Method for controlling a two-stroke internal-combustion engine

• US 5,404,857 A
• Filed: 10/29/1993
• Issued: 04/11/1995
• Est. Priority Date: 10/29/1992
• Status: Expired due to Fees

• Current Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG), Regents of the University of California (University of California)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Schommers, Joachim
• Primary Examiner(s): Okonsky, David A.
• Application Number:
  US08/143,193
• Time in Patent Office: 529 Days
• Field of Search: 123/198 DB, 123/674, 123/675, 123/435, 123/436, 123/481, 123/73 C
• US Class Current: 123/481
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 77/085 with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2400/04 Two-stroke combustion engines with electronic control
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809

Abstract

The invention relates to a method for controlling a two-stroke internal-combustion engine with fuel injection in the low load range, in which the fuel supply to the combustion space is interrupted for a number of working strokes stored in a characteristic diagram which is a function of operating parameters. In this case, the stored characteristic diagram is adaptively corrected continuously by means of parameters which characterize the readiness to ignite or the ignition behavior of the internal-combustion engine.

Claims

1. A method for controlling a two-stroke internal-combustion engine with fuel injection in the low load range, in which the supply of fuel to the combustion space is interrupted or released as a function of operating parameters, wherein

for each injection operation, the number of working strokes (f_required) for which the fuel injection is to be interrupted is read out from a characteristic diagram (F) which is a function of operating parameters,

the fuel supply is interrupted for said number of working strokes (f_required), after said number of working strokes without fuel injection have been carried out, the capability of the working gas to ignite is checked, and

the characteristic diagram (F) is adaptively corrected as a function of the capability of the working gas to ignite.

2. A method according to claim 1, wherein the capability of the working gas to ignite is satisfied if the oxygen concentration measured in the exhaust gas flow of the internal-combustion engine exceeds a specified threshold value.

3. A method according to claim 1, wherein the capability of the working gas to ignite is satisfied if the concentration of one or more combustion products contained in the exhaust gas flow falls below specified threshold values.

4. A method for controlling a two-stroke internal-combustion engine with fuel injection in the low load range, in which the supply of fuel to the combustion space is interrupted or released as a function of operating parameters wherein

for each injection operation, the number of working strokes (f_required) for which the fuel injection is to be interrupted is read out from the characteristic diagram (F) which is a function of operating parameters,

after said number of working strokes (f_required) have been carried out, fuel is injected and it is then checked whether a combustion has taken place, and

the characteristic diagram (F) is adaptively corrected as a function of the result of the checking of the combustion operation.

5. A method according to claim 4, wherein the checking of the combustion operation takes place by the analysis of a rotational uniformity and/or by the evaluation of a signal of a combustion space pressure transducer.

6. A method according to claim 4, wherein if it is recognized during the checking that no combustion has taken place, a reduced amount of fuel is injected during the next injection operation.