Intake system for an internal combustion engine

An internal combustion engine comprising combustion chamber means, an intake system having intake valve means and intake passage means leading through said intake valve means to said combustion chamber means for providing a supply of intake gas to said combustion chamber means, valve timing control means for governing opening and closing timings of said intake valve means so that said intake valve means is closed at a controlled timing in the compression stroke whereby a controlled amount of the intake gas is returned from said combustion chamber means to said intake passage means in the compression stroke to thereby control effective charge to the combustion chamber means, detecting means for detecting at least one factor which is related to engine speed and producing an engine speed signal, manually operated reference setting means for determining a reference speed value, engine overrun preventing means for comparing said engine speed signal with said reference value and retarding the closing timing of the intake valve means to thereby decrease the effective charge when said engine speed signal is greater than said reference value.

An internal combustion engine comprising:

• combustion chamber means in which intake and compression strokes are carried out, an intake system having intake passage means for providing a supply of intake gas to said combustion chamber means, charge control means for returning a controlled amount of the intake gas in the combustion chamber means to said intake passage means in the compression stroke to thereby control effective charge to the combustion chamber means, detecting means for detecting at least one factor which is related to engine speed and producing an engine speed signal, manually operated reference setting means for determining a reference speed value, and engine output restricting means for comparing the engine speed signal with said reference value for providing a signal for restricting engine output when said engine speed signal is greater than said reference value;
• and
• exhaust gas recirculating means for recirculating exhaust gas to said intake system, said engine output restricting means including means for increasing the amount of exhaust gas recirculated to the intake system to thereby decrease the effective charge to the combustion chamber means.

An internal combustion engine comprising:

• combustion chamber means in which intake and compression strokes are carried out, an intake system having intake passage means for providing a supply of intake gas to said combustion chamber means, charge control means for returning a controlled amount of the intake gas in the combustion chamber means to said intake passage means in the compression stroke to thereby control effective charge to the combustion chamber means, detecting means for detecting at least one factor which is related to engine speed and producing an engine speed signal, manually operated reference setting means for determining a reference speed value, and engine output restricting means for comparing the engine speed signal with said reference value for providing a signal for rericting engine output when said engine speed signal is greater than said reference value, said engine output restricting means including means for retarding ignition timing to thereby decrease engine output.