CN109504502B - A compound anti-oxidative and anti-wear gasoline engine lubricating oil - Google Patents

Abstract

The invention relates to a method of using FeS ₂ /carbon composite nanomaterials as lubricating oil anti-wear agents, using sulfonates and salicylates to improve cleaning performance, molybdenum dialkyldithiocarbamate (MoDTC) and phenols without Ash is an antioxidant, and the addition of high-molecular polymers improves high and low temperature performance. The optimized composite additive has excellent performance and reduces fuel consumption by about 16-20%. Such results indicate that an optimized lubricant ratio can provide a highly efficient economical engine, which may be a suitable direction for vehicle manufacturers and users to suppress engine fuel costs and engine durability under different operating conditions.

Description

A compound anti-oxidative and anti-wear gasoline engine lubricating oil

technical field

The invention relates to the preparation of a compound lubricating oil additive, in particular to the application of a gasoline engine lubricating oil additive, and the performance test of the compound lubricant for improving the efficiency and fuel economy of the gasoline engine is carried out.

Background technique

With growing concerns about energy shortages and environmental protection, transportation vehicles account for about 19% of the world's energy consumption each year. Friction between surfaces is the main cause of energy dissipation in automotive engines. The total power produced by the engine is reduced in the range of 17-19% due to frictional losses. The ability of lubricants to improve fuel economy is critical globally. Therefore, research on frictional power loss reduction has gained great attention as a promising direction for fuel-efficient gasoline engine performance. Reducing total vehicle friction losses could save the U.S. economy $120 billion annually. To address this issue, we address nanotribology in engines as the main strategy to minimize frictional power loss, sliding surface wear and overheat generation, which will ultimately lead to improved performance of automotive engines. Lubricant additives employing nanocomposites are considered to be an attractive and widely adopted technique for lubricant modification as it does not require any major hardware modification. To improve engine efficiency, new approaches need to be explored to replace the use of environmentally harmful additives, which lead to undesirable emissions (zinc dialkyldithiophosphate (ZDDP)) without affecting the friction properties of automotive engines such as environmental Friendly additives such as ionic liquids and nanoparticles. The research of nanomaterials has become one of the fastest growing research fields in many energy-related fields due to their excellent properties. Rameshkumar et al. investigated the effect of adding iron oxide nanoparticles on lubricating oil (SAE10W-30). The results show that the use of nano-lubricants can improve fuel economy. Another study also showed that the use of molybdenum can improve the fuel economy of gasoline engines by 3-5% at full load. A common approach to obtaining fuel economy from lubricants is to reduce their viscosity and minimize the boundary coefficient of friction. Fuel economy is reduced by 5-10% with MoS nano _- lubricant. The investigation of the decline in vehicle fuel consumption has become a major research direction in different countries. Fundamentally, an engine's Brake Specific Fuel Consumption (BSFC) indicates the amount of fuel consumed per unit of work. BSFC decreases with increasing load until a minimum BSFC is reached and then increases in a phenomenon known as overfueling. In addition, engine load has a large impact on engine efficiency and BSFC. Mechanical efficiency generally increases with engine load. Researchers have long studied fuel economy by optimizing the viscosity characteristics of engine oils (5W-30). The results show that an increase in lubricating oil viscosity index improves fuel economy. In addition, the optimization of lubricating oil additive performance not only depends on the improvement of friction performance, an excellent lubricating oil additive must meet the optimal conditions of all parties. To improve the problems of piston deposits, piston cleanliness, soot-induced viscosity thickening and oxidation-induced viscosity thickening, compound and optimized lubricating oil additives came into being.

A gasoline lubricating oil compound agent, which should have excellent cleaning performance, sludge dispersing performance, anti-wear, anti-oxidation and anti-corrosion properties. This design belongs to the category of compound additives.

SUMMARY OF THE INVENTION

The invention overcomes the deficiencies of the existing conditions, and provides a composite additive gasoline lubricating oil composite agent with excellent cleaning performance, sludge dispersing performance, anti-wear, anti-oxidation and anti-corrosion performance.

The present invention is realized by the following technical solutions

A compound antioxidant and anti-wear type gasoline engine lubricating oil additive, which in mass fraction comprises 25-55% of a cleaning agent, 20-60% of an ashless dispersant, 5-25% of an antioxidant and 5-20% of an anti-wear agent, Wherein the anti-wear agent is FeS ₂ /carbon composite material.

Further, the above-mentioned additives include 30-50% of detergent, 35-55% of ashless dispersant, 10-20% of antioxidant and 5-15% of anti-wear agent in terms of mass fraction.

The cleaning agent is a metal cleaning agent, more specifically a combination of both sulfonate and alkyl salicylate;

Ashless dispersant is high molecular weight succinimide dispersant (T161);

Antioxidant is molybdenum dialkyldithiocarbamate (MoDTC) and/or phenolic ashless antioxidant; more preferably molybdenum dialkyldithiocarbamate (MoDTC) accounts for 65%, phenolic ashless Antioxidants account for 35%.

Further, the general structural formula of phenolic ashless antioxidants

R ₃ , R ₄ : methyl, ethyl, tert-butyl; R ₅ =C _m H _2m+1 (m=5-20).

The present invention also claims a method for preparing an anti-wear agent. Compared with the gC ₃ N ₄ /FeS ₂ composite of the related patent invention, the present invention no longer relies on the nitride-containing compound containing C ₃ N ₄ , and directly interacts with the porous carbon. The compound is more convenient and efficient, and the preparation of the anti-wear agent is simpler, the raw materials are readily available, and it is suitable for production. Preparation steps include:

The first step: preparation of carbon, PEI (polyetherimide) is dissolved in deionized water to obtain a PEI solution; bromoacetonitrile is added to ethanol, wherein the mass ratio of PEI (polyetherimide) to bromoacetonitrile is 2:1. Stir until dissolved to prepare a mixture of bromoacetonitrile and ethanol; slowly drop the mixture of bromoacetonitrile and ethanol into the PEI solution to prepare the precursor PEI; take AgN(CN) with a 1:1 molar ratio to the precursor PEI material _2. Add it to the precursor PEI, add water and stir to obtain PEI-DCA; calcine the PEI-DCA to obtain the desired carbon material.

The calcination is carried out to 800℃ under _N2 atmosphere;

The second step: FeS ₂ /carbon composite material preparation, the carbon material synthesized in the first step was added to deionized water for ultrasonic treatment; then FeCl ₂ ·4H ₂ O, PVP, sulfur powder, NaOH solution (concentration of 0.75 mol/L), respectively added to the above solution for reaction, wherein the mass ratio of carbon material, FeCl ₂ ·4H ₂ O, PVP, sulfur powder and NaOH is 4:5:7:5:3.5. Thus, FeS ₂ /carbon nanocomposites were obtained.

The above reaction conditions are sealing, hydrothermal reaction at 200°C for 20h.

For the convenience of comparison, carbon material nanosheets were prepared by the same method without adding FeCl ₂ ·4H ₂ O and sulfur powder; FeS ₂ was prepared without adding carbon.

The present invention also claims a composite anti-oxidative and anti-wear gasoline engine lubricating oil, which is added with the above-mentioned lubricating oil additive.

Effective Gain of the Invention

Different types of cleaning agents, dispersants, anti-wear agents and antioxidants are optimally configured to achieve the optimal performance requirements of the composite composition. Among them, the biggest feature of the present invention is that FeS ₂ /carbon composite material is the most anti-wear agent, which not only has good anti-wear performance, but also the spherical FeS ₂ particles play the role of nano-bearings between the friction surfaces, thereby reducing friction and reducing wear. . With the dosage of 6.5%, the quality of the gasoline engine composition can reach the GB11121SE standard.

Description of drawings

The present invention has the following accompanying drawings:

Fig. 1 is the friction coefficient of the compound lubricating oil additive of different concentrations of the present invention and base oil;

Fig. 2 is the functional relationship between engine braking power (a) and torque (b) of the present invention and throttle valve opening at 3000rpm;

Figure 3 shows the fuel consumption and vehicle speed of the lubricating oil (5W-30) of the present invention and the composite lubricating oil compound additive.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings.

Example 1

Anti-wear agent: preparation of FeS ₂ /carbon composites;

Preparation of _FeS2 /carbon composites as lubricating oil additive antiwear agent

Step 1: Preparation of carbon. Dissolve 5g of PEI (polyetherimide) in 15ml of deionized water, stir, transfer to a single-neck bottle after complete dissolution, and continue to stir for standby; add 2.4g of bromoacetonitrile to 10ml of ethanol, and stir until dissolved; The mixture of bromoacetonitrile and ethanol was slowly added dropwise to the PEI solution, stirred for 36 hours, rotary-evaporated at 45 degrees, washed with ether, and dried in vacuo. Denoted as precursor PEI. AgN(CN) ₂ with a molar ratio of 1:1 to the precursor PEI material was added to 5 g of the precursor material, stirred with water for 12 hours, labeled PEI-DCA, rotary evaporated, washed, and vacuum dried. The PEI-DCA material was put into a tube furnace under _N2 atmosphere and burned to 800 °C to obtain the desired carbon material.

The second step: FeS ₂ /carbon composite preparation. First, 0.20 g of carbon material was added to 50 ml of deionized water, and sonicated for 2 h. Then, 0.25g FeCl ₂ ·4H ₂ O, 0.35g PVP, 0.25g sulfur powder, 6ml NaOH solution (concentration 0.75mol/L) were added to the above solution, magnetic stirring for 0.5h, and then the mixed solutions were placed separately Put it into a 100mL stainless steel hydrothermal reaction kettle (the lining material is polytetrafluoroethylene), and seal it, and the reaction conditions are 200 ℃ hydrothermal reaction for 20h. The obtained product was washed with water and alcohol, and then the washed sample was dried in vacuum at 60° C. for 12 hours, thereby obtaining FeS ₂ /carbon nanocomposite.

For the convenience of comparison, carbon material nanosheets were prepared by the same method without adding FeCl ₂ ·4H ₂ O and sulfur powder; FeS ₂ was prepared without adding carbon. Detergents: Sulfonates and Alkyl Salicylates

R ₁ =C _m H _2m+1 (m=10-20)

M=Na,Ca,Mg

R ₂ =C _m H _2m+1 (m=10-15)

M=Na,Ca,Mg

Ashless Dispersant: High Molecular Weight Succinimide Dispersant (T161)

Ashless dispersants are mainly used to control the formation of sludge in gasoline engines, control sludge deposition, and neutralize the acid generated by combustion. This lubricating oil adopts high molecular weight succinimide dispersant (T161) with good low temperature and high temperature dispersion performance.

Antioxidant: Molybdenum dialkyldithiocarbamate (MoDTC) and phenolic ashless antioxidant MoDTC is a compound of inorganic molybdenum core and dialkyldithiocarbamate. The ligand provides oil solubility. The molybdenum core is 5-valent dinuclear molybdenum or 4-valent trinuclear molybdenum.

Weigh 144g of molybdenum trioxide and add it to 216mL of water, then add 202g of NaHS solution with a mass fraction of 40% dropwise at 40°C for 1 h. Then add 34g of a sodium hydrosulfite solution with a mass fraction of 85%. Add 324g methanol, 254g diisooctylamine. 80g of carbon disulfide was acidified with 50.5g of sulfuric acid (35% by mass). The reaction was carried out at 72°C for 5h. After cooling to room temperature, the water-methanol layer was removed to obtain a brown oil. This was washed with water and methanol, and dried under reduced pressure to obtain 425 g of a yellow oil. After chemical testing, it contains 20.8% molybdenum and 21.5% sulfur.

Among them, sulfur is an antioxidant, which resists oxidation in the molecule and improves the oxidation stability of the lubricating oil; the thermal decomposition of MoDTC is an endothermic process. It can absorb the instantaneous high temperature caused by metal contact friction, reduce the oil temperature, protect the oil quality of the lubricating oil, and prolong the oil change period.

General structure of phenolic ashless antioxidants

R ₃ , R ₄ : methyl, ethyl, tert-butyl; R ₅ =C _m H _2m+1 (m=5-20)

The main technical features of the present invention are: the optimal configuration of different types of cleaning agents, dispersants, anti-wear agents and antioxidants, so that the composite agent composition achieves optimal performance requirements. Among them, the biggest feature of the present invention is that FeS ₂ /carbon composite material is the most anti-wear agent, which not only has good anti-wear performance, but also the spherical FeS ₂ particles play the role of nano-bearings between the friction surfaces, thereby reducing friction and reducing wear. . With the dosage of 6.5%, the quality of the gasoline engine composition can reach the GB11121SE standard.

In the configuration of oil products, the effective dosage of each component is as follows:

The optimized result content is as follows:

Metal cleaner (combination of both sulfonate and alkyl salicylates) 40%

Ashless dispersant (high molecular weight succinimide dispersant (T161)) 38%

Antioxidants (molybdenum dialkyldithiocarbamate (MoDTC) and phenolic ashless antioxidants) 15%

Among them: molybdenum dialkyldithiocarbamate (MoDTC) accounts for 65%, and phenolic ashless antioxidant accounts for 35%

Anti-wear agent (FeS ₂ /carbon composite) 7%.

Tribological performance test

7 wt.% FeS ₂ /carbon composite was added to the base oil liquid paraffin, and for comparison, the carbon material nanosheets and FeS ₂ particles were also treated in the same way. The solid powder weighed above is uniformly dispersed in the base oil using an ultrasonic cleaner to form a dense liquid sample. The tribological properties of the samples were tested by a UMT-2 multifunctional friction tester (CETR, USA). Since it is a comparative experiment, the time selected for this experiment is 10 min. The stainless steel ball is 9Cr18 steel with a diameter of 9mm and a hardness of 62HRC, and the grinding disc is a 45# steel block with a size of Φ40mm×6mm.

Engine Setup and Test Procedures

The experiments were carried out on a gasoline engine (model HXDG16-BD-TJ, multi-point injection, independent ignition, water-cooled and naturally aspirated). Engine performance was measured using an AVL dynamometer. The technical specifications of the engine and vehicle are shown in Table 1.

Table 1 Engine and Vehicle Specifications

To evaluate the nanoadditives measurements were made under different operating conditions to confirm the effect of the nanoadditives, which allowed the evaluation of lubricants under different lubrication conditions in an engine. In addition, engine performance comparisons were performed using Automotive Operating Conditions (NEDC) to confirm the effect of nano-additives on different operating conditions of the engine. The evaluation of the NEDC driving cycle allows the simulation of nanoadditives under real operating conditions, with an emphasis on fuel consumption. Experiments with the NEDC driving cycle have been done on the AVL dynamometer. Each NEDC test was started when the engine was cold started (35°C).

In order to study the change of friction coefficient of various lubricating additives under different addition amounts, the tribological properties of the lubricating additives are respectively compound lubricating oil composites. The experimental conditions are: load 20N, speed 300rpm, time 10min. As shown in Figure 1, the friction coefficient values obtained in each group of experiments are very low, and the relative error of the friction coefficient is less than 10%. , the lubricating additive is that with the increase of the content, the comprehensive tribological properties of the lubricating oil containing the complex lubricating oil compound are also gradually improved. During the friction process, the spherical-like FeS ₂ particles act as nano-bearings between the friction surfaces, thereby reducing friction and wear. The excellent tribological performance of _FeS2 /carbon composites as lubricant additives is attributed to the synergistic effect between _FeS2 particles and carbon.

Figure 2 tests the effect of throttle position on the braking power and engine torque of the compound lubricating oil compound and engine oil (5W-30) at an engine speed of 3000 rpm. The results show that braking power and torque increase with increasing throttle opening. Torque and power are available at the wide-open throttle due to higher volumetric efficiency. Exhaust inertia is relatively high in wide-open throttle with moderate or high engine speeds. The inertia of the exhaust gas creates a vacuum that draws new charges into the cylinder through valve overlap. Therefore, longer overlap periods result in better cylinder filling and increased volumetric efficiency.

In a comparison of the fuel consumption results, Figure 3 provides the relationship between vehicle speed and fuel consumption for calculating how much economic profit would be from the use of nano-lubricants in an engine car. The results compare the engine fuel consumption per 100 km for different transmission shifts using lubricating oil (5W-30) and complex lubricant additives. It can be clearly observed that using the compound lubricant can save up to 4L/100km at low speed and 2.4L/100km at economy speed (70km/h), while saving 1.5L/100km. The fuel consumption at high speeds corresponds to a lower gear reduction ratio compared to an engine oil without additives. Based on previous results, composite additives are very effective at lower throttle openings and lower engine speeds (urban) due to the predominance of boundaries or mixed lubrication conditions under engine operating conditions.

Through the above experiments, composite lubricants improved gasoline engine performance at all operating points and NEDC drive cycles. It turns out that these results have a direct correlation with fuel economy, with the following main conclusions:

1. The comprehensive tribological properties of compound additives containing compound lubricating oil are improved. During the friction process, the spherical-like FeS ₂ particles act as nano-bearings between the friction surfaces, thereby reducing friction and wear. The excellent tribological performance of _FeS2 /carbon nanocomposites as lubricant additives is attributed to the synergistic effect between _FeS2 particles and carbon.

2. The use of a compound lubricant compound additive can increase braking power and engine torque under all specified operating conditions compared to a lubricant without particles (5W-30). The reason is that with the use of complex lubricant complex additives, the total frictional power is reduced by 5-7%. The antioxidants and detergents used are in the optimal content to exert the best effect. As a result, the mechanical efficiency of the engine is increased by 0.7-2.5%.

3. About 16-20% reduction in fuel consumption corresponding to the complex lubricant compound. Therefore, the fuel consumption reduction recorded during the NEDC test requires a fuel economy of about 4L/100km in the city.

4. The compound lubricant additive accelerates the warm-up phase by 24% under operating conditions due to increased lubricating oil sensitivity. The result is a 4-10% reduction in fuel consumption.

Claims (9)

1. a preparation method of antiwear agent, the step comprises: The first step: the preparation of carbon, first prepare a polyetherimide PEI solution; add bromoacetonitrile to ethanol, stir until dissolved to prepare a mixture of bromoacetonitrile and ethanol; slowly drop the mixture of bromoacetonitrile and ethanol into the In the PEI solution, the precursor PEI is prepared, wherein the mass ratio of PEI to bromoacetonitrile is (1.5-2.5): 1; AgN(CN) ₂ with a molar ratio of 1:1 to the precursor PEI material is added to the precursor PEI , adding water and stirring to obtain PEI-DCA; calcining PEI-DCA to obtain the desired carbon material; The second step: FeS ₂ /carbon composite material preparation, firstly add the carbon material synthesized in the first step into deionized water and carry out ultrasonic treatment; then, FeCl ₂ ·4H ₂ O, PVP, sulfur powder with a concentration of 0.75mol /L NaOH solution was added to the above solution for reaction, thereby obtaining FeS ₂ /carbon nanocomposite material; wherein, the mass ratio of carbon material, FeCl ₂ ·4H ₂ O, PVP, sulfur powder and NaOH was 4: 5:7:5:3.5; the calcination is calcined to 800°C under N ₂ atmosphere; the reaction conditions are sealing and hydrothermal reaction at 200°C for 10-30h. 2. A compound anti-oxidant and anti-wear type gasoline engine lubricating oil additive, characterized in that: by mass fraction, it comprises 25-55% of detergent, 20-60% of ashless dispersant, 5-25% of antioxidant and anti-wear agent 5-20% of the anti-wear agent, wherein the anti-wear agent is FeS ₂ /carbon composite material, prepared by the preparation method of claim 1 . 3. The additive according to claim 2, characterized in that: by mass fraction, it comprises 30-50% of cleaning agent, 35-55% of ashless dispersant, 10-20% of antioxidant and 5-15% of anti-wear agent . 4. The additive according to claim 2, wherein the cleaning agent is a metal cleaning agent. 5. The additive according to claim 2, wherein the cleaning agent is a combination of sulfonate and alkyl salicylate. 6. additive according to claim 2 is characterized in that: ashless dispersant is high molecular weight succinimide dispersant; The antioxidants are molybdenum dialkyldithiocarbamates and/or phenolic ashless antioxidants. 7. The additive according to claim 6, wherein the molybdenum dialkyldithiocarbamate accounts for 65%, and the phenolic ashless antioxidant accounts for 35%. 8. The additive according to claim 6 or claim 7, wherein the general structural formula of the phenolic ashless antioxidant is

R ₃ , R ₄ : methyl, ethyl, tert-butyl; R ₅ =C _m H _2m+1 (m=5-20). 9. A composite anti-oxidative and anti-wear gasoline engine lubricating oil, characterized in that: adding the lubricating oil additive according to any one of claims 4-8.

Images