low, and it is possible to adjust the fuel pressure with a good 8 degrees according to various operating conditions. It has many important practical advantages, such as:

[Brief Description of the Drawings] Fig. 1 is a longitudinal sectional view of a conventional fuel pressure adjustment mechanism for an injector, Fig. 2 is a longitudinal sectional view of an embodiment of the fuel pressure adjustment mechanism for an injector according to the present invention, and Fig. 3 is a longitudinal sectional view of an embodiment of the fuel pressure adjustment mechanism for an injector according to the present invention. A block circuit diagram of an example control system, FIG. 4 shows the injector pulse I
FIG. 5 is a longitudinal sectional view of another embodiment, and FIG. 6 is a block circuit diagram of the control system of the other embodiment. DESCRIPTION OF SYMBOLS 1...Injector, 2...Fuel circulation path, 13.Electromagnetic fuel pressure adjustment valve, 18..Pressure sensor, 19..Control circuit, 20.Electromagnetic pump. 1 Jino, τ-1 [ Fig. 1 Fig. 2 Fig. 4 Fig. 4

Claims (4)

[Claims] (1) An electromagnetic fuel pressure regulating valve provided on the return path of a fuel circulation path connecting the fuel tank and the injector, and a pressure sensor provided in the fuel chamber of the electromagnetic fuel pressure regulating valve;
While receiving a signal from the pressure sensor, the opening degree of the electromagnetic fuel pressure regulating valve is adjusted in accordance with the operating parameters of the engine including at least the amount of intake air, so that the fuel pressure becomes a target value with respect to the manifold negative pressure. A fuel pressure adjustment mechanism for an injector, comprising a control circuit that performs feedback control. (2) An electromagnetic fuel pressure adjustment valve provided on the return path of the fuel circulation path connecting the fuel tank and the injector, an electromagnetic pump provided on the outbound path of the fuel circulation path, and the electromagnetic fuel pressure adjustment valve provided on the return path of the fuel circulation path connecting the fuel tank and the injector. A pressure sensor provided in the fuel chamber of the valve, and an opening degree of the electromagnetic fuel pressure regulating valve and the electromagnetic pump in response to a signal from the pressure sensor and an operating parameter of the engine including at least the amount of intake air. A fuel pressure adjustment mechanism for an injector, comprising a control circuit that performs feedback control of fuel pressure to a target value with respect to manifold negative pressure by adjusting the rotation speed of the injector. (3) The fuel pressure adjustment mechanism for an injector according to claim (1) or (2), wherein the operating parameter ξ parameter is an intake air amount, a throttle opening, and an engine speed. (4) Claim (1) characterized in that the operating parameters are intake air amount, torque, and engine speed.
Or the fuel pressure adjustment mechanism for an injector according to (2).