JP2001050114A - Internal combustion engine control device for gaseous fuel vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate restart even in case where an internal combustion engine is stopped by misfire by judging whether the internal combustion engine in a gaseous fuel vehicle is stopped by misfire, and discharging remaining fuel in a cylinder at the time of restart of the internal combustion engine in the case where it is judged that the engine is stopped by misfire. SOLUTION: In an engine 1 of a gaseous fuel vehicle, CNG (compressed natural gas) is supplied from a tank 2 through a piping 3. The CNG is injected from an injector to an intake pipe 12 through a delivery 10, and then, ignition combustion is carried out by an ignition plug 13 after the CNG is mixed with air. In an ECU 19, it is judged that stall is generated in an engine 1 in the case where the value of rotating speed of the engine 1 inputted from a rotating speed sensor 22 is smaller than a prescribed value. After that, when ON-signal of an ignition key 21 is inputted, stall caused by rich misfire is judged since an air fuel ratio feed back correcting value memorized at the time of stop of an engine 1 is smaller than a prescribed value, and then, scavenging control is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for an internal combustion engine of a gas fueled vehicle for controlling the restart of the internal combustion engine of the gaseous fueled vehicle.

[0002]

2. Description of the Related Art A gas-fueled vehicle obtains a driving force by burning a mixture of gaseous fuel and air in a cylinder of an internal combustion engine.
CNG vehicles using sed Natural Gas) are generally known. CNG vehicles, and stored in a compressed state CNG to vehicle has been in the tank (approximately 200~250kgf / cm ^2), after reducing the pressure in every several kgf / cm ^2, and supplied to the interior of the intake port from the injector A mixture is being generated.

[0003]

However, the engine of the CNG vehicle described above has a narrow combustion limit on the rich side as compared with a gasoline engine. There is a problem that the gas remains in the gas phase as it is, making it difficult to restart the engine.

An object of the present invention is to provide an internal combustion engine control apparatus for a gas-fueled vehicle that can be easily restarted even when the internal combustion engine is stopped due to misfire.

[0005]

According to a first aspect of the present invention, there is provided an internal combustion engine control apparatus for a gas-fueled vehicle, wherein: And a residual fuel discharging means for discharging residual fuel in the cylinder at the next start of the internal combustion engine when the misfire stop determining means determines that the engine is stopped due to misfire.

According to a second aspect of the present invention, the misfire of the internal combustion engine of the first aspect of the invention is a misfire due to excess fuel. I do.

According to a third aspect of the present invention, there is provided an internal combustion engine control apparatus for a gaseous fuel vehicle, wherein the residual fuel discharging means of the internal combustion engine control apparatus for a gaseous fuel vehicle does not perform fuel injection. It is a means for performing cranking.

[0008] According to the internal combustion engine control apparatus for a gas-fueled vehicle according to the present invention, when the internal combustion engine is restarted,
Since the internal combustion engine is started after the residual fuel is discharged by the residual fuel discharging means, the internal combustion engine can be easily started even when the internal combustion engine is stopped due to the misfire.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an internal combustion engine control device for a gas-fueled vehicle according to an embodiment.

This internal combustion engine control device is mounted on a CNG vehicle that is a gas-fueled vehicle. Engine 1 which is an internal combustion engine
Has basically the same configuration as a normal gasoline engine, but only its fuel system has a different configuration to supply CNG. CNG is filled in the tank 2 mounted on the vehicle, and the engine 1
Is supplied to the engine 1 through a pipe 3 provided to the engine 1.

A filling port 4 is also connected to the tank 2, and filling of the tank 2 with CNG is performed from the filling port 4. A check valve 5 is provided between the tank 2 and the filling port 4. The check valve 5 prevents CNG from being discharged from the filling port 4. A shutoff valve 6 is built in a connection portion between the tank 2 and the pipe 3. The shut-off valve 6 prevents CNG from being released from the tank 2 when the pipe 3 is damaged.

On the pipe 3 between the tank 2 and the engine 1, a gas filter 7 and a regulator 8
Are arranged. The gas filter 7 removes impurities such as dust in the CNG. The regulator 8 reduces the pressure of CNG stored under high pressure in the tank 2 and supplies it to the engine 1. CNG is stored in the tank 2 in a state of being compressed under high pressure in order to increase the storage volume efficiency (the pressure decreases with the remaining amount, but the initial pressure is high). When supplying by the regulator 8, several kgf / cm ²
The pressure is reduced to

The regulator 8 also has a function as a shut-off valve, and has a role of shutting off the supply of CNG to the engine 1 when the engine 1 is stopped. Further, the regulator 8 also has a role as an oil trapper for removing an oil component contained in the gaseous fuel. Oil which is inevitably mixed in the process of compressing CNG at a gas station and filling the tank 2 appears as mist in the CNG when the pressure of the CNG is reduced, so that the regulator 8 collects this oil. .

The most engine 1 side of the pipe 3 is the engine 1
CNG into the injector 9 attached to each cylinder
Are connected to a delivery 10 for distributing the data. Delivery 1
At 0, a pressure sensor 11 for detecting the pressure of CNG is attached. Since the energy density of CNG changes depending on the pressure, the change in density can be detected from the value detected by the pressure sensor 11 to correct the fuel injection amount.
CNG supplied from the injector 9 into the intake pipe 12 (intake port) is mixed with air to generate an air-fuel mixture, and is ignited by the ignition plug 13 in the cylinder (cylinder) of the engine 1 and burns. Engine 1 by combustion of the mixture
Generates a driving force.

The exhaust gas after the combustion of the air-fuel mixture is exhausted to an exhaust pipe 14 and purified by exhaust purification catalysts 15 and 16 before being released to the atmosphere. Engine 1 here
Has two exhaust purification catalysts 15 and 16. On the side of the exhaust pipe 14 close to the engine 1, a start-time catalyst 15 is provided. The start-up catalyst 15 is heated to the activation temperature early by the exhaust heat of the engine 1 and expresses its catalytic function earlier. On the other hand, an underfloor catalyst 16 is disposed downstream of the starting catalyst 15 in the exhaust pipe 14. The underfloor catalyst 16 is disposed under the floor of the vehicle, and purifies exhaust gas that cannot be completely purified by the catalyst 15 at the time of starting.

[0016] the downstream side of the upstream side and the underfloor catalyst 16 start catalyst 15 of the exhaust pipe 14, O ₂ sensor 17, 18 is an air-fuel ratio sensor are respectively attached. The O ₂ sensors 17 and 18 detect the air-fuel ratio of the air-fuel mixture from the oxygen concentration in the exhaust gas. In particular, O ₂ on the engine 1 side
The sensor 17 is an O ₂ sensor with a heater, and is heated to the activation temperature earlier by the electric power supplied from the battery, and expresses its detection function earlier.
A correction value (FAF) for feedback-correcting the air-fuel ratio is obtained based on the air-fuel ratio detected by the O ₂ sensors 17 and 18. That is, the O ₂ sensors 17 and 18
If the detected air-fuel ratio is richer than the stoichiometric air-fuel ratio, the value of FAF is decreased, and if lean, the value is increased.

The above-described regulator 8 and pressure sensor 1
1, the spark plug 13 and the O ₂ sensor 17, 18 is an electronic control unit that comprehensively controls the operation of the engine 1 (EC
U) 19. The opening and closing of the fuel cutoff valve in the regulator 8 is performed based on an opening and closing signal from the ECU 19. The detection results of the pressure sensor 11 and the O ₂ sensors 17 and 18 are sent to the ECU 19.

The ECU 19 is also connected to a negative pressure sensor 20 mounted on the intake pipe 12. The negative pressure sensor 20 detects an intake pipe pressure (negative pressure), and detects an intake air amount from the detected intake pipe pressure. Further, an ON signal is input from the ignition key 21 to the ECU 19, and the rotation speed of the engine 1 is input from the rotation speed sensor 22 to the ECU 19.

The ECU 19 controls the engine 1 based on optimal values such as the fuel injection amount, ignition timing, and opening / closing timing of intake / exhaust valves, which are calculated based on outputs from various sensors.

FIG. 2 is a flowchart showing a process for detecting engine stall in the internal combustion engine control device. First, the ECU 19 determines whether or not the rotational speed NE of the engine 1 input from the rotational speed sensor 22 is smaller than a predetermined value A (step S10).
If not smaller, it is determined that the engine 1 is rotating normally, and the FAF at that time is set to FAF (o
ld) (Step S12) and Step S1
It returns to the process of 0.

On the other hand, in step S10, the rotational speed N
If E is smaller than the predetermined value A, it is determined that a stall has occurred in the engine 1, a stall determination flag is set (XSTL = 1) (step S11), and the FAF at that time is stored (step S12). . In addition,
The process based on this flowchart is repeated until engine stall is detected, but ends when engine stall is detected.

FIG. 3 is a flowchart showing a restart process in the internal combustion engine control device. In the processing in this flowchart, the ignition key 21 is operated to restart the engine 1, and the ON signal is output from the ECU 1
9 is started.

First, the ECU 19 determines whether or not the stall determination flag is set (XSTL = 1) (step S20). Here, when the stall determination flag is not set, normal engine start is performed, so that control such as normal fuel injection is performed (step S23).

On the other hand, if the stall determination flag is set (XSTL = 1), it is a restart after the engine stall, so it is determined whether or not the engine stall is caused by a rich misfire ( Step S21).
That is, when an engine stall occurs due to a rich misfire, the FAF (old) stored when the engine is stopped.
Is smaller than the predetermined value B, FAF (old) <
In the case of B, it is determined that the engine is stalled due to rich misfire, and scavenging control is first performed (step S2).
2).

The scavenging control is a control for performing cranking without supplying fuel from the injector 9 for a certain period of time and discharging the rich mixture remaining in the cylinder to the outside of the cylinder. After the scavenging control, control such as normal fuel injection is performed (step S2).
3).

In this internal combustion engine control device, the engine 1 is started after the residual fuel in the cylinder is discharged at the time of restart, so that even if the engine 1 is stopped due to misfire, the engine 1 can be easily started. be able to.

In each of the above embodiments, the engine 1 supplies fuel to the intake pipe 12 (intake port). However, the fuel is supplied directly into the cylinder of the engine 1. It may be an in-cylinder injection type engine.
Further, the internal combustion engine control device of the present invention may be used for a gas fuel vehicle other than a CNG vehicle.

[0028]

According to the present invention, at the time of restart, the internal combustion engine is started after the residual fuel due to misfire is discharged by the residual fuel discharging means, so that even when the internal combustion engine is stopped due to misfire, Starting can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an internal combustion engine control device for a gas-fueled vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a process of detecting an internal combustion engine stall in the internal combustion engine control device for the gaseous fuel vehicle according to the embodiment of the present invention;

FIG. 3 is a flowchart showing a restart process in the internal combustion engine control device for the gas-fueled vehicle according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Tank, 3 ... Piping, 9 ... Injector, 11 ... Pressure sensor, 13 ... Spark plug, 17, 18
... O ₂ sensor, 19 ... ECU, 22 ... rotation sensor.

Continued on the front page F term (reference) 3G092 AB08 BA05 BB03 DE01S DG08 EA14 EA17 EA28 EC01 EC09 FA32 FB06 HA05Z HB03Z HC06Y HD06Z HE01Z HF05X HF19Z 3G301 HA22 JA00 JB09 KA04 KA28 LB02 LC03 MA13 NC01 PD01

Claims (3)

[Claims] 1. A misfire stop judging means for judging whether or not the cause of a stop of an internal combustion engine of a gas fueled vehicle is a misfire. An internal combustion engine control apparatus for a gas-fueled vehicle, comprising: a residual fuel discharging unit that discharges residual fuel in a cylinder at the time of starting. 2. The control apparatus according to claim 1, wherein the misfire of the internal combustion engine is a misfire due to excess fuel. 3. The control apparatus for an internal combustion engine of a gas-fueled vehicle according to claim 1, wherein said residual fuel discharging means is means for performing cranking without performing fuel injection.