Methods for reducing harmful emissions from a diesel engine

A method for improving the operation of a diesel engine by lowering the emissions of unburned hydrocarbons and carbon monoxide, comprising:

• providing a diesel fuel and combustion air;
• providing a platinum group metal catalyst composition selected from the group consisting of alcoholates, sulfonates, beta-diketonates, soaps, and mixtures of these;
• combusting the fuel in a diesel engine to produce exhaust gases;
• and, directing exhaust gases into an exhaust system,
• wherein the platinum group metal catalyst composition is introduced into the fuel, exhaust gases or.combustion air, in amounts effective to provide platinum group metal in the exhaust system at a level of up to 1 ppm based on the volume of fuel burned to produce the exhaust gases.

A method for operating a diesel engine with reduced emissions of NO.sub.x, particulates, gaseous hydrocarbons and carbon monoxide, comprising:

• providing a diesel engine and a source of diesel fuel;
• providing a combustion air mixture including incoming air and exhaust gases from a previous combustion cycle of the engine;
• providing a platinum group metal catalyst composition and an auxiliary catalytic metal composition comprising cerium;
• introducing the combustion air mixture into the cylinder of a diesel engine;
• compressing the combustion air within the cylinder;
• injecting the diesel fuel into the cylinder of a diesel engine;
• combusting the fuel to produce exhaust gases;
• directing the exhaust gases into an exhaust system including a diesel trap to remove particulates from the exhaust gases;
• and,
• mixing a portion of the exhaust gases with incoming combustion air to provide a combustion air mixture for a subsequent combustion cycle;
• wherein the amount of exhaust gases present in the combustion air mixture in the cylinder of the diesel engine is effective to lower the production of NO.sub.x by the engine utilizing said combustion air mixture as compared to combustion air not containing exhaust gases;
• and
• wherein a platinum group metal catalyst composition and the auxiliary catalytic metal composition are present in the fuel, combustion air mixture, or exhaust gases in amounts effective to provide sufficient platinum group metal and auxiliary catalyst metal in the exhaust system to lower the emissions of unburned hydrocarbons and carbon monoxide and to lower the balance point of the trap.

A method for improving the operation of a diesel engine including a diesel trap by lowering the emissions of NO.sub.x, unburned hydrocarbons and carbon monoxide, while also reducing the balance point of the trap, the method comprising:

• providing a diesel engine and a source of diesel fuel;
• providing a platinum group metal catalyst composition and an auxiliary catalytic metal composition containing at least one of copper and cerium;
• introducing combustion air into the cylinder of a diesel engine;
• compressing the combustion air within the cylinder;
• injecting the diesel fuel into the cylinder of a diesel engine, the injection timing of the diesel engine being set in a manner designed to reduce the nitrogen oxides emissions from the engine after combustion of a diesel fuel;
• combusting the fuel to produce exhaust gases containing particulates and platinum group metal catalyst and the auxiliary catalytic metal;
• and, directing exhaust gases into an exhaust system including a diesel trap which removes at least a portion of the particulates from the exhaust gases,
• wherein the platinum group metal catalyst composition and the auxiliary catalytic metal composition are introduced into the fuel, exhaust gases or combustion air, in amounts effective to provide sufficient platinum group metal and auxiliary catalyst metal in the exhaust system to lower the balance point temperature of particulates in the trap and to reduce emissions of unburned hydrocarbons and carbon monoxide.

A method for improving the operation of a diesel engine exhaust system comprising:

• adding a platinum group metal composition and at one least auxiliary catalytic metal composition selected from the group consisting of compounds of sodium, lithium, potassium, cerium, iron, copper, calcium, magnesium, manganese, and mixtures of these, to a diesel fuel in effective amount such that exhaust produced by combustion catalyzes the exhaust system including a diesel trap effectively to lower the emissions of unburned hydrocarbons and carbon monoxide;
• operating a diesel engine by burning the fuel;
• and
• passing the exhaust from the operation of the engine through the exhaust system including the diesel trap to reduce the emissions of particulates, hydrocarbons and carbon monoxide and reduce the balance point for the trap.

A method for improving the operation of a diesel engine including a diesel trap by lowering the emissions of NO.sub.x, unburned hydrocarbons and carbon monoxide, while also reducing the balance point of the trap, the method comprising:

• providing a diesel engine and a source of diesel fuel;
• providing a platinum group metal catalyst composition and an auxiliary catalytic metal composition containing cerium;
• introducing combustion air into the cylinder of a diesel engine;
• compressing the combustion air within the cylinder;
• injecting the diesel fuel into the cylinder of a diesel engine, thereby combusting the fuel to produce exhaust gases containing particulates and platinum group metal catalyst and cerium catalyst;
• and, directing exhaust gases into an exhaust system including a diesel trap which removes at least a portion of the particulates from the exhaust gases,
• wherein the platinum group metal catalyst composition and the auxiliary catalytic metal composition are introduced into the fuel, exhaust gases or combustion air, in amounts effective to provide sufficient platinum group metal and cerium catalyst in the exhaust system to lower the balance point temperature of particulates in the trap and to reduce emissions of particulates, unburned hydrocarbons and carbon monoxide.

A method for improving the operation of a diesel engine including a diesel trap by lowering the emissions of NO.sub.x, unburned hydrocarbons and carbon monoxide, while also reducing the balance point of the trap, the method comprising:

• providing a diesel engine and a source of diesel fuel;
• providing a platinum group metal catalyst composition and an auxiliary catalytic metal composition selected from the group consisting of compounds of sodium, lithium, potassium, cerium, iron, copper, calcium, magnesium, manganese, and mixtures;
• introducing combustion air into the cylinder of a diesel engine;
• compressing the combustion air within the cylinder;
• injecting the diesel fuel into the cylinder of a diesel engine, thereby combusting the fuel to produce exhaust gases containing particulates and platinum group metal catalyst and auxiliary catalytic metal;
• and, directing exhaust gases into an exhaust system including a diesel trap which removes at least a portion of the particulates from the exhaust gases,
• wherein the platinum group metal catalyst composition and the auxiliary catalytic metal composition are introduced.into the fuel, exhaust gases or combustion air, in amounts effective to provide sufficient platinum group metal and auxiliary catalytic metal in the exhaust system to lower the balance point temperature of particulates in the trap and to reduce emissions of particulates, unburned hydrocarbons and carbon monoxide.