US 5,685,285 A · Internal combustion engine controller

Abstract

The invention provides an internal combustion engine controller for an internal combustion engine having a fuel tank which can be purged of fuel vapor via a purge line connected through a canister unit, to a suction input of the internal combustion engine. The amount of fuel vapor stored in the canister or the amount of fuel vapor supplied to the internal combustion engine according to the operating state and operation range of the engine are calculated, and the purge control valve and air-fuel ratio control characteristics are adjusted using the calculated value. At the same time, appropriate control of the amount of fuel vapor and purge control valve when diagnosing the purge pipe system failure by application of pressure to the purge pipe system, are provided. Both internal combustion engine control with the minimum change in air-fuel ratio and purge control are ensured, and highly reliable diagnosis of the purge pipe system is realized.

Claims29

Dependent claims

An internal combustion engine controller comprising:

(a) a fuel tank;
(b) a canister to store fuel vapor;
(c) a purge pipe system leading from the fuel tank to an air suction system of the internal combustion engine via the canister;
(d) a purge control unit acting on the purge control valve in the purge pipe system and controlling a volume of fuel vapor to be supplied to the internal combustion engine;
(e) an internal combustion engine operating state detecting unit to determine an operating state of the internal combustion engine;
(f) an internal combustion engine control unit to control the internal combustion engine according to its operating state;
(g) an air-fuel ratio sensor to detect the air-fuel ratio of mixed fuel gas supplied to the internal combustion engine;
and
(h) an air-fuel ratio control unit to control the air-fuel ratio to a target ratio based on the result of detecting the air-fuel ratio;
wherein said internal combustion engine controller further comprises a first calculation unit which uses a deviation of a detected air-fuel ratio from a control value of said air-fuel ratio control unit to perform a first calculation of at least one of the amount of fuel vapor stored in said canister and the amount of the fuel supplied to said internal combustion engine, when the purge control valve is open and said internal combustion engine is at a specified operating state.

7 more elements

An internal combustion engine controller comprising:

(a) a fuel tank;
(b) a canister to store fuel vapor;
(c) a purge pipe system leading from the fuel tank to an air suction system of the internal combustion engine via the canister;
(d) a purge control unit that generates a purge control value which acts on a purge control valve installed in the purge pipe system and controls a volume of fuel vapor to be supplied to said internal combustion engine;
(e) an internal combustion engine operating state detecting unit to determine an operating state of the internal combustion engine;
(f) an internal combustion engine control unit to control the internal combustion engine according to its operating state;
(g) an air-fuel ratio sensor to detect a air-fuel ratio of mixed fuel gas supplied to the internal combustion engine;
and
(h) an air-fuel ratio control unit to control said air-fuel ratio to a target ratio based on a result of detecting the air-fuel ratio;
wherein
said internal combustion engine control unit further comprises a rich/lean evaluation unit to distinguish between a "richer" side and a "leaner" side relative to a specified air-fuel ratio;
said purge control value is controlled so as to increase it by a specified range when the amount of fuel vapor supplied to said internal combustion engine is increased and when an evaluation of said rich/lean evaluation unit has shifted from "richer" to "leaner";
and
said purge control value is otherwise maintained by controlling said purge control valve in a direction of opening it through said purge control unit.

11 more elements

Dependencies are inferred from the claim text.

Internal combustion engine controller

Life of this patent

Internal combustion engine controller

Life of this patent

Abstract

Claims29