LUBRICATING OIL COMPOSITION FOR DIESEL ENGINES

Abstract

The invention provides a lubricating oil composition for diesel engines which contains a GTL base oil with a kinematic viscosity at 100 C. of 4.5 to 5.5 mm2/s, a comblike PMA (polymethacrylate) based viscosity index improver and a boron-containing dispersant and/or boron-containing detergent, the total content of the boron-containing dispersant and/or boron-containing detergent in terms of conversion to boron content relative to the total amount of the composition being not less than 0.025 mass %, and which satisfies 0W-30 or 5W-30 in the SAE J300 standard.

Claims

1. A lubricating oil composition for diesel engines characterised in that it contains: a) a GTL base oil with a kinematic viscosity at 100 C. of 4.5 to 5.5 mm.sup.2/s, b) a comb-like PMA (polymethacrylate) based viscosity index improver, and c) a boron-containing dispersant and/or boron-containing detergent, wherein the total amount of boron-containing dispersant and/or boron-containing detergent incorporated in terms of conversion to boron content relative to the total amount of the composition being not less than 0.025 mass %, and wherein it satisfies 0W-30 or 5W-30 in the SAE J300 standard.

2. The lubricating oil composition for diesel engines in accordance with claim 1 which includes a non-comb-like PMA (polymethacrylate) based viscosity index improver and an SCP (styrene-diene copolymer) based viscosity index improver and/or an OCP (olefin copolymer) based viscosity index improver, and which further satisfies at least one of the following (1) to (3). (1) Non-comb-like PMA based viscosity index improver content/total viscosity index improver content: not more than 0.7, (2) OCP based viscosity index improver content/total viscosity index improver content: not more than 0.2, (3) SCP based viscosity index improver content/total viscosity index improver content: not more than 0.3.

3. The lubricating oil composition for diesel engines in accordance with claim 1 satisfying the following viscosity characteristic: $\frac{\begin{array}{c}[\mathrm{HTHS}.Math..Math.100.Math..Math..Math.C..Math.\mathrm{viscosity}\left(\mathrm{capillary}.Math..Math.\mathrm{method}\right)-\\ \mathrm{HTHS}.Math..Math.100.Math..Math..Math.C..Math.\mathrm{viscosity}\left(\mathrm{TBS}.Math..Math.\mathrm{method}\right)]\end{array}}{\mathrm{HTHS}.Math..Math.100.Math..Math..Math.C..Math.\mathrm{viscosity}\left(\mathrm{TBS}.Math..Math.\mathrm{method}\right)}=0.07.Math..Math.\mathrm{to}.Math..Math.0.15$

Description

EXAMPLES

[0060] The invention is further explained next by means of examples of embodiment and comparative examples, but the invention is in no way limited by these examples.

[0061] The raw materials used in the examples of embodiment were as follows. The characteristics of the various base oils are shown in Table 1.

Base Oils

[0062] Base oil 1:XHVI 4 (GTL oil)

[0063] Base oil 2:XHVI 8 (GTL oil)

[0064] Base oil 3:XHVI 3 (GTL oil)

[0065] Base oil 4:Yubase 4 (mineral oil)

[0066] Base oil 5:Yubase 8 (mineral oil)

[0067] Base oil 6:Yubase 3 (mineral oil)

Additives Packages

[0068] DH-2 DI package 1: As shown in the tables, in the examples of embodiment when 14.00% was added, the boron content of the lubricating oil became 0.033 mass % {including boron-containing dispersant (borated calcium alkyltoluene sulphonate) and boron-containing detergent (borated succinate ester-based dispersant), and amount of other additives same as DI packages 2 and 3}

[0069] DH-2 DI package 2: As shown in the tables, in the examples of embodiment when 14.00% was added, the boron content of the lubricating oil became 0.027 mass % {including boron-containing dispersant (borated calcium alkyltoluene sulphonate) and boron-containing detergent (borated succinate ester-based dispersant), and amount of other additives same as DI packages 1 and 3}

[0070] DH-2 DI package 3: As shown in the tables, in the examples of embodiment when 14.00% was added, the boron content of the lubricating oil became 0.020 mass % {including boron-containing dispersant (borated calcium alkyltoluene sulphonate) and boron-containing detergent (borated succinate ester-based dispersant), and amount of other additives same as DI packages 1 and 2}

Viscosity Index Improvers

[0071] Viscosity index improver solution 1: Solution containing Viscoplex 3-220 (comb-like PMA-based viscosity index improver) (approx. 40% dilution)

[0072] Viscosity index improver solution 2: Solution containing Viscoplex 3-201 (comb-like PMA-based viscosity index improver) (approx. 60% dilution)

[0073] Viscosity index improver solution 3: Solution containing Viscoplex 6-954 (non-comb-like PMA-based viscosity index improver) (approx. 40% dilution)

[0074] Viscosity index improver solution 4: Solution containing Lz7177B (olefin copolymer -based viscosity index improver) (approx. 87.5% dilution)

[0075] Viscosity index improver solution 5: Solution containing Infineum (registered trade mark) SV150 (styrene-diene copolymer-based viscosity index improver) (approx. 93.5% dilution)

Defoamer

[0076] DCF 3 mass % solution

TABLE-US-00001 TABLE 1 Base Base Base Base Base Base Base oil name oil 1 oil 2 oil 3 oil 4 oil 5 oil 6 API category Group Group Group Group Group Group 3 3 2 3 3 2 Kinematic viscosity @ 100 C. mm2/s 4.1 7.6 2.7 4.2 7.6 3.1 @ 40 C. mm2/s 17.9 43.7 9.9 19.3 46.6 12.4 Viscosity index 130 143 112 125 129 10.4 JIS K 2283 Noack evaporative loss 13.2 4.6 42.5 14.8 5.6 44 mass % ASTM D5800 Ring analysis ASTM D3238 % CA 0 0 0 0 0 0 % CN 7.9 12 9.2 21.8 22.9 31.2 % CP 92.1 88 90.8 78.2 77.1 68.8 Sulphur content <0.01 <0.01 3.3 2.75 4 2.5 mass % ASTM D2622 Flash point (CCC) C. 220 3.45 204 220 256 194 JIS K2265-4 Pour point C. 37.5 3.8 37.5 2.1 12.5 32.5 JIS K 2269

[0077] The aforementioned raw materials were blended as shown in Tables 2 and 3, and the lubricating oil compositions of Examples of Embodiment 1 to 8 and Comparative Examples 1 to 10 were obtained.

Evaluation

[0078] Next, evaluation tests were carried out in respect of the lubricating oil compositions of Examples of Embodiment 1 to 8 and Comparative Examples 1 to 10. It was confirmed that all the lubricating oil compositions for Examples of Embodiment 1 to 8 satisfied 5W-30.

[0079] An evaluation of the fuel consumption characteristics was carried out on the basis of fuel consumption bench tests using a 4000 cc diesel engine of Japanese make. The operating conditions were set up with reference to the Ministry of Land, Infrastructure and Transport 10.Math.15 mode. The gallery temperature at measurement time was set at 90 C. The results shown in Tables 2 and 3 show the rate of improvement (%) in fuel economy when taking as a criterion a commercial diesel engine oil classified as SAE viscosity grade 10W-30. In the evaluation, if the rate of improvement (%) in fuel economy was at least 1.0, the fuel consumption characteristics were marked (good).

[0080] The Noack volatility (%) was measured on the basis of ASTM D5800. For the evaluation, if the Noack volatility (%) was not more than 13.0, volatility was marked (good).

[0081] Hot tube tests were carried out in accordance with the Japan Petroleum Institute's standard JPI-5S-55-99 Engine oilsHot tube test. The test conditions were set at a test temperature of 290 C./300 C., test duration 16 hours, sample oil feed rate of 0.3 ml/hour and air flow of 10 ml/hour, and if the evaluation (merit points) of the colour of discoloured portion of the glass tube after completion of the test was at least 7.0, detergency was marked (good).

[0082] The [capillary viscosityTBS viscosity)/TBS viscosity] was calculated by following the aforementioned method.

[0083] In addition, the (40 C.) kinematic viscosity, (100 C.) kinematic viscosity, viscosity index (VI), boron content (total value), calcium content (total value), phosphorus content (total value), zinc content (total value), nitrogen content (total value) and molybdenum content (total value) were calculated (the base stock Vk 100 C. was the 100 C. kinematic viscosity of the base oil mixture).

TABLE-US-00002 TABLE 2 Inventive Examples Example 1 2 3 4 5 6 7 8 Base oil 1 57.60 57.60 57.60 57.60 57.60 57.60 57.60 57.60 Base oil 2 28.37 28.37 28.37 28.37 28.37 28.37 28.37 28.37 DH2 DI 14.00 14.00 14.00 14.00 14.00 14.00 14.00 package 1 DH2 DI 14.00 package 2 VI imp. 5.5 3.3 2.75 4 2.5 5.5 solution 1 (3.30) (1.98) (1.65) (2.40) (1.50) (3.30) (comb-like PMA) VI imp. 12.4 3.45 solution 2 (4.96) (1.38) (comb-like PMA) VI imp. 3.8 2.05 solution 3 (2.28) (1.23) (non-comb- like PMA) VI imp. 3.1 solution 4 (0.39) (olefin copolymer) VI imp. 4.7 9.4 solution 5 (0.31) (0.61) (styrene-diene copolymer) Defoamer 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Fuel economy improvement ratio 60 C. (%) Volatility NOACK Detergency HIT (300 C.) Vk40 42.23 42.42 49.46 49.24 46.89 45.73 49.51 42.24 mm.sup.2/s Vk100 10.43 11.00 10.46 10.51 10.45 10.34 10.24 10.45 mm.sup.2/s VI 248 264 208 210 221 224 201 248 Base stock 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Vk 100 C. mm.sup.2/s (HTHS 0.10 0.11 0.09 0.08 0.08 0.10 0.09 0.10 (capillary, 100 C.)-HTHS (TBS, 100 C.)/ HTHS (TBS, 100 C.) B mass % 0.033 0.033 0.033 0.033 0.033 0.033 0.033 0.027 Ca mass % 0.220 0.220 0.220 0.220 0.220 0.220 0.220 0.220 P mass % 0.096 0.096 0.096 0.096 0.096 0.096 0.096 0.096 Zn mass % 0.110 0.110 0.110 0.110 0.110 0.110 0.110 0.110 N mass % 0.120 0.120 0.120 0.120 0.120 0.120 0.120 0.120 Mo mass % <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Fuel efficiency test, oil temp. 60 C. FE improvement 1.5 1.5 1.4 1.0 1.3 1.3 1.1 1.5 ratio against 10W-30 DH-2 oil % NOACK % 10.0 10.3 10.2 10.0 10.0 10.01 10.04 10.0 Hot tube 290 C. 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 merit point Hot tube 300 C. 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 merit point Note: Figures in brackets are polymer amounts minus diluents.

TABLE-US-00003 TABLE 3 Comparative Examples Comparative Example 1 2 3 4 5 6 7 8 9 10 Base oil 1 57.60 57.60 57.60 57.60 24.80 79.36 57.60 Base oil 2 84.43 28.37 28.37 28.37 28.37 57.87 28.37 Base oil 3 76.47 Base oil 4 63.39 Base oil 5 17.88 DH2 DI package 14.00 14.00 14.00 14.00 14.00 14.00 14.00 14.00 14.00 1 DH2 DI package 2 DH2 DI package 3 14.00 VI imp. 1.54 3.3 6.61 9.5 4.7 5.5 solution 1 (0.92) (1.96) (3.97) (5.70) (2.82) (3.30) (comb-like PMA) VI imp. solution 2 (comb-like PMA) VI imp. 5.1 3.8 solution 3 (3.10) (2.28) (non-comb-like PMA) VI imp. 7.6 2.3 solution 4 (0.95) (0.29) (olefin copolymer) VI imp. 18.5 solution 5 (1.20) (styrene-diene copolymer) Defoamer 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Fuel economy characteristics FE improvement X X X X X X ratio 60 C. (%) Volatility X X X NOACK Detergency X HTT (300 C.) Vk40 61.49 51.91 58.97 53.70 58.35 52.85 38.52 33.41 44.28 42.30 mm.sup.2/s Vk100 10.48 10.49 10.42 10.53 10.56 10.49 10.51 10.71 10.48 10.46 mm.sup.2/s VI 160 197 167 190 173 193 278 332 237 249 Base stock 7.5 5.0 5.0 5.0 5.0 6.0 4.0 2.7 5.0 5.0 Vk 100 C. mm.sup.2/s (HTHS 0.03 0.06 0.06 0.06 0.06 0.06 0.17 0.19 0.10 0.10 (capillary, 100 C.)-HTHS (TBS, 100 C.)/ HTHS (TBS, 100 C.) B mass % 0.033 0.033 0.033 0.033 0.033 0.033 0.033 0.033 0.033 0.020 Ca mass % 0.220 0.220 0.220 0.220 0.220 0.220 0.220 0.220 0.220 0.220 P mass % 0.096 0.096 0.096 0.096 0.096 0.096 0.096 0.096 0.096 0.096 Zn mass % 0.110 0.110 0.110 0.110 0.110 0.110 0.110 0.110 0.110 0.110 N mass % 0.120 0.120 0.120 0.120 0.120 0.120 0.120 0.120 0.120 0.100 Mo mass % <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Fuel efficiency test, oil temp. 60 C. FE improvement 0.7 0.8 0.7 0.7 0.7 0.9 2.7 3.7 1.0 1.5 ratio against 10W-30 DH-2 oil % NOACK 5.1 9.8 10.1 10.1 11.2 8.0 14.0 42.0 13.3 10.3 % Hot tube 290 C. 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 merit point Hot tube 300 C. 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 0.5 merit point Note: Figures in brackets are polymer amounts minus diluents.