초록 ▼

A speed-governed lean burn engine and its fuel and air delivery apparatus are provided with a control system that monitors engine conditions, including actual speed relative to a desired speed setting, to determine which of two air to fuel ratios the engine operates with under the existing condition

A speed-governed lean burn engine and its fuel and air delivery apparatus are provided with a control system that monitors engine conditions, including actual speed relative to a desired speed setting, to determine which of two air to fuel ratios the engine operates with under the existing conditions: either a stoichiometric ratio or a lean-burn ratio. A stoichiometric ratio is to provide short periods of smooth and rapid response to an increased load during which NOx emissions are reduced by a three-way catalyst in the exhaust from the engine. The lean-burn ratio during other periods of operation is sufficiently lean to exhibit low NOx emissions and allows operation with low fuel consumption. The invention can be applied to improve performance of gas fueled truck engines, for example.

대표청구항 ▼

[ What is claimed is:] [1.] A speed-governed engine and a low NOx fuel system therefor comprising:an engine having a plurality of cylinders providing a like plurality of combustion chambers;fuel and air delivery apparatus communicating with the respective combustion chambers;exhaust apparatus includ

[ What is claimed is:] [1.] A speed-governed engine and a low NOx fuel system therefor comprising:an engine having a plurality of cylinders providing a like plurality of combustion chambers;fuel and air delivery apparatus communicating with the respective combustion chambers;exhaust apparatus including a catalyst for minimizing NOx emissions from the engine;an adjustable speed setting device that can be set to a desired engine speed; anda control unit for maintaining the engine at the desired engine speed regardless of load variations, said control unit being arranged to receive a plurality of signals including signals representing the desired engine speed and actual engine speed, and to apply one or more control signals to the fuel and air delivery apparatus to adjust the ratio of air to fuel and the quantity of fuel delivered by the fuel and air delivery apparatus, said control unit being operative to regulate the ratio of air to fuel either substantially at a stoichiometric ratio in which said catalyst is effective to minimize NOx emissions or at a lean burn ratio at which NOx emissions are also minimal.