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Turbulent Jet Ignition is an advanced pre-chamber initiated combustion system for an otherwise standard spark ignition engine found in current on-road vehicles. This next-generation pre-chamber design overcomes previous packaging obstacles by simply replacing the spark plug in a modern four-valve, pent roof spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, distributed ignition sites, which consume the main charge rapidly and with minimal combustion variability. The fast burn rates allow for increased levels of dilution (lean burn and/or EGR) when compared to conventional spark ignition combustion, with dilution levels being comparable to other low temperature combustion technologies (homogeneous charge compression ignition - HCCI) without the complex control drawbacks.

This paper provides some insight into the future direction for developing smaller capacity downsized engines, which will be needed to meet tight CO₂ targets and the world's future powertrain requirements. This paper focuses on the combustion system development and combustion analysis results for a downsized 0.43-liter highly turbocharged engine. The inline two-cylinder engine used in experiments was specifically designed and constructed to enable 25 bar BMEP. Producing this specific output is one way forward for future passenger vehicle powertrains, enabling in excess of 50% swept capacity reduction whilst maintaining comparable vehicle performance. Previous experiments and analysis have found that the extent to which larger engines can be downsized while still maintaining equal performance is combustion limited.

A validated model which attributes fuel consumption to 11 components of a vehicle's energy loss, has been applied to investigate the benefits from improvements in design parameters which can reduce fuel use. Sensitivity analysis of a large, family sized car, gives the ranked order of design variables for improving fuel consumption as: vehicle mass, idle fuel rate or engine friction (or both) and rolling resistance for urban driving. Amongst the remaining parameters aerodynamic drag is lowly ranked but, in highway driving, it ranks first along with vehicle mass and rolling resistance, thus indicating that the proportion of urban to highway driving, which will vary from country to country is important. Driving conditions should be optimised along with vehicle design for best energy conservation and greenhouse gas mitigation.

This paper describes the mechanical component design, lubrication, tuning and control aspects of a restricted, odd fire, highly turbocharged (TC) engine for Formula SAE competition. The engine was specifically designed and configured for the purpose, being a twin cylinder inline arrangement with double overhead camshafts and four valves per cylinder. Most of the engine components were specially cast or machined from billets. A detailed theoretical analysis was completed to determine engine specifications and operating conditions. Results from the analysis indicated a new engine design was necessary to sustain highly TC operation. Dry sump lubrication was implemented after initial oil surge problems were found with the wet sump system during vehicle testing. The design and development of the system is outlined, together with brake performance effects for the varying systems.

In this paper, performance, efficiency and emission experimental results are presented from a prototype 434 cm3, highly turbocharged (TC), two cylinder engine with brake power limited to approximately 60 kW. These results are compared to current small engines found in today's automobile marketplace. A normally aspirated (NA) 1.25 liter, four cylinder, modern production engine with similar brake power output is used for comparison. Results illustrate the potential for downsized engines to significantly reduce fuel consumption while still maintaining engine performance. This has advantages in reducing vehicle running costs together with meeting tighter carbon dioxide (CO2) emission standards. Experimental results highlight the performance potential of smaller engines with intake boosting. This is demonstrated with the test engine achieving 25 bar brake mean effective pressure (BMEP).

In recent times new tools have emerged to aid the optimization of engine design. The particle swarm optimizer, used here is one of these tools. However, applying it to the optimization of the S.I. engine for high efficiency and low NOx emission has shown the preference of ultra lean burn strategy combined with high compression ratios. For combined power, efficiency and emissions benefits, there are two restricting factors, limiting the applicability of this strategy, knocking and cyclic variability. In the ultra lean region, knocking is not an important issue but the variability is a major concern. This paper demonstrates the application of a variability model to limit the search domain for the optimization program. The results show that variability constrains the possible gains in fuel consumption and emission reduction, through optimizing cam phasing, mixture and spark timing. The fuel consumption gain is reduced by about 11% relative.

This paper reports comparative results for liquid phase versus gaseous phase port injection in a single cylinder engine. It follows previous research in a multi-cylinder engine where liquid phase was found to have advantages over gas phase at most operating conditions. Significant variations in cylinder to cylinder mixture distribution were found for both phases and leading to uncertainty in the findings. The uncertainty was avoided in this paper as in the engine used, a high speed Waukesha ASTM CFR, identical manifold conditions could be assured and MBT spark found for each fuel supply system over a wide range of mixtures. These were extended to lean burn conditions where gaseous fuelling in the multi-cylinder engine had been reported to be at least an equal performer to liquid phase. The experimental data confirm the power and efficiency advantages of liquid phase injection over gas phase injection and carburetion in multi-cylinder engine tests.

This paper compares the performance, efficiency, emissions and combustion parameters of a prototype two cylinder 430 cm3 engine which has been tested in a variety of normally aspirated (NA) modes with compression ratio (CR) variations. Experiments were completed using 98-RON pump gasoline with modes defined by alterations to the induction system, which included carburetion and port fuel injection (PFI). The results from this paper provide some insight into the CR effects for small NA spark ignition (SI) engines. This information provides future direction for the development of smaller engines as engine downsizing grows in popularity due to rising oil prices and recent carbon dioxide (CO2) emission regulations. Results are displayed in the engine speed, manifold absolute pressure (MAP) and CR domains, with engine speeds exceeding 10000 rev/min and CRs ranging from 9 to 13. Combustion analysis is also included, allowing mass fraction burn (MFB) comparison.

A fleet of 50, 1986-1987 model year cars designed for unleaded gasoline has been tested on the road and on a chassis dynamometer over 5 driving cycles and a wide range of other manoeuvres including steady speeds. It was found that the fuel consumption of this fleet was 17 to 23% (depending on test cycle) less than that of a corresponding fleet to leaded fuelled cars of 1980 model year average. Exhaust emissions were significantly lowered in the range of 45 to 93%. However trend line analysis of the several data sets indicates that the ULG fleet has about 6% higher fuel consumption than would have been expected if there had been a continuing evolution of leaded vehicle technology. The data base produced has applicability to a wide range of planning and design tasks, and those illustrated indicate the effects of speed limit changes and advisory speed signs on fuel consumption and emissions.

This paper compares the performance of a small two cylinder, 430 cm3 engine which has been tested in a variety of normally aspirated (NA) and forced induction modes on 98-RON pump gasoline. These modes are defined by variations in the induction system and associated compression ratio (CR) alterations needed to avoid knock and maximize volumetric efficiency (ηVOL). These modes included: (A) NA with carburetion (B) NA with port fuel injection (PFI) (C) Mildly Supercharged (SC) with PFI (D) Highly Turbocharged (TC) with PFI The results have significant relevance in defining the limitations for small downsized spark ignition (SI) engines, with power increases needed via intake boosting to compensate for the reduced swept volume. Performance is compared in the varying modes with comparisons of brake mean effective pressure (BMEP), brake power, ηVOL, brake specific fuel consumption (BSFC) and brake thermal efficiency (ηTH).

This paper describes the turbocharger development of a restricted 430 cm3 odd firing two cylinder engine. The downsized test engine used for development was specifically designed and configured for Formula SAE, SAE's student Formula race-car competition. A well recognised problem in turbocharging Formula SAE engines arises from the rules, which dictate that the throttle and air intake restrictor must be on the suction side of the compressor. As a consequence of upstream throttling, oil from the compressor side seal assembly is drawn into the inlet manifold. The development process used to solve the oil consumption issue for a Garrett GT-12 turbocharger is outlined, together with cooling and control issues. The development methodology used to achieve high pressure ratio turbocharging is discussed, along with exhaust manifold development and operating limitations. This includes experimental and modeling results for both pulse and constant pressure type turbocharging.

This paper is based on extensive experimental research with lean burn, high compression ratio engines using LPG, CNG and gasoline fuels. It also builds on recent experience with highly boosted spark ignition gasoline and LPG engines and single cylinder engine research used for model calibration. The final experimental foundation is an evaluation of jet assisted ignition that generally allows a lean mixture shift of more than one unit in lambda with consequential benefits of improved thermal efficiency and close to zero NOx. The capability of an ultra lean burn spark ignition engine is described. The concept is operation at air-fuel ratios similar to the diesel engine but with essentially homogenous charge, although some stratification may be desirable. To achieve high thermal efficiency this engine has optimized compression ratio but with variable valve timing which enables reduction in the effective compression ratio when desirable.

Gasoline Direct Injection (DI) is a technique that was successful in motor sports several decades ago and is now relatively popular in passenger car applications only. DI gasoline fuel injectors have been recently improved considerably, with much higher fuel flow rates and much finer atomization enabled by the advances in fuel pressure and needle actuation. These improved injector performance and the general interest in reducing fuel consumption also in motor sports have made this option interesting again. This paper compares Port Fuel Injection (PFI) and DI of gasoline fuel in a high performance, four cylinder spark ignition engine for super bike racing. Computations are performed with a code for gas exchange, heat transfer and combustion, simulating turbulent combustion and knock.

This paper extends previous development of the ALSI concept, by investigating the performance delivered with a turbocharged version of this engine. The research is based on extensive experimental research with lean burn, high compression ratio engines using hydrogen, LPG, CNG and gasoline fuels. It also builds on recent experience with highly boosted spark ignition gasoline and LPG engines and single cylinder engine research used extensively for model calibration. The final experimental foundation is the wide ranging evaluation of jet assisted ignition that generally allows a lean limit mixture shift of more than one unit of lambda with consequential benefits of improved thermal efficiency and close to zero NOx. The paper describes the capability of the ultra lean burn spark ignition engine with the mild boost needed provided by a Honeywell turbocharger.

This paper explores through engine simulations the use of LPG and CNG gas fuels in a 1.5 liter Spark Ignition (SI) four cylinder gasoline engine with double over head camshafts, four valves per cylinder equipped with a novel mixture preparation and ignition system comprising centrally located Direct Injection (DI) injector and Jet Ignition (JI) nozzles. With DI technology, the fuel may be introduced within the cylinder after completion of the valve events. DI of fuel reduces the embedded air displacement effects of gaseous fuels and lowers the charge temperature. DI also allows lean stratified bulk combustion with enhanced rate of combustion and reduced heat transfer to the cylinder walls creating a bulk lean stratified mixture.

This paper provides insight into abnormal combustion events observed during engine development of a highly turbocharged downsized engine configuration. The results and findings in this paper may contribute to the understanding of problems in small downsized engines which are becoming more common in the search for reduced fuel consumption. These problems are combustion limitations at high manifold pressures and compression ratios as designers and engineers endeavor to further reduce engine capacities. Abnormal combustion effects, analysis and development efforts are described for the 0.43 liter test engine, which was fitted with a port fuel injection fuel delivery system. The inline two cylinder engine used in experiments was specifically designed, constructed and developed to enable 25 bar BMEP and 60 kW of brake power to be reliably achieved while operating on pump gasoline.

Increasing engine power and efficiency using a particle swarm optimization technique is investigated by using thermodynamics based quasi-steady engine simulation model. A simplified engine friction model is also incorporated to estimate the brake power output. Further, a simple knock model is used to make sure of knock free engine operation. Model is calibrated and validated to a Ford Falcon AU six-cylinder gasoline engine. Nine different engine-operating parameters are considered as input variables for the optimization; spark timing, equivalence ratio, compression ratio, inlet and exhaust vale opening timing and durations, maximum inlet valve lift and manifold pressure. Significant improvement of the engine power output for a given amount of induced gas is observed with the optimized conditions when compared to the corresponding power output with the reference engines normal operating conditions.

Turbulent Jet Ignition is an advanced spark initiated pre-chamber combustion system for otherwise standard spark ignition engines found in current passenger vehicles. This next generation pre-chamber design simply replaces the spark plug in a conventional spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition results from the partially combusted (reacting) pre-chamber products initiating combustion in the main chamber. The distributed ignition sites enable relatively small flame travel distances enabling short combustion durations and high burn rates. Multiple benefits include extending the knock limit and initiating combustion in very dilute mixtures (excess air and or EGR), with dilution levels being comparable to other low temperature combustion technologies (HCCI), without the complex control drawbacks.

This paper presents a study of the performance of a 6-cylinder, spark-ignited, port-fuel-injected, production engine modified for hydrogen fueling. The engine modifications include turbo-charging, multiple fuel injectors per port and charge-dilution control techniques. Pumping losses are reduced through ultra-lean burn and throttle-less operation alongside high charge dilution ratio control achieved by twin independent variable cam timing without external EGR. Lean-burn combustion, engine-out emissions and brake thermal efficiency results are examined in detail. In particular, low NO emissions and brake thermal efficiencies near 38% are observed experimentally at the same operating conditions. The former is explained in terms of the usual thermal NOx pathway. Usage of throttle position, injection timings and cam timings for avoiding preignition and knock over the entire engine map are also discussed.

A real time energy management (EMS) optimizing algorithm is introduced that performs similar to offline dynamic programming (DP) for parallel HEVs. The EMS and the DP are compared, especially with the addition of a local hill climbing technique, to the example performance prediction of the fuel consumption of a 1.67 tonne large car using a 50 kW Honda Insight engine (representing 65% power reduction from standard) as reference. Then the performance of the vehicle in HEV mode, with a parallel 30 kW motor/generator is examined. The average improvement of this vehicle over five drive cycles from around the world is about 50% reduction in fuel consumption. Next the engine is replaced with an advanced SI turbocharged engine with assisted ignition which returns the performance to that expected of this class of car i.e. 0-100 km/h acceleration time of 7 s. This results in a 14% average reduction in fuel consumption across the five cycles compared with the base Honda engine.