38 results about "Diesel injection" patented technology

The invention discloses a natural gas-diesel oil injection switching control system of a dual-fuel diesel engine, which relates to the technical field of automatic control and comprises a data acquisition monitoring module, a fuel analysis module, a prediction control module, a control optimization module and a switching protection module. Engine operation parameter data are collected in real time through an engine sensor interface and preprocessed, and fuel dynamic proportion analysis is carried out according to different rotating speeds and load intervals of an engine by taking a preset proportion as an initial reference datum and applying an intelligent algorithm; the engine can obtain the most appropriate natural gas and diesel oil mixing proportion under various working conditions, according to an ideal gas state equation, based on pressure and temperature data, monitored in real time, in a gas supply pipeline, dynamic compensation is conducted on the gas volume flow, real-time gas supply energy is calculated, the gas supply amount can be accurately controlled in the mode, and the gas supply efficiency is improved. It is guaranteed that the engine obtains stable and accurate energy supply, and therefore stable operation of the engine is maintained.

The invention provides a control method of a dual-fuel methanol-diesel dual direct injection engine and a vehicle, and the method comprises the following steps: determining the temperature working condition of the vehicle according to the environment temperature of the vehicle; under the extremely cold working condition, a diesel oil nozzle is controlled to inject diesel oil according to the first-time pre-injection, the second-time pre-injection, the third-time pre-injection and the main injection of each cycle, in the successive injection process, the corresponding angle of a crank angle in front of a compression top dead center is gradually reduced, and the injection amount is gradually increased; under the cold working condition, a diesel oil nozzle is controlled to inject diesel oil according to injection parameters corresponding to second-time pre-injection, third-time pre-injection and main injection; under the normal-temperature working condition, a diesel oil nozzle is controlled to inject diesel oil according to injection parameters corresponding to third-time pre-injection and main injection; and under the high-temperature working condition, a dual-fuel mode is directly entered, the diesel nozzle is controlled to inject diesel, and the methanol nozzle is controlled to inject methanol. Through the control method provided by the invention, the problem of poor cold starting performance caused by adopting a single diesel injection rate in the cold starting stage is solved.

The utility model discloses a multi-cylinder diesel oil injection pump oil mass control sleeve assembly assistive device which comprises a base, at least two oil mass control sleeve installation openings are formed in the front face of the base at intervals along a straight line, and an open structure communicated with the oil mass control sleeve installation openings is formed in the back face of the base. The pressing assembly comprises a pressing plate detachably installed on the back face of the base through a fastener and a rubber pressure transmitting plate clamped between the pressing plate and the base. The step positioning module is composed of a plurality of positioning bodies which are sequentially embedded in the oil mass control sleeve installation openings, and the axial heights of the positioning bodies are arranged in an equal difference progressive increase mode from one end to the other end; the toothed bar positioning mechanism comprises a toothed bar positioning plate which is vertically and fixedly arranged on the side edge of the mounting opening where the highest positioning body is located, and a toothed bar positioning pin which is detachably inserted into the positioning groove and is connected with the toothed bar in a matched mode is arranged at the top of the toothed bar positioning plate. The assembly assistive device has remarkable advantages in the aspects of press fitting, positioning, benchmark providing and the like, the assembly efficiency, precision and yield are improved, the service life is prolonged, and the practicability is high.

The invention aims to provide a single needle valve type high-response methanol-diesel injector based on opposed electromagnetic valve control, and belongs to the field of engines. Opposite type double-medium channel control assemblies are installed in an ejector connector body, an ejector middle body and an ejector throttling block, a methanol / diesel shared nozzle assembly is installed in a nozzle body, a diesel connector and a methanol connector are installed on the side of the ejector connector body, a high-pressure diesel channel is arranged in the diesel connector, and a high-pressure methanol channel is arranged in the methanol connector. Free connection and disconnection of an internal high-pressure methanol path and an internal high-pressure diesel path can be controlled, then independent injection of methanol fuel and diesel fuel is achieved, the two fuel injection modes are controlled through the same needle valve, the fuel is injected through the same injection hole, and the advantages of being high in reliability and simple in structure are achieved. And after methanol / diesel oil injection is finished, rapid cut-off of an internal passage of the injector and rapid seating of the needle valve can be achieved, and the response characteristic of fuel injection mode switching of the injector is improved.

The purpose of this invention is to provide a dual-fuel injector with variable injection patterns, belonging to the category of fuel injection devices. It includes a diesel injection section and a low-carbon fuel injection section, both located within the injector body. The diesel injection section, from top to bottom, includes a diesel accumulator chamber, a No. 1 injection control pipeline co-control module, a super hysteresis electromagnetic control needle valve limit module, and a diesel nozzle. The low-carbon fuel injection section, from top to bottom, includes a two-stage booster module, a low-carbon fuel thermal management accumulator module, a No. 2 injection control pipeline co-control module, and a low-carbon fuel nozzle. This invention enables independent injection of diesel and low-carbon fuels and effectively controls the phase state of the low-carbon fuel injected into the cylinder. By controlling the injection pressure and needle valve lift, it achieves flexible and variable injection patterns to meet the needs of different engine operating conditions. It also enables high-response needle valve closure and prevents secondary opening of the needle valve due to pressure fluctuations.

The invention belongs to the technical field of engines, and discloses a methanol-diesel dual-fuel engine control method and device based on methanol substitution rate adaptive optimization, and the method comprises the following steps: step 1, calibrating an initial rotating speed-shaft power-methanol substitution rate MAP according to engine bench test data; 2, when the engine runs, the following signals including the rotating speed, the shaft power, the methanol injection amount, the diesel injection amount and the combustion state are collected and processed in real time; 3, calculating the current actual methanol substitution rate in real time according to the collected methanol injection amount and diesel injection amount; 4, according to the rotating speed and the shaft power which are currently collected in real time, the initial or latest self-learned rotating speed-shaft power-methanol substitution rate MAP graph is inquired, and the target methanol substitution rate under the working condition is obtained; pID control is adopted, SRtarget serves as a set value, SRactual serves as a process value, control output is obtained through calculation, and the diesel oil injection amount and the methanol injection amount are adjusted.

The invention discloses a dual-fuel single-cylinder engine combustion system based on water spraying-EGR cooperative control and a control method of the dual-fuel single-cylinder engine combustion system, and belongs to the technical field of engines. A dual-fuel single-cylinder engine combustion system based on water spray-EGR cooperative control comprises a hydrogen direct injection system, a diesel injection system, an air inlet channel water spray system, a turbocharging system, an EGR system and an electric control system, and a high-pressure water pump of the water spray system is connected with an air compressor of the turbocharging system through a coupler; the system further comprises an exhaust water circulation system, the exhaust water circulation system comprises a water-steam separator, the water-steam separator is connected to an engine exhaust pipeline, and the water separation end of the water-steam separator is connected with the water tank through a pipeline. One end of the EGR system is connected to an engine exhaust pipeline behind the water-steam separator, and the other end of the EGR system is connected to an engine air inlet pipeline in front of the air compressor. And the ECU performs water spraying-EGR cooperative control according to the working condition of the engine.

The invention aims to provide a wide-range methanol / diesel oil dual-fuel injector with high injection stability, and belongs to the field of engines. A methanol injection control multi-way electromagnetic valve assembly is installed in the diesel oil connector body, a diesel oil injection control electromagnetic valve assembly is installed in the injector intermediate body, an oil way stop valve assembly is installed in the cone valve body, multi-position nested needle valve assemblies are installed in the inner needle valve intermediate body and the nozzle body, and a high-pressure methanol connector is installed on the side of the methanol connector body. A high-pressure diesel connector is installed on the side of the diesel connector body. According to the methanol / diesel oil dual-fuel independent injection system, methanol / diesel oil dual-fuel independent injection can be achieved, the methanol injection working condition range can be remarkably widened, the injector needle valve response characteristic is improved, the oil return amount is reduced, and then the methanol injection stability is improved; and various injection modes such as methanol micro-injection, diesel injection and methanol large-flow shoe-shaped injection can be realized.

The application provides a dual-fuel engine starting method, device, storage medium and system, the engine comprising: a methanol injector and a diesel injector, the methanol injector being installed to an air inlet pipe of the engine, and the diesel injector being installed to a cylinder cover of a cylinder of the engine, the method comprising: receiving and responding to an engine starting instruction, acquiring a plurality of temperature parameters, and determining a minimum temperature parameter in all the temperature parameters; when the minimum temperature parameter is less than a preset temperature, controlling the diesel injector to inject a preset first injection amount of diesel into the engine cylinder; determining a speed change rate of a process in which an engine speed changes from static to a first preset speed, and determining a second injection amount of diesel and a third injection amount of methanol according to the speed change rate and simultaneously controlling the diesel injector and the methanol injector to inject, so as to start the engine. The application solves the problem that methanol fuel has low vapor pressure and large latent heat, and thus it is difficult to start the engine at low temperature.

The invention discloses a diesel gasification device and a cyclic quantitative control method. The controller firstly preheats the heating piece and then controls the air inlet valve to be opened, so that air enters the mixing cavity through the air inlet pipe and the heating net, and the pressure in the cavity is adjusted to a preset pressure threshold upper limit Ptar1; the controller calculates the target fuel injection quantity of the liquid fuel injector according to the air state in the mixing cavity and the target equivalence ratio and controls the liquid fuel injector to complete fuel injection; the controller controls an oil and gas injection valve to be opened, an oil and gas mixture is injected till the lower limit Ptar2 of a preset pressure threshold value is reached, and after injection is finished, the controller calculates the residual air amount and the residual fuel oil amount in a mixing cavity based on the pressure, temperature and oxygen concentration detection signals after injection; and the controller opens the air inlet valve to supplement air to the mixing cavity until the pressure in the cavity reaches the pressure threshold upper limit Ptar1, then the air inlet valve is closed, the air supplement amount is determined according to the pressure difference before and after air supplement, and the needed oil supplement amount is calculated in combination with the target equivalence ratio. According to the invention, spray crushing and atomization are realized no longer depending on ultrahigh injection pressure.

A burner comprises a housing and a combustion chamber assembly. The combustion chamber assembly comprises a barrel portion, a mounting base, a first spark plug, a second spark plug, and a diesel nozzle assembly. The barrel portion comprises a combustion chamber. The mounting base comprises an air inlet passage and a mounting barrel portion. The first spark plug and the second spark plug both protrude into the combustion chamber. The diesel nozzle assembly is mounted on the mounting barrel portion, and the diesel nozzle assembly is configured to inject diesel into the combustion chamber. The diesel nozzle assembly comprises a valve needle, a first swirling assembly located at the bottom of the valve needle, and a sleeve portion located below the first swirling assembly, wherein the first swirling assembly comprises an inlet hole and a throttling injection hole, the sleeve portion is provided with a mixing chamber communicated with the throttling injection hole, and the mixing chamber is used for mixing diesel and air. The throttling injection hole improves continuity of diesel injection under low power.

The invention discloses an integrated combustion chamber of a diesel generating set, and relates to the technical field of diesel engines. When oil mist and air are not uniformly mixed, the phenomenon that the oil mist cannot be fully combusted during combustion occurs, and a large amount of carbon deposit occurs in the combustion chamber, according to the combustion chamber of the integrated diesel generating set, through cooperation of the protruding cambered surface at the center of the top of the piston and the cambered surface at the edge of the piston, when diesel oil is injected after the air is guided in, the combustion efficiency is improved, and the combustion efficiency is improved. The spraying direction of diesel oil corresponds to the center position of the top of the piston, the diesel oil is matched with upward movement of the piston when the diesel oil gas impacts downwards, the gas is guided through the protruding cambered surface, the diesel oil gas is diffused all around and fully mixed with air, and the situation that combustion is insufficient and carbon deposition is serious at the combustion position due to uneven mixing of the diesel oil is avoided.

The present application relates to dual-fuel engine technical field, especially to a kind of methanol-diesel dual-fuel engine's fuel control method, comprising: obtaining the real-time data of engine speed value, load value and temperature value;Real-time data is input into the engine operating condition model established in advance, and the fuel demand characteristic parameter of current operating condition is output;Fuel demand characteristic parameter is input into the injection ratio model established in advance, and the injection ratio value of diesel and methanol is output;Based on injection ratio value, generate the fuel injection scheme of diesel and methanol;According to fuel injection scheme, time sequence control algorithm is used to generate diesel injection command and methanol injection command with time phase difference, and the mixing effect of diesel and methanol is monitored in real time;Not only can the injection ratio of diesel and methanol be accurately adjusted, but also the sufficient mixing of two kinds of fuels can be ensured through real-time monitoring, the fuel utilization efficiency is improved, the emission is reduced, and the stable operation and performance output of engine are ensured.

The invention belongs to the field of dual-fuel engine starting, and particularly discloses a control method and system for the process from starting to idling of a dual-fuel engine, and the method comprises the steps that the diesel oil injection quantity, the injection advance angle, the diesel oil rail pressure and the throttle valve required opening degree in the engine starting process are obtained; starting an engine according to the fuel injection quantity and the injection advance angle; judging whether the rotating speed of the engine exceeds an idling takeover value; if the engine is not started again, the diesel injection advance angle is delayed in the starting process, the fuel injection quantity is increased, and the idling set value is triggered to be gradually transited to the final idling target value from the idling takeover value until the rotating speed of the engine exceeds the idling takeover value; if yes, directly triggering the idling set value to gradually transit to the final idling target value from the idling takeover value; and after the idle speed is stable, the injection quantity and the injection advance angle of the diesel oil are gradually transited to the injection quantity and the injection advance angle of micro-injection ignition.

The invention aims to provide a high-flow dual-fuel injection system cooperatively controlled by multiple electromagnetic valves, and belongs to the field of injection systems. Comprising a diesel oil supply module which comprises a fuel filter, an electronic unit pump and a pressure stabilizing assembly; the methanol fuel supply module comprises a conveying pump set and a common rail pipe; a diesel oil and methanol integrated injector structurally comprises a diesel oil injection unit and a methanol injection unit with different control strategies. The diesel oil conveying system and the methanol supply system which are independent of each other are adopted, the dual-fuel mixed injection function is achieved, meanwhile, diesel oil is used as a control medium for methanol injection, and the corrosion risk of methanol to an injector material is reduced. According to the invention, oil supply of the electronic control unit pump is matched with the electronic control injector, and large-flow injection of two fuels of diesel oil and methanol is realized through cooperative control of multiple electromagnetic valves. Through the design of the diaphragm type voltage stabilizer, the influence of oil supply pressure fluctuation of the electronic unit pump on the working performance of the ejector is improved.

The invention provides an application method for improving methanol combustion efficiency in a medium-speed diesel and methanol dual-fuel engine, and relates to the field of engine combustion technologies and alternative fuels. 2, an air inlet system is transformed; step 3, performing a dual-mode control strategy; 4, load self-adaptive adjustment is carried out; 5, the combustion efficiency is improved, and the problems that the calorific value of methanol is less than half of that of diesel oil, the volume calorific value is low, and if an existing diesel oil injection system is directly used, the engine power is greatly reduced are solved; the diesel oil injection performance is deteriorated by simply increasing the injection quantity; in addition, when the air inlet channel is used for spraying the methanol, the problem of methanol knocking easily occurs, and the substitution rate of the methanol is limited is solved.

This utility model discloses a dual-fuel engine injector that can solve the problem of nozzle blockage, belonging to the field of injector technology. It includes an injector body and a needle valve body. A first needle valve passes through the needle valve body, and a second needle valve passes through the first needle valve. Multiple diesel injection holes are arranged at the bottom of the first needle valve. The inner wall of the diesel injection holes contains multiple spiral grooves, including several main spiral grooves and several secondary spiral grooves. The secondary spiral grooves are spirally arranged at the inlet and outlet ends of the diesel injection holes, and the main spiral grooves are spirally arranged continuously between the inlet and outlet secondary spiral grooves. Before the diesel fuel enters the main spiral groove and undergoes large-scale rotation, it is slowly accelerated at the inlet end of the secondary spiral groove. After flowing out of the main spiral groove, the rotational scale is reduced at the outlet end of the secondary spiral groove, ensuring the flow cross-sectional area. This allows the diesel fuel in the injection holes to generate rotational motion and increase speed, achieving a flushing effect on the inner wall, while also stabilizing the injection flow at the outlet end, ensuring stable combustion in the engine cavity.

The application provides a method and device for determining oil dilution, a storage medium and an electronic device. The method comprises the following steps: determining that a diesel particulate filter enters an active regeneration process, the active regeneration process being a process of removing particles deposited in a filter of the diesel particulate filter by injecting diesel into a cylinder through post-injection; obtaining a first diesel injection amount and a second diesel injection amount, the first diesel injection amount being a total amount of diesel injected into the cylinder through post-injection, and the second diesel injection amount being an amount of diesel entering a diesel oxidation catalyst for reaction; determining a third diesel injection amount according to a difference between the first diesel injection amount and the second diesel injection amount, the third diesel injection amount being an amount of diesel injected onto an inner wall of the cylinder through post-injection. The method can accurately identify the oil dilution condition based on the calculation of the amount of diesel injected onto the inner wall of the cylinder through post-injection in the DPF active regeneration process chemical reaction.

This invention provides a system and control method for an ammonia-diesel dual-fuel engine. The system includes a valve assembly unit, an engine, an electronic controller, and a waste liquid collection tank. The electronic controller is electrically connected to the electronic control components in the valve assembly unit and the engine, controlling the operation of each component in the valve assembly unit and the engine. The valve assembly unit and the engine are connected to the waste liquid collection tank, and ammonia gas is discharged to the waste liquid collection tank under the control of the electronic controller. The control method includes: stopping the supply of ammonia gas to the engine cylinders when the engine switches from dual-fuel mode to diesel mode; simultaneously increasing the diesel injection volume into the cylinders to ensure smooth engine operation after the ammonia fuel supply stops; and collecting the ammonia gas discharged from the valve assembly unit and the engine into the waste liquid collection tank for unified treatment. This ensures that the engine can successfully switch to diesel mode in a short time, guarantees stable engine operation, and avoids the hazards caused by ammonia gas leakage.

A portable tool is provided for releasing a stuck component, such as a drive shaft, diesel injector, or ball joint, using a single manually operable device. The tool comprises an impact rod with a movable impact weight and a stop at one end, and a fastening element at the other end for connecting to an adjustable cable loop. The cable loop secures around the stuck component using a tool-free adjustment mechanism that includes a bent part, a U-shaped bolt with a threaded leg, and a locking screw. A pivotable hook with a spring clip fastener connects the cable loop to the impact rod, allowing axial force transfer when the impact weight is actuated. The tool enables effective and damage-free component release by a single user without requiring additional tools, and is adaptable for use on various components in motor vehicles or other mechanical systems.

This application discloses a control device and method for the intake system of an ammonia-diesel dual-fuel engine, relating to the field of ammonia-diesel engines. The method determines the current ammonia injection flow rate based on the ammonia temperature and pressure before injection, the ammonia nozzle's drive pulse width, and the nozzle's flow characteristics. It then controls the ammonia fuel supply system to supply ammonia based on this flow rate. The method also determines the current diesel injection flow rate based on the diesel injection pressure, the characteristics of the diesel nozzle, and the drive pulse width. Finally, it determines the ammonia-diesel energy substitution ratio based on the current diesel and ammonia injection flow rates, identifies the engine operating conditions, and obtains the required intake flow rate based on the engine operating conditions and the ammonia-diesel energy substitution ratio. The method controls the opening of two electronically controlled throttle valves based on the difference between the actual intake flow rate determined by the intake flow meter and the required intake flow rate, achieving quantitative control of the intake flow rate. This application can improve the thermal efficiency of ammonia-diesel engine combustion and reduce emissions of unburned ammonia and nitrogen oxides.

The application discloses a diesel engine plateau cold start control method and system, and relates to the technical field of diesel engines.The method comprises the following steps: acquiring the running parameter information of the diesel engine in real time, and calculating the in-cylinder background temperature and the in-cylinder background pressure of the piston top dead center of the diesel engine; judging whether the diesel engine reaches the ignition condition under the current working condition according to the comparison between the engine running parameters and the diesel engine ignition critical MAP (mapping) diagram; if the diesel engine reaches the ignition condition, determining the optimal fuel injection pressure of the diesel engine under the current working condition based on the injection strategy MAP diagram, and controlling the fuel injection of the diesel engine; and if the diesel engine does not reach the ignition condition, determining the low-temperature start auxiliary measure of the diesel engine under the current working condition based on the diesel engine ignition critical MAP diagram, and controlling the operation until the diesel engine reaches the ignition condition.The application can more accurately judge whether the diesel engine reaches the ignition condition under the plateau cold start condition, more reasonably match the diesel fuel injection strategy and the auxiliary measure, and more efficiently and lowly consume improve the plateau cold start performance of the diesel engine.

The present application relates to a kind of modular multi-fuel pre-reserve low carbon zero carbon dual fuel engine, belong to mechanical engineering technical field, it includes cylinder head assembly, cylinder head assembly is equipped with high-pressure dual fuel injection cylinder head, high-pressure dual fuel injection cylinder head is equipped with diesel injector, new fuel injector and exhaust valve mechanism, diesel injector is connected with diesel supply module, new fuel injector is connected with new fuel supply and purge module, diesel injector, new fuel injector and exhaust valve mechanism are simultaneously connected with servo oil driving module;Diesel injector, new fuel injector, exhaust valve mechanism are all driven by servo oil, and the control pressure required is realized by corresponding servo oil pressure increasing or reducing unit.The present application is aimed at methanol, ammonia, LPG and other normal pressure or high-pressure liquid fuel, using modular design method, maximum degree realizes multi-fuel common design and reservation, only a small part of module is replaced, and the quick replacement of different fuel low-speed machine can be realized.

The application provides an ammonia-diesel dual-fuel engine combustion control system and method, and relates to the technical field of engines.The control system comprises an engine, an ammonia supply device, a control device and a diesel supply device, the cylinder head of the engine is provided with a diesel electrically-controlled nozzle, and the intake valve of the engine is communicated with an air inlet pipe.The ammonia supply device comprises an ammonia tank, an ammonia pipeline and an ammonia nozzle, the control device is used for adjusting the energy replacement rate of ammonia by controlling the ammonia fuel injection amount of the ammonia nozzle and the diesel injection amount of the diesel electrically-controlled nozzle, and controlling the diesel electrically-controlled nozzle to adopt different injection modes under different ammonia energy replacement rates.The control strategy of the overall excess air coefficient being 1.0 is adopted to reduce the nitrogen oxide and particulate matter emissions in tail gas, different injection modes are adopted according to different ammonia energy replacement rates, the optimal in-cylinder combustion effect is achieved under different ammonia energy replacement rates, the power of the engine is improved, the amount of nitrogen oxide and particulate matter emissions is reduced, and the engine realizes high-efficiency and stable combustion.

The invention relates to a control method and system for starting fuel of a diesel micro-injection ignition natural gas engine, and relates to the field of engines, the engine starting process is divided into a motor driving stage with different rotating speed characteristics, an ignition stage, a rotating speed increasing stage and an idling transition stage; the diesel injection quantity in the motor driving stage is dynamically calculated according to the engine intake density; in the ignition stage, diesel injection amount is gradually reduced, and natural gas injection is introduced; in the rotating speed rising stage, when the rotating speed change rate is large, the natural gas injection amount is reduced, and when the rotating speed change rate is small or even negative, the natural gas injection amount is increased; in the idling transition stage, the diesel oil and natural gas injection amount is linearly and smoothly transited to the target injection amount of the idling working condition; the diesel oil injection amount of each stage is controlled at the micro-injection ignition level, so that the design and model selection of the oil delivery pump only need to meet the micro-injection oil amount requirement during normal operation of the engine. Cooperative injection of diesel oil and natural gas is implemented in stages in the starting process, and the requirement for the oil supply capacity of the oil delivery pump is remarkably lowered.

The invention discloses a soot and pollutant emission control system of a low-speed two-stroke dual-fuel engine with the cylinder diameter of 460 mm and a control method of the soot and pollutant emission control system. A cylinder cover of the engine is provided with a methanol fuel injector and a diesel injector; the included angle between the nozzle axis of the diesel injector and the nozzle axis of the methanol fuel injector is 30 degrees, diesel oil jetted by the diesel injector and methanol oil jetted by the methanol fuel injector are mutually crossed and mixed in the combustion chamber, the fuel injection proportion is controlled according to fuel energy, the injection amount of methanol accounts for 95% of the total fuel energy, and the injection amount of methanol accounts for 5% of the total fuel energy. And the injection amount of the diesel oil accounts for 5% of the total fuel energy. By means of innovative injection system arrangement, an accurate fuel control strategy and an operation parameter range optimized through system experiments, reliable ignition, stable combustion and collaborative emission reduction under high-proportion methanol replacement are achieved, and the system is an existing marine power system.

The application provides a diesel-methanol mixed fuel engine control method and system, comprising: acquiring real-time working condition data including engine speed, load and temperature parameters, determining the optimal supply ratio of diesel and methanol under the current working condition according to the real-time working condition data and combining a preset fuel characteristic difference model; calculating the mixed gas concentration of methanol and diesel according to the optimal supply ratio; if the mixed gas concentration exceeds a preset threshold, adjusting the injection pressure of methanol to make the mixed gas concentration return to the target range. If the combustion rate is lower than the preset lower limit value after increasing the methanol injection frequency, the injection direction of the methanol injector is adjusted to improve the mixing uniformity; if the combustion rate is still lower than the preset lower limit value, the methanol injection timing is adjusted to make the methanol injection and the diesel injection form the best cooperation in time, so as to ensure the stable engine output power and meet the high-efficiency and clean operation target.

The invention discloses a diesel engine combustion cooperative control system and method based on an SCR operation state, and the method comprises the steps: constructing a residual ammonia estimation model through real-time detection of operation parameters such as engine rotation speed, load, exhaust temperature, exhaust flow and the like and NOx concentration in SCR upstream exhaust gas, and carrying out the online estimation of a residual ammonia state possibly existing at the SCR downstream, when the residual ammonia state quantity exceeds a residual ammonia threshold value, reverse constraint correction is applied to the urea injection quantity, and a combustion side coordinated regulation mechanism is synchronously triggered; and on the basis of the discrete state space model containing the residual ammonia state variable, unified closed-loop adjustment is carried out on the urea injection amount, the EGR proportion, the hydrogen supply amount and the diesel injection amount. According to the method, the perception capability and control robustness of the system on the ammonia supply allowance change under the transient working condition and the load fluctuation condition are improved.

A method of cleaning up internal diesel injector deposits in a severely fouled engine, the method including combusting in the engine a diesel fuel composition having (a) a quaternary ammonium salt additive; and (b) one or more further nitrogen-containing detergents; in which the quaternary ammonium salt additive includes the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; in which each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.