Method for controlling the metering of fuel in an injection system and control arrangement therefor

A method for controlling the metering of fuel of an injection system of an internal combustion engine having an intake manifold including an engine having an exhaust-gas turbocharger, the method comprising the steps of:

• determining the inducted air mass (L) in said intake manifold of said engine as a primary control quantity utilizing an air mass measuring apparatus;
• computing a cylinder charge with a control apparatus;
• providing a substitute signal (P) as said primary control quantity;
• detecting a leak occurring in said intake manifold from a changed pressure ratio;
• switching over to said substitute signal (P) when said leak is detected;
• and,
• switching over to said substitute signal (F) after the elapse of a preset delay time after the detection of said leak.

A control arrangement for computing a cylinder charge of an internal combustion engine having an intake manifold including an engine having a turbocharger, the control arrangement comprising:

• an air mass measuring apparatus for determining the inducted air mass flow in the intake manifold as a primary control quantity;
• a control apparatus for computing said cylinder charge utilizing said inducted air mass flow;
• said control apparatus including a characteristic field stored therein with a real pressure ratio in said intake manifold as a function of engine rpm (n) and a throttle flap angle (a) with said characteristic field being stored during non-fault operation;
• means for computing a substitute signal (P) as said primary control quantity from said characteristic field when a leak occurs in said intake manifold;
• and,
• means for switching over to said substitute signal (2) as a primary control quantity when said leak is detected thereby ensuring a continued operation of said engine.

A control arrangement for computing a cylinder charge of an internal combustion engine having an intake manifold including an engine having a turbocharger, the control arrangement comprising:

• an air mass measuring apparatus for determining the inducted air mass flow in the intake manifold as a primary control quantity;
• a control apparatus for computing said cylinder charge utilizing said inducted air mass flow;
• said control apparatus including a characteristic field stored therein with a real pressure ratio in said intake manifold as a function of engine rpm (n) and a throttle flap angle (a);
• means for computing a substitute signal (P) as said primary control quantity when a leak occurs in said intake manifold;
• means for switching over to said substitute signal (P) when said leak is detected;
• and,
• the pressure ratio of an intake manifold pressure to a charging pressure of said exhaust-gas turbocharger being stored in said characteristic field.

A control arrangement for computing a cylinder charge of an internal combustion engine having an intake manifold including an engine having a turbocharger, the control arrangement comprising:

• an air mass measuring apparatus for determining the inducted air mass flow in the intake manifold as a primary control quantity;
• a control apparatus for computing said cylinder charge utilizing said inducted air mass flow;
• said control apparatus including a characteristic field stored therein with a real pressure ratio in said intake manifold as a function of engine rpm (n) and a throttle flap angle (a);
• means for computing a substitute signal (P) as said primary control quantity when a leak occurs in said intake manifold;
• means for switching over to said substitute signal CP) when said leak is detected;
• and,
• said switching means being a delay switch for a time-delayed switchover to said substitute signal (P).