JP2008101525A - Control device of dual-fuel engine and control device of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a dual-fuel engine capable of suppressing the consumption of a fuel which cannot be easily supplemented, and a control device of a hybrid vehicle having a dual-fuel engine in which the consumption of the fuel which cannot be easily supplemented is suppressed without causing torque shock. <P>SOLUTION: Hydrogen is used as the fuel while a catalyst is not activated. After the catalyst is activated, the fuel is changed to a gasoline and hydrogen by operating a switch for the operation. When the gasoline is used, a map for gasoline is used for the operation. When the hydrogen is used, a map for hydrogen is used for the rich operation and the lean operation. When the hydrogen is used by operating the switch and the residual amount of hydrogen is less, the lean operating area is so increased or the degree of leanliness is increased as to suppress the consumption of the hydrogen. In this case, the insufficient amount of the drive torque of the vehicle is compensated for by supplying a power from a battery to a motor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a dual fuel engine that can switch between a first fuel and a second fuel as a fuel to be used, and a control device for a hybrid vehicle including the dual fuel engine.

It is a dual fuel engine that switches between gasoline, which is liquid fuel, and CNG (compressed natural gas), which is gas fuel, and always uses gas fuel until the catalyst is activated at the time of cold start. What has improved emission performance is conventionally known (for example, refer to Patent Document 1).
JP 2000-213394 A

  The fuel used in the engine can be switched between liquid fuel such as gasoline and light oil and gaseous fuel such as hydrogen and CNG (compressed natural gas), and the exhaust purification catalyst is activated as in the conventional dual fuel engine, for example. Until then, in a dual fuel engine that uses gaseous fuel under certain conditions, such as using gaseous fuel with excellent exhaust emission performance, liquid fuel such as hydrogen and CNG gas fuel, such as few refueling stands Therefore, it is desirable to suppress the consumption of gaseous fuel as much as possible so that it can be used when necessary. However, in the prior art, no consideration is given to securing the amount of gaseous fuel for such a necessary time.

  In the case of the conventional dual fuel engine, the gas fuel is used only until the catalyst is activated at the time of cold start. Separately, the driver uses the gas fuel in a clean-oriented manner. There is a demand for switching the fuel to be used by the occupants at times other than when the catalyst is inactive, such as allowing the fuel to be switched freely by operating the switch when it is desired to use it. . Therefore, for example, a switch for fuel switching is provided on the instrument panel (instrument panel for short) in front of the driver's seat of the vehicle so that the driver can select the fuel to be used by operating the switch. It is considered to always run with gaseous fuel if the fuel is selected. However, if gas fuel can be used at times other than when the catalyst is inactive, consumption of gas fuel that is not easily replenished increases, and gas that is used when it is originally needed, such as when the catalyst is inactive. It becomes difficult to secure fuel.

  Therefore, the present invention provides a dual fuel engine control device that can suppress the consumption of fuel that is not easily replenished, such as gaseous fuel, and the dual fuel that can suppress the consumption of fuel that is not easily replenished without causing a torque shock. It aims at providing the control apparatus of the hybrid vehicle provided with the engine.

  The present invention relates to a dual fuel engine control device capable of switching between a first fuel that is relatively easy to replenish as a fuel to be used and a second fuel that is not easily replenished, and is based on whether or not a predetermined condition is satisfied. Fuel selection means for selecting the fuel to be used, and when the second fuel is used, the air-fuel ratio of the air-fuel mixture supplied to the engine in a predetermined operation region is leaner than the air-fuel ratio in the other operation regions. Operating range in which the air-fuel ratio is leaned by the leaning control means when the remaining amount of the second fuel is equal to or less than a predetermined amount. A control device for a dual fuel engine is provided, characterized in that it is provided with a lean region expansion means for expanding the engine.

  According to the control device for the dual fuel engine, the fuel to be used is selected based on whether or not the predetermined condition is satisfied. In addition, when the second fuel is used, the air-fuel ratio is made lean in a predetermined operating region, and when the remaining amount of the second fuel is less than a predetermined amount, the leaned region is expanded, thereby The consumption of the second fuel that is not easily replenished is suppressed.

  The present invention is also a dual fuel engine control device capable of switching between a first fuel, which is relatively easy to replenish, and a second fuel, which is not easily replenished, as a fuel to be used. And a fuel selection means for selecting the fuel to be used based on the air-fuel ratio, and the air-fuel ratio of the air-fuel mixture supplied to the engine in the predetermined operation region when the second fuel is used is compared with the air-fuel ratio in the other operation regions. The leaning control means for leaning, the remaining amount detecting means for detecting the remaining amount of the second fuel, and the leaning control means reduce the air-fuel ratio when the remaining amount of the second fuel is less than a predetermined amount. There is provided a dual fuel engine control device comprising a lean degree changing means for increasing a lean degree in an operating region.

  According to the control device for the dual fuel engine, the fuel to be used is selected based on whether or not the predetermined condition is satisfied. In addition, when the second fuel is used, the air-fuel ratio is leaned in a predetermined operation region, and when the remaining amount of the second fuel is less than a predetermined amount, the lean degree is large in the leaning operation region. Accordingly, consumption of the second fuel that is not easily replenished is suppressed.

  The control apparatus for the dual fuel engine determines the active state of the catalyst by detecting a value related to the active state of the exhaust purification catalyst, the first fuel being liquid fuel and the second fuel being gaseous fuel. A catalyst activity determination unit may be provided, and the fuel selection unit may select the second fuel as the fuel to be used when the catalyst is not activated under a predetermined condition that the catalyst is not activated.

  According to this dual fuel engine control device, the gaseous fuel is selected as the fuel to be used when the catalyst is not activated, thereby improving the exhaust emission performance when the catalyst is inactive. When the gaseous fuel is used, the air-fuel ratio is leaned in a predetermined operation region, and when the remaining amount of the gaseous fuel is equal to or less than the predetermined amount, the leaned region is expanded or leaned. The lean degree is increased in the operation region, thereby suppressing the consumption of the second fuel that is not easily replenished.

  Further, in the control device for the dual fuel engine, the “predetermined condition” in the “fuel selection means for selecting the fuel to be used based on whether or not the predetermined condition is satisfied” is the first predetermined condition, and the “fuel selecting means” Is a first fuel selection means, comprising: a second fuel selection means for executing a control for selecting a fuel to be used based on whether or not a second predetermined condition other than the first predetermined condition is satisfied; The region expanding means or the lean degree changing means is a control or lean degree that expands the operating range in which the air-fuel ratio is made lean only when the second fuel (gaseous fuel) is selected as the fuel to be used by the second fuel selecting means. It can be configured to execute control to increase.

  When the gaseous fuel is selected as the fuel to be used because the catalyst is not activated, the operating range for leaning the air-fuel ratio when the remaining amount of the gaseous fuel is less than the specified amount is expanded, or the lean degree If the above-described control is performed to increase the exhaust gas temperature, the exhaust gas temperature decreases, and therefore the time until the catalyst is activated becomes longer. Therefore, the control for expanding the operation range for leaning the air-fuel ratio or the control for increasing the lean degree is not performed when the gaseous fuel is selected because the catalyst is not activated, and the catalyst is not activated. This is executed only when gaseous fuel is selected based on the establishment and non-establishment of the second predetermined condition such as a switch operation by the driver other than the above (first predetermined condition). It is possible to suppress the consumption of gaseous fuel that is not easily replenished while promoting the conversion.

  The present invention is also a control device for a hybrid vehicle including a dual fuel engine having the control device configured as described above, and includes a motor capable of outputting a drive torque of the vehicle and a battery capable of supplying electric power to the motor. And a drive torque supplementing means for supplementing the shortage of the driving torque of the vehicle by supplying power from the battery to the motor when the control by the lean area expanding means or the lean degree changing means is being executed. A control device for a hybrid vehicle is provided.

  The control device for the dual fuel engine performs leaning that makes the air-fuel ratio of the air-fuel mixture supplied to the engine leaner than the air-fuel ratio in other operating regions when the second fuel is used. In this case, the predetermined operation region in which the air-fuel ratio is made lean, that is, the lean operation region, and the other operation region, that is, the rich operation region, are separated so as to satisfy the required torque of the engine. If the lean area is expanded or the degree of leanness is increased, the required torque is not generated and the torque becomes insufficient. In the case of a hybrid vehicle, the power generation amount of the generator decreases, and as a result, the motor demands it. However, there is a problem that the driving torque of the vehicle is reduced because the electric power to be supplied cannot be supplied. Therefore, when the control to increase the lean area or increase the lean degree is executed, the shortage of the driving torque of the vehicle is supplemented by the power supply from the battery to the motor, thereby reducing the lean area. It is possible to compensate for the vehicle's torque shortage caused by enlarging or increasing the degree of lean, and it is possible to suppress consumption of the second fuel that is not easily replenished without causing a torque shock.

  Thus, according to the dual fuel engine control device of the present invention, when the remaining amount of the second fuel is less than or equal to the predetermined amount in the dual fuel engine, the lean operation range when the second fuel is used or the lean degree By enlarging the fuel consumption, it is possible to suppress the consumption of the second fuel that is not easily replenished so that it can be used when necessary.

  The control device for the dual fuel engine is configured to select the gaseous fuel when the first fuel is liquid fuel, the second fuel is gaseous fuel, and the catalyst is not activated, so that the catalyst is inactive. Exhaust emission performance at the time can be improved, in which case, when the remaining amount of gaseous fuel is below a predetermined amount, by expanding the lean operation area when using gaseous fuel, or by increasing the lean degree, The consumption of gaseous fuel can be suppressed so as not to hinder the use until the catalyst is activated, and in particular, the control for expanding the lean operation range and the control for increasing the lean degree are referred to as the active state of the catalyst. This is performed only when gaseous fuel is selected based on other conditions, thereby facilitating catalyst activation and eliminating gaseous fuel that is not easily replenished. It is possible to suppress.

  Further, according to the control apparatus for a hybrid vehicle equipped with the dual fuel engine of the present invention, the shortage of the driving torque of the vehicle by expanding the lean region or increasing the lean degree when the second fuel is used is transferred from the battery to the motor. It is possible to compensate by supplying the electric power, and it is possible to suppress the consumption of the second fuel that is not easily replenished without causing a torque shock.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 8 show an example of an embodiment of the present invention. 1 is an overall view of a drive system of a hybrid vehicle equipped with a dual fuel engine of this embodiment, FIG. 2 is a control block diagram of the dual fuel engine, and FIG. 3 is an explanatory diagram of a basic concept of fuel switching control of the dual fuel engine. 4 is a graph showing an engine operation map to be selected when the hydrogen remaining amount of the dual fuel engine is large, and FIG. 5 is an engine operation to be selected when the hydrogen amount of the dual fuel engine is small. FIG. 6 is a graph showing an example of a map, FIG. 6 is a graph showing another example of an engine operation map selected when the hydrogen remaining amount of a dual fuel engine is low, and FIG. 7 is a fuel of the dual fuel engine. Flow chart of switching control and vehicle drive control, FIG. Is a flowchart of an engine operation map selected when the hydrogen engine use.

  In this embodiment, a dual fuel engine that can be operated by switching between gasoline (first fuel) and hydrogen (second fuel) is not a motor that drives the vehicle by directly transmitting the driving force of the engine to the axle. It is mounted on a hybrid vehicle of a hybrid system (referred to as a series hybrid) that drives the vehicle and moves the engine to generate electric power to be supplied to the motor.

  The hybrid vehicle drive system of this embodiment is as shown in FIG. 1, and supplies gasoline to the engine 1 from the engine 1 (dual fuel engine), the gasoline fuel tank 2 and the hydrogen fuel tank 3, and the gasoline fuel tank 2. A hydrogen supply passage 5 for supplying hydrogen from the gasoline supply passage 4 and the hydrogen fuel tank 3 to the engine 1, a generator (generator) 7 driven by the output shaft 6 of the engine 1, and an axle through a differential (differential) 8 A motor (electric motor) 10 that drives the motor 9, a battery (high voltage battery) 11 that stores electric power for driving the motor, an AC-DC converter 12 that converts alternating current into direct current, and an alternating current generated by the generator 7 Current path 13 that flows to AC-DC converter 12 to convert DC to DC, A DC-AC converter 14 that converts the current into a current, a current path 15 that passes a direct current from the AC-DC converter 12 to the battery 11, a direct current from the AC-DC converter 12 that is separated from the current path 15, and the battery 11. Current path 16 for flowing the direct current to the DC-AC converter 14, and a current path 17 for supplying the alternating current from the DC-AC converter 14 to the motor 10.

  Although not shown, a DC path from the AC-DC converter 12 to the battery 11 has a current path 15 that is closer to the battery 11 than a branch point of the current path 16 to the DC-AC converter 14. A battery changeover switch is provided for switching between a position where the direct current from the battery is supplied to the high voltage battery 11 side and a position where the direct current is supplied to the motor 10 via the DC-AC converter 14.

And the driving | running | working form of this hybrid vehicle is as follows.
The engine 1 does not always move. When the vehicle is started or when the torque is low, a large driving force is not necessary. Therefore, the engine 1 is not moved and the electric power of the high voltage battery 11 is DC- The vehicle is driven by being supplied to the motor 10 via the AC converter 16.

  On the other hand, when the torque increases and becomes a medium torque state, the amount of electricity stored in the battery 11 decreases as the electric power is taken out from the battery 11. In this case, the engine 1 is operated, and the engine 1 generates the generator. 7 is driven, and the electric power generated by the generator 7 is supplied to the motor 10 to drive the vehicle.

  When the torque is further increased and the torque becomes high, the amount of power generated by the engine 1 cannot be satisfied. Therefore, both the power generated by the generator 7 by driving the engine 1 and the power of the battery 11 are motorized. 10 to drive the vehicle.

  Also, when the battery 11 has a small amount of charge and needs to be charged, then the engine 1 is not running, for example, running at a low torque, and the charge amount of the battery 11 is steadily decreasing. In the case of the situation, the engine 1 is started and the battery 11 is charged.

  In addition, when the battery 11 has a small amount of charge and needs to be charged, the engine 1 is already running, for example, the power generated by the generator 7 by driving the engine 1 with high torque. When both the electric power of the battery 11 is supplied to the motor 10 and the storage amount of the battery 11 is reduced, the battery 11 waits for a middle torque state and exceeds the electric power required by the motor 10. The engine 1 is driven so as to obtain a power generation amount, the power generation amount of the generator 7 is kept as high as possible, the surplus power is supplied to the battery 11, and the battery 11 is charged.

  In this series hybrid system, as shown in FIG. 2, the engine 1 rotates along a pair of rotor housings 101 and 102 and an inner peripheral surface thereof supported by an output shaft 6 (eccentric shaft) 2. A two-rotor rotary engine including two rotors 103 and 104 (a pair of rotor housings 101 and 102 is schematically shown in a left and right direction in FIG. 2), and is common to the upstream side of the intake passage 105 A throttle valve 106 is provided in the passage portion, and a throttle valve actuator 107 that drives the throttle valve 106 is disposed. Further, gasoline fuel injection valves 108 and 109 for performing port injection are provided in two independent passage portions branched downstream of the intake passage 105, and fuel is supplied to the rotor housings 101 and 102 in the combustion chamber. Fuel injection valves 110 and 111 for hydrogen are installed so as to inject. Further, two spark plugs 112, 113; 114, 115 are installed in each rotor housing 101, 102. The throttle valve actuator 107, the fuel injection valves 108 and 109 for gasoline, the fuel injection valves 110 and 111 for hydrogen, and the spark plugs 112 and 113; 114 and 115 are controlled by a computer (PCM) 120. A control system is configured.

  In this computer (PCM) 120, various signals for throttle control, air-fuel ratio control, ignition timing control, etc. are input in the same manner as in a conventionally known engine, in addition to a battery current / voltage sensor 121 and The detection signals of the pressure sensor 122 of the hydrogen fuel tank 3, the fuel sensor 123 of the gasoline fuel tank 2, the fuel changeover switch 124 provided in the instrument panel (instrument panel), and the catalyst temperature sensor 125 are input. . The computer (PCM) 120 controls the power supplied to the motor 10 by controlling the AC-DC converter 12 and the DC-AC converter 14 based on the input signals, controls the battery switching switch, and switches the fuel. Control the valve.

  The battery current / voltage sensor 121 is attached to the battery 11. The battery current / voltage sensor 121 obtains the electric power that enters the battery 11 and the electric power that leaves the battery 11 from the current and voltage, and detects the amount of electricity stored in the battery 11. The catalyst temperature sensor 125 is attached to the catalyst and directly detects the catalyst temperature. However, the catalyst temperature may be estimated from the exhaust temperature.

  This engine 1 is operated by switching the fuel to be used between gasoline and hydrogen. Until the catalyst is activated at the start of the engine, hydrogen is automatically used to improve the exhaust emission performance, and the catalyst is activated. After that, if the driver selects gasoline, the driver switches to gasoline, and if the driver selects hydrogen, the hydrogen is used as it is. Also, even when the catalyst is not activated, if hydrogen is out of fuel, the engine is started with gasoline. Also, when hydrogen is used and hydrogen runs out of fuel, it is automatically switched to gasoline, and when gasoline is used and gasoline runs out of fuel, it is automatically switched to hydrogen. In the engine 1, after the catalyst is activated, the driver can switch the fuel by operating the fuel switch 124 of the instrument panel. Which fuel is currently being used is indicated on the display part with a speedometer.

  Further, in the engine 1, as shown in FIG. 3, the use of hydrogen is prohibited when the remaining amount of hydrogen is in a state of running out of fuel where the hydrogen cannot be injected from the injector (first predetermined amount or less). Switch fuel to gasoline.

  Further, for the purpose of securing the hydrogen to be used until the catalyst is activated, when the remaining amount of hydrogen is reduced and the fuel is almost exhausted, the fuel changeover switch 124 of the driver switches the fuel to be used. Is prohibited. The fuel used is gasoline except when the catalyst is inactive. Then, the fuel shortage lamp is turned on to prompt the driver to supply hydrogen.

  When the remaining amount of hydrogen is larger (greater than the second predetermined amount), both the use of hydrogen when the catalyst is inactive and the use of hydrogen by the driver's switch operation are possible.

  When the engine 1 is operated using hydrogen and the remaining amount of hydrogen is greater than a predetermined amount, a graph of the engine speed (rpm) and the required torque (Nm) is used as an air-fuel ratio map. The engine operation map (map A) shown in FIG. 4 is selected, and the operation is divided into rich operation and lean operation.

  Hydrogen has much better exhaust emission performance than gasoline. However, in the case of hydrogen, since the torque is not generated when the lean operation is performed, a region of the rich operation must be provided to some extent. However, when the air-fuel ratio is made rich in hydrogen operation, the combustion temperature rises and NOx is likely to be generated. Therefore, the rich operation and the lean operation are separated.

  Specifically, as shown in FIG. 4, a region requiring a considerable torque is set as a region for rich operation, and in this region, operation is performed at λ (excess air ratio) = 0.9 to 1.0. Then, a region where the load is low (required torque is small), such as during idling, is set as a lean operation region, and operation is performed at λ = 2.0. On the other hand, even during idling, when the load is high (the required torque is large) such as when the air conditioner is at its strongest, the lean operation is performed at about λ = 1.8. In addition, when the engine speed increases, in the case of hydrogen, the ignitability is good, so there is a problem that abnormal combustion occurs, and particularly when the fuel is dense, abnormal combustion is likely to occur. Originally, it is a place where a rich operation is desired to generate torque, but unavoidably, a lean operation is performed at λ = 1.5 to 1.6.

  Further, in this engine 1, when hydrogen is used in the operation of the fuel changeover switch 124 and the remaining amount of hydrogen is low (when the remaining amount of hydrogen is less than a predetermined amount), the hydrogen is kept as much as possible. In order to reduce hydrogen consumption as much as possible, the air-fuel ratio map is shown in the graph of the engine speed (rpm) and the required torque (Nm) in FIG. 5 or FIG. 6 so as to suppress the hydrogen consumption. The engine operation map (map B) is selected, and the lean operation region is expanded or the lean degree in the lean operation region is increased.

  In the engine operation map of FIG. 5, the lean operation region of λ = 2.0 on the low load side is expanded to the high torque side with reference to the engine operation map (map A) of FIG. 4, and λ = 1 on the high rotation side. The lean operation range of .5 to 1.6 is expanded to the low rotation side.

  Further, in the engine operation map of FIG. 6, the rich operation region and the lean operation region itself are not changed with reference to the engine operation map (map A) of FIG. 4, and the low operation side λ = 2.0 lean operation region. The lean degree of the lean operation region of λ = 1.5 to 1.6 on the high rotation side is increased to λ = 2.0 to 2.1.

  However, if the above control when the remaining amount of hydrogen is low is performed when hydrogen is used in an inactive state of the catalyst, the lean operation range will be expanded or the degree of leanness will increase, leading to a decrease in exhaust temperature and catalyst activation. The time until is longer. Therefore, this control is not performed when hydrogen is used in an inactive state of the catalyst. When the catalyst is not activated, even if the remaining amount of hydrogen is small, the operation is performed according to the map A in FIG.

  In this hybrid vehicle, when the control for expanding the lean operation range or the control for increasing the lean degree is executed, power supply from the battery 11 to the motor 10 is made up to compensate for the shortage of the drive torque of the vehicle. Control.

  In the case of the series hybrid system, if the lean operation range is expanded or the lean degree is increased, the engine torque is not correspondingly generated, the power generation amount of the generator 7 is reduced, and the power supplied from the generator 7 to the motor 10 is reduced. The motor torque that is required by the motor 10 cannot be output. Therefore, the power supply from the battery 11 is controlled to compensate for the insufficient driving torque.

  The fuel switching control and vehicle drive control procedures of this embodiment are as shown in the flowchart of FIG. 7. When starting, first, in step S1, the required torque of the vehicle is calculated from the vehicle speed and the accelerator opening, and then In step S2, the value of the battery charge amount is read. In step S3, it is determined whether or not there is an engine operation request based on the required torque of the vehicle and the battery charge amount.

  When the required torque of the vehicle is not large (predetermined value or more) or the battery storage amount is small (predetermined amount or less), it is determined that there is no engine operation request. In that case, in step S4, The motor is driven by power supplied from the battery (the engine does not move at this time).

  Further, when the required torque of the vehicle is large (predetermined value or more) or when the battery storage amount is small (predetermined amount or less), it is determined that there is an engine operation request. In that case, in step S5, the catalyst The temperature (the detected value of the catalyst temperature sensor) is read, and it is determined in step S6 whether the catalyst temperature has reached the catalyst activation temperature.

  If the catalyst activation temperature has not been reached, hydrogen is selected as the fuel in step S7. In step S8, map A (engine operation map in FIG. 4) is selected as the engine operation map, the engine is controlled based on map A, and the process returns.

  If the catalyst activation temperature has been reached, in step S9, the fuel selected by the fuel changeover switch is read. In step S10, an engine operation map corresponding to the selected fuel is read. That is, an engine operation map for gasoline is read when gasoline is selected, and an engine operation map for hydrogen is read when hydrogen is selected. However, as an engine operation map for hydrogen, there are a map A (engine operation map in FIG. 4) and a map B (engine operation map in FIG. 5 or engine operation map in FIG. 6), and the remaining amount of hydrogen is small ( When the amount is equal to or less than the predetermined amount, the map B is read, and the map A is read otherwise.

  In step S11, it is determined whether the engine is operating. That is, even if it is determined in step S3 that there is an engine operation request, there are cases where the engine is already in operation and the engine is not yet operated. .

  If the engine is not operating, the generator is started by the generator in step S12, and the process returns.

  If the engine is in operation, the engine is controlled based on the map corresponding to the selected fuel in step S13. That is, when gasoline is selected, control is performed using an engine operation map for gasoline, and when hydrogen is selected, map A for hydrogen (engine operation map in FIG. 4) or map B (depending on the remaining amount of hydrogen). The engine operation map of FIG. 5 or the engine operation map of FIG.

  In step S14, it is determined whether the vehicle is operating with hydrogen and the map B (the engine operation map of FIG. 5 or the engine operation map of FIG. 6) is selected. If so, the process of complementing the insufficient torque with battery assist is performed, and the process returns.

  Further, when it is not a hydrogen operation, that is, when it is operated with gasoline, or when the map B is not selected even in the hydrogen operation, that is, when the remaining amount of hydrogen is sufficient and the map A is selected. Return as it is.

  The procedure for selecting the engine operation map when using hydrogen is as shown in the flowchart of FIG. 8, which starts. In step S101, the detection value of the pressure sensor of the hydrogen fuel tank is read. Determine whether the amount is less than or equal to a predetermined amount.

  If the remaining amount of hydrogen exceeds a predetermined amount, map A (engine operation map in FIG. 4) is selected as the engine operation map in step S103, and if it is less than the predetermined amount, map B (in FIG. 5). The engine operation map or the engine operation map of FIG. 6) is selected.

  As mentioned above, although an example of embodiment was demonstrated, this invention is not limited to this, It can implement with a various form.

  For example, although the above embodiment is a case of a series hybrid vehicle, the present invention can also be applied to a hybrid vehicle in which the output of the engine is directly transmitted to the vehicle as a driving force.

  The dual fuel engine control device of the present invention can also be applied to a normal dual fuel engine vehicle in which only the engine output is the driving force of the vehicle.

  As the fuel used for the engine, light oil or the like may be used as the liquid fuel, and CNG or the like may be used as the gaseous fuel.

  Also, the fuel used may be two types of different liquid fuels or two types of different gaseous fuels.

  In the above embodiment, the driver operates the instrument panel switch as a fuel switching condition. However, when the required torque of the vehicle is small, the driver automatically switches to hydrogen, which is difficult to generate engine torque. When the torque is large, it may be automatically switched to gasoline that produces engine torque. A plurality of such switching conditions may be provided.

1 is an overall view of a drive system for a hybrid vehicle equipped with a dual fuel engine according to an embodiment of the present invention. It is a control block diagram of the dual fuel engine of the embodiment of the present invention. It is basic concept explanatory drawing of the fuel switching control of the dual fuel engine of embodiment of this invention. It is the figure which graphed the engine driving | operation map selected when there is much hydrogen remaining amount at the time of hydrogen use of the dual fuel engine of embodiment of this invention. It is the figure which graphed an example of the engine operation map selected when the hydrogen remaining amount at the time of hydrogen use of the dual fuel engine of embodiment of this invention is small. It is the figure which graphed the other example of the engine driving | operation map selected when the hydrogen residual amount at the time of hydrogen use of the dual fuel engine of embodiment of this invention is small. It is a flowchart of the fuel switching control and vehicle drive control of the dual fuel engine in the embodiment of the present invention. It is a flowchart of the engine operation map selection at the time of hydrogen use of the dual fuel engine in embodiment of this invention.

Explanation of symbols

1 engine (dual fuel engine)
2 Gasoline fuel tank 3 Hydrogen fuel tank 7 Generator (generator)
8 differential 9 axle 10 motor (electric motor)
11 Battery (High voltage battery)
12 AC-DC converter 14 DC-AC converter 108, 109 Fuel injection valve 110, 111 for gasoline Fuel injection valve 120 for hydrogen 120 Computer (PCM)
121 Battery Current / Voltage Sensor 122 Hydrogen Fuel Tank Pressure Sensor 123 Gasoline Fuel Tank Fuel Sensor 124 Fuel Changeover Switch 125 Catalyst Temperature Sensor

Claims (5)

A control device for a dual fuel engine that can switch between a first fuel that is relatively easy to replenish as a use fuel and a second fuel that is not easily replenished,
The fuel selection means for selecting the fuel to be used based on whether or not the predetermined condition is satisfied,
Leaning control means for leaning the air-fuel ratio of the air-fuel mixture supplied to the engine in a predetermined operating region when the second fuel is used compared to the air-fuel ratio in other operating regions;
A remaining amount detecting means for detecting a remaining amount of the second fuel;
A dual fuel engine control device comprising: a lean region expanding means for expanding an operating region in which the air-fuel ratio is leaned by the lean control means when the remaining amount of the second fuel is equal to or less than a predetermined amount. . A control device for a dual fuel engine that can switch between a first fuel that is relatively easy to replenish as a use fuel and a second fuel that is not easily replenished,
The fuel selection means for selecting the fuel to be used based on whether or not the predetermined condition is satisfied,
Leaning control means for leaning the air-fuel ratio of the air-fuel mixture supplied to the engine in a predetermined operating region when the second fuel is used compared to the air-fuel ratio in other operating regions;
A remaining amount detecting means for detecting a remaining amount of the second fuel;
A dual fuel engine, comprising: a lean degree changing means for increasing a lean degree in an operating range in which the air-fuel ratio is leaned by the lean control means when the remaining amount of the second fuel is a predetermined amount or less. Control device. The first fuel is a liquid fuel, the second fuel is a gaseous fuel, and comprises catalyst activity determination means for detecting a value related to the activity state of an exhaust purification catalyst to determine the catalyst activity state, The predetermined condition is that the catalyst is not activated, and the fuel selection means selects the second fuel as a fuel to be used when the catalyst is not activated. The control apparatus of the dual fuel engine of 1 or 2. The predetermined condition is a first predetermined condition, the fuel selection means is a first fuel selection means, and the fuel used is based on the establishment and non-establishment of a second predetermined condition other than the first predetermined condition. When the second fuel selection means is selected, and the lean area expansion means or the lean degree changing means is selected by the second fuel selection means as the fuel to be used. 4. The control apparatus for a dual fuel engine according to claim 3, wherein only the control for expanding the operation range for leaning the air-fuel ratio or the control for increasing the lean degree is executed. A control device for a hybrid vehicle comprising a dual fuel engine having the control device according to claim 1, 2, 3 or 4,
A motor capable of outputting a driving torque of the vehicle and a battery capable of supplying electric power to the motor;
When the control by the lean area expanding means or the lean degree changing means is being executed, drive torque complementing means for complementing the shortage of the drive torque of the vehicle by supplying power from the battery to the motor is provided. A control device for a hybrid vehicle.

Images