JPH03249367A - Evaporative fuel controller for vehicle - Google Patents

Abstract

PURPOSE:To make improvements in startability and drivability of an internal combustion engine as well as to reduce an exhaust harmful component value by judging the extent of evaporative fuel flow rate as evaporative fuel pressure, and regulating a fuel supply to the engine according to this evaporative fuel pressure and fuel temperature. CONSTITUTION:A control means 40 operates and controls a purge valve 34 to open a second intake passage 26-2 at the specified driving area of an internal combustion engine 2, while it outputs a fuel injection pulse signal, for controlling a fuel injection valve 20 of a fuel supply mechanism 21, to regulate a fuel supply to the engine 2 according to a fuel temperature state being detected by a fuel temperature sensor 36 and evaporative fuel flow rate (evaporative fuel pressure) being measured by a flow meter 32. With this constitution, an air-fuel ratio is properly secured and startability and drivability in the engine are improved, while a variation in exhaust gas value becomes lessened and, what is more, an exhaust gas harmful component value is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an evaporative fuel control device for a vehicle, and in particular, it determines the evaporative fuel flow rate as evaporative fuel pressure, and controls the internal combustion engine according to the evaporative fuel pressure and fuel temperature. The present invention relates to an evaporative fuel control device for a vehicle that can adjust the amount of fuel supplied to a vehicle to ensure a proper air-fuel ratio, thereby improving the startability and drivability of an internal combustion engine, and reducing the value of harmful components in exhaust gas.

[Prior Art] Evaporative fuel that leaks into the atmosphere from fuel tanks, float chambers of vaporizers, etc. contains large amounts of hydrocarbons (HC) and is one of the causes of air pollution, and also causes fuel loss. Various techniques are known to prevent this problem. A typical example of this is to temporarily adsorb and hold evaporated fuel in a canister containing an adsorbent such as activated carbon.
There is an evaporated fuel control device that purges evaporated fuel adsorbed and held in a canister and supplies it to an intake system during operation of an internal combustion engine.

As this evaporative fuel control device, for example,
Publication No. 36251, Publication of Utility Model Publication No. 83-193760,
It is disclosed in Japanese Patent Application Laid-Open No. 1-193071. The device described in Japanese Utility Model Application Publication No. 63-138251 is equipped with a solenoid valve that directly or indirectly opens and closes the purge passage, and is also provided with a steam generation amount detection means for detecting the amount of fuel vapor generated in the fuel tank. The amount of purge is adjusted by controlling the opening and closing of the purge passage based on the amount generated and engine operating conditions. Also, Utsukai Showa 63-19
The device described in Publication No. 3780 is capable of closing the atmospheric passage of the canister with a solenoid valve during high-load operation when the fuel system temperature is above a predetermined temperature, and is capable of inhaling highly concentrated evaporated fuel into the intake system. This promotes purging efficiency of evaporated fuel. Furthermore, in the device described in JP-A-1-193071, even if a different type of fuel is replenished, the valve means is closed for a predetermined period of time until the evaporated fuel of the newly replenished fuel is supplied into the canister. The operation of the fuel tank is controlled to maintain the previous flow rate to prevent the air-fuel ratio from increasing due to the intake of atmospheric air through the canister, and to prevent fuel overflow due to exceeding the capacity of the canister.

[Problems to be Solved by the Invention] By the way, in the evaporative fuel control device, the flow rate of the evaporated fuel leaving the intake passage changes due to differences in the pressure of the evaporative fuel from the fuel tank, etc., and as a result, the air-fuel ratio fluctuates unnecessarily. Was.

Therefore, conventionally, when setting the air-fuel ratio of an internal combustion engine, an intermediate air-fuel ratio was set with respect to the pressure of evaporated fuel.
The air-fuel ratio cannot be adjusted appropriately depending on the pressure of evaporated fuel, etc., which leads to a decline in the startability and drivability of the internal combustion engine, and increases the dispersion of exhaust gas values and increases the values of harmful exhaust gas components. There was the inconvenience of doing so.

[Object of the Invention] Therefore, the object of the invention is to eliminate the above-mentioned disadvantages.
By determining the vaporized fuel flow rate as the vaporized fuel pressure and adjusting the amount of fuel supplied to the internal combustion engine according to the vaporized fuel pressure and fuel temperature, the air-fuel ratio can be maintained appropriately even if the vaporized fuel pressure etc. changes. An object of the present invention is to provide a evaporative fuel control device for a vehicle that can improve the startability and drivability of an internal combustion engine, reduce variations in exhaust gas values, and reduce the values of harmful exhaust gas components.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a method for removing the fuel tank from the fuel tank while the internal combustion engine is stopped, in the middle of a ventilation passage that communicates the inside of the fuel tank with the intake passage of the intake system of the internal combustion engine. In the evaporated fuel control device for a vehicle, the canister is provided with a canister that adsorbs and holds the evaporated fuel generated in the internal combustion engine, and causes the adsorbed and held evaporated fuel to be released and supplied to the intake passage by introducing fresh air during operation of the internal combustion engine. A flow meter is provided to measure the flow rate of evaporated fuel from the fuel tank to the canister, and a purge valve is provided to open and close the vent passage between the canister and the intake passage to supply and disconnect the evaporated fuel from the canister to the intake passage. and a fuel temperature sensor for detecting the fuel temperature in the fuel tank, and opening the ventilation passage in a predetermined operating range of the internal combustion engine (operating the purge valve and controlling the fuel temperature state detected by the fuel temperature sensor). The present invention is characterized by further comprising a control means for controlling the operation of a fuel supply mechanism to adjust the amount of fuel supplied to the internal combustion engine according to the flow rate of fuel vapor measured by the flowmeter.

[Function] According to the configuration of the present invention, when the internal combustion engine reaches a predetermined operating region, that is, a purge region where vaporized fuel is supplied, the control means operates the purge valve to open the air passage, and also controls the signal from the flow meter. is determined as the evaporated fuel pressure,
It also inputs signals from the temperature sensor, and controls the operation of the fuel supply mechanism according to the states of these signals, that is, the evaporated fuel pressure and fuel temperature, to adjust the amount of fuel supplied to the internal combustion engine. As a result, in internal combustion engines, an appropriate air-fuel ratio is ensured according to the vaporized fuel flow rate (evaporative fuel pressure) and fuel temperature conditions, improving startability and drivability of the internal combustion engine, and reducing variations in exhaust gas values. This can reduce the value of harmful components in exhaust gas.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail and specifically based on the drawings.

Figure 1.2 shows an embodiment of the invention. In the figure, 2 is an internal combustion engine, 4 is an intake manifold, 6 is an intake passage, 8 is an intake valve, 10 is a combustion chamber, 12 is a piston,
14 is an exhaust valve, 16 is an exhaust passage, and 18 is a fuel tank. The intake manifold 4 is provided with a fuel injection valve 20 that injects fuel into the combustion chamber 10 side. This fuel injection valve 20 constitutes a fuel supply mechanism 21.

This fuel injection valve 20 is supplied with fuel that is pumped into a fuel supply passage 24 by driving a fuel pump 22 in the fuel tank 18 .

In order to guide the evaporated fuel generated in the fuel tank 18, a vent passage 26 is provided, one end communicating with the upper part of the fuel tank 18 and the other end communicating with the intake passage 6.

A canister 28 is interposed in the middle of this ventilation path 26. Therefore, the ventilation passage 26 is divided into a first ventilation passage 26 - 1 between the fuel tank 18 and the canister 28 and a second ventilation passage 26 - 2 between the canister 28 and the intake passage 6 .

The canister 28 adsorbs and holds evaporated fuel generated in the fuel tank 18 while the internal combustion engine 2 is stopped, and also introduces fresh air (indicated by the white arrow in FIG. 1) while the internal combustion engine 2 is operating. The vaporized fuel retained in the intake air is removed (purged) and the removed vaporized fuel is supplied to the intake passage 6 as purge fuel.

A two-way check valve 30 and a flow meter 32 for measuring the flow rate of evaporated fuel from the fuel tank 18 side are sequentially provided in the first air passage 26-1 from the fuel tank 18 side.

Further, the second air passage 26-2 is provided with a device for supplying and disconnecting the separated evaporated fuel from the canister 28 to the intake passage 6 (the second air passage 26-2
A purge valve 34 that opens and closes 6-2 is provided.

Furthermore, the fuel tank 18 is provided with a fuel temperature sensor 36 that detects the temperature of the fuel within the fuel tank 18 .

Furthermore, the internal combustion engine 2 is provided with an engine temperature sensor 38 that detects the cooling water temperature as the engine temperature.

These flowmeter 32, purge valve 34, fuel temperature sensor 36, and engine temperature sensor 38 are connected to the control means (ECM) 4.
Contacting 0.

The control means 40 also includes an ignition switch 4.
2 and the ignition coil 4 to input the engine speed signal.
4 is in contact.

As a result, the control means 40 removes the predetermined operating range of the internal combustion engine 2, that is, the fully closed state (idle state) of the intake throttle valve (not shown) and the fully open state of the intake throttle valve. In other operating regions, the purge valve 34 is operated and controlled to open the second intake passage 26-2, and the fuel temperature sensor 36
Fuel for controlling the operation of the fuel injection valve 20 of the fuel supply mechanism 21 in order to adjust the amount of fuel supplied to the internal combustion engine 2 according to the fuel temperature state detected by the fuel temperature state and the vaporized fuel flow rate measured by the flow meter 32. It outputs an injection pulse signal.

Next, the operation of this embodiment will be explained based on the flowchart of FIG.

In the control means 40, when the program starts (step 101) and the ignition switch 42 is turned on (step 102), the engine water temperature Ts from the engine temperature sensor 38 is compared with the set engine water temperature T, and it is determined whether Ts<T. It is determined whether or not (step 103).

If Ts>T and No in step 103, the restart mode is set (step 104), while if Ts<T and YES in step 103, the internal combustion engine 2 is started (step 105).

Then, when the internal combustion engine 2 is started, the engine operating state is detected from the ignition coil 44, and it is determined whether the predetermined engine operating region is a purge region where evaporated fuel is supplied (step 106).

This purge region is a region other than the fully closed state (idle state) of the intake throttle valve (not shown) and the fully open state of the intake throttle valve.

If it is not a purge area and the answer is No in step 106, no measurement of the vaporized fuel flow rate is made, that is, the signal from the flow meter 32 is ignored (step 107).

On the other hand, if YES in the purge area in step 106, the purge valve 34 is turned on to open the second air passage 26-2 (step 108).

Then, the fuel temperature (THF) in the fuel tank 18 is measured based on the signal from the fuel temperature sensor 36 (step 109).

Next, the first set fuel temperature (TI) set at a low value is compared with the measured fuel temperature (THF), and TI > T
It is determined whether or not it is HF (step 110).

If TI>THF and YES in step 110, the first set evaporative fuel flow rate Ql and the measured evaporative fuel flow rate Q are compared to determine whether Ql≦Q (step 111).

In this step 111, if Q1≧Q and No, the fuel injection to the fuel injection valve 20 is performed, and the NO7 response signal is
The operation of the fuel injection valve 20 is controlled by a fuel injection pulse signal that reflects the correction coefficient Kl (step 112) and adds 1 to this first correction coefficient, thereby adjusting the amount of fuel supplied to the internal combustion engine 2.

Further, if Ql≦Q and YES in step 111, 2 is reflected in the second correction coefficient in the fuel injection pulse signal to the fuel injection valve 20 (step 113L). The operation of the fuel injection valve 20 is controlled by the injection pulse signal, and the amount of fuel supplied to the internal combustion engine 2 is adjusted.

The first correction coefficient Kl has a value larger than the second correction coefficient by 2.

On the other hand, in step 110, TI<THF and N
In the case of o, the first set fuel temperature TI, the second set fuel temperature T2 which is larger than the first set fuel temperature TI, and the measured fuel temperature THF are compared to determine whether TI≦THF≦T2. A determination is made (step 114).

In this step 114, TI≦THF≦T2 and YE
In the case of S, the second set evaporated fuel flow rate Q2 and the measured fuel flow rate Q are compared (step 115).

In this step 115, if Q2≦Q and YES, the fuel is injected to the fuel injection valve 20, and 2 is reflected in the second correction coefficient without NO7 (step 116). The operation of the fuel injection valve 20 is controlled by the injection stop, and the amount of fuel supplied to the internal combustion engine 2 is adjusted.

Further, if Q2≧Q and NO in step 115, the first correction coefficient Kl is reflected in the fuel injection nollus to the fuel injection valve 20 (step 117), and this first correction coefficient Kl is taken into account. The fuel injection valve 20 is operated and controlled by the fuel injection pulse signal, and the amount of fuel supplied to the internal combustion engine 2 is adjusted.

On the other hand, if T1≦THF≦T2 and No in step 114, the third set evaporative fuel flow rate Q3 and the measured evaporative fuel flow rate Q are compared to determine whether Q3≦Q (step 118 ).

In this step 118, if Q3≦Q and YES, 2 is reflected in the second correction coefficient in the fuel injection pulse signal to the fuel injection valve 20 (step 119), and the fuel with 2 added to this second correction coefficient is The operation of the fuel injection valve 20 is controlled by the injection pulse signal, and the amount of fuel supplied to the internal combustion engine 2 is adjusted.

Further, if Q3≧Q and NO in step 118, the first fuel injection pulse signal to the fuel injection valve 20 is
1 is reflected in the correction coefficient (step 120), and this first
The operation of the fuel injection valve 20 is controlled by the fuel injection pulse signal that takes into account the correction coefficient Kl, and the amount of fuel supplied to the internal combustion engine 2 is adjusted.

That is, in this embodiment, the purpose of measuring the flow rate of evaporated fuel by the flowmeter 32 is to minimize variations in startability, drivability, exhaust gas values, etc. of the internal combustion engine 2 due to differences in pressure of evaporated fuel. Therefore, the difference in the measured vaporized fuel flow rate is measured as the difference in vaporized fuel pressure, and the fuel injection amount is controlled to maintain good operating conditions at all times.

In addition, since the pressure of evaporated fuel is easily affected by the fuel temperature, a fuel temperature sensor 36 is provided, and conditions for the evaporated fuel flow rate are set based on the first and second set fuel temperatures T11 and T2. Based on the flow rate determination, the first and second correction coefficients of the fuel injection pulse signal are set to 11K2.

As a result, the amount of fuel supplied to the internal combustion engine 2 is adjusted according to the vaporized fuel flow rate (evaporated fuel pressure) and the fuel temperature state, so that an appropriate air-fuel ratio is always ensured from low to high temperatures, and the internal combustion engine 2 is started. In addition to improving performance and drivability, it is possible to reduce variations in exhaust gas values and reduce exhaust gas harmful component values.

In this embodiment, in order to ensure the optimum air-fuel ratio even when restarting the internal combustion engine 2, it is also possible to apply a correction coefficient to the starting injection pulse signal.

In this case, the correction coefficient is set when the ignition switch 44 is turned OFF.
F is also stored in the control means 40, and at the time of restart, the correction coefficient from the previous operation is applied.

Furthermore, the conditions for measuring the vaporized fuel flow rate are engine speed (N11 N2) and intake pipe pressure (Pt).

P2) is used as a parameter and measured within a predetermined range thereof.

[Effects of the Invention As is clear from the detailed explanation above, according to this invention,
In a predetermined operating range of the internal combustion engine, the air passage is opened and the purge valve is operated and controlled to supply the separated evaporated fuel from the canister to the intake passage, and the fuel temperature state detected by the fuel temperature sensor and the evaporated fuel measured by the flow meter are controlled. By providing a control means for controlling the operation of the fuel supply mechanism to adjust the amount of fuel supplied to the internal combustion engine according to the flow rate (evaporated fuel pressure), The amount of fuel supplied to the internal combustion engine can be adjusted to ensure an appropriate air-fuel ratio, thereby improving the startability and drivability of the internal combustion engine, as well as reducing the variation in exhaust gas values and reducing the values of harmful exhaust gas components.

[Brief explanation of drawings]

1.2 shows an embodiment of the present invention, FIG. 1 is a system configuration diagram of the evaporative fuel control device, and FIG. 2 is a flowchart explaining the operation. In the figure, 2 is an internal combustion engine, 4 is an intake manifold, 18
is a fuel tank, 20 is a fuel injection valve, 26 is a ventilation passage, 28
is a canister, 32 is a flow meter, 34 is a purge valve, 3
6 is a fuel temperature sensor, and 40 is a control means.

Claims (1)

[Claims] 1. Vaporized fuel generated in the fuel tank when the internal combustion engine is stopped is adsorbed and held in the air passageway that communicates the inside of the fuel tank with the intake passage of the intake system of the internal combustion engine, and fresh air is absorbed while the internal combustion engine is operating. In the evaporative fuel control device for a vehicle, the evaporative fuel control device is provided with a canister that releases the evaporative fuel adsorbed and held by the introduction of a canister and supplies the evaporated fuel to the intake passage. A purge valve is provided for opening and closing the vent passage between the canister and the intake passage in order to supply and disconnect the separated evaporated fuel from the canister to the intake passage, and a fuel temperature sensor is provided for detecting the fuel temperature in the fuel tank, and the internal combustion controlling the operation of the purge valve to open the air passage in a predetermined operating range of the engine, and controlling the operation of the purge valve to open the air passage to the internal combustion engine according to the fuel temperature state detected by the fuel temperature sensor and the vaporized fuel flow rate measured by the flow meter. 1. An evaporative fuel control device for a vehicle, comprising a control means for controlling the operation of a fuel supply mechanism to adjust the amount of fuel supplied.