Field of invention

The present invention relates to the achievement of the engine emission norms to Euro3 or BS3 equivalent emission regulations with mechanical inline block type fuel injection pump on the automotive diesel engines used on commercial vehicles.

The invention is related to BS3 emission norms using a Conventional block type Inline Fuel Injection Pump (referred to as also inline fuel injection pump in this patent application) without electronics. It is designed to achieve the Euro3 or BS3 standards by inventing Euro3 or BS3 emission compliant engines using Conventional Inline Fuel Injection Pump instead of using electronic controlling devices.

Background of invention

Emission norms are introduced to limit exhaust pollutants emitted by vehicular engines to improve and control ambient air quality.

The Global trend is stage wise tightening of norms. Emission norms are mandatory and vehicles must comply with the level applicable for the country. For India it is called Bharat Stage 1, 2, 3 etc. To achieve these norms there are several methods and options. Choice of high pressure fuel injection system to achieve norms for different levels is,

• For BS1 - inline / Rotary Mechanical FIE system -can also be called-1st generation

• For BS2 - Rotary Mechanical system -2nd generation

• For BS3 - VP37 Electronic diesel control FIE system / Common rail FIE system-3rd generation.

Emission Legislation:

BS2 Emission Norms (g/kWh) Equivalent to Euro-2

Emission Cycle to be used while testing:

Steady state 13mode cycle, called R49 is being followed in BS2 legislation. It is a simple test cycle where we can operate the engine in only Two speeds where, Maximum Power occurs and Maximum Torque occurs.

Out of 13 modes, five modes in Rated power and five modes in Maximum Torque and remaining three will be low idle speed. Meeting emission norms is quite easy due to only two operating speeds involved, by using a small mechanical timer device this can be easily achieved.

BS2 legislation also calls for a smoke cycle called Free acceleration smoke (FAS) which depends on the injected quantity across the engine speeds, and its limit is 65Hatride units.

BS3 Emission Norms fg/kWh) Equivalent to Euro-3:

Emission Cycle: European Steady State (ESC):

European Steady state cycle (ESC) is being followed in BS3 legislation. It is not a simple test cycle like R49 (BS2) test cycle. Here the controlling authority will select three speeds based on the engine torque curve called ESC speeds A,B,C whereas we are operating the engine at only Two speeds in BS2.

This cycle involves 13 test modes, out of 13modes, four modes in speed C, Speed B and speed A and one at idle low idle speed.

ESC test cycle is designed carefully to simulate the actual driving pattern on road to predict the on road emission levels. Since this tough cycle covers three different operating speeds more flexible controlling devises are required, and needs a electronic injection timing control system and high pressure fuel injection system.

This also involves FAS smoke cycle and in addition to this, a cycle called European Load response cycle (ELR) for smoke instead of FAS, where finer control is required to limit the smoke in this transient cycle without affecting the acceleration capability of the vehicle.

To meet the above mentioned tighter emission norms electronic governors were introduced in the Fuel injection equipment for precise governing. Our work demonstrates our claim of achieving Euro3 emission norms without any aid of electronic governors.

Objects of invention

The main object of the present invention is to provide BS3 or Euro3 emission compliant engines using Conventional Inline Fuel Injection Pump.

Another object of the present invention is to provide BS3 or Euro3 emission compliant engines without using electronic controlling devices.

Yet another object of the present invention is to provide a very low cost mechanical system which satisfies BS3 or Euro3 emission norms where no electronics involved and customer friendly.

Another object of the present invention is to provide BS3 or Euro3 emission compliant engines without using electronic controlling devices whose fuel efficiency is at par with any other engine with existing electronic systems for BS 3 emission norms.

Summary of invention

The invention is a simple adaption of the diesel engines described by optimization of all the interacting parameters to control and achieve the emission limits of Euro 3 or BS 3 equivalent emission norms on the diesel engines.

The invention has successfully achieved the emission limits of Euro 3 or BS 3 equivalent emission norms on the diesel engines by optimizing all influencing parameters and demonstrated the feasibility of achieving using the mechanical inline Fuel injection pump without any electronic control and with only mechanical FIPs meeting emissions beyond EUR02 or BS2 equivalent norms with or without after treatment device.

The modern high pressure electronic fuel injection systems demand very high quality fuels in terms of filtering and lubricity. In case, an inferior fuel is used the repair cost and down time are prohibitive. Therefore, a simple mechanical inline fuel injection pump lubricated by engine oil was used to develop a cost effective yet advanced diesel engine, without sacrificing the fuel economy.

The engine is friendly to service in remote areas of developing countries compared to electronic engines. The engine is as consistent in emission performance as an electronic engine. Several steps were taken during manufacturing to achieve the consistency. The fuel economy is within 2% of electronic engines as seen over the entire performance map and also in experimental buses.

Brief description of drawings

According to the present invention,

Figure 1 shows the average Emission and performance test results of 20 engines.

Figure 2 shows the Emission comparison between Mechanical inline FIE system and VP37 FIE (EDC) with electronic governor.

Figure 3 shows the difference in part load SFC between inline mechanical FIP and rotary FIP with electronic governor

Figure 4 schematic diagram of the fuel injection system with mechanical fuel injection pump.

Figure 5 shows a schematic diagram of fuel layout of a rotary FIE with electronic governor developed for meeting BS3 or Euro3 emission targets.

Figure 6 shows the Schematic diagram of Engine layout.

Figure 7 & 8 shows the effect in smoke due to Cylinder head swirl ratio and Nozzle tip protrusion.

Figure 9 & 10 shows the dynamic start of injection and combustion begin between inline mechanical FIP and rotary electronic FIP

Figure 11 & 12 shows the effect of excess Airflow in Nox and smoke.

Figure 13, 14 & 15 shows the effect of DOC in PM, HC & CO emissions.

Figure 16 shows a typical diesel engine layout with inline mechanical FIE to meet BS3 emission norms.

Figure 17 shows a typical diesel engine with rotary FIE with electronic governor developed for meeting BS3 or Euro3 emission targets.

Statement of invention

Accordingly the present invention provides an Euro3 or BS3 Emission Compliant Engine with Cost Effective Fuel Injection Pump comprising fine tuning of cylinder head swirl ratio;

optimizing injection jet penetration and nozzle tip protrusion to control the lower speed smoke and emission;

air management to get the equivalent combustion product of EDC FIE system;

fine tuning or controlling of start of combustion and duration of combustion;

diesel oxidation catalyst for oxidizing Soluble Organic Fraction, hydro-carbons, particulate matter and CO.

Brief description of invention

The industry had demonstrated the achievement of Euro2 or BS2 equivalent emission norms using mechanical inline FIS or the rotary FIS on the diesel engines through out the world.

There had been no claim of achievement or patent applied for achieving Euro 3 or BS 3 equivalent emission norms using mechanical FIS and DOC and in particular the Bosch 'A' Type mechanical inline FIP.

There are cases of using inline pump in conjunction with electronic control meeting Euro 3 or BS 3 equivalent emission norms.

The invention discloses about achieving emission control norms beyond Euro 2 or BS 2 equivalent emission norms with mechanical inline pumps only on diesel engines, without any electronic control interface.

The new combustion system uses totally an unconventional low pressure fuel injection system where an attempt is made to develop a Euro-3 or BS3 emission compliant engine using a first generation FIE system consisting of Mechanical inline Fuel injection pump, where no electronic devises are incorporated.

By fine tuning the basic combustion principles and proper matching of combustion elements like Piston bowl geometry, Injection nozzle geometry, cylinder swirl geometry, start of injection, High pressure pipe and controlled injection jet penetration and ROHR etc., we have been able to achieve BS3 emission norms using a Conventional Inline Fuel Injection Pump without electronics for the first time in the country.

Detailed description of invention

The invention discloses about new combustion system having totally an unconventional low pressure fuel injection system where we attempted to develop a Euro-3 and BS3 emission compliant engine using a first generation FIE system consisting of Mechanical inline Fuel injection pump, where no electronic devises are incorporated.

By fine tuning the basic combustion principles and proper matching of combustion elements like Piston bowl geometry, Injection nozzle geometry, cylinder swirl geometry, start of injection, High pressure pipe and controlled injection jet penetration and ROHR etc., by this invention it is able to achieve BS3 emission norms using a Conventional Inline Low pressure Fuel Injection Pump without electronics.

Other parameters controlled tightly to follow the BS3 emission standards are given below
1. Cylinder Head Swirl Ratio (SR)
2. Static injection timing
3. Boost pressure / Air flow
4. Nozzle Hole Size, Jet penetration and Nozzle tip protrusion
5. Dynamic start of Injection (SOI)
Cylinder Head Swirl Ratio (SR):

Cylinder head Swirl ratio is a vital parameter where rotation of air induces in the cylinder with respect to vertical cylinder axis. Swirl ratio is highly affected the lower speed smoke levels. SR was fine tuned to reduce the lower end smoke. Ref. Figure 7.

Injection Jet Penetration and Nozzle Tip Protrusion:

• Injection jet penetration and nozzle tip protrusion was optimized to control the lower emission speed smoke.

• Injector tip position in case of BS3 electronics engine is 3.0mm from cylinder head

• Injector tip position is changed to 2.5mm from the cylinder head in case of BS3 inline

• Because of this reduced position of injector, Jet penetration is getting increased and allowing more oxidation of fuel droplets and hence lower speed smoke level is getting relatively reduced even with low injection pressure levels. This helps to meet the BS3 soot emission levels even with retarded injection timing compared with EDC FIE system. Ref Figure 8.

Air Management:

• Due to the Mechanical FIE limitations described above, we are attempting to overcome this limitation by proper air management to get the equivalent combustion product of EDC FIE system.

• Diesel engine always runs at higher Air fuel ratio. Legislative emission levels are calculated based on the product of the product of air flow and Emission PPM level divided by weighted power.

• We have limited the emission products by managing an optimum and comparatively lean Air fuel ratio with EDC FIE system.

• New Turbocharger was developed with optimum air / fuel ratio to meet the legislative emission norms. Ref Figure. 11 & 12.

Start of Combustion (SOC):

• Start of Combustion and duration of combustion is controlled by the parameters like start of Injection, Injection pressure, number of injection holes, in cylinder air swirl ratio, Boost pressure, piston bowl design and fuel properties. Ignition delay is key parameter defines the quality of combustion which is determine by the above said parameters. By fine tuning the above said parameters SOI was maintained very close to the Electronic governing system (EDC). Ref Figure 9&10.

Diesel Oxidation Catalyst (DOC):

• Soxhlet analysis (chemical extraction method for soot) showed the engine-out particulate matter has 25% Soluble Organic Fraction (SOF) and 75% soot. To control the particulate emission, a low-cost maintenance-free one-way diesel oxidation catalyst was developed. The 6.9 liter catalyst with a suitable wash coat to handle 350 ppm sulphur in fuel was developed. The platinum loading was optimized experimentally; the optimum loading was 3 mg/cu. ft. The catalyst reduced SOF by 65% and hence PM by 10%. The optimum DOC also reduced CO and HC by 70%. The catalyst does not oxidize sulphur to sulphates at high exhaust temperature and does not get poisoned. Figure 13, 14 & 15 shows the effect of DOC in PM, HC and CO emissions.

• Even though the soot emissions from different engines were nearly identical, the SOF was different due to control of very small amount of oil and fuel in the exhaust. By passing through the DOC, the hydrocarbons are completely burned and the residual soot manifests itself as PM which is consistent for three different engines. Similarly, CO and HC are consistent after the DOC.

• Mechanical system limitations are well understood and managed by proper handling of Combustion geometries and Air management to control the NOx and soot emissions and achieved BS3 or Euro3 emissions norms.

Test Results:

So far 25engines were tested and confirmed Euro3 or BS3 emission norms. More than 5 engines are already running in field in different vehicular application. Vehicle kmpl is on par with engine with electronic governors.

Emission results of first 13engines tested at R&D lab:

Comparison of the Engines with Inline Fuel Pump and Distributor Type Electronic Fuel Pump:

The combustion parameters are comparable with the similar engine using an electronic fuel injection system in the zone where the ESC A, B and C speeds lie. However, with electronic fuel injection system because the fuel timing could be easily adjusted, the parameters deviate outside this zone. Therefore, the emissions satisfy Euro-3 norms with sufficient engineering margin. The statistical data of average emissions of NOx, HC, CO, PM, free-acceleration smoke and ELR smoke with deviations are plotted for a sample of 20 engines. Fig.l shows the average Emission and performance test results of 20engines. Fig.2 shows the Emission comparison between Mechanical inline FIE system and VP37 FIE (EDC) with electronic governor. Fig 3 shows the cycle averaged specific fuel consumption values of the electronic engine and the engine under discussion were within 2 %.

Figure 6 shows the Schematic diagram of Engine layout wherein CL1 is Air cleaner, TCI is a Turbocharger, COl is a Charger cooler, PL1 is Inlet manifold, C1-C6 are the Engine cylinders and PL2 is a Exhaust muffler with DOC.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:

1. An Euro3 or BS3 Emission Compliant Engine with Cost Effective Fuel Injection Pump comprising

fine tuning of cylinder head swirl ratio;

optimizing injection jet penetration and nozzle tip protrusion to control the lower speed smoke and emission;

air management to get the equivalent combustion product of EDC FIE system;

fine tuning or controlling of start of combustion and duration of combustion;

diesel oxidation catalyst for oxidizing Soluble Organic Fraction, hydro-carbons, particulate matter and CO.

2. The engine as claimed in claim 1 wherein in fine tuning of said Cylinder head swirl ratio the rotation of air induces in the cylinder with respect to vertical cylinder axis affecting the lower speed smoke levels to reduce the lower end smoke.

3. The engine as claimed in claim 1 wherein said injector tip position is changed to 2.5mm from the cylinder head in case of BS3 inline to increase the jet penetration and allow more oxidation of fuel droplets to reduce lower speed smoke level relatively even with low injection pressure levels to achieve the BS3 soot emission levels with retarded injection timing.

4. The engine as claimed in claim 1 wherein said air management to get the equivalent combustion product of EDC FIE system is achieved by limiting the emission products by managing air fuel ratio to meet the legislative emission norms by specially designed turbocharger with optimum air / fuel ratio.

5. The engine as claimed in claim 1 wherein said start of combustion and duration of combustion is controlled by fine tuning the parameters like start of injection, injection pressure, number of injection holes in cylinder, air swirl ratio, boost pressure, piston bowl design and fuel properties to achieve ignition delay for proper combustion and to maintain start of ignition close to the Electronic governing system (EDC).

6. The engine as claimed in claim 1 wherein to control said particulate emission, a low-cost maintenance-free one-way diesel oxidation catalyst (DOC) with a suitable wash coat to handle 350 ppm sulphur in fuel is provided to restrict oxidization of sulphur to sulphates at high exhaust temperature and does not get poisoned.

7. The engine as claimed in claim 1 wherein said diesel oxidation catalyst reduces Soluble Organic Fraction (SOF) by 65% and hence PM by 10%, CO and HC by 70%.

8. The engine as claimed in claim 1 wherein said by proper implementation of combustion geometries and air management to control the NOx and soot emissions said BS3 or Euro3 emissions norms are achieved.

9. The Euro3 or BS3 Emission Compliant Engine with Cost Effective inline block type Fuel Injection Pump substantially as herein described in description as illustrated with reference to accompanying drawings.