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EP-3557034-B1 - CONTROLLER AND CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE

EP3557034B1EP 3557034 B1EP3557034 B1EP 3557034B1EP-3557034-B1

Inventors

  • MIYATA, KOUMEI
  • TOYA, MASANORI
  • IDOGAWA, MASANAO
  • SASAKI, KOSUKE

Dates

Publication Date
20260506
Application Date
20190325

Claims (10)

  1. A controller (70) for an internal combustion engine (10), wherein the internal combustion engine (10) incorporating the controller (70) includes a port injection valve (16) that injects fuel into an intake passage (12), and the controller (70) is configured to perform: a base injection amount calculation process of calculating a base injection amount (Qb), the base injection amount (Qb) being an injection amount proportional to an amount of fresh air (η) introduced into a cylinder (20) of the internal combustion engine (10); a required correction amount outputting process (M38, M44, M46, M32, M34, M48, M50, M52) of outputting a required correction amount (KAF, Dp, Dd, LAF, ΔQ) for the base injection amount (Qb); a division process of dividing the base injection amount (Qb) into a synchronous injection amount (Qs) and an asynchronous injection amount (Qns), the synchronous injection amount (Qs) being an injection amount of an intake-synchronous injection in which the fuel is injected in synchronization with a period in which an intake valve (18) is open, and the asynchronous injection amount (Qns) being an injection amount of an intake-asynchronous injection in which the fuel is injected at a time advanced with respect to the intake-synchronous injection; a selective correction process (S20, S24) of correcting the asynchronous injection amount (Qns) according to the required correction amount (KAF, Dp, Dd, LAF, ΔQ) and not correcting the synchronous injection amount (Qs); and a manipulation process (S28, S16) of manipulating the port injection valve (16) according to the synchronous injection amount (Qs) and the corrected asynchronous injection amount (Qns), characterized in that the required correction amount (Dp, Dd) includes a required amount for setting a decrement of the base injection amount (Qb) to be greater when a disturbing fuel ratio is higher than when the disturbing fuel ratio is lower by a feedforward control based on the disturbing fuel ratio, and the disturbing fuel ratio is a ratio of an amount of fuel flowing into the combustion chamber (24) other than the fuel injected from the port injection valve (16) to an amount of fuel flowing into the combustion chamber (24) of the internal combustion engine (10) in one combustion cycle.
  2. The controller for an internal combustion engine according to claim 1, wherein the internal combustion engine (10) further includes: a canister (64) that collects fuel vapor from a fuel tank (60), which stores the fuel injected from the port injection valve (16); and an adjusting device (66) that adjusts an amount of fluid flowing from the canister (64) into the intake passage (12), the controller (70) is configured to perform a flow rate control process (M16, M18) of controlling a flow rate of the fuel vapor flowing from the canister (64) into the intake passage (12) by manipulating the adjusting device (66), the required correction amount (Dp) includes a required amount for setting the decrement of the base injection amount (Qb) to be greater when a vapor ratio as the disturbing fuel ratio is high than when the vapor ratio is low, and the vapor ratio is a ratio of the flow rate of the fuel vapor to the flow rate of the fluid in the intake passage (12).
  3. The controller for an internal combustion engine according to any one of claims 1 to 2, wherein the required correction amount (ΔQ) includes a required amount for setting an increment of the base injection amount (Qb) to be greater when a temperature (THW) of the internal combustion engine (10) is low than when the temperature (THW) is high.
  4. The controller for an internal combustion engine according to any one of claims 1 to 3, wherein the required correction amount (KAF, LAF) includes a required amount for correcting the base injection amount (Qb) according to a manipulation amount (δ) for feedback-controlling a detection value (Af) of an air-fuel ratio sensor (82) to a target value (Af*), and the air-fuel ratio sensor (82) is provided in an exhaust passage (32) of the internal combustion engine (10).
  5. The controller for an internal combustion engine according to any one of claims 1 to 4, wherein the required correction amount (ΔQ) includes a required amount for correcting the base injection amount (Qb) according to a variation of the amount of fresh air (η) in a transient period in which the amount of the introduced fresh air (η) varies.
  6. The controller for an internal combustion engine according to any one of claims 1 to 5, wherein the controller (70) is configured to perform a required injection amount calculation process (M30, M32, M50, M52) of calculating a required injection amount (Qb·KAF·Kw + ΔQ) for adjusting an air-fuel ratio to a target air-fuel ratio based on the amount of fresh air (η) introduced into the cylinder (20) of the internal combustion engine (10); a multiple injection process (S138, S116) of manipulating the port injection valve (16) to perform the intake-synchronous injection and the intake-asynchronous injection to inject the required injection amount (Qb·KAF·Kw + ΔQ) of fuel; a fuel reduction process (ΔQ < 0, S124) of reducing the required injection amount (Qb·KAF·Kw + ΔQ) even when the amount of the introduced fresh air (η) does not vary if a predetermined condition is satisfied; and a dual fuel amount correction process (S132) of increasing the asynchronous injection amount (Qns) to be equal to or greater than a minimum injection amount (Qmin) allowable for the port injection valve (16) and reducing the synchronous injection amount (Qs) if the asynchronous injection amount (Qns) is smaller than the minimum injection amount (Qmin) (NO in S126), the asynchronous injection amount (Qns) being determined by the required injection amount (Qb·KAF·Kw + ΔQ) reduced in the fuel reduction process (ΔQ < 0, S124).
  7. The controller for an internal combustion engine according to claim 6, wherein the dual fuel amount correction process (S128, S132) is to designate a difference (ΔINS) between the asynchronous injection amount (Qns) yet to be corrected and the minimum injection amount (Qmin) as an increasing correction amount for the asynchronous injection amount (Qns) and a reduction correction amount for the synchronous injection amount (Qs), the controller (70) is further configured to perform a selection process (S110, S130) of selecting either a single injection process (S114, S116) or the multiple injection process (S138, S116), the single injection process (S114, S130) involving injecting the required injection amount (Qb·KAF·Kw + ΔQ) of fuel by the intake-asynchronous injection by manipulating the port injection valve (16), and the selection process (S130) includes a process of selecting the single injection process (S114, S116) if the synchronous injection amount (Qs) reduced by the reduction correction amount (ΔINS) is smaller than the minimum injection amount (Qmin) (NO in S130).
  8. The controller for an internal combustion engine according to claim 6 or 7, wherein the predetermined condition includes a condition (i) that the amount of fresh air (η) decreases, and the fuel reduction process (ΔQ < 0, S124) includes a transient correction process of reducing the required injection amount (Qb·KAF·Kw + ΔQ) by reducing the asynchronous injection amount (Qns) if the amount of fresh air (η) decreases (section (b) of Fig. 15).
  9. The controller for an internal combustion engine according to any one of claims 6 to 8, wherein the controller (70) is further configured to perform a selection process (S130) of selecting either a single injection process (S114, S116) or the multiple injection process (S138, S116), the single injection process (S114, S116) involving injecting the required injection amount (Qb·KAF·Kw + ΔQ) of fuel by the intake-asynchronous injection by manipulating the port injection valve (16), the predetermined condition includes a condition (ii) that switching from a state where the single injection process (S114, S116) is selected to a state where the multiple injection process (S138, S116) is selected occurs, the fuel reduction process (ΔQ < 0, S124) includes a transient correction process of reducing the required injection amount (Qb·KAF·Kw + ΔQ) by reducing the asynchronous injection amount (Qns) if switching from the state where the single injection process (S114, S116) is selected in the selection process (S130) to the state where the multiple injection process (S138, S116) is selected occurs (section (b) of Fig. 16).
  10. The controller for an internal combustion engine according to any one of claims 6 to 9, wherein the division process (S118 to S124) involves dividing the required injection amount (Qb·KAF·Kw + ΔQ) into the asynchronous injection amount (Qns) and the synchronous injection amount (Qs), and the fuel reduction process (ΔQ < 0, S124) is a process of reducing only the asynchronous injection amount (Qns).

Description

BACKGROUND The present disclosure relates to a controller and a control method for an internal combustion engine. The internal combustion engine which incorporates the controller or to which the control method is applied includes a port injection valve through which fuel is injected into an intake passage. For example, the controller described in Japanese Patent Laid-Open No. 5-256172 divides the required injection amount, which is determined based on the amount of fresh air introduced into a cylinder of an internal combustion engine, between a leading injection, which is an injection during the intake stroke, and a trailing injection, which is an injection during the subsequent combustion stroke. More specifically, the controller calculates the required injection amount by correcting the injection amount depending on the amount of introduced fresh air according to coolant temperature. Furthermore, the controller divides the required injection amount by a division ratio and corrects one of the divisional injection amounts to determine the final injection amount for the leading injection. That is, the fuel injection controller according to the literature described above executes a multiple injection process that involves dividing the required amount of fuel, which is based on the amount of intake air, between an intake stroke injection and an exhaust stroke injection and manipulating a port injection valve to inject the fuel in a divisional manner. The intake stroke injection is an injection of fuel in the intake stroke, and the exhaust stroke injection is an injection of fuel in the exhaust stroke. JP 2007 107405 A relates to a 'Fuel injection control device for internal combustion engine'. SUMMARY The invention is defined in the appended claims. Examples of the present disclosure will now be described. Example 1. A controller for an internal combustion engine is provided, according to appended claim 1. The internal combustion engine incorporating the controller includes a port injection valve that injects fuel into an intake passage. The controller is configured to perform: a base injection amount calculation process of calculating a base injection amount, the base injection amount being an injection amount proportional to an amount of fresh air introduced into a cylinder of the internal combustion engine; a division process of dividing the base injection amount into a synchronous injection amount and an asynchronous injection amount, the synchronous injection amount being an injection amount of an intake-synchronous injection in which the fuel is injected in synchronization with a period in which an intake valve is open, and the asynchronous injection amount being an injection amount of an intake-asynchronous injection in which the fuel is injected at a time advanced with respect to the intake-synchronous injection; a required correction amount outputting process of outputting a required correction amount for the base injection amount; a selective correction process of correcting the asynchronous injection amount according to the required correction amount and not correcting the synchronous injection amount; and a manipulation process of manipulating the port injection valve according to the synchronous injection amount and the corrected asynchronous injection amount. With the configuration described above, while the asynchronous injection amount is corrected according to the required correction amount, the synchronous injection amount is not corrected. Therefore, compared with a case where both the asynchronous injection amount and the synchronous injection amount are corrected according to the required correction amount, the synchronous injection amount can be more easily maintained at an adequate value for reducing PN, which is the count of particulate matter (PM). The inventors have studied the possibility of injecting part of the required injection amount by intake-synchronous injection instead of injecting the whole of the required injection amount of fuel by intake-asynchronous injection, in order to reduce PN, which is the count of particulate matter (PM) in the exhaust gas. In the intake-asynchronous injection, fuel is injected in advance of the intake stroke. In the intake-synchronous injection, fuel is injected in synchronization with the time when the intake valve is opened. The inventors have found that it can be difficult to sufficiently reduce PN if the injection amount of the intake-synchronous injection varies as a result of the injection amount responsive to the amount of the introduced fresh air being corrected in terms of various factors. The configuration described above addresses this possibility. Furthermore, the required correction amount includes a required amount for setting a decrement of the base injection amount to be greater when a disturbing fuel ratio is higher than when the disturbing fuel ratio is lower by a feedforward control based on the disturbing fuel ratio. The dist